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commit fc98c3c8c9dcafd67adcce69e6ce3191d5306c9c upstream.
Use rcuidle console tracepoint because, apparently, it may be issued
from an idle CPU:
hw-breakpoint: Failed to enable monitor mode on CPU 0.
hw-breakpoint: CPU 0 failed to disable vector catch
===============================
[ ERR: suspicious RCU usage. ]
4.10.0-rc8-next-20170215+ #119 Not tainted
-------------------------------
./include/trace/events/printk.h:32 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
RCU used illegally from idle CPU!
rcu_scheduler_active = 2, debug_locks = 0
RCU used illegally from extended quiescent state!
2 locks held by swapper/0/0:
#0: (cpu_pm_notifier_lock){......}, at: [<c0237e2c>] cpu_pm_exit+0x10/0x54
#1: (console_lock){+.+.+.}, at: [<c01ab350>] vprintk_emit+0x264/0x474
stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.0-rc8-next-20170215+ #119
Hardware name: Generic OMAP4 (Flattened Device Tree)
console_unlock
vprintk_emit
vprintk_default
printk
reset_ctrl_regs
dbg_cpu_pm_notify
notifier_call_chain
cpu_pm_exit
omap_enter_idle_coupled
cpuidle_enter_state
cpuidle_enter_state_coupled
do_idle
cpu_startup_entry
start_kernel
This RCU warning, however, is suppressed by lockdep_off() in printk().
lockdep_off() increments the ->lockdep_recursion counter and thus
disables RCU_LOCKDEP_WARN() and debug_lockdep_rcu_enabled(), which want
lockdep to be enabled "current->lockdep_recursion == 0".
Link: http://lkml.kernel.org/r/20170217015932.11898-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Russell King <rmk@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 25f71d1c3e98ef0e52371746220d66458eac75bc upstream.
The UEVENT user mode helper is enabled before the initcalls are executed
and is available when the root filesystem has been mounted.
The user mode helper is triggered by device init calls and the executable
might use the futex syscall.
futex_init() is marked __initcall which maps to device_initcall, but there
is no guarantee that futex_init() is invoked _before_ the first device init
call which triggers the UEVENT user mode helper.
If the user mode helper uses the futex syscall before futex_init() then the
syscall crashes with a NULL pointer dereference because the futex subsystem
has not been initialized yet.
Move futex_init() to core_initcall so futexes are initialized before the
root filesystem is mounted and the usermode helper becomes available.
[ tglx: Rewrote changelog ]
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: jiang.biao2@zte.com.cn
Cc: jiang.zhengxiong@zte.com.cn
Cc: zhong.weidong@zte.com.cn
Cc: deng.huali@zte.com.cn
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1483085875-6130-1-git-send-email-yang.yang29@zte.com.cn
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0b3589be9b98994ce3d5aeca52445d1f5627c4ba upstream.
Andres reported that MMAP2 records for anonymous memory always have
their protection field 0.
Turns out, someone daft put the prot/flags generation code in the file
branch, leaving them unset for anonymous memory.
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Don Zickus <dzickus@redhat.com
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: anton@ozlabs.org
Cc: namhyung@kernel.org
Fixes: f972eb63b100 ("perf: Pass protection and flags bits through mmap2 interface")
Link: http://lkml.kernel.org/r/20170126221508.GF6536@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ff9f8a7cf935468a94d9927c68b00daae701667e upstream.
We perform the conversion between kernel jiffies and ms only when
exporting kernel value to user space.
We need to do the opposite operation when value is written by user.
Only matters when HZ != 1000
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b6416e61012429e0277bd15a229222fd17afc1c1 upstream.
Modules that use static_key_deferred need a way to synchronize with
any delayed work that is still pending when the module is unloaded.
Introduce static_key_deferred_flush() which flushes any pending
jump label updates.
Signed-off-by: David Matlack <dmatlack@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f931ab479dd24cf7a2c6e2df19778406892591fb upstream.
Both arch_add_memory() and arch_remove_memory() expect a single threaded
context.
For example, arch/x86/mm/init_64.c::kernel_physical_mapping_init() does
not hold any locks over this check and branch:
if (pgd_val(*pgd)) {
pud = (pud_t *)pgd_page_vaddr(*pgd);
paddr_last = phys_pud_init(pud, __pa(vaddr),
__pa(vaddr_end),
page_size_mask);
continue;
}
pud = alloc_low_page();
paddr_last = phys_pud_init(pud, __pa(vaddr), __pa(vaddr_end),
page_size_mask);
The result is that two threads calling devm_memremap_pages()
simultaneously can end up colliding on pgd initialization. This leads
to crash signatures like the following where the loser of the race
initializes the wrong pgd entry:
BUG: unable to handle kernel paging request at ffff888ebfff0000
IP: memcpy_erms+0x6/0x10
PGD 2f8e8fc067 PUD 0 /* <---- Invalid PUD */
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
CPU: 54 PID: 3818 Comm: systemd-udevd Not tainted 4.6.7+ #13
task: ffff882fac290040 ti: ffff882f887a4000 task.ti: ffff882f887a4000
RIP: memcpy_erms+0x6/0x10
[..]
Call Trace:
? pmem_do_bvec+0x205/0x370 [nd_pmem]
? blk_queue_enter+0x3a/0x280
pmem_rw_page+0x38/0x80 [nd_pmem]
bdev_read_page+0x84/0xb0
Hold the standard memory hotplug mutex over calls to
arch_{add,remove}_memory().
Fixes: 41e94a851304 ("add devm_memremap_pages")
Link: http://lkml.kernel.org/r/148357647831.9498.12606007370121652979.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit c1a9eeb938b5433947e5ea22f89baff3182e7075 upstream.
When a disfunctional timer, e.g. dummy timer, is installed, the tick core
tries to setup the broadcast timer.
If no broadcast device is installed, the kernel crashes with a NULL pointer
dereference in tick_broadcast_setup_oneshot() because the function has no
sanity check.
Reported-by: Mason <slash.tmp@free.fr>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Richard Cochran <rcochran@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Cc: Sebastian Frias <sf84@laposte.net>
Cc: Thibaud Cornic <thibaud_cornic@sigmadesigns.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[resolves a messed up backport, so no matching upstream commit]
The backport of upstream commit 777c6e0daebb ("hotplug: Make
register and unregister notifier API symmetric") to linux-4.4.y
introduced a harmless warning in 'allnoconfig' builds as spotted by
kernelci.org:
kernel/cpu.c:226:13: warning: 'cpu_notify_nofail' defined but not used [-Wunused-function]
So far, this is the only stable tree that is affected, as linux-4.6 and
higher contain commit 984581728eb4 ("cpu/hotplug: Split out cpu down functions")
that makes the function used in all configurations, while older longterm
releases so far don't seem to have a backport of 777c6e0daebb.
The fix for the warning is trivial: move the unused function back
into the #ifdef section where it was before.
Link: https://kernelci.org/build/id/586fcacb59b514049ef6c3aa/logs/
Fixes: 1c0f4e0ebb79 ("hotplug: Make register and unregister notifier API symmetric") in v4.4.y
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 794de08a16cf1fc1bf785dc48f66d36218cf6d88 upstream.
Both the wakeup and irqsoff tracers can use the function graph tracer when
the display-graph option is set. The problem is that they ignore the notrace
file, and record the entry of functions that would be ignored by the
function_graph tracer. This causes the trace->depth to be recorded into the
ring buffer. The set_graph_notrace uses a trick by adding a large negative
number to the trace->depth when a graph function is to be ignored.
On trace output, the graph function uses the depth to record a stack of
functions. But since the depth is negative, it accesses the array with a
negative number and causes an out of bounds access that can cause a kernel
oops or corrupt data.
Have the print functions handle cases where a tracer still records functions
even when they are in set_graph_notrace.
Also add warnings if the depth is below zero before accessing the array.
Note, the function graph logic will still prevent the return of these
functions from being recorded, which means that they will be left hanging
without a return. For example:
# echo '*spin*' > set_graph_notrace
# echo 1 > options/display-graph
# echo wakeup > current_tracer
# cat trace
[...]
_raw_spin_lock() {
preempt_count_add() {
do_raw_spin_lock() {
update_rq_clock();
Where it should look like:
_raw_spin_lock() {
preempt_count_add();
do_raw_spin_lock();
}
update_rq_clock();
Cc: Namhyung Kim <namhyung.kim@lge.com>
Fixes: 29ad23b00474 ("ftrace: Add set_graph_notrace filter")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9c1645727b8fa90d07256fdfcc45bf831242a3ab upstream.
The clocksource delta to nanoseconds conversion is using signed math, but
the delta is unsigned. This makes the conversion space smaller than
necessary and in case of a multiplication overflow the conversion can
become negative. The conversion is done with scaled math:
s64 nsec_delta = ((s64)clkdelta * clk->mult) >> clk->shift;
Shifting a signed integer right obvioulsy preserves the sign, which has
interesting consequences:
- Time jumps backwards
- __iter_div_u64_rem() which is used in one of the calling code pathes
will take forever to piecewise calculate the seconds/nanoseconds part.
This has been reported by several people with different scenarios:
David observed that when stopping a VM with a debugger:
"It was essentially the stopped by debugger case. I forget exactly why,
but the guest was being explicitly stopped from outside, it wasn't just
scheduling lag. I think it was something in the vicinity of 10 minutes
stopped."
When lifting the stop the machine went dead.
The stopped by debugger case is not really interesting, but nevertheless it
would be a good thing not to die completely.
But this was also observed on a live system by Liav:
"When the OS is too overloaded, delta will get a high enough value for the
msb of the sum delta * tkr->mult + tkr->xtime_nsec to be set, and so
after the shift the nsec variable will gain a value similar to
0xffffffffff000000."
Unfortunately this has been reintroduced recently with commit 6bd58f09e1d8
("time: Add cycles to nanoseconds translation"). It had been fixed a year
ago already in commit 35a4933a8959 ("time: Avoid signed overflow in
timekeeping_get_ns()").
Though it's not surprising that the issue has been reintroduced because the
function itself and the whole call chain uses s64 for the result and the
propagation of it. The change in this recent commit is subtle:
s64 nsec;
- nsec = (d * m + n) >> s:
+ nsec = d * m + n;
+ nsec >>= s;
d being type of cycle_t adds another level of obfuscation.
This wouldn't have happened if the previous change to unsigned computation
would have made the 'nsec' variable u64 right away and a follow up patch
had cleaned up the whole call chain.
There have been patches submitted which basically did a revert of the above
patch leaving everything else unchanged as signed. Back to square one. This
spawned a admittedly pointless discussion about potential users which rely
on the unsigned behaviour until someone pointed out that it had been fixed
before. The changelogs of said patches added further confusion as they made
finally false claims about the consequences for eventual users which expect
signed results.
Despite delta being cycle_t, aka. u64, it's very well possible to hand in
a signed negative value and the signed computation will happily return the
correct result. But nobody actually sat down and analyzed the code which
was added as user after the propably unintended signed conversion.
Though in sensitive code like this it's better to analyze it proper and
make sure that nothing relies on this than hunting the subtle wreckage half
a year later. After analyzing all call chains it stands that no caller can
hand in a negative value (which actually would work due to the s64 cast)
and rely on the signed math to do the right thing.
Change the conversion function to unsigned math. The conversion of all call
chains is done in a follow up patch.
This solves the starvation issue, which was caused by the negative result,
but it does not solve the underlying problem. It merily procrastinates
it. When the timekeeper update is deferred long enough that the unsigned
multiplication overflows, then time going backwards is observable again.
It does neither solve the issue of clocksources with a small counter width
which will wrap around possibly several times and cause random time stamps
to be generated. But those are usually not found on systems used for
virtualization, so this is likely a non issue.
I took the liberty to claim authorship for this simply because
analyzing all callsites and writing the changelog took substantially
more time than just making the simple s/s64/u64/ change and ignore the
rest.
Fixes: 6bd58f09e1d8 ("time: Add cycles to nanoseconds translation")
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Reported-by: Liav Rehana <liavr@mellanox.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Parit Bhargava <prarit@redhat.com>
Cc: Laurent Vivier <lvivier@redhat.com>
Cc: "Christopher S. Hall" <christopher.s.hall@intel.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20161208204228.688545601@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2d13bb6494c807bcf3f78af0e96c0b8615a94385 upstream.
We've got a delay loop waiting for secondary CPUs. That loop uses
loops_per_jiffy. However, loops_per_jiffy doesn't actually mean how
many tight loops make up a jiffy on all architectures. It is quite
common to see things like this in the boot log:
Calibrating delay loop (skipped), value calculated using timer
frequency.. 48.00 BogoMIPS (lpj=24000)
In my case I was seeing lots of cases where other CPUs timed out
entering the debugger only to print their stack crawls shortly after the
kdb> prompt was written.
Elsewhere in kgdb we already use udelay(), so that should be safe enough
to use to implement our timeout. We'll delay 1 ms for 1000 times, which
should give us a full second of delay (just like the old code wanted)
but allow us to notice that we're done every 1 ms.
[akpm@linux-foundation.org: simplifications, per Daniel]
Link: http://lkml.kernel.org/r/1477091361-2039-1-git-send-email-dianders@chromium.org
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Brian Norris <briannorris@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4d1f0fb096aedea7bb5489af93498a82e467c480 upstream.
NMI handler doesn't call set_irq_regs(), it's set only by normal IRQ.
Thus get_irq_regs() returns NULL or stale registers snapshot with IP/SP
pointing to the code interrupted by IRQ which was interrupted by NMI.
NULL isn't a problem: in this case watchdog calls dump_stack() and
prints full stack trace including NMI. But if we're stuck in IRQ
handler then NMI watchlog will print stack trace without IRQ part at
all.
This patch uses registers snapshot passed into NMI handler as arguments:
these registers point exactly to the instruction interrupted by NMI.
Fixes: 55537871ef66 ("kernel/watchdog.c: perform all-CPU backtrace in case of hard lockup")
Link: http://lkml.kernel.org/r/146771764784.86724.6006627197118544150.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit f84df2a6f268de584a201e8911384a2d244876e3 upstream.
When the user namespace support was merged the need to prevent
ptrace from revealing the contents of an unreadable executable
was overlooked.
Correct this oversight by ensuring that the executed file
or files are in mm->user_ns, by adjusting mm->user_ns.
Use the new function privileged_wrt_inode_uidgid to see if
the executable is a member of the user namespace, and as such
if having CAP_SYS_PTRACE in the user namespace should allow
tracing the executable. If not update mm->user_ns to
the parent user namespace until an appropriate parent is found.
Reported-by: Jann Horn <jann@thejh.net>
Fixes: 9e4a36ece652 ("userns: Fail exec for suid and sgid binaries with ids outside our user namespace.")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 64b875f7ac8a5d60a4e191479299e931ee949b67 upstream.
When the flag PT_PTRACE_CAP was added the PTRACE_TRACEME path was
overlooked. This can result in incorrect behavior when an application
like strace traces an exec of a setuid executable.
Further PT_PTRACE_CAP does not have enough information for making good
security decisions as it does not report which user namespace the
capability is in. This has already allowed one mistake through
insufficient granulariy.
I found this issue when I was testing another corner case of exec and
discovered that I could not get strace to set PT_PTRACE_CAP even when
running strace as root with a full set of caps.
This change fixes the above issue with strace allowing stracing as
root a setuid executable without disabling setuid. More fundamentaly
this change allows what is allowable at all times, by using the correct
information in it's decision.
Fixes: 4214e42f96d4 ("v2.4.9.11 -> v2.4.9.12")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit bfedb589252c01fa505ac9f6f2a3d5d68d707ef4 upstream.
During exec dumpable is cleared if the file that is being executed is
not readable by the user executing the file. A bug in
ptrace_may_access allows reading the file if the executable happens to
enter into a subordinate user namespace (aka clone(CLONE_NEWUSER),
unshare(CLONE_NEWUSER), or setns(fd, CLONE_NEWUSER).
This problem is fixed with only necessary userspace breakage by adding
a user namespace owner to mm_struct, captured at the time of exec, so
it is clear in which user namespace CAP_SYS_PTRACE must be present in
to be able to safely give read permission to the executable.
The function ptrace_may_access is modified to verify that the ptracer
has CAP_SYS_ADMIN in task->mm->user_ns instead of task->cred->user_ns.
This ensures that if the task changes it's cred into a subordinate
user namespace it does not become ptraceable.
The function ptrace_attach is modified to only set PT_PTRACE_CAP when
CAP_SYS_PTRACE is held over task->mm->user_ns. The intent of
PT_PTRACE_CAP is to be a flag to note that whatever permission changes
the task might go through the tracer has sufficient permissions for
it not to be an issue. task->cred->user_ns is always the same
as or descendent of mm->user_ns. Which guarantees that having
CAP_SYS_PTRACE over mm->user_ns is the worst case for the tasks
credentials.
To prevent regressions mm->dumpable and mm->user_ns are not considered
when a task has no mm. As simply failing ptrace_may_attach causes
regressions in privileged applications attempting to read things
such as /proc/<pid>/stat
Acked-by: Kees Cook <keescook@chromium.org>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Fixes: 8409cca70561 ("userns: allow ptrace from non-init user namespaces")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 777c6e0daebb3fcefbbd6f620410a946b07ef6d0 upstream.
Yu Zhao has noticed that __unregister_cpu_notifier only unregisters its
notifiers when HOTPLUG_CPU=y while the registration might succeed even
when HOTPLUG_CPU=n if MODULE is enabled. This means that e.g. zswap
might keep a stale notifier on the list on the manual clean up during
the pool tear down and thus corrupt the list. Resulting in the following
[ 144.964346] BUG: unable to handle kernel paging request at ffff880658a2be78
[ 144.971337] IP: [<ffffffffa290b00b>] raw_notifier_chain_register+0x1b/0x40
<snipped>
[ 145.122628] Call Trace:
[ 145.125086] [<ffffffffa28e5cf8>] __register_cpu_notifier+0x18/0x20
[ 145.131350] [<ffffffffa2a5dd73>] zswap_pool_create+0x273/0x400
[ 145.137268] [<ffffffffa2a5e0fc>] __zswap_param_set+0x1fc/0x300
[ 145.143188] [<ffffffffa2944c1d>] ? trace_hardirqs_on+0xd/0x10
[ 145.149018] [<ffffffffa2908798>] ? kernel_param_lock+0x28/0x30
[ 145.154940] [<ffffffffa2a3e8cf>] ? __might_fault+0x4f/0xa0
[ 145.160511] [<ffffffffa2a5e237>] zswap_compressor_param_set+0x17/0x20
[ 145.167035] [<ffffffffa2908d3c>] param_attr_store+0x5c/0xb0
[ 145.172694] [<ffffffffa290848d>] module_attr_store+0x1d/0x30
[ 145.178443] [<ffffffffa2b2b41f>] sysfs_kf_write+0x4f/0x70
[ 145.183925] [<ffffffffa2b2a5b9>] kernfs_fop_write+0x149/0x180
[ 145.189761] [<ffffffffa2a99248>] __vfs_write+0x18/0x40
[ 145.194982] [<ffffffffa2a9a412>] vfs_write+0xb2/0x1a0
[ 145.200122] [<ffffffffa2a9a732>] SyS_write+0x52/0xa0
[ 145.205177] [<ffffffffa2ff4d97>] entry_SYSCALL_64_fastpath+0x12/0x17
This can be even triggered manually by changing
/sys/module/zswap/parameters/compressor multiple times.
Fix this issue by making unregister APIs symmetric to the register so
there are no surprises.
Fixes: 47e627bc8c9a ("[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU")
Reported-and-tested-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Link: http://lkml.kernel.org/r/20161207135438.4310-1-mhocko@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 1be5d4fa0af34fb7bafa205aeb59f5c7cc7a089d upstream.
While debugging the rtmutex unlock vs. dequeue race Will suggested to use
READ_ONCE() in rt_mutex_owner() as it might race against the
cmpxchg_release() in unlock_rt_mutex_safe().
Will: "It's a minor thing which will most likely not matter in practice"
Careful search did not unearth an actual problem in todays code, but it's
better to be safe than surprised.
Suggested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20161130210030.431379999@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit dbb26055defd03d59f678cb5f2c992abe05b064a upstream.
David reported a futex/rtmutex state corruption. It's caused by the
following problem:
CPU0 CPU1 CPU2
l->owner=T1
rt_mutex_lock(l)
lock(l->wait_lock)
l->owner = T1 | HAS_WAITERS;
enqueue(T2)
boost()
unlock(l->wait_lock)
schedule()
rt_mutex_lock(l)
lock(l->wait_lock)
l->owner = T1 | HAS_WAITERS;
enqueue(T3)
boost()
unlock(l->wait_lock)
schedule()
signal(->T2) signal(->T3)
lock(l->wait_lock)
dequeue(T2)
deboost()
unlock(l->wait_lock)
lock(l->wait_lock)
dequeue(T3)
===> wait list is now empty
deboost()
unlock(l->wait_lock)
lock(l->wait_lock)
fixup_rt_mutex_waiters()
if (wait_list_empty(l)) {
owner = l->owner & ~HAS_WAITERS;
l->owner = owner
==> l->owner = T1
}
lock(l->wait_lock)
rt_mutex_unlock(l) fixup_rt_mutex_waiters()
if (wait_list_empty(l)) {
owner = l->owner & ~HAS_WAITERS;
cmpxchg(l->owner, T1, NULL)
===> Success (l->owner = NULL)
l->owner = owner
==> l->owner = T1
}
That means the problem is caused by fixup_rt_mutex_waiters() which does the
RMW to clear the waiters bit unconditionally when there are no waiters in
the rtmutexes rbtree.
This can be fatal: A concurrent unlock can release the rtmutex in the
fastpath because the waiters bit is not set. If the cmpxchg() gets in the
middle of the RMW operation then the previous owner, which just unlocked
the rtmutex is set as the owner again when the write takes place after the
successfull cmpxchg().
The solution is rather trivial: verify that the owner member of the rtmutex
has the waiters bit set before clearing it. This does not require a
cmpxchg() or other atomic operations because the waiters bit can only be
set and cleared with the rtmutex wait_lock held. It's also safe against the
fast path unlock attempt. The unlock attempt via cmpxchg() will either see
the bit set and take the slowpath or see the bit cleared and release it
atomically in the fastpath.
It's remarkable that the test program provided by David triggers on ARM64
and MIPS64 really quick, but it refuses to reproduce on x86-64, while the
problem exists there as well. That refusal might explain that this got not
discovered earlier despite the bug existing from day one of the rtmutex
implementation more than 10 years ago.
Thanks to David for meticulously instrumenting the code and providing the
information which allowed to decode this subtle problem.
Reported-by: David Daney <ddaney@caviumnetworks.com>
Tested-by: David Daney <david.daney@cavium.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: 23f78d4a03c5 ("[PATCH] pi-futex: rt mutex core")
Link: http://lkml.kernel.org/r/20161130210030.351136722@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit bedc1969150d480c462cdac320fa944b694a7162 upstream.
Carrying out the following steps results in a softlockup in the
RCU callback-offload (rcuo) kthreads:
1. Connect to ixgbevf, and set the speed to 10Gb/s.
2. Use ifconfig to bring the nic up and down repeatedly.
[ 317.005148] IPv6: ADDRCONF(NETDEV_CHANGE): eth2: link becomes ready
[ 368.106005] BUG: soft lockup - CPU#1 stuck for 22s! [rcuos/1:15]
[ 368.106005] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 368.106005] task: ffff88057dd8a220 ti: ffff88057dd9c000 task.ti: ffff88057dd9c000
[ 368.106005] RIP: 0010:[<ffffffff81579e04>] [<ffffffff81579e04>] fib_table_lookup+0x14/0x390
[ 368.106005] RSP: 0018:ffff88061fc83ce8 EFLAGS: 00000286
[ 368.106005] RAX: 0000000000000001 RBX: 00000000020155c0 RCX: 0000000000000001
[ 368.106005] RDX: ffff88061fc83d50 RSI: ffff88061fc83d70 RDI: ffff880036d11a00
[ 368.106005] RBP: ffff88061fc83d08 R08: 0000000000000001 R09: 0000000000000000
[ 368.106005] R10: ffff880036d11a00 R11: ffffffff819e0900 R12: ffff88061fc83c58
[ 368.106005] R13: ffffffff816154dd R14: ffff88061fc83d08 R15: 00000000020155c0
[ 368.106005] FS: 0000000000000000(0000) GS:ffff88061fc80000(0000) knlGS:0000000000000000
[ 368.106005] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 368.106005] CR2: 00007f8c2aee9c40 CR3: 000000057b222000 CR4: 00000000000407e0
[ 368.106005] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 368.106005] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 368.106005] Stack:
[ 368.106005] 00000000010000c0 ffff88057b766000 ffff8802e380b000 ffff88057af03e00
[ 368.106005] ffff88061fc83dc0 ffffffff815349a6 ffff88061fc83d40 ffffffff814ee146
[ 368.106005] ffff8802e380af00 00000000e380af00 ffffffff819e0900 020155c0010000c0
[ 368.106005] Call Trace:
[ 368.106005] <IRQ>
[ 368.106005]
[ 368.106005] [<ffffffff815349a6>] ip_route_input_noref+0x516/0xbd0
[ 368.106005] [<ffffffff814ee146>] ? skb_release_data+0xd6/0x110
[ 368.106005] [<ffffffff814ee20a>] ? kfree_skb+0x3a/0xa0
[ 368.106005] [<ffffffff8153698f>] ip_rcv_finish+0x29f/0x350
[ 368.106005] [<ffffffff81537034>] ip_rcv+0x234/0x380
[ 368.106005] [<ffffffff814fd656>] __netif_receive_skb_core+0x676/0x870
[ 368.106005] [<ffffffff814fd868>] __netif_receive_skb+0x18/0x60
[ 368.106005] [<ffffffff814fe4de>] process_backlog+0xae/0x180
[ 368.106005] [<ffffffff814fdcb2>] net_rx_action+0x152/0x240
[ 368.106005] [<ffffffff81077b3f>] __do_softirq+0xef/0x280
[ 368.106005] [<ffffffff8161619c>] call_softirq+0x1c/0x30
[ 368.106005] <EOI>
[ 368.106005]
[ 368.106005] [<ffffffff81015d95>] do_softirq+0x65/0xa0
[ 368.106005] [<ffffffff81077174>] local_bh_enable+0x94/0xa0
[ 368.106005] [<ffffffff81114922>] rcu_nocb_kthread+0x232/0x370
[ 368.106005] [<ffffffff81098250>] ? wake_up_bit+0x30/0x30
[ 368.106005] [<ffffffff811146f0>] ? rcu_start_gp+0x40/0x40
[ 368.106005] [<ffffffff8109728f>] kthread+0xcf/0xe0
[ 368.106005] [<ffffffff810971c0>] ? kthread_create_on_node+0x140/0x140
[ 368.106005] [<ffffffff816147d8>] ret_from_fork+0x58/0x90
[ 368.106005] [<ffffffff810971c0>] ? kthread_create_on_node+0x140/0x140
==================================cut here==============================
It turns out that the rcuos callback-offload kthread is busy processing
a very large quantity of RCU callbacks, and it is not reliquishing the
CPU while doing so. This commit therefore adds an cond_resched_rcu_qs()
within the loop to allow other tasks to run.
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[ paulmck: Substituted cond_resched_rcu_qs for cond_resched. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Dhaval Giani <dhaval.giani@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit ceb75787bc75d0a7b88519ab8a68067ac690f55a upstream.
Make sure to drop the reference taken by class_find_device() after
opening the RTC device.
Fixes: 77437fd4e61f (pm: boot time suspend selftest)
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit cfe02a8a973e7e5f66926b8ae38dfce404b19e29 upstream.
When all subsystems are disabled, gcc notices that cgroup_subsys_enabled_key
is a zero-length array and that any access to it must be out of bounds:
In file included from ../include/linux/cgroup.h:19:0,
from ../kernel/cgroup.c:31:
../kernel/cgroup.c: In function 'cgroup_add_cftypes':
../kernel/cgroup.c:261:53: error: array subscript is above array bounds [-Werror=array-bounds]
return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
../include/linux/jump_label.h:271:40: note: in definition of macro 'static_key_enabled'
static_key_count((struct static_key *)x) > 0; \
^
We should never call the function in this particular case, so this is
not a bug. In order to silence the warning, this adds an explicit check
for the CGROUP_SUBSYS_COUNT==0 case.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit ee26c013cdee0b947e29d6cadfb9ff3341c69ff9 upstream.
Without this patch irq_domain_disassociate() cannot properly release the
interrupt. In fact, irq_map_generic_chip() checks a bit on 'gc->installed'
but said bit is never cleared, only set.
Commit 088f40b7b027 ("genirq: Generic chip: Add linear irq domain support")
added irq_map_generic_chip() function and also stated "This lacks a removal
function for now".
This commit provides an implementation of an unmap function that can be
called by irq_domain_disassociate().
[ tglx: Made the function static and removed the export as we have neither
a prototype nor a modular user. ]
Fixes: 088f40b7b027 ("genirq: Generic chip: Add linear irq domain support")
Signed-off-by: Sebastian Frias <sf84@laposte.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mason <slash.tmp@free.fr>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/579F5C5A.2070507@laposte.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
commit 58bfea9532552d422bde7afa207e1a0f08dffa7d upstream.
In commit 27727df240c7 ("Avoid taking lock in NMI path with
CONFIG_DEBUG_TIMEKEEPING"), I changed the logic to open-code
the timekeeping_get_ns() function, but I forgot to include
the unit conversion from cycles to nanoseconds, breaking the
function's output, which impacts users like perf.
This results in bogus perf timestamps like:
swapper 0 [000] 253.427536: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.426573: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.426687: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.426800: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.426905: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.427022: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.427127: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.427239: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.427346: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.427463: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 255.426572: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
Instead of more reasonable expected timestamps like:
swapper 0 [000] 39.953768: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.064839: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.175956: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.287103: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.398217: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.509324: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.620437: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.731546: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.842654: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.953772: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 41.064881: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
Add the proper use of timekeeping_delta_to_ns() to convert
the cycle delta to nanoseconds as needed.
Thanks to Brendan and Alexei for finding this quickly after
the v4.8 release. Unfortunately the problematic commit has
landed in some -stable trees so they'll need this fix as
well.
Many apologies for this mistake. I'll be looking to add a
perf-clock sanity test to the kselftest timers tests soon.
Fixes: 27727df240c7 "timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING"
Reported-by: Brendan Gregg <bgregg@netflix.com>
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Tested-and-reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1475636148-26539-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 6bd58f09e1d8cc6c50a824c00bf0d617919986a1 upstream.
The timekeeping code does not currently provide a way to translate
externally provided clocksource cycles to system time. The cycle count
is always provided by the result clocksource read() method internal to
the timekeeping code. The added function timekeeping_cycles_to_ns()
calculated a nanosecond value from a cycle count that can be added to
tk_read_base.base value yielding the current system time. This allows
clocksource cycle values external to the timekeeping code to provide a
cycle count that can be transformed to system time.
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: kevin.b.stanton@intel.com
Cc: kevin.j.clarke@intel.com
Cc: hpa@zytor.com
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 735f2770a770156100f534646158cb58cb8b2939 upstream.
Commit fec1d0115240 ("[PATCH] Disable CLONE_CHILD_CLEARTID for abnormal
exit") has caused a subtle regression in nscd which uses
CLONE_CHILD_CLEARTID to clear the nscd_certainly_running flag in the
shared databases, so that the clients are notified when nscd is
restarted. Now, when nscd uses a non-persistent database, clients that
have it mapped keep thinking the database is being updated by nscd, when
in fact nscd has created a new (anonymous) one (for non-persistent
databases it uses an unlinked file as backend).
The original proposal for the CLONE_CHILD_CLEARTID change claimed
(https://lkml.org/lkml/2006/10/25/233):
: The NPTL library uses the CLONE_CHILD_CLEARTID flag on clone() syscalls
: on behalf of pthread_create() library calls. This feature is used to
: request that the kernel clear the thread-id in user space (at an address
: provided in the syscall) when the thread disassociates itself from the
: address space, which is done in mm_release().
:
: Unfortunately, when a multi-threaded process incurs a core dump (such as
: from a SIGSEGV), the core-dumping thread sends SIGKILL signals to all of
: the other threads, which then proceed to clear their user-space tids
: before synchronizing in exit_mm() with the start of core dumping. This
: misrepresents the state of process's address space at the time of the
: SIGSEGV and makes it more difficult for someone to debug NPTL and glibc
: problems (misleading him/her to conclude that the threads had gone away
: before the fault).
:
: The fix below is to simply avoid the CLONE_CHILD_CLEARTID action if a
: core dump has been initiated.
The resulting patch from Roland (https://lkml.org/lkml/2006/10/26/269)
seems to have a larger scope than the original patch asked for. It
seems that limitting the scope of the check to core dumping should work
for SIGSEGV issue describe above.
[Changelog partly based on Andreas' description]
Fixes: fec1d0115240 ("[PATCH] Disable CLONE_CHILD_CLEARTID for abnormal exit")
Link: http://lkml.kernel.org/r/1471968749-26173-1-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Tested-by: William Preston <wpreston@suse.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@hack.frob.com>
Cc: Andreas Schwab <schwab@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit e7d316a02f683864a12389f8808570e37fb90aa3 upstream.
We have scripts which write to certain fields on 3.18 kernels but this
seems to be failing on 4.4 kernels. An entry which we write to here is
xfrm_aevent_rseqth which is u32.
echo 4294967295 > /proc/sys/net/core/xfrm_aevent_rseqth
Commit 230633d109e3 ("kernel/sysctl.c: detect overflows when converting
to int") prevented writing to sysctl entries when integer overflow
occurs. However, this does not apply to unsigned integers.
Heinrich suggested that we introduce a new option to handle 64 bit
limits and set min as 0 and max as UINT_MAX. This might not work as it
leads to issues similar to __do_proc_doulongvec_minmax. Alternatively,
we would need to change the datatype of the entry to 64 bit.
static int __do_proc_doulongvec_minmax(void *data, struct ctl_table
{
i = (unsigned long *) data; //This cast is causing to read beyond the size of data (u32)
vleft = table->maxlen / sizeof(unsigned long); //vleft is 0 because maxlen is sizeof(u32) which is lesser than sizeof(unsigned long) on x86_64.
Introduce a new proc handler proc_douintvec. Individual proc entries
will need to be updated to use the new handler.
[akpm@linux-foundation.org: coding-style fixes]
Fixes: 230633d109e3 ("kernel/sysctl.c:detect overflows when converting to int")
Link: http://lkml.kernel.org/r/1471479806-5252-1-git-send-email-subashab@codeaurora.org
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit ae6c33ba6e37eea3012fe2640b22400ef3f2d0f3 upstream.
Commit bbeddf52adc1 ("printk: move braille console support into separate
braille.[ch] files") moved the parsing of braille-related options into
_braille_console_setup(), changing the type of variable str from char*
to char**. In this commit, memcmp(str, "brl,", 4) was correctly updated
to memcmp(*str, "brl,", 4) but not memcmp(str, "brl=", 4).
Update the code to make "brl=" option work again and replace memcmp()
with strncmp() to make the compiler able to detect such an issue.
Fixes: bbeddf52adc1 ("printk: move braille console support into separate braille.[ch] files")
Link: http://lkml.kernel.org/r/20160823165700.28952-1-nicolas.iooss_linux@m4x.org
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 2c81a6477081966fe80b8c6daa68459bca896774 upstream.
The following commit:
66eb579e66ec ("perf: allow for PMU-specific event filtering")
added the pmu::filter_match() callback. This was intended to
avoid HW constraints on events from resulting in extremely
pessimistic scheduling.
However, pmu::filter_match() is only called for the leader of each event
group. When the leader is a SW event, we do not filter the groups, and
may fail at pmu::add() time, and when this happens we'll give up on
scheduling any event groups later in the list until they are rotated
ahead of the failing group.
This can result in extremely sub-optimal event scheduling behaviour,
e.g. if running the following on a big.LITTLE platform:
$ taskset -c 0 ./perf stat \
-e 'a57{context-switches,armv8_cortex_a57/config=0x11/}' \
-e 'a53{context-switches,armv8_cortex_a53/config=0x11/}' \
ls
<not counted> context-switches (0.00%)
<not counted> armv8_cortex_a57/config=0x11/ (0.00%)
24 context-switches (37.36%)
57589154 armv8_cortex_a53/config=0x11/ (37.36%)
Here the 'a53' event group was always eligible to be scheduled, but
the 'a57' group never eligible to be scheduled, as the task was always
affine to a Cortex-A53 CPU. The SW (group leader) event in the 'a57'
group was eligible, but the HW event failed at pmu::add() time,
resulting in ctx_flexible_sched_in giving up on scheduling further
groups with HW events.
One way of avoiding this is to check pmu::filter_match() on siblings
as well as the group leader. If any of these fail their
pmu::filter_match() call, we must skip the entire group before
attempting to add any events.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: 66eb579e66ec ("perf: allow for PMU-specific event filtering")
Link: http://lkml.kernel.org/r/1465917041-15339-1-git-send-email-mark.rutland@arm.com
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 28b89b9e6f7b6c8fef7b3af39828722bca20cfee upstream.
A discrepancy between cpu_online_mask and cpuset's effective_cpus
mask is inevitable during hotplug since cpuset defers updating of
effective_cpus mask using a workqueue, during which time nothing
prevents the system from more hotplug operations. For that reason
guarantee_online_cpus() walks up the cpuset hierarchy until it finds
an intersection under the assumption that top cpuset's effective_cpus
mask intersects with cpu_online_mask even with such a race occurring.
However a sequence of CPU hotplugs can open a time window, during which
none of the effective CPUs in the top cpuset intersect with
cpu_online_mask.
For example when there are 4 possible CPUs 0-3 and only CPU0 is online:
======================== ===========================
cpu_online_mask top_cpuset.effective_cpus
======================== ===========================
echo 1 > cpu2/online.
CPU hotplug notifier woke up hotplug work but not yet scheduled.
[0,2] [0]
echo 0 > cpu0/online.
The workqueue is still runnable.
[2] [0]
======================== ===========================
Now there is no intersection between cpu_online_mask and
top_cpuset.effective_cpus. Thus invoking sys_sched_setaffinity() at
this moment can cause following:
Unable to handle kernel NULL pointer dereference at virtual address 000000d0
------------[ cut here ]------------
Kernel BUG at ffffffc0001389b0 [verbose debug info unavailable]
Internal error: Oops - BUG: 96000005 [#1] PREEMPT SMP
Modules linked in:
CPU: 2 PID: 1420 Comm: taskset Tainted: G W 4.4.8+ #98
task: ffffffc06a5c4880 ti: ffffffc06e124000 task.ti: ffffffc06e124000
PC is at guarantee_online_cpus+0x2c/0x58
LR is at cpuset_cpus_allowed+0x4c/0x6c
<snip>
Process taskset (pid: 1420, stack limit = 0xffffffc06e124020)
Call trace:
[<ffffffc0001389b0>] guarantee_online_cpus+0x2c/0x58
[<ffffffc00013b208>] cpuset_cpus_allowed+0x4c/0x6c
[<ffffffc0000d61f0>] sched_setaffinity+0xc0/0x1ac
[<ffffffc0000d6374>] SyS_sched_setaffinity+0x98/0xac
[<ffffffc000085cb0>] el0_svc_naked+0x24/0x28
The top cpuset's effective_cpus are guaranteed to be identical to
cpu_online_mask eventually. Hence fall back to cpu_online_mask when
there is no intersection between top cpuset's effective_cpus and
cpu_online_mask.
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: cgroups@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 924d8696751c4b9e58263bc82efdafcf875596a6 upstream.
rtree_next_node() walks the linked list of leaf nodes to find the next
block of pages in the struct memory_bitmap. If it walks off the end of
the list of nodes, it walks the list of memory zones to find the next
region of memory. If it walks off the end of the list of zones, it
returns false.
This leaves the struct bm_position's node and zone pointers pointing
at their respective struct list_heads in struct mem_zone_bm_rtree.
memory_bm_find_bit() uses struct bm_position's node and zone pointers
to avoid walking lists and trees if the next bit appears in the same
node/zone. It handles these values being stale.
Swap rtree_next_node()s 'step then test' to 'test-next then step',
this means if we reach the end of memory we return false and leave
the node and zone pointers as they were.
This fixes a panic on resume using AMD Seattle with 64K pages:
[ 6.868732] Freezing user space processes ... (elapsed 0.000 seconds) done.
[ 6.875753] Double checking all user space processes after OOM killer disable... (elapsed 0.000 seconds)
[ 6.896453] PM: Using 3 thread(s) for decompression.
[ 6.896453] PM: Loading and decompressing image data (5339 pages)...
[ 7.318890] PM: Image loading progress: 0%
[ 7.323395] Unable to handle kernel paging request at virtual address 00800040
[ 7.330611] pgd = ffff000008df0000
[ 7.334003] [00800040] *pgd=00000083fffe0003, *pud=00000083fffe0003, *pmd=00000083fffd0003, *pte=0000000000000000
[ 7.344266] Internal error: Oops: 96000005 [#1] PREEMPT SMP
[ 7.349825] Modules linked in:
[ 7.352871] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G W I 4.8.0-rc1 #4737
[ 7.360512] Hardware name: AMD Overdrive/Supercharger/Default string, BIOS ROD1002C 04/08/2016
[ 7.369109] task: ffff8003c0220000 task.stack: ffff8003c0280000
[ 7.375020] PC is at set_bit+0x18/0x30
[ 7.378758] LR is at memory_bm_set_bit+0x24/0x30
[ 7.383362] pc : [<ffff00000835bbc8>] lr : [<ffff0000080faf18>] pstate: 60000045
[ 7.390743] sp : ffff8003c0283b00
[ 7.473551]
[ 7.475031] Process swapper/0 (pid: 1, stack limit = 0xffff8003c0280020)
[ 7.481718] Stack: (0xffff8003c0283b00 to 0xffff8003c0284000)
[ 7.800075] Call trace:
[ 7.887097] [<ffff00000835bbc8>] set_bit+0x18/0x30
[ 7.891876] [<ffff0000080fb038>] duplicate_memory_bitmap.constprop.38+0x54/0x70
[ 7.899172] [<ffff0000080fcc40>] snapshot_write_next+0x22c/0x47c
[ 7.905166] [<ffff0000080fe1b4>] load_image_lzo+0x754/0xa88
[ 7.910725] [<ffff0000080ff0a8>] swsusp_read+0x144/0x230
[ 7.916025] [<ffff0000080fa338>] load_image_and_restore+0x58/0x90
[ 7.922105] [<ffff0000080fa660>] software_resume+0x2f0/0x338
[ 7.927752] [<ffff000008083350>] do_one_initcall+0x38/0x11c
[ 7.933314] [<ffff000008b40cc0>] kernel_init_freeable+0x14c/0x1ec
[ 7.939395] [<ffff0000087ce564>] kernel_init+0x10/0xfc
[ 7.944520] [<ffff000008082e90>] ret_from_fork+0x10/0x40
[ 7.949820] Code: d2800022 8b400c21 f9800031 9ac32043 (c85f7c22)
[ 7.955909] ---[ end trace 0024a5986e6ff323 ]---
[ 7.960529] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
Here struct mem_zone_bm_rtree's start_pfn has been returned instead of
struct rtree_node's addr as the node/zone pointers are corrupt after
we walked off the end of the lists during mark_unsafe_pages().
This behaviour was exposed by commit 6dbecfd345a6 ("PM / hibernate:
Simplify mark_unsafe_pages()"), which caused mark_unsafe_pages() to call
duplicate_memory_bitmap(), which uses memory_bm_find_bit() after walking
off the end of the memory bitmap.
Fixes: 3a20cb177961 (PM / Hibernate: Implement position keeping in radix tree)
Signed-off-by: James Morse <james.morse@arm.com>
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 62822e2ec4ad091ba31f823f577ef80db52e3c2c upstream.
Restore the processor state before calling any other functions to
ensure per-CPU variables can be used with KASLR memory randomization.
Tracing functions use per-CPU variables (GS based on x86) and one was
called just before restoring the processor state fully. It resulted
in a double fault when both the tracing & the exception handler
functions tried to use a per-CPU variable.
Fixes: bb3632c6101b (PM / sleep: trace events for suspend/resume)
Reported-and-tested-by: Borislav Petkov <bp@suse.de>
Reported-by: Jiri Kosina <jikos@kernel.org>
Tested-by: Rafael J. Wysocki <rafael@kernel.org>
Tested-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 1245800c0f96eb6ebb368593e251d66c01e61022 upstream.
The iter->seq can be reset outside the protection of the mutex. So can
reading of user data. Move the mutex up to the beginning of the function.
Fixes: d7350c3f45694 ("tracing/core: make the read callbacks reentrants")
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 1ae2293dd6d2f5c823cf97e60b70d03631cd622f upstream.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 377ccbb483738f84400ddf5840c7dd8825716985 upstream.
With the latest gcc compilers, they give a warning if
__builtin_return_address() parameter is greater than 0. That is because if
it is used by a function called by a top level function (or in the case of
the kernel, by assembly), it can try to access stack frames outside the
stack and crash the system.
The tracing system uses __builtin_return_address() of up to 2! But it is
well aware of the dangers that it may have, and has even added precautions
to protect against it (see the thunk code in arch/x86/entry/thunk*.S)
Linus originally added KBUILD_CFLAGS that would suppress the warning for the
entire kernel, as simply adding KBUILD_CFLAGS to the tracing directory
wouldn't work. The tracing directory plays a bit with the CFLAGS and
requires a little more logic.
This adds that special logic to only suppress the warning for the tracing
directory. If it is used anywhere else outside of tracing, the warning will
still be triggered.
Link: http://lkml.kernel.org/r/20160728223043.51996267@grimm.local.home
Tested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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|
> 2 ../kernel/cpuset.c:2101:11: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types]
> 1 ../kernel/cpuset.c:2101:2: warning: initialization from incompatible pointer type
> 1 ../kernel/cpuset.c:2101:2: warning: (near initialization for 'cpuset_cgrp_subsys.fork')
This got introduced by 06ec7a1d7646 ("cpuset: make sure new tasks
conform to the current config of the cpuset"). In the upstream
kernel, the function prototype was changed as of b53202e63089
("cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends").
That patch is not suitable for stable kernels, and fortunately
the warning seems harmless as the prototypes only differ in the
second argument that is unused. Adding that argument gets rid
of the warning:
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4364e1a29be16b2783c0bcbc263f61236af64281 upstream.
virq is not required to be the same for all msi descs. Use the base irq number
from the desc in the debug printk.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 236dec051078a8691950f56949612b4b74107e48 upstream.
Using "make tinyconfig" produces a couple of annoying warnings that show
up for build test machines all the time:
.config:966:warning: override: NOHIGHMEM changes choice state
.config:965:warning: override: SLOB changes choice state
.config:963:warning: override: KERNEL_XZ changes choice state
.config:962:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state
.config:933:warning: override: SLOB changes choice state
.config:930:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state
.config:870:warning: override: SLOB changes choice state
.config:868:warning: override: KERNEL_XZ changes choice state
.config:867:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state
I've made a previous attempt at fixing them and we discussed a number of
alternatives.
I tried changing the Makefile to use "merge_config.sh -n
$(fragment-list)" but couldn't get that to work properly.
This is yet another approach, based on the observation that we do want
to see a warning for conflicting 'choice' options, and that we can
simply make them non-conflicting by listing all other options as
disabled. This is a trivial patch that we can apply independent of
plans for other changes.
Link: http://lkml.kernel.org/r/20160829214952.1334674-2-arnd@arndb.de
Link: https://storage.kernelci.org/mainline/v4.7-rc6/x86-tinyconfig/build.log
https://patchwork.kernel.org/patch/9212749/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 135e8c9250dd5c8c9aae5984fde6f230d0cbfeaf upstream.
The origin of the issue I've seen is related to
a missing memory barrier between check for task->state and
the check for task->on_rq.
The task being woken up is already awake from a schedule()
and is doing the following:
do {
schedule()
set_current_state(TASK_(UN)INTERRUPTIBLE);
} while (!cond);
The waker, actually gets stuck doing the following in
try_to_wake_up():
while (p->on_cpu)
cpu_relax();
Analysis:
The instance I've seen involves the following race:
CPU1 CPU2
while () {
if (cond)
break;
do {
schedule();
set_current_state(TASK_UN..)
} while (!cond);
wakeup_routine()
spin_lock_irqsave(wait_lock)
raw_spin_lock_irqsave(wait_lock) wake_up_process()
} try_to_wake_up()
set_current_state(TASK_RUNNING); ..
list_del(&waiter.list);
CPU2 wakes up CPU1, but before it can get the wait_lock and set
current state to TASK_RUNNING the following occurs:
CPU3
wakeup_routine()
raw_spin_lock_irqsave(wait_lock)
if (!list_empty)
wake_up_process()
try_to_wake_up()
raw_spin_lock_irqsave(p->pi_lock)
..
if (p->on_rq && ttwu_wakeup())
..
while (p->on_cpu)
cpu_relax()
..
CPU3 tries to wake up the task on CPU1 again since it finds
it on the wait_queue, CPU1 is spinning on wait_lock, but immediately
after CPU2, CPU3 got it.
CPU3 checks the state of p on CPU1, it is TASK_UNINTERRUPTIBLE and
the task is spinning on the wait_lock. Interestingly since p->on_rq
is checked under pi_lock, I've noticed that try_to_wake_up() finds
p->on_rq to be 0. This was the most confusing bit of the analysis,
but p->on_rq is changed under runqueue lock, rq_lock, the p->on_rq
check is not reliable without this fix IMHO. The race is visible
(based on the analysis) only when ttwu_queue() does a remote wakeup
via ttwu_queue_remote. In which case the p->on_rq change is not
done uder the pi_lock.
The result is that after a while the entire system locks up on
the raw_spin_irqlock_save(wait_lock) and the holder spins infintely
Reproduction of the issue:
The issue can be reproduced after a long run on my system with 80
threads and having to tweak available memory to very low and running
memory stress-ng mmapfork test. It usually takes a long time to
reproduce. I am trying to work on a test case that can reproduce
the issue faster, but thats work in progress. I am still testing the
changes on my still in a loop and the tests seem OK thus far.
Big thanks to Benjamin and Nick for helping debug this as well.
Ben helped catch the missing barrier, Nick caught every missing
bit in my theory.
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[ Updated comment to clarify matching barriers. Many
architectures do not have a full barrier in switch_to()
so that cannot be relied upon. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <nicholas.piggin@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/e02cce7b-d9ca-1ad0-7a61-ea97c7582b37@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 06f4e94898918bcad00cdd4d349313a439d6911e upstream.
A new task inherits cpus_allowed and mems_allowed masks from its parent,
but if someone changes cpuset's config by writing to cpuset.cpus/cpuset.mems
before this new task is inserted into the cgroup's task list, the new task
won't be updated accordingly.
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5efc244346f9f338765da3d592f7947b0afdc4b5 upstream.
Prior to the change the function would blindly deference mm, exe_file
and exe_file->f_inode, each of which could have been NULL or freed.
Use get_task_exe_file to safely obtain stable exe_file.
Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit cd81a9170e69e018bbaba547c1fd85a585f5697a upstream.
For more convenient access if one has a pointer to the task.
As a minor nit take advantage of the fact that only task lock + rcu are
needed to safely grab ->exe_file. This saves mm refcount dance.
Use the helper in proc_exe_link.
Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 070c43eea5043e950daa423707ae3c77e2f48edb upstream.
If kexec_apply_relocations fails, kexec_load_purgatory frees pi->sechdrs
and pi->purgatory_buf. This is redundant, because in case of error
kimage_file_prepare_segments calls kimage_file_post_load_cleanup, which
will also free those buffers.
This causes two warnings like the following, one for pi->sechdrs and the
other for pi->purgatory_buf:
kexec-bzImage64: Loading purgatory failed
------------[ cut here ]------------
WARNING: CPU: 1 PID: 2119 at mm/vmalloc.c:1490 __vunmap+0xc1/0xd0
Trying to vfree() nonexistent vm area (ffffc90000e91000)
Modules linked in:
CPU: 1 PID: 2119 Comm: kexec Not tainted 4.8.0-rc3+ #5
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
dump_stack+0x4d/0x65
__warn+0xcb/0xf0
warn_slowpath_fmt+0x4f/0x60
? find_vmap_area+0x19/0x70
? kimage_file_post_load_cleanup+0x47/0xb0
__vunmap+0xc1/0xd0
vfree+0x2e/0x70
kimage_file_post_load_cleanup+0x5e/0xb0
SyS_kexec_file_load+0x448/0x680
? putname+0x54/0x60
? do_sys_open+0x190/0x1f0
entry_SYSCALL_64_fastpath+0x13/0x8f
---[ end trace 158bb74f5950ca2b ]---
Fix by setting pi->sechdrs an pi->purgatory_buf to NULL, since vfree
won't try to free a NULL pointer.
Link: http://lkml.kernel.org/r/1472083546-23683-1-git-send-email-bauerman@linux.vnet.ibm.com
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6c4687cc17a788a6dd8de3e27dbeabb7cbd3e066 upstream.
__replace_page() wronlgy calls mem_cgroup_cancel_charge() in "success" path,
it should only do this if page_check_address() fails.
This means that every enable/disable leads to unbalanced mem_cgroup_uncharge()
from put_page(old_page), it is trivial to underflow the page_counter->count
and trigger OOM.
Reported-and-tested-by: Brenden Blanco <bblanco@plumgrid.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Fixes: 00501b531c47 ("mm: memcontrol: rewrite charge API")
Link: http://lkml.kernel.org/r/20160817153629.GB29724@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 27727df240c7cc84f2ba6047c6f18d5addfd25ef upstream.
When I added some extra sanity checking in timekeeping_get_ns() under
CONFIG_DEBUG_TIMEKEEPING, I missed that the NMI safe __ktime_get_fast_ns()
method was using timekeeping_get_ns().
Thus the locking added to the debug checks broke the NMI-safety of
__ktime_get_fast_ns().
This patch open-codes the timekeeping_get_ns() logic for
__ktime_get_fast_ns(), so can avoid any deadlocks in NMI.
Fixes: 4ca22c2648f9 "timekeeping: Add warnings when overflows or underflows are observed"
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1471993702-29148-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a4f8f6667f099036c88f231dcad4cf233652c824 upstream.
It was reported that hibernation could fail on the 2nd attempt, where the
system hangs at hibernate() -> syscore_resume() -> i8237A_resume() ->
claim_dma_lock(), because the lock has already been taken.
However there is actually no other process would like to grab this lock on
that problematic platform.
Further investigation showed that the problem is triggered by setting
/sys/power/pm_trace to 1 before the 1st hibernation.
Since once pm_trace is enabled, the rtc becomes unmeaningful after suspend,
and meanwhile some BIOSes would like to adjust the 'invalid' RTC (e.g, smaller
than 1970) to the release date of that motherboard during POST stage, thus
after resumed, it may seem that the system had a significant long sleep time
which is a completely meaningless value.
Then in timekeeping_resume -> tk_debug_account_sleep_time, if the bit31 of the
sleep time happened to be set to 1, fls() returns 32 and we add 1 to
sleep_time_bin[32], which causes an out of bounds array access and therefor
memory being overwritten.
As depicted by System.map:
0xffffffff81c9d080 b sleep_time_bin
0xffffffff81c9d100 B dma_spin_lock
the dma_spin_lock.val is set to 1, which caused this problem.
This patch adds a sanity check in tk_debug_account_sleep_time()
to ensure we don't index past the sleep_time_bin array.
[jstultz: Problem diagnosed and original patch by Chen Yu, I've solved the
issue slightly differently, but borrowed his excelent explanation of the
issue here.]
Fixes: 5c83545f24ab "power: Add option to log time spent in suspend"
Reported-by: Janek Kozicki <cosurgi@gmail.com>
Reported-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: linux-pm@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xunlei Pang <xpang@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Zhang Rui <rui.zhang@intel.com>
Link: http://lkml.kernel.org/r/1471993702-29148-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 568ac888215c7fb2fabe8ea739b00ec3c1f5d440 upstream.
cgroup_threadgroup_rwsem is acquired in read mode during process exit
and fork. It is also grabbed in write mode during
__cgroups_proc_write(). I've recently run into a scenario with lots
of memory pressure and OOM and I am beginning to see
systemd
__switch_to+0x1f8/0x350
__schedule+0x30c/0x990
schedule+0x48/0xc0
percpu_down_write+0x114/0x170
__cgroup_procs_write.isra.12+0xb8/0x3c0
cgroup_file_write+0x74/0x1a0
kernfs_fop_write+0x188/0x200
__vfs_write+0x6c/0xe0
vfs_write+0xc0/0x230
SyS_write+0x6c/0x110
system_call+0x38/0xb4
This thread is waiting on the reader of cgroup_threadgroup_rwsem to
exit. The reader itself is under memory pressure and has gone into
reclaim after fork. There are times the reader also ends up waiting on
oom_lock as well.
__switch_to+0x1f8/0x350
__schedule+0x30c/0x990
schedule+0x48/0xc0
jbd2_log_wait_commit+0xd4/0x180
ext4_evict_inode+0x88/0x5c0
evict+0xf8/0x2a0
dispose_list+0x50/0x80
prune_icache_sb+0x6c/0x90
super_cache_scan+0x190/0x210
shrink_slab.part.15+0x22c/0x4c0
shrink_zone+0x288/0x3c0
do_try_to_free_pages+0x1dc/0x590
try_to_free_pages+0xdc/0x260
__alloc_pages_nodemask+0x72c/0xc90
alloc_pages_current+0xb4/0x1a0
page_table_alloc+0xc0/0x170
__pte_alloc+0x58/0x1f0
copy_page_range+0x4ec/0x950
copy_process.isra.5+0x15a0/0x1870
_do_fork+0xa8/0x4b0
ppc_clone+0x8/0xc
In the meanwhile, all processes exiting/forking are blocked almost
stalling the system.
This patch moves the threadgroup_change_begin from before
cgroup_fork() to just before cgroup_canfork(). There is no nee to
worry about threadgroup changes till the task is actually added to the
threadgroup. This avoids having to call reclaim with
cgroup_threadgroup_rwsem held.
tj: Subject and description edits.
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
Acked-by: Zefan Li <lizefan@huawei.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 98f368e9e2630a3ce3e80fb10fb2e02038cf9578 upstream.
When checking the current cred for a capability in a specific user
namespace, it isn't always desirable to have the LSMs audit the check.
This patch adds a noaudit variant of ns_capable() for when those
situations arise.
The common logic between ns_capable() and the new ns_capable_noaudit()
is moved into a single, shared function to keep duplicated code to a
minimum and ease maintainability.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 5f65e5ca286126a60f62c8421b77c2018a482b8a ]
Using INVALID_[UG]ID for the LSM file creation context doesn't
make sense, so return an error if the inode passed to
set_create_file_as() has an invalid id.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit bbf66d897adf2bb0c310db96c97e8db6369f39e1 ]
Hyper-V vmbus module registers TSC page clocksource when loaded. This is
the clocksource with the highest rating and thus it becomes the watchdog
making unloading of the vmbus module impossible.
Separate clocksource_select_watchdog() from clocksource_enqueue_watchdog()
and use it on clocksource register/rating change/unregister.
After all, lobotomized monkeys may need some love too.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1453483913-25672-1-git-send-email-vkuznets@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit dd4e17ab704269bce71402285f5e8b9ac24b1eff ]
Recently, in commit 37cf4dc3370f I forgot to check if the timeval being passed
was actually a timespec (as is signaled with ADJ_NANO).
This resulted in that patch breaking ADJ_SETOFFSET users who set
ADJ_NANO, by rejecting valid timespecs that were compared with
valid timeval ranges.
This patch addresses this by checking for the ADJ_NANO flag and
using the timepsec check instead in that case.
Reported-by: Harald Hoyer <harald@redhat.com>
Reported-by: Kay Sievers <kay@vrfy.org>
Fixes: 37cf4dc3370f "time: Verify time values in adjtimex ADJ_SETOFFSET to avoid overflow"
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Link: http://lkml.kernel.org/r/1453417415-19110-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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