diff options
| author | Yang Shi <yang.shi@linaro.org> | 2016-06-27 14:31:34 +0800 |
|---|---|---|
| committer | Alex Shi <alex.shi@linaro.org> | 2016-06-28 11:35:10 +0800 |
| commit | 076bdfc53685ae6b7947ccca96cf331dd246cc0f (patch) | |
| tree | e0fae5324933030d2413fc2ad7fd25fb3d150d1f | |
| parent | a1a4aac321e240336530902d4879fb234af5eba9 (diff) | |
tracing, kasan: Silence Kasan warning in check_stack of stack_tracer
commit 6e22c8366416251a3d88ba6c92d13d595089f0ed upstream
When enabling stack trace via "echo 1 > /proc/sys/kernel/stack_tracer_enabled",
the below KASAN warning is triggered:
BUG: KASAN: stack-out-of-bounds in check_stack+0x344/0x848 at addr ffffffc0689ebab8
Read of size 8 by task ksoftirqd/4/29
page:ffffffbdc3a27ac0 count:0 mapcount:0 mapping: (null) index:0x0
flags: 0x0()
page dumped because: kasan: bad access detected
CPU: 4 PID: 29 Comm: ksoftirqd/4 Not tainted 4.5.0-rc1 #129
Hardware name: Freescale Layerscape 2085a RDB Board (DT)
Call trace:
[<ffffffc000091300>] dump_backtrace+0x0/0x3a0
[<ffffffc0000916c4>] show_stack+0x24/0x30
[<ffffffc0009bbd78>] dump_stack+0xd8/0x168
[<ffffffc000420bb0>] kasan_report_error+0x6a0/0x920
[<ffffffc000421688>] kasan_report+0x70/0xb8
[<ffffffc00041f7f0>] __asan_load8+0x60/0x78
[<ffffffc0002e05c4>] check_stack+0x344/0x848
[<ffffffc0002e0c8c>] stack_trace_call+0x1c4/0x370
[<ffffffc0002af558>] ftrace_ops_no_ops+0x2c0/0x590
[<ffffffc00009f25c>] ftrace_graph_call+0x0/0x14
[<ffffffc0000881bc>] fpsimd_thread_switch+0x24/0x1e8
[<ffffffc000089864>] __switch_to+0x34/0x218
[<ffffffc0011e089c>] __schedule+0x3ac/0x15b8
[<ffffffc0011e1f6c>] schedule+0x5c/0x178
[<ffffffc0001632a8>] smpboot_thread_fn+0x350/0x960
[<ffffffc00015b518>] kthread+0x1d8/0x2b0
[<ffffffc0000874d0>] ret_from_fork+0x10/0x40
Memory state around the buggy address:
ffffffc0689eb980: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f4 f4 f4
ffffffc0689eba00: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
>ffffffc0689eba80: 00 00 f1 f1 f1 f1 00 f4 f4 f4 f3 f3 f3 f3 00 00
^
ffffffc0689ebb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffc0689ebb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
The stacker tracer traverses the whole kernel stack when saving the max stack
trace. It may touch the stack red zones to cause the warning. So, just disable
the instrumentation to silence the warning.
Link: http://lkml.kernel.org/r/1455309960-18930-1-git-send-email-yang.shi@linaro.org
Signed-off-by: Yang Shi <yang.shi@linaro.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
| -rw-r--r-- | kernel/trace/trace_stack.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 3f34496244e9..20769e5fd57b 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -143,7 +143,11 @@ check_stack(unsigned long ip, unsigned long *stack) p = start; for (; p < top && i < max_stack_trace.nr_entries; p++) { - if (*p == stack_dump_trace[i]) { + /* + * The READ_ONCE_NOCHECK is used to let KASAN know that + * this is not a stack-out-of-bounds error. + */ + if ((READ_ONCE_NOCHECK(*p)) == stack_dump_trace[i]) { this_size = stack_dump_index[i++] = (top - p) * sizeof(unsigned long); found = 1; |