path: root/fs/binfmt_elf.c
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2009-01-08ELF: implement AT_RANDOM for glibc PRNG seedingKees Cook
While discussing[1] the need for glibc to have access to random bytes during program load, it seems that an earlier attempt to implement AT_RANDOM got stalled. This implements a random 16 byte string, available to every ELF program via a new auxv AT_RANDOM vector. [1] Ulrich said: glibc needs right after startup a bit of random data for internal protections (stack canary etc). What is now in upstream glibc is that we always unconditionally open /dev/urandom, read some data, and use it. For every process startup. That's slow. ... The solution is to provide a limited amount of random data to the starting process in the aux vector. I suggested 16 bytes and this is what the patch implements. If we need only 16 bytes or less we use the data directly. If we need more we'll use the 16 bytes to see a PRNG. This avoids the costly /dev/urandom use and it allows the kernel to use the most adequate source of random data for this purpose. It might not be the same pool as that for /dev/urandom. Concerns were expressed about the depletion of the randomness pool. But this patch doesn't make the situation worse, it doesn't deplete entropy more than happens now. Signed-off-by: Kees Cook <> Cc: Jakub Jelinek <> Cc: Andi Kleen <> Cc: Ulrich Drepper <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-12-28Merge branch 'for-linus' of git:// Torvalds
* 'for-linus' of git:// (85 commits) [S390] provide documentation for hvc_iucv kernel parameter. [S390] convert ctcm printks to dev_xxx and pr_xxx macros. [S390] convert zfcp printks to pr_xxx macros. [S390] convert vmlogrdr printks to pr_xxx macros. [S390] convert zfcp dumper printks to pr_xxx macros. [S390] convert cpu related printks to pr_xxx macros. [S390] convert qeth printks to dev_xxx and pr_xxx macros. [S390] convert sclp printks to pr_xxx macros. [S390] convert iucv printks to dev_xxx and pr_xxx macros. [S390] convert ap_bus printks to pr_xxx macros. [S390] convert dcssblk and extmem printks messages to pr_xxx macros. [S390] convert monwriter printks to pr_xxx macros. [S390] convert s390 debug feature printks to pr_xxx macros. [S390] convert monreader printks to pr_xxx macros. [S390] convert appldata printks to pr_xxx macros. [S390] convert setup printks to pr_xxx macros. [S390] convert hypfs printks to pr_xxx macros. [S390] convert time printks to pr_xxx macros. [S390] convert cpacf printks to pr_xxx macros. [S390] convert cio printks to pr_xxx macros. ...
2008-12-25[S390] arch_setup_additional_pages argumentsMartin Schwidefsky
arch_setup_additional_pages currently gets two arguments, the binary format descripton and an indication if the process uses an executable stack or not. The second argument is not used by anybody, it could be removed without replacement. What actually does make sense is to pass an indication if the process uses the elf interpreter or not. The glibc code will not use anything from the vdso if the process does not use the dynamic linker, so for statically linked binaries the architecture backend can choose not to map the vdso. Acked-by: Ingo Molnar <> Signed-off-by: Martin Schwidefsky <>
2008-11-14CRED: Make execve() take advantage of copy-on-write credentialsDavid Howells
Make execve() take advantage of copy-on-write credentials, allowing it to set up the credentials in advance, and then commit the whole lot after the point of no return. This patch and the preceding patches have been tested with the LTP SELinux testsuite. This patch makes several logical sets of alteration: (1) execve(). The credential bits from struct linux_binprm are, for the most part, replaced with a single credentials pointer (bprm->cred). This means that all the creds can be calculated in advance and then applied at the point of no return with no possibility of failure. I would like to replace bprm->cap_effective with: cap_isclear(bprm->cap_effective) but this seems impossible due to special behaviour for processes of pid 1 (they always retain their parent's capability masks where normally they'd be changed - see cap_bprm_set_creds()). The following sequence of events now happens: (a) At the start of do_execve, the current task's cred_exec_mutex is locked to prevent PTRACE_ATTACH from obsoleting the calculation of creds that we make. (a) prepare_exec_creds() is then called to make a copy of the current task's credentials and prepare it. This copy is then assigned to bprm->cred. This renders security_bprm_alloc() and security_bprm_free() unnecessary, and so they've been removed. (b) The determination of unsafe execution is now performed immediately after (a) rather than later on in the code. The result is stored in bprm->unsafe for future reference. (c) prepare_binprm() is called, possibly multiple times. (i) This applies the result of set[ug]id binaries to the new creds attached to bprm->cred. Personality bit clearance is recorded, but now deferred on the basis that the exec procedure may yet fail. (ii) This then calls the new security_bprm_set_creds(). This should calculate the new LSM and capability credentials into *bprm->cred. This folds together security_bprm_set() and parts of security_bprm_apply_creds() (these two have been removed). Anything that might fail must be done at this point. (iii) bprm->cred_prepared is set to 1. bprm->cred_prepared is 0 on the first pass of the security calculations, and 1 on all subsequent passes. This allows SELinux in (ii) to base its calculations only on the initial script and not on the interpreter. (d) flush_old_exec() is called to commit the task to execution. This performs the following steps with regard to credentials: (i) Clear pdeath_signal and set dumpable on certain circumstances that may not be covered by commit_creds(). (ii) Clear any bits in current->personality that were deferred from (c.i). (e) install_exec_creds() [compute_creds() as was] is called to install the new credentials. This performs the following steps with regard to credentials: (i) Calls security_bprm_committing_creds() to apply any security requirements, such as flushing unauthorised files in SELinux, that must be done before the credentials are changed. This is made up of bits of security_bprm_apply_creds() and security_bprm_post_apply_creds(), both of which have been removed. This function is not allowed to fail; anything that might fail must have been done in (c.ii). (ii) Calls commit_creds() to apply the new credentials in a single assignment (more or less). Possibly pdeath_signal and dumpable should be part of struct creds. (iii) Unlocks the task's cred_replace_mutex, thus allowing PTRACE_ATTACH to take place. (iv) Clears The bprm->cred pointer as the credentials it was holding are now immutable. (v) Calls security_bprm_committed_creds() to apply any security alterations that must be done after the creds have been changed. SELinux uses this to flush signals and signal handlers. (f) If an error occurs before (d.i), bprm_free() will call abort_creds() to destroy the proposed new credentials and will then unlock cred_replace_mutex. No changes to the credentials will have been made. (2) LSM interface. A number of functions have been changed, added or removed: (*) security_bprm_alloc(), ->bprm_alloc_security() (*) security_bprm_free(), ->bprm_free_security() Removed in favour of preparing new credentials and modifying those. (*) security_bprm_apply_creds(), ->bprm_apply_creds() (*) security_bprm_post_apply_creds(), ->bprm_post_apply_creds() Removed; split between security_bprm_set_creds(), security_bprm_committing_creds() and security_bprm_committed_creds(). (*) security_bprm_set(), ->bprm_set_security() Removed; folded into security_bprm_set_creds(). (*) security_bprm_set_creds(), ->bprm_set_creds() New. The new credentials in bprm->creds should be checked and set up as appropriate. bprm->cred_prepared is 0 on the first call, 1 on the second and subsequent calls. (*) security_bprm_committing_creds(), ->bprm_committing_creds() (*) security_bprm_committed_creds(), ->bprm_committed_creds() New. Apply the security effects of the new credentials. This includes closing unauthorised files in SELinux. This function may not fail. When the former is called, the creds haven't yet been applied to the process; when the latter is called, they have. The former may access bprm->cred, the latter may not. (3) SELinux. SELinux has a number of changes, in addition to those to support the LSM interface changes mentioned above: (a) The bprm_security_struct struct has been removed in favour of using the credentials-under-construction approach. (c) flush_unauthorized_files() now takes a cred pointer and passes it on to inode_has_perm(), file_has_perm() and dentry_open(). Signed-off-by: David Howells <> Acked-by: James Morris <> Acked-by: Serge Hallyn <> Signed-off-by: James Morris <>
2008-11-14CRED: Use RCU to access another task's creds and to release a task's own credsDavid Howells
Use RCU to access another task's creds and to release a task's own creds. This means that it will be possible for the credentials of a task to be replaced without another task (a) requiring a full lock to read them, and (b) seeing deallocated memory. Signed-off-by: David Howells <> Acked-by: James Morris <> Acked-by: Serge Hallyn <> Signed-off-by: James Morris <>
2008-11-14CRED: Wrap current->cred and a few other accessorsDavid Howells
Wrap current->cred and a few other accessors to hide their actual implementation. Signed-off-by: David Howells <> Acked-by: James Morris <> Acked-by: Serge Hallyn <> Signed-off-by: James Morris <>
2008-11-14CRED: Separate task security context from task_structDavid Howells
Separate the task security context from task_struct. At this point, the security data is temporarily embedded in the task_struct with two pointers pointing to it. Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in entry.S via asm-offsets. With comment fixes Signed-off-by: Marc Dionne <> Signed-off-by: David Howells <> Acked-by: James Morris <> Acked-by: Serge Hallyn <> Signed-off-by: James Morris <>
2008-10-20Merge branch 'v28-timers-for-linus' of ↵Linus Torvalds
git:// * 'v28-timers-for-linus' of git:// (36 commits) fix documentation of sysrq-q really Fix documentation of sysrq-q timer_list: add base address to clock base timer_list: print cpu number of clockevents device timer_list: print real timer address NOHZ: restart tick device from irq_enter() NOHZ: split tick_nohz_restart_sched_tick() NOHZ: unify the nohz function calls in irq_enter() timers: fix itimer/many thread hang, fix timers: fix itimer/many thread hang, v3 ntp: improve adjtimex frequency rounding timekeeping: fix rounding problem during clock update ntp: let update_persistent_clock() sleep hrtimer: reorder struct hrtimer to save 8 bytes on 64bit builds posix-timers: lock_timer: make it readable posix-timers: lock_timer: kill the bogus ->it_id check posix-timers: kill ->it_sigev_signo and ->it_sigev_value posix-timers: sys_timer_create: cleanup the error handling posix-timers: move the initialization of timer->sigq from send to create path posix-timers: sys_timer_create: simplify and s/tasklist/rcu/ ... Fix trivial conflicts due to sysrq-q description clahes in Documentation/sysrq.txt and drivers/char/sysrq.c
2008-10-20coredump_filter: add hugepage dumpingKOSAKI Motohiro
Presently hugepage's vma has a VM_RESERVED flag in order not to be swapped. But a VM_RESERVED vma isn't core dumped because this flag is often used for some kernel vmas (e.g. vmalloc, sound related). Thus hugepages are never dumped and it can't be debugged easily. Many developers want hugepages to be included into core-dump. However, We can't read generic VM_RESERVED area because this area is often IO mapping area. then these area reading may change device state. it is definitly undesiable side-effect. So adding a hugepage specific bit to the coredump filter is better. It will be able to hugepage core dumping and doesn't cause any side-effect to any i/o devices. In additional, libhugetlb use hugetlb private mapping pages as anonymous page. Then, hugepage private mapping pages should be core dumped by default. Then, /proc/[pid]/core_dump_filter has two new bits. - bit 5 mean hugetlb private mapping pages are dumped or not. (default: yes) - bit 6 mean hugetlb shared mapping pages are dumped or not. (default: no) I tested by following method. % ulimit -c unlimited % ./crash_hugepage 50 % ./crash_hugepage 50 -p % ls -lh % gdb ./crash_hugepage core % % echo 0x43 > /proc/self/coredump_filter % ./crash_hugepage 50 % ./crash_hugepage 50 -p % ls -lh % gdb ./crash_hugepage core #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <sys/mman.h> #include <string.h> #include "hugetlbfs.h" int main(int argc, char** argv){ char* p; int ch; int mmap_flags = MAP_SHARED; int fd; int nr_pages; while((ch = getopt(argc, argv, "p")) != -1) { switch (ch) { case 'p': mmap_flags &= ~MAP_SHARED; mmap_flags |= MAP_PRIVATE; break; default: /* nothing*/ break; } } argc -= optind; argv += optind; if (argc == 0){ printf("need # of pages\n"); exit(1); } nr_pages = atoi(argv[0]); if (nr_pages < 2) { printf("nr_pages must >2\n"); exit(1); } fd = hugetlbfs_unlinked_fd(); p = mmap(NULL, nr_pages * gethugepagesize(), PROT_READ|PROT_WRITE, mmap_flags, fd, 0); sleep(2); *(p + gethugepagesize()) = 1; /* COW */ sleep(2); /* crash! */ *(int*)0 = 1; return 0; } Signed-off-by: KOSAKI Motohiro <> Reviewed-by: Kawai Hidehiro <> Cc: Hugh Dickins <> Cc: William Irwin <> Cc: Adam Litke <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-10-20Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', ↵Thomas Gleixner
'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus
2008-10-16[PATCH] remove unused ibcs2/PER_SVR4 in SET_PERSONALITYMartin Schwidefsky
The SET_PERSONALITY macro is always called with a second argument of 0. Remove the ibcs argument and the various tests to set the PER_SVR4 personality. Signed-off-by: Martin Schwidefsky <>
2008-09-14timers: fix itimer/many thread hangFrank Mayhar
Overview This patch reworks the handling of POSIX CPU timers, including the ITIMER_PROF, ITIMER_VIRT timers and rlimit handling. It was put together with the help of Roland McGrath, the owner and original writer of this code. The problem we ran into, and the reason for this rework, has to do with using a profiling timer in a process with a large number of threads. It appears that the performance of the old implementation of run_posix_cpu_timers() was at least O(n*3) (where "n" is the number of threads in a process) or worse. Everything is fine with an increasing number of threads until the time taken for that routine to run becomes the same as or greater than the tick time, at which point things degrade rather quickly. This patch fixes bug 9906, "Weird hang with NPTL and SIGPROF." Code Changes This rework corrects the implementation of run_posix_cpu_timers() to make it run in constant time for a particular machine. (Performance may vary between one machine and another depending upon whether the kernel is built as single- or multiprocessor and, in the latter case, depending upon the number of running processors.) To do this, at each tick we now update fields in signal_struct as well as task_struct. The run_posix_cpu_timers() function uses those fields to make its decisions. We define a new structure, "task_cputime," to contain user, system and scheduler times and use these in appropriate places: struct task_cputime { cputime_t utime; cputime_t stime; unsigned long long sum_exec_runtime; }; This is included in the structure "thread_group_cputime," which is a new substructure of signal_struct and which varies for uniprocessor versus multiprocessor kernels. For uniprocessor kernels, it uses "task_cputime" as a simple substructure, while for multiprocessor kernels it is a pointer: struct thread_group_cputime { struct task_cputime totals; }; struct thread_group_cputime { struct task_cputime *totals; }; We also add a new task_cputime substructure directly to signal_struct, to cache the earliest expiration of process-wide timers, and task_cputime also replaces the it_*_expires fields of task_struct (used for earliest expiration of thread timers). The "thread_group_cputime" structure contains process-wide timers that are updated via account_user_time() and friends. In the non-SMP case the structure is a simple aggregator; unfortunately in the SMP case that simplicity was not achievable due to cache-line contention between CPUs (in one measured case performance was actually _worse_ on a 16-cpu system than the same test on a 4-cpu system, due to this contention). For SMP, the thread_group_cputime counters are maintained as a per-cpu structure allocated using alloc_percpu(). The timer functions update only the timer field in the structure corresponding to the running CPU, obtained using per_cpu_ptr(). We define a set of inline functions in sched.h that we use to maintain the thread_group_cputime structure and hide the differences between UP and SMP implementations from the rest of the kernel. The thread_group_cputime_init() function initializes the thread_group_cputime structure for the given task. The thread_group_cputime_alloc() is a no-op for UP; for SMP it calls the out-of-line function thread_group_cputime_alloc_smp() to allocate and fill in the per-cpu structures and fields. The thread_group_cputime_free() function, also a no-op for UP, in SMP frees the per-cpu structures. The thread_group_cputime_clone_thread() function (also a UP no-op) for SMP calls thread_group_cputime_alloc() if the per-cpu structures haven't yet been allocated. The thread_group_cputime() function fills the task_cputime structure it is passed with the contents of the thread_group_cputime fields; in UP it's that simple but in SMP it must also safely check that tsk->signal is non-NULL (if it is it just uses the appropriate fields of task_struct) and, if so, sums the per-cpu values for each online CPU. Finally, the three functions account_group_user_time(), account_group_system_time() and account_group_exec_runtime() are used by timer functions to update the respective fields of the thread_group_cputime structure. Non-SMP operation is trivial and will not be mentioned further. The per-cpu structure is always allocated when a task creates its first new thread, via a call to thread_group_cputime_clone_thread() from copy_signal(). It is freed at process exit via a call to thread_group_cputime_free() from cleanup_signal(). All functions that formerly summed utime/stime/sum_sched_runtime values from from all threads in the thread group now use thread_group_cputime() to snapshot the values in the thread_group_cputime structure or the values in the task structure itself if the per-cpu structure hasn't been allocated. Finally, the code in kernel/posix-cpu-timers.c has changed quite a bit. The run_posix_cpu_timers() function has been split into a fast path and a slow path; the former safely checks whether there are any expired thread timers and, if not, just returns, while the slow path does the heavy lifting. With the dedicated thread group fields, timers are no longer "rebalanced" and the process_timer_rebalance() function and related code has gone away. All summing loops are gone and all code that used them now uses the thread_group_cputime() inline. When process-wide timers are set, the new task_cputime structure in signal_struct is used to cache the earliest expiration; this is checked in the fast path. Performance The fix appears not to add significant overhead to existing operations. It generally performs the same as the current code except in two cases, one in which it performs slightly worse (Case 5 below) and one in which it performs very significantly better (Case 2 below). Overall it's a wash except in those two cases. I've since done somewhat more involved testing on a dual-core Opteron system. Case 1: With no itimer running, for a test with 100,000 threads, the fixed kernel took 1428.5 seconds, 513 seconds more than the unfixed system, all of which was spent in the system. There were twice as many voluntary context switches with the fix as without it. Case 2: With an itimer running at .01 second ticks and 4000 threads (the most an unmodified kernel can handle), the fixed kernel ran the test in eight percent of the time (5.8 seconds as opposed to 70 seconds) and had better tick accuracy (.012 seconds per tick as opposed to .023 seconds per tick). Case 3: A 4000-thread test with an initial timer tick of .01 second and an interval of 10,000 seconds (i.e. a timer that ticks only once) had very nearly the same performance in both cases: 6.3 seconds elapsed for the fixed kernel versus 5.5 seconds for the unfixed kernel. With fewer threads (eight in these tests), the Case 1 test ran in essentially the same time on both the modified and unmodified kernels (5.2 seconds versus 5.8 seconds). The Case 2 test ran in about the same time as well, 5.9 seconds versus 5.4 seconds but again with much better tick accuracy, .013 seconds per tick versus .025 seconds per tick for the unmodified kernel. Since the fix affected the rlimit code, I also tested soft and hard CPU limits. Case 4: With a hard CPU limit of 20 seconds and eight threads (and an itimer running), the modified kernel was very slightly favored in that while it killed the process in 19.997 seconds of CPU time (5.002 seconds of wall time), only .003 seconds of that was system time, the rest was user time. The unmodified kernel killed the process in 20.001 seconds of CPU (5.014 seconds of wall time) of which .016 seconds was system time. Really, though, the results were too close to call. The results were essentially the same with no itimer running. Case 5: With a soft limit of 20 seconds and a hard limit of 2000 seconds (where the hard limit would never be reached) and an itimer running, the modified kernel exhibited worse tick accuracy than the unmodified kernel: .050 seconds/tick versus .028 seconds/tick. Otherwise, performance was almost indistinguishable. With no itimer running this test exhibited virtually identical behavior and times in both cases. In times past I did some limited performance testing. those results are below. On a four-cpu Opteron system without this fix, a sixteen-thread test executed in 3569.991 seconds, of which user was 3568.435s and system was 1.556s. On the same system with the fix, user and elapsed time were about the same, but system time dropped to 0.007 seconds. Performance with eight, four and one thread were comparable. Interestingly, the timer ticks with the fix seemed more accurate: The sixteen-thread test with the fix received 149543 ticks for 0.024 seconds per tick, while the same test without the fix received 58720 for 0.061 seconds per tick. Both cases were configured for an interval of 0.01 seconds. Again, the other tests were comparable. Each thread in this test computed the primes up to 25,000,000. I also did a test with a large number of threads, 100,000 threads, which is impossible without the fix. In this case each thread computed the primes only up to 10,000 (to make the runtime manageable). System time dominated, at 1546.968 seconds out of a total 2176.906 seconds (giving a user time of 629.938s). It received 147651 ticks for 0.015 seconds per tick, still quite accurate. There is obviously no comparable test without the fix. Signed-off-by: Frank Mayhar <> Cc: Roland McGrath <> Cc: Alexey Dobriyan <> Cc: Andrew Morton <> Signed-off-by: Ingo Molnar <>
2008-07-26tracehook: execRoland McGrath
This moves all the ptrace hooks related to exec into tracehook.h inlines. This also lifts the calls for tracing out of the binfmt load_binary hooks into search_binary_handler() after it calls into the binfmt module. This change has no effect, since all the binfmt modules' load_binary functions did the call at the end on success, and now search_binary_handler() does it immediately after return if successful. We consolidate the repeated code, and binfmt modules no longer need to import ptrace_notify(). Signed-off-by: Roland McGrath <> Cc: Oleg Nesterov <> Reviewed-by: Ingo Molnar <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-07-25Merge branch 'merge' of ↵Linus Torvalds
git:// * 'merge' of git:// (34 commits) powerpc: Wireup new syscalls Move update_mmu_cache() declaration from tlbflush.h to pgtable.h powerpc/pseries: Remove kmalloc call in handling writes to lparcfg powerpc/pseries: Update arch vector to indicate support for CMO ibmvfc: Add support for collaborative memory overcommit ibmvscsi: driver enablement for CMO ibmveth: enable driver for CMO ibmveth: Automatically enable larger rx buffer pools for larger mtu powerpc/pseries: Verify CMO memory entitlement updates with virtual I/O powerpc/pseries: vio bus support for CMO powerpc/pseries: iommu enablement for CMO powerpc/pseries: Add CMO paging statistics powerpc/pseries: Add collaborative memory manager powerpc/pseries: Utilities to set firmware page state powerpc/pseries: Enable CMO feature during platform setup powerpc/pseries: Split retrieval of processor entitlement data into a helper routine powerpc/pseries: Add memory entitlement capabilities to /proc/ppc64/lparcfg powerpc/pseries: Split processor entitlement retrieval and gathering to helper routines powerpc/pseries: Remove extraneous error reporting for hcall failures in lparcfg powerpc: Fix compile error with binutils 2.15 ... Fixed up conflict in arch/powerpc/platforms/52xx/Kconfig manually.
2008-07-25coredump: elf_core_dump: use core_state->dumper listOleg Nesterov
Kill the nasty rcu_read_lock() + do_each_thread() loop, use the list encoded in mm->core_state instead, s/GFP_ATOMIC/GFP_KERNEL/. This patch allows futher cleanups in binfmt_elf.c, in particular we can kill the parallel info->threads list. Signed-off-by: Oleg Nesterov <> Acked-by: Roland McGrath <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-07-25coredump: elf_core_dump: skip kernel threadsOleg Nesterov
linux_binfmt->core_dump() runs before the process does exit_aio(), this means that we can hit the kernel thread which shares the same ->mm. Afaics, nothing really bad can happen, but perhaps it makes sense to fix this minor bug. It is sad we have to iterate over all threads in system and use GFP_ATOMIC. Hopefully we can kill theses ugly do_each_thread()s, but this needs some nontrivial changes in mm_struct and do_coredump. Signed-off-by: Oleg Nesterov <> Cc: Roland McGrath <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-07-25ELF loader support for auxvec base platform stringNathan Lynch
Some IBM POWER-based platforms have the ability to run in a mode which mostly appears to the OS as a different processor from the actual hardware. For example, a Power6 system may appear to be a Power5+, which makes the AT_PLATFORM value "power5+". This means that programs are restricted to the ISA supported by Power5+; Power6-specific instructions are treated as illegal. However, some applications (virtual machines, optimized libraries) can benefit from knowledge of the underlying CPU model. A new aux vector entry, AT_BASE_PLATFORM, will denote the actual hardware. For example, on a Power6 system in Power5+ compatibility mode, AT_PLATFORM will be "power5+" and AT_BASE_PLATFORM will be "power6". The idea is that AT_PLATFORM indicates the instruction set supported, while AT_BASE_PLATFORM indicates the underlying microarchitecture. If the architecture has defined ELF_BASE_PLATFORM, copy that value to the user stack in the same manner as ELF_PLATFORM. Signed-off-by: Nathan Lynch <> Acked-by: Andrew Morton <> Signed-off-by: Benjamin Herrenschmidt <>
2008-07-22execve filename: document and export via auxiliary vectorJohn Reiser
The Linux kernel puts the filename argument of execve() into the new address space. Many developers are surprised to learn this. Those who know and could use it, object "But it's not documented." Those who want to use it dislike the expression (char *)(1+ strlen(env[-1+ n_env]) + env[-1+ n_env]) because it requires locating the last original environment variable, and assumes that the filename follows the characters. This patch documents the insertion of the filename, and makes it easier to find by adding a new tag AT_EXECFN in the ElfXX_auxv_t; see <elf.h>. In many cases readlink("/proc/self/exe",) gives the same answer. But if all the original pages get unmapped, then the kernel erases the symlink for /proc/self/exe. This can happen when a program decompressor does a good job of cleaning up after uncompressing directly to memory, so that the address space of the target program looks the same as if compression had never happened. One example is . One notable use of the underlying concept (what path containED the executable) is glibc expanding $ORIGIN in DT_RUNPATH. In practice for the near term, it may be a good idea for user-mode code to use both /proc/self/exe and AT_EXECFN as fall-back methods for each other. /proc/self/exe can fail due to unmapping, AT_EXECFN can fail because it won't be present on non-new systems. The auxvec or {AT_EXECFN}.d_val also can get overwritten, although in nearly all cases this would be the result of a bug. The runtime cost is one NEW_AUX_ENT using two words of stack space. The underlying value is maintained already as bprm->exec; setup_arg_pages() in fs/exec.c slides it for stack_shift, etc. Signed-off-by: John Reiser <> Cc: Roland McGrath <> Cc: Jakub Jelinek <> Cc: Ulrich Drepper <> Cc: Benjamin Herrenschmidt <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-06-16Remove last traces of a.out support from ELF loader.David Woodhouse
In commit d20894a23708c2af75966534f8e4dedb46d48db2 ("Remove a.out interpreter support in ELF loader"), Andi removed support for a.out interpreters from the ELF loader, which was only ever needed for the transition from a.out to ELF. This removes the last traces of that support, in particular the inclusion of <linux/a.out.h>. Signed-off-by: David Woodhouse <> Acked-by: Peter Korsgaard <> Signed-off-by: Linus Torvalds <>
2008-05-16[Patch] fs/binfmt_elf.c: fix wrong return valuesWANG Cong
create_elf_tables() returns 0 on success. But when strnlen_user() "fails", it returns 0 directly. So this is wrong. Signed-off-by: WANG Cong <> Cc: Alexander Viro <> Signed-off-by: Al Viro <>
2008-05-16[Patch] fs/binfmt_elf.c: fix a wrong freeWANG Cong
In kmalloc failing path, we shouldn't free pointers in 'info', because the struct 'info' is uninitilized when kmalloc is called. And when kmalloc returns NULL, it's needless to kfree it. Signed-off-by: WANG Cong <> Cc: Alexander Viro <> Reviewed-by: Pekka Enberg <> -- Signed-off-by: Al Viro <>
2008-04-29elf: fix shadowed variables in fs/binfmt_elf.cWANG Cong
Fix these sparse warings: fs/binfmt_elf.c:1749:29: warning: symbol 'tmp' shadows an earlier one fs/binfmt_elf.c:1734:28: originally declared here fs/binfmt_elf.c:2009:26: warning: symbol 'vma' shadows an earlier one fs/binfmt_elf.c:1892:24: originally declared here [ chose better variable name] Signed-off-by: WANG Cong <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-04-29BINFMT: fill_elf_header cleanup - use straight memset firstCyrill Gorcunov
This patch does simplify fill_elf_header function by setting to zero the whole elf header first. So we fillup the fields we really need only. before: text data bss dec hex filename 11735 80 0 11815 2e27 fs/binfmt_elf.o after: text data bss dec hex filename 11710 80 0 11790 2e0e fs/binfmt_elf.o viola, 25 bytes of text is freed Signed-off-by: Cyrill Gorcunov <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-04-25[PATCH] sanitize handling of shared descriptor tables in failing execve()Al Viro
* unshare_files() can fail; doing it after irreversible actions is wrong and de_thread() is certainly irreversible. * since we do it unconditionally anyway, we might as well do it in do_execve() and save ourselves the PITA in binfmt handlers, etc. * while we are at it, binfmt_som actually leaked files_struct on failure. As a side benefit, unshare_files(), put_files_struct() and reset_files_struct() become unexported. Signed-off-by: Al Viro <>
2008-03-04core dump: user_regset writebackRoland McGrath
This makes the user_regset-based core dump code call user_regset writeback hooks when available. This is necessary groundwork to allow IA64 to set CORE_DUMP_USE_REGSET. Cc: Shaohua Li <> Signed-off-by: Roland McGrath <> Cc: "Luck, Tony" <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-02-08Remove a.out interpreter support in ELF loaderAndi Kleen
Following the deprecation schedule the a.out ELF interpreter support is removed now with this patch. a.out ELF interpreters were an transition feature for moving a.out systems to ELF, but they're unlikely to be still needed. Pure a.out systems will still work of course. This allows to simplify the hairy ELF loader. Signed-off-by: Andi Kleen <> Cc: David Howells <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-02-08aout: suppress A.OUT library support if !CONFIG_ARCH_SUPPORTS_AOUTDavid Howells
Suppress A.OUT library support if CONFIG_ARCH_SUPPORTS_AOUT is not set. Not all architectures support the A.OUT binfmt, so the ELF binfmt should not be permitted to go looking for A.OUT libraries to load in such a case. Not only that, but under such conditions A.OUT core dumps are not produced either. To make this work, this patch also does the following: (1) Makes the existence of the contents of linux/a.out.h contingent on CONFIG_ARCH_SUPPORTS_AOUT. (2) Renames dump_thread() to aout_dump_thread() as it's only called by A.OUT core dumping code. (3) Moves aout_dump_thread() into asm/a.out-core.h and makes it inline. This is then included only where needed. This means that this bit of arch code will be stored in the appropriate A.OUT binfmt module rather than the core kernel. (4) Drops A.OUT support for Blackfin (according to Mike Frysinger it's not needed) and FRV. This patch depends on the previous patch to move STACK_TOP[_MAX] out of asm/a.out.h and into asm/processor.h as they're required whether or not A.OUT format is available. [ uml: re-remove accidentally restored code] Signed-off-by: David Howells <> Cc: <> Signed-off-by: Jeff Dike <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-02-06brk randomization: introduce CONFIG_COMPAT_BRKIngo Molnar
based on similar patch from: Pavel Machek <> Introduce CONFIG_COMPAT_BRK. If disabled then the kernel is free (but not obliged to) randomize the brk area. Heap randomization breaks ancient binaries, so we keep COMPAT_BRK enabled by default. Signed-off-by: Ingo Molnar <>
2008-02-03fs/binfmt_elf.c: spello fixOhad Ben-Cohen
s/litle/little Signed-off-by: Ohad Ben-Cohen <> Signed-off-by: Adrian Bunk <>
2008-01-30x86: remove iBCS supportAndi Kleen
ibcs2 support has never been supported on 2.6 kernels as far as I know, and if it has it must have been an external patch. Anyways, if anybody applies an external patch they could as well readd the ibcs checking code to the ELF loader in the same patch. But there is no reason to keep this code running in all Linux kernels. This will save at least two strcmps each ELF execution. No deprecation period because it could not have been used anyway. Signed-off-by: Andi Kleen <> Signed-off-by: Andrew Morton <> Signed-off-by: Ingo Molnar <> Signed-off-by: Thomas Gleixner <>
2008-01-30elf core dump: notes user_regsetRoland McGrath
This modifies the ELF core dump code under #ifdef CORE_DUMP_USE_REGSET. It changes nothing when this macro is not defined. When it's #define'd by some arch header (e.g. asm/elf.h), the arch must support the user_regset (linux/regset.h) interface for reading thread state. This provides an alternate version of note segment writing that is based purely on the user_regset interfaces. When CORE_DUMP_USE_REGSET is set, the arch need not define macros such as ELF_CORE_COPY_REGS and ELF_ARCH. All that information is taken from the user_regset data structures. The core dumps come out exactly the same if arch's definitions for its user_regset details are correct. Signed-off-by: Roland McGrath <> Signed-off-by: Ingo Molnar <> Signed-off-by: Thomas Gleixner <>
2008-01-30elf core dump: notes reorgRoland McGrath
This pulls out the code for writing the notes segment of an ELF core dump into separate functions. This cleanly isolates into one cluster of functions everything that deals with the note formats and the hooks into arch code to fill them. The top-level elf_core_dump function itself now deals purely with the generic ELF format and the memory segments. This only moves code around into functions that can be inlined away. It should not change any behavior at all. Signed-off-by: Roland McGrath <> Signed-off-by: Ingo Molnar <> Signed-off-by: Thomas Gleixner <>
2008-01-30x86: PIE executable randomization, checkpatch fixesAndrew Morton
#39: FILE: arch/ia64/ia32/binfmt_elf32.c:229: +elf32_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type, unsigned long unused) WARNING: no space between function name and open parenthesis '(' #39: FILE: arch/ia64/ia32/binfmt_elf32.c:229: +elf32_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type, unsigned long unused) WARNING: line over 80 characters #67: FILE: arch/x86/kernel/sys_x86_64.c:80: + new_begin = randomize_range(*begin, *begin + 0x02000000, 0); ERROR: use tabs not spaces #110: FILE: arch/x86/kernel/sys_x86_64.c:185: + ^I mm->cached_hole_size = 0;$ ERROR: use tabs not spaces #111: FILE: arch/x86/kernel/sys_x86_64.c:186: + ^I^Imm->free_area_cache = mm->mmap_base;$ ERROR: use tabs not spaces #112: FILE: arch/x86/kernel/sys_x86_64.c:187: + ^I}$ ERROR: use tabs not spaces #141: FILE: arch/x86/kernel/sys_x86_64.c:216: + ^I^I/* remember the largest hole we saw so far */$ ERROR: use tabs not spaces #142: FILE: arch/x86/kernel/sys_x86_64.c:217: + ^I^Iif (addr + mm->cached_hole_size < vma->vm_start)$ ERROR: use tabs not spaces #143: FILE: arch/x86/kernel/sys_x86_64.c:218: + ^I^I mm->cached_hole_size = vma->vm_start - addr;$ ERROR: use tabs not spaces #157: FILE: arch/x86/kernel/sys_x86_64.c:232: + ^Imm->free_area_cache = TASK_UNMAPPED_BASE;$ ERROR: need a space before the open parenthesis '(' #291: FILE: arch/x86/mm/mmap_64.c:101: + } else if(mmap_is_legacy()) { WARNING: braces {} are not necessary for single statement blocks #302: FILE: arch/x86/mm/mmap_64.c:112: + if (current->flags & PF_RANDOMIZE) { + mm->mmap_base += ((long)rnd) << PAGE_SHIFT; + } WARNING: line over 80 characters #314: FILE: fs/binfmt_elf.c:48: +static unsigned long elf_map (struct file *, unsigned long, struct elf_phdr *, int, int, unsigned long); WARNING: no space between function name and open parenthesis '(' #314: FILE: fs/binfmt_elf.c:48: +static unsigned long elf_map (struct file *, unsigned long, struct elf_phdr *, int, int, unsigned long); WARNING: line over 80 characters #429: FILE: fs/binfmt_elf.c:438: + eppnt, elf_prot, elf_type, total_size); ERROR: need space after that ',' (ctx:VxV) #480: FILE: fs/binfmt_elf.c:939: + elf_prot, elf_flags,0); ^ total: 9 errors, 7 warnings, 461 lines checked Your patch has style problems, please review. If any of these errors are false positives report them to the maintainer, see CHECKPATCH in MAINTAINERS. Please run checkpatch prior to sending patches Cc: "Luck, Tony" <> Cc: Arjan van de Ven <> Cc: Jakub Jelinek <> Cc: Jiri Kosina <> Cc: KAMEZAWA Hiroyuki <> Cc: Roland McGrath <> Signed-off-by: Andrew Morton <> Signed-off-by: Ingo Molnar <> Signed-off-by: Thomas Gleixner <>
2008-01-30x86: PIE executable randomizationJiri Kosina
main executable of (specially compiled/linked -pie/-fpie) ET_DYN binaries onto a random address (in cases in which mmap() is allowed to perform a randomization). The code has been extraced from Ingo's exec-shield patch [ fix used-uninitialsied warning] [ fixed ia32 ELF on x86_64 handling] Signed-off-by: Jiri Kosina <> Cc: KAMEZAWA Hiroyuki <> Cc: Arjan van de Ven <> Cc: Roland McGrath <> Cc: Jakub Jelinek <> Cc: "Luck, Tony" <> Signed-off-by: Andrew Morton <> Signed-off-by: Ingo Molnar <> Signed-off-by: Thomas Gleixner <>
2008-01-30x86: randomize brkJiri Kosina
Randomize the location of the heap (brk) for i386 and x86_64. The range is randomized in the range starting at current brk location up to 0x02000000 offset for both architectures. This, together with pie-executable-randomization.patch and pie-executable-randomization-fix.patch, should make the address space randomization on i386 and x86_64 complete. Arjan says: This is known to break older versions of some emacs variants, whose dumper code assumed that the last variable declared in the program is equal to the start of the dynamically allocated memory region. (The dumper is the code where emacs effectively dumps core at the end of it's compilation stage; this coredump is then loaded as the main program during normal use) iirc this was 5 years or so; we found this way back when I was at RH and we first did the security stuff there (including this brk randomization). It wasn't all variants of emacs, and it got fixed as a result (I vaguely remember that emacs already had code to deal with it for other archs/oses, just ifdeffed wrongly). It's a rare and wrong assumption as a general thing, just on x86 it mostly happened to be true (but to be honest, it'll break too if gcc does something fancy or if the linker does a non-standard order). Still its something we should at least document. Note 2: afaik it only broke the emacs *build*. I'm not 100% sure about that (it IS 5 years ago) though. [ deuglification ] Signed-off-by: Jiri Kosina <> Cc: Arjan van de Ven <> Cc: Roland McGrath <> Cc: Jakub Jelinek <> Signed-off-by: Andrew Morton <> Signed-off-by: Ingo Molnar <> Signed-off-by: Thomas Gleixner <>
2008-01-07core dump: real_parent ppidRoland McGrath
The pr_ppid field reported in core dumps should match what getppid() would have returned to that process, regardless of whether a debugger is attached. Signed-off-by: Roland McGrath <> Signed-off-by: Linus Torvalds <>
2007-10-19pid namespaces: changes to show virtual ids to userPavel Emelyanov
This is the largest patch in the set. Make all (I hope) the places where the pid is shown to or get from user operate on the virtual pids. The idea is: - all in-kernel data structures must store either struct pid itself or the pid's global nr, obtained with pid_nr() call; - when seeking the task from kernel code with the stored id one should use find_task_by_pid() call that works with global pids; - when showing pid's numerical value to the user the virtual one should be used, but however when one shows task's pid outside this task's namespace the global one is to be used; - when getting the pid from userspace one need to consider this as the virtual one and use appropriate task/pid-searching functions. [ build fix] [ nuther build fix] [ yet nuther build fix] [ remove unneeded casts] Signed-off-by: Pavel Emelyanov <> Signed-off-by: Alexey Dobriyan <> Cc: Sukadev Bhattiprolu <> Cc: Oleg Nesterov <> Cc: Paul Menage <> Cc: "Eric W. Biederman" <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-19pid namespaces: round up the APIPavel Emelianov
The set of functions process_session, task_session, process_group and task_pgrp is confusing, as the names can be mixed with each other when looking at the code for a long time. The proposals are to * equip the functions that return the integer with _nr suffix to represent that fact, * and to make all functions work with task (not process) by making the common prefix of the same name. For monotony the routines signal_session() and set_signal_session() are replaced with task_session_nr() and set_task_session(), especially since they are only used with the explicit task->signal dereference. Signed-off-by: Pavel Emelianov <> Acked-by: Serge E. Hallyn <> Cc: Kirill Korotaev <> Cc: "Eric W. Biederman" <> Cc: Cedric Le Goater <> Cc: Herbert Poetzl <> Cc: Sukadev Bhattiprolu <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-17Break ELF_PLATFORM and stack pointer randomization dependencyFranck Bui-Huu
Currently arch_align_stack() is used by fs/binfmt_elf.c to randomize stack pointer inside a page. But this happens only if ELF_PLATFORM symbol is defined. ELF_PLATFORM is normally set if the architecture wants to load implementation specific libraries for optimization. And currently a lot of architectures just yield this symbol to NULL. This is the case for MIPS architecture where ELF_PLATFORM is NULL but arch_align_stack() has been redefined to do stack inside page randomization. So in this case no randomization is actually done. This patch breaks this dependency which seems to be useless and allows platforms such MIPS to do the randomization. Signed-off-by: Franck Bui-Huu <> Cc: Ingo Molnar <> Cc: Arjan van de Ven <> Cc: Ralf Baechle <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-17increase AT_VECTOR_SIZE to terminate saved_auxv properlyOlaf Hering
include/asm-powerpc/elf.h has 6 entries in ARCH_DLINFO. fs/binfmt_elf.c has 14 unconditional NEW_AUX_ENT entries and 2 conditional NEW_AUX_ENT entries. So in the worst case, saved_auxv does not get an AT_NULL entry at the end. The saved_auxv array must be terminated with an AT_NULL entry. Make the size of mm_struct->saved_auxv arch dependend, based on the number of ARCH_DLINFO entries. Signed-off-by: Olaf Hering <> Cc: Roland McGrath <> Cc: Jakub Jelinek <> Cc: Richard Henderson <> Cc: Ivan Kokshaysky <> Cc: "Luck, Tony" <> Cc: Benjamin Herrenschmidt <> Cc: Paul Mackerras <> Cc: Paul Mundt <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-17Add MMF_DUMP_ELF_HEADERSRoland McGrath
This adds the MMF_DUMP_ELF_HEADERS option to /proc/pid/coredump_filter. This dumps the first page (only) of a private file mapping if it appears to be a mapping of an ELF file. Including these pages in the core dump may give sufficient identifying information to associate the original DSO and executable file images and their debugging information with a core file in a generic way just from its contents (e.g. when those binaries were built with ld --build-id). I expect this to become the default behavior eventually. Existing versions of gdb can be confused by the core dumps it creates, so it won't enabled by default for some time to come. Soon many people will have systems with a gdb that handle these dumps, so they can arrange to set the bit at boot and have it inherited system-wide. This also cleans up the checking of the MMF_DUMP_* flag bits, which did not need to be using atomic macros. Signed-off-by: Roland McGrath <> Cc: Hidehiro Kawai <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-17Deprecate a.out ELF interpretersAndi Kleen
The Linux ELF loader is quite complicated and messy code (that could probably need a rewrite, but that's a different chapter). One particular messy part in it is the support for non ELF a.out ld.sos. This was originally added to make transition from a.out to ELF easier because an a.out ELF could be still build using an older a.out toolkit. But by now that should be fully obsolete and removing it would clean up binfmt_elf.c up a bit. I propose to deprecate this support and remove for 2.6.25. Drawback is that someone still runs their system with a.out they would need to update the when updating to a new kernel. This patch just adds an entry to the deprecation file and a printk warning users. [ better warning message] Signed-off-by: Andi Kleen <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-17core_pattern: ignore RLIMIT_CORE if core_pattern is a pipeNeil Horman
For some time /proc/sys/kernel/core_pattern has been able to set its output destination as a pipe, allowing a user space helper to receive and intellegently process a core. This infrastructure however has some shortcommings which can be enhanced. Specifically: 1) The coredump code in the kernel should ignore RLIMIT_CORE limitation when core_pattern is a pipe, since file system resources are not being consumed in this case, unless the user application wishes to save the core, at which point the app is restricted by usual file system limits and restrictions. 2) The core_pattern code should be able to parse and pass options to the user space helper as an argv array. The real core limit of the uid of the crashing proces should also be passable to the user space helper (since it is overridden to zero when called). 3) Some miscellaneous bugs need to be cleaned up (specifically the recognition of a recursive core dump, should the user mode helper itself crash. Also, the core dump code in the kernel should not wait for the user mode helper to exit, since the same context is responsible for writing to the pipe, and a read of the pipe by the user mode helper will result in a deadlock. This patch: Remove the check of RLIMIT_CORE if core_pattern is a pipe. In the event that core_pattern is a pipe, the entire core will be fed to the user mode helper. Signed-off-by: Neil Horman <> Cc: <> Cc: <> Cc: Jeremy Fitzhardinge <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-17x86: replace NT_PRXFPREG with ELF_CORE_XFPREG_TYPE #defineMark Nelson
Replace NT_PRXFPREG with ELF_CORE_XFPREG_TYPE in the coredump code which allows for more flexibility in the note type for the state of 'extended floating point' implementations in coredumps. New note types can now be added with an appropriate #define. This does #define ELF_CORE_XFPREG_TYPE to be NT_PRXFPREG in all current users so there's are no change in behaviour. This will let us use different note types on powerpc for the Altivec/VMX state that some PowerPC cpus have (G4, PPC970, POWER6) and for the SPE (signal processing extension) state that some embedded PowerPC cpus from Freescale have. Signed-off-by: Mark Nelson <> Cc: Paul Mackerras <> Cc: Thomas Gleixner <> Cc: Ingo Molnar <> Cc: Andi Kleen <> Cc: <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-16remove ZERO_PAGENick Piggin
The commit b5810039a54e5babf428e9a1e89fc1940fabff11 contains the note A last caveat: the ZERO_PAGE is now refcounted and managed with rmap (and thus mapcounted and count towards shared rss). These writes to the struct page could cause excessive cacheline bouncing on big systems. There are a number of ways this could be addressed if it is an issue. And indeed this cacheline bouncing has shown up on large SGI systems. There was a situation where an Altix system was essentially livelocked tearing down ZERO_PAGE pagetables when an HPC app aborted during startup. This situation can be avoided in userspace, but it does highlight the potential scalability problem with refcounting ZERO_PAGE, and corner cases where it can really hurt (we don't want the system to livelock!). There are several broad ways to fix this problem: 1. add back some special casing to avoid refcounting ZERO_PAGE 2. per-node or per-cpu ZERO_PAGES 3. remove the ZERO_PAGE completely I will argue for 3. The others should also fix the problem, but they result in more complex code than does 3, with little or no real benefit that I can see. Why? Inserting a ZERO_PAGE for anonymous read faults appears to be a false optimisation: if an application is performance critical, it would not be doing many read faults of new memory, or at least it could be expected to write to that memory soon afterwards. If cache or memory use is critical, it should not be working with a significant number of ZERO_PAGEs anyway (a more compact representation of zeroes should be used). As a sanity check -- mesuring on my desktop system, there are never many mappings to the ZERO_PAGE (eg. 2 or 3), thus memory usage here should not increase much without it. When running a make -j4 kernel compile on my dual core system, there are about 1,000 mappings to the ZERO_PAGE created per second, but about 1,000 ZERO_PAGE COW faults per second (less than 1 ZERO_PAGE mapping per second is torn down without being COWed). So removing ZERO_PAGE will save 1,000 page faults per second when running kbuild, while keeping it only saves less than 1 page clearing operation per second. 1 page clear is cheaper than a thousand faults, presumably, so there isn't an obvious loss. Neither the logical argument nor these basic tests give a guarantee of no regressions. However, this is a reasonable opportunity to try to remove the ZERO_PAGE from the pagefault path. If it is found to cause regressions, we can reintroduce it and just avoid refcounting it. The /dev/zero ZERO_PAGE usage and TLB tricks also get nuked. I don't see much use to them except on benchmarks. All other users of ZERO_PAGE are converted just to use ZERO_PAGE(0) for simplicity. We can look at replacing them all and maybe ripping out ZERO_PAGE completely when we are more satisfied with this solution. Signed-off-by: Nick Piggin <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus "snif" Torvalds <>
2007-09-19[POWERPC] spufs: Cleanup ELF coredump extra notes logicMichael Ellerman
To start with, arch_notes_size() etc. is a little too ambiguous a name for my liking, so change the function names to be more explicit. Calling through macros is ugly, especially with hidden parameters, so don't do that, call the routines directly. Use ARCH_HAVE_EXTRA_ELF_NOTES as the only flag, and based on it decide whether we want the extern declarations or the empty versions. Since we have empty routines, actually use them in the coredump code to save a few #ifdefs. We want to change the handling of foffset so that the write routine updates foffset as it goes, instead of using file->f_pos (so that writing to a pipe works). So pass foffset to the write routine, and for now just set it to file->f_pos at the end of writing. It should also be possible for the write routine to fail, so change it to return int and treat a non-zero return as failure. Signed-off-by: Michael Ellerman <> Signed-off-by: Jeremy Kerr <> Signed-off-by: Paul Mackerras <>
2007-07-21revert "PIE randomization"Andrew Morton
There are reports of this causing userspace failures ( Revert. Cc: Jan Kratochvil <> Cc: Jiri Kosina <> Cc: Ingo Molnar <> Cc: Roland McGrath <> Cc: Jakub Jelinek <> Cc: Ulrich Kunitz <> Cc: "H. Peter Anvin" <> Cc: "Bret Towe" <> Cc: "Luck, Tony" <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-07-19coredump masking: ELF: enable core dump filteringKawai, Hidehiro
This patch enables core dump filtering for ELF-formatted core file. Signed-off-by: Hidehiro Kawai <> Cc: Alan Cox <> Cc: David Howells <> Cc: Hugh Dickins <> Cc: Nick Piggin <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-07-19mm: variable length argument supportOllie Wild
Remove the arg+env limit of MAX_ARG_PAGES by copying the strings directly from the old mm into the new mm. We create the new mm before the binfmt code runs, and place the new stack at the very top of the address space. Once the binfmt code runs and figures out where the stack should be, we move it downwards. It is a bit peculiar in that we have one task with two mm's, one of which is inactive. [ limit stack size] Signed-off-by: Ollie Wild <> Signed-off-by: Peter Zijlstra <> Cc: <> Cc: Hugh Dickins <> [ unexport bprm_mm_init] Signed-off-by: Adrian Bunk <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-07-16binfmt_elf warning fixAndrew Morton
fs/binfmt_elf.c: In function 'load_elf_binary': fs/binfmt_elf.c:1002: warning: 'interp_map_addr' may be used uninitialized in this function The compiler (gcc-4.1.0) is correct, but it failed to notice that we didn't use the resulting value. Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>