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2010-05-11revert "procfs: provide stack information for threads" and its fixup commitsRobin Holt
Originally, commit d899bf7b ("procfs: provide stack information for threads") attempted to introduce a new feature for showing where the threadstack was located and how many pages are being utilized by the stack. Commit c44972f1 ("procfs: disable per-task stack usage on NOMMU") was applied to fix the NO_MMU case. Commit 89240ba0 ("x86, fs: Fix x86 procfs stack information for threads on 64-bit") was applied to fix a bug in ia32 executables being loaded. Commit 9ebd4eba7 ("procfs: fix /proc/<pid>/stat stack pointer for kernel threads") was applied to fix a bug which had kernel threads printing a userland stack address. Commit 1306d603f ('proc: partially revert "procfs: provide stack information for threads"') was then applied to revert the stack pages being used to solve a significant performance regression. This patch nearly undoes the effect of all these patches. The reason for reverting these is it provides an unusable value in field 28. For x86_64, a fork will result in the task->stack_start value being updated to the current user top of stack and not the stack start address. This unpredictability of the stack_start value makes it worthless. That includes the intended use of showing how much stack space a thread has. Other architectures will get different values. As an example, ia64 gets 0. The do_fork() and copy_process() functions appear to treat the stack_start and stack_size parameters as architecture specific. I only partially reverted c44972f1 ("procfs: disable per-task stack usage on NOMMU") . If I had completely reverted it, I would have had to change mm/Makefile only build pagewalk.o when CONFIG_PROC_PAGE_MONITOR is configured. Since I could not test the builds without significant effort, I decided to not change mm/Makefile. I only partially reverted 89240ba0 ("x86, fs: Fix x86 procfs stack information for threads on 64-bit") . I left the KSTK_ESP() change in place as that seemed worthwhile. Signed-off-by: Robin Holt <holt@sgi.com> Cc: Stefani Seibold <stefani@seibold.net> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06coredump: suppress uid comparison test if core output files are pipesNeil Horman
Modify uid check in do_coredump so as to not apply it in the case of pipes. This just got noticed in testing. The end of do_coredump validates the uid of the inode for the created file against the uid of the crashing process to ensure that no one can pre-create a core file with different ownership and grab the information contained in the core when they shouldn' tbe able to. This causes failures when using pipes for a core dumps if the crashing process is not root, which is the uid of the pipe when it is created. The fix is simple. Since the check for matching uid's isn't relevant for pipes (a process can't create a pipe that the uermodehelper code will open anyway), we can just just skip it in the event ispipe is non-zero Reverts a pipe-affecting change which was accidentally made in : commit c46f739dd39db3b07ab5deb4e3ec81e1c04a91af : Author: Ingo Molnar <mingo@elte.hu> : AuthorDate: Wed Nov 28 13:59:18 2007 +0100 : Commit: Linus Torvalds <torvalds@woody.linux-foundation.org> : CommitDate: Wed Nov 28 10:58:01 2007 -0800 : : vfs: coredumping fix Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06coredump: set ->group_exit_code for other CLONE_VM tasks tooOleg Nesterov
User visible change. do_coredump() kills all threads which share the same ->mm but only the coredumping process gets the proper exit_code. Other tasks which share the same ->mm die "silently" and return status == 0 to parent. This is historical behaviour, not actually a bug. But I think Frank Heckenbach rightly dislikes the current behaviour. Simple test-case: #include <stdio.h> #include <unistd.h> #include <signal.h> #include <sys/wait.h> int main(void) { int stat; if (!fork()) { if (!vfork()) kill(getpid(), SIGQUIT); } wait(&stat); printf("stat=%x\n", stat); return 0; } Before this patch it prints "stat=0" despite the fact the child was killed by SIGQUIT. After this patch the output is "stat=3" which obviously makes more sense. Even with this patch, only the task which originates the coredumping gets "|= 0x80" if the core was actually dumped, but at least the coredumping signal is visible to do_wait/etc. Reported-by: Frank Heckenbach <f.heckenbach@fh-soft.de> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Cc: Roland McGrath <roland@redhat.com> Cc: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06coredump: pass mm->flags as a coredump parameter for consistencyMasami Hiramatsu
Pass mm->flags as a coredump parameter for consistency. --- 1787 if (mm->core_state || !get_dumpable(mm)) { <- (1) 1788 up_write(&mm->mmap_sem); 1789 put_cred(cred); 1790 goto fail; 1791 } 1792 [...] 1798 if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ <-(2) 1799 flag = O_EXCL; /* Stop rewrite attacks */ 1800 cred->fsuid = 0; /* Dump root private */ 1801 } --- Since dumpable bits are not protected by lock, there is a chance to change these bits between (1) and (2). To solve this issue, this patch copies mm->flags to coredump_params.mm_flags at the beginning of do_coredump() and uses it instead of get_dumpable() while dumping core. This copy is also passed to binfmt->core_dump, since elf*_core_dump() uses dump_filter bits in mm->flags. [akpm@linux-foundation.org: fix merge] Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06exec: create initial stack independent of PAGE_SIZEMichael Neuling
Currently we create the initial stack based on the PAGE_SIZE. This is unnecessary. This creates this initial stack independent of the PAGE_SIZE. It also bumps up the number of 4k pages allocated from 20 to 32, to align with 64K page systems. Signed-off-by: Michael Neuling <mikey@neuling.org> Cc: Helge Deller <deller@gmx.de> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Americo Wang <xiyou.wangcong@gmail.com> Cc: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06fs: use rlimit helpersJiri Slaby
Make sure compiler won't do weird things with limits. E.g. fetching them twice may return 2 different values after writable limits are implemented. I.e. either use rlimit helpers added in commit 3e10e716abf3 ("resource: add helpers for fetching rlimits") or ACCESS_ONCE if not applicable. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06mm: change anon_vma linking to fix multi-process server scalability issueRik van Riel
The old anon_vma code can lead to scalability issues with heavily forking workloads. Specifically, each anon_vma will be shared between the parent process and all its child processes. In a workload with 1000 child processes and a VMA with 1000 anonymous pages per process that get COWed, this leads to a system with a million anonymous pages in the same anon_vma, each of which is mapped in just one of the 1000 processes. However, the current rmap code needs to walk them all, leading to O(N) scanning complexity for each page. This can result in systems where one CPU is walking the page tables of 1000 processes in page_referenced_one, while all other CPUs are stuck on the anon_vma lock. This leads to catastrophic failure for a benchmark like AIM7, where the total number of processes can reach in the tens of thousands. Real workloads are still a factor 10 less process intensive than AIM7, but they are catching up. This patch changes the way anon_vmas and VMAs are linked, which allows us to associate multiple anon_vmas with a VMA. At fork time, each child process gets its own anon_vmas, in which its COWed pages will be instantiated. The parents' anon_vma is also linked to the VMA, because non-COWed pages could be present in any of the children. This reduces rmap scanning complexity to O(1) for the pages of the 1000 child processes, with O(N) complexity for at most 1/N pages in the system. This reduces the average scanning cost in heavily forking workloads from O(N) to 2. The only real complexity in this patch stems from the fact that linking a VMA to anon_vmas now involves memory allocations. This means vma_adjust can fail, if it needs to attach a VMA to anon_vma structures. This in turn means error handling needs to be added to the calling functions. A second source of complexity is that, because there can be multiple anon_vmas, the anon_vma linking in vma_adjust can no longer be done under "the" anon_vma lock. To prevent the rmap code from walking up an incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag. This bit flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h to make sure it is impossible to compile a kernel that needs both symbolic values for the same bitflag. Some test results: Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test box with 16GB RAM and not quite enough IO), the system ends up running >99% in system time, with every CPU on the same anon_vma lock in the pageout code. With these changes, AIM7 hits the cross-over point around 29.7k users. This happens with ~99% IO wait time, there never seems to be any spike in system time. The anon_vma lock contention appears to be resolved. [akpm@linux-foundation.org: cleanups] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Larry Woodman <lwoodman@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06mm: avoid false sharing of mm_counterKAMEZAWA Hiroyuki
Considering the nature of per mm stats, it's the shared object among threads and can be a cache-miss point in the page fault path. This patch adds per-thread cache for mm_counter. RSS value will be counted into a struct in task_struct and synchronized with mm's one at events. Now, in this patch, the event is the number of calls to handle_mm_fault. Per-thread value is added to mm at each 64 calls. rough estimation with small benchmark on parallel thread (2threads) shows [before] 4.5 cache-miss/faults [after] 4.0 cache-miss/faults Anyway, the most contended object is mmap_sem if the number of threads grows. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-22fs/exec.c: fix initial stack reservationMichael Neuling
803bf5ec259941936262d10ecc84511b76a20921 ("fs/exec.c: restrict initial stack space expansion to rlimit") attempts to limit the initial stack to 20*PAGE_SIZE. Unfortunately, in attempting ensure the stack is not reduced in size, we ended up not changing the stack at all. This size reduction check is not necessary as the expand_stack call does this already. This caused a regression in UML resulting in most guest processes being killed. Signed-off-by: Michael Neuling <mikey@neuling.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Cc: Anton Blanchard <anton@samba.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: James Morris <jmorris@namei.org> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jouni Malinen <j@w1.fi> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-11fs/exec.c: restrict initial stack space expansion to rlimitMichael Neuling
When reserving stack space for a new process, make sure we're not attempting to expand the stack by more than rlimit allows. This fixes a bug caused by b6a2fea39318e43fee84fa7b0b90d68bed92d2ba ("mm: variable length argument support") and unmasked by fc63cf237078c86214abcb2ee9926d8ad289da9b ("exec: setup_arg_pages() fails to return errors"). This bug means that when limiting the stack to less the 20*PAGE_SIZE (eg. 80K on 4K pages or 'ulimit -s 79') all processes will be killed before they start. This is particularly bad with 64K pages, where a ulimit below 1280K will kill every process. To test, do: 'ulimit -s 15; ls' before and after the patch is applied. Before it's applied, 'ls' should be killed. After the patch is applied, 'ls' should no longer be killed. A stack limit of 15KB since it's small enough to trigger 20*PAGE_SIZE. Also 15KB not a multiple of PAGE_SIZE, which is a trickier case to handle correctly with this code. 4K pages should be fine to test with. [kosaki.motohiro@jp.fujitsu.com: cleanup] [akpm@linux-foundation.org: cleanup cleanup] Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Americo Wang <xiyou.wangcong@gmail.com> Cc: Anton Blanchard <anton@samba.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: James Morris <jmorris@namei.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-02Fix 'flush_old_exec()/setup_new_exec()' splitLinus Torvalds
Commit 221af7f87b9 ("Split 'flush_old_exec' into two functions") split the function at the point of no return - ie right where there were no more error cases to check. That made sense from a technical standpoint, but when we then also combined it with the actual personality setting going in between flush_old_exec() and setup_new_exec(), it needs to be a bit more careful. In particular, we need to make sure that we really flush the old personality bits in the 'flush' stage, rather than later in the 'setup' stage, since otherwise we might be flushing the _new_ personality state that we're just setting up. So this moves the flags and personality flushing (and 'flush_thread()', which is the arch-specific function that generally resets lazy FP state etc) of the old process into flush_old_exec(), so that it doesn't affect any state that execve() is setting up for the new process environment. This was reported by Michal Simek as breaking his Microblaze qemu environment. Reported-and-tested-by: Michal Simek <michal.simek@petalogix.com> Cc: Peter Anvin <hpa@zytor.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-29Split 'flush_old_exec' into two functionsLinus Torvalds
'flush_old_exec()' is the point of no return when doing an execve(), and it is pretty badly misnamed. It doesn't just flush the old executable environment, it also starts up the new one. Which is very inconvenient for things like setting up the new personality, because we want the new personality to affect the starting of the new environment, but at the same time we do _not_ want the new personality to take effect if flushing the old one fails. As a result, the x86-64 '32-bit' personality is actually done using this insane "I'm going to change the ABI, but I haven't done it yet" bit (TIF_ABI_PENDING), with SET_PERSONALITY() not actually setting the personality, but just the "pending" bit, so that "flush_thread()" can do the actual personality magic. This patch in no way changes any of that insanity, but it does split the 'flush_old_exec()' function up into a preparatory part that can fail (still called flush_old_exec()), and a new part that will actually set up the new exec environment (setup_new_exec()). All callers are changed to trivially comply with the new world order. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-17mm: introduce coredump parameter structureMasami Hiramatsu
Introduce coredump parameter data structure (struct coredump_params) to simplify binfmt->core_dump() arguments. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Suggested-by: Ingo Molnar <mingo@elte.hu> Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-17do_wait() optimization: do not place sub-threads on task_struct->children listOleg Nesterov
Thanks to Roland who pointed out de_thread() issues. Currently we add sub-threads to ->real_parent->children list. This buys nothing but slows down do_wait(). With this patch ->children contains only main threads (group leaders). The only complication is that forget_original_parent() should iterate over sub-threads by hand, and de_thread() needs another list_replace() when it changes ->group_leader. Henceforth do_wait_thread() can never see task_detached() && !EXIT_DEAD tasks, we can remove this check (and we can unify do_wait_thread() and ptrace_do_wait()). This change can confuse the optimistic search in mm_update_next_owner(), but this is fixable and minor. Perhaps badness() and oom_kill_process() should be updated, but they should be fixed in any case. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Ratan Nalumasu <rnalumasu@gmail.com> Cc: Vitaly Mayatskikh <vmayatsk@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15procfs: allow threads to rename siblings via /proc/pid/tasks/tid/commjohn stultz
Setting a thread's comm to be something unique is a very useful ability and is helpful for debugging complicated threaded applications. However currently the only way to set a thread name is for the thread to name itself via the PR_SET_NAME prctl. However, there may be situations where it would be advantageous for a thread dispatcher to be naming the threads its managing, rather then having the threads self-describe themselves. This sort of behavior is available on other systems via the pthread_setname_np() interface. This patch exports a task's comm via proc/pid/comm and proc/pid/task/tid/comm interfaces, and allows thread siblings to write to these values. [akpm@linux-foundation.org: cleanups] Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Mike Fulton <fultonm@ca.ibm.com> Cc: Sean Foley <Sean_Foley@ca.ibm.com> Cc: Darren Hart <dvhltc@us.ibm.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-03Merge branch 'master' into nextJames Morris
2009-11-12exec: setup_arg_pages() fails to return errorsAnton Blanchard
In setup_arg_pages we work hard to assign a value to ret, but on exit we always return 0. Also remove a now duplicated exit path and branch to out_unlock instead. Signed-off-by: Anton Blanchard <anton@samba.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-25LSM: imbed ima calls in the security hooksMimi Zohar
Based on discussions on LKML and LSM, where there are consecutive security_ and ima_ calls in the vfs layer, move the ima_ calls to the existing security_ hooks. Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-09-24task_struct cleanup: move binfmt field to mm_structHiroshi Shimamoto
Because the binfmt is not different between threads in the same process, it can be moved from task_struct to mm_struct. And binfmt moudle is handled per mm_struct instead of task_struct. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24exec: fix set_binfmt() vs sys_delete_module() raceOleg Nesterov
sys_delete_module() can set MODULE_STATE_GOING after search_binary_handler() does try_module_get(). In this case set_binfmt()->try_module_get() fails but since none of the callers check the returned error, the task will run with the wrong old ->binfmt. The proper fix should change all ->load_binary() methods, but we can rely on fact that the caller must hold a reference to binfmt->module and use __module_get() which never fails. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24exec: allow do_coredump() to wait for user space pipe readers to completeNeil Horman
Allow core_pattern pipes to wait for user space to complete One of the things that user space processes like to do is look at metadata for a crashing process in their /proc/<pid> directory. this is racy however, since do_coredump in the kernel doesn't wait for the user space process to complete before it reaps the crashing process. This patch corrects that. Allowing the kernel to wait for the user space process to complete before cleaning up the crashing process. This is a bit tricky to do for a few reasons: 1) The user space process isn't our child, so we can't sys_wait4 on it 2) We need to close the pipe before waiting for the user process to complete, since the user process may rely on an EOF condition I've discussed several solutions with Oleg Nesterov off-list about this, and this is the one we've come up with. We add ourselves as a pipe reader (to prevent premature cleanup of the pipe_inode_info), and remove ourselves as a writer (to provide an EOF condition to the writer in user space), then we iterate until the user space process exits (which we detect by pipe->readers == 1, hence the > 1 check in the loop). When we exit the loop, we restore the proper reader/writer values, then we return and let filp_close in do_coredump clean up the pipe data properly. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Reported-by: Earl Chew <earl_chew@agilent.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Andi Kleen <andi@firstfloor.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24exec: let do_coredump() limit the number of concurrent dumps to pipesNeil Horman
Introduce core pipe limiting sysctl. Since we can dump cores to pipe, rather than directly to the filesystem, we create a condition in which a user can create a very high load on the system simply by running bad applications. If the pipe reader specified in core_pattern is poorly written, we can have lots of ourstandig resources and processes in the system. This sysctl introduces an ability to limit that resource consumption. core_pipe_limit defines how many in-flight dumps may be run in parallel, dumps beyond this value are skipped and a note is made in the kernel log. A special value of 0 in core_pipe_limit denotes unlimited core dumps may be handled (this is the default value). [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Reported-by: Earl Chew <earl_chew@agilent.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Andi Kleen <andi@firstfloor.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24exec: make do_coredump() more resilient to recursive crashesNeil Horman
Change how we detect recursive dumps. Currently we have a mechanism by which we try to compare pathnames of the crashing process to the core_pattern path. This is broken for a dozen reasons, and just doesn't work in any sort of robust way. I'm replacing it with the use of a 0 RLIMIT_CORE value. Since helper apps set RLIMIT_CORE to zero, we don't write out core files for any process with that particular limit set. It the core_pattern is a pipe, any non-zero limit is translated to RLIM_INFINITY. This allows complete dumps to be captured, but prevents infinite recursion in the event that the core_pattern process itself crashes. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Reported-by: Earl Chew <earl_chew@agilent.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Andi Kleen <andi@firstfloor.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-23procfs: provide stack information for threadsStefani Seibold
A patch to give a better overview of the userland application stack usage, especially for embedded linux. Currently you are only able to dump the main process/thread stack usage which is showed in /proc/pid/status by the "VmStk" Value. But you get no information about the consumed stack memory of the the threads. There is an enhancement in the /proc/<pid>/{task/*,}/*maps and which marks the vm mapping where the thread stack pointer reside with "[thread stack xxxxxxxx]". xxxxxxxx is the maximum size of stack. This is a value information, because libpthread doesn't set the start of the stack to the top of the mapped area, depending of the pthread usage. A sample output of /proc/<pid>/task/<tid>/maps looks like: 08048000-08049000 r-xp 00000000 03:00 8312 /opt/z 08049000-0804a000 rw-p 00001000 03:00 8312 /opt/z 0804a000-0806b000 rw-p 00000000 00:00 0 [heap] a7d12000-a7d13000 ---p 00000000 00:00 0 a7d13000-a7f13000 rw-p 00000000 00:00 0 [thread stack: 001ff4b4] a7f13000-a7f14000 ---p 00000000 00:00 0 a7f14000-a7f36000 rw-p 00000000 00:00 0 a7f36000-a8069000 r-xp 00000000 03:00 4222 /lib/libc.so.6 a8069000-a806b000 r--p 00133000 03:00 4222 /lib/libc.so.6 a806b000-a806c000 rw-p 00135000 03:00 4222 /lib/libc.so.6 a806c000-a806f000 rw-p 00000000 00:00 0 a806f000-a8083000 r-xp 00000000 03:00 14462 /lib/libpthread.so.0 a8083000-a8084000 r--p 00013000 03:00 14462 /lib/libpthread.so.0 a8084000-a8085000 rw-p 00014000 03:00 14462 /lib/libpthread.so.0 a8085000-a8088000 rw-p 00000000 00:00 0 a8088000-a80a4000 r-xp 00000000 03:00 8317 /lib/ld-linux.so.2 a80a4000-a80a5000 r--p 0001b000 03:00 8317 /lib/ld-linux.so.2 a80a5000-a80a6000 rw-p 0001c000 03:00 8317 /lib/ld-linux.so.2 afaf5000-afb0a000 rw-p 00000000 00:00 0 [stack] ffffe000-fffff000 r-xp 00000000 00:00 0 [vdso] Also there is a new entry "stack usage" in /proc/<pid>/{task/*,}/status which will you give the current stack usage in kb. A sample output of /proc/self/status looks like: Name: cat State: R (running) Tgid: 507 Pid: 507 . . . CapBnd: fffffffffffffeff voluntary_ctxt_switches: 0 nonvoluntary_ctxt_switches: 0 Stack usage: 12 kB I also fixed stack base address in /proc/<pid>/{task/*,}/stat to the base address of the associated thread stack and not the one of the main process. This makes more sense. [akpm@linux-foundation.org: fs/proc/array.c now needs walk_page_range()] Signed-off-by: Stefani Seibold <stefani@seibold.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-23getrusage: fill ru_maxrss valueJiri Pirko
Make ->ru_maxrss value in struct rusage filled accordingly to rss hiwater mark. This struct is filled as a parameter to getrusage syscall. ->ru_maxrss value is set to KBs which is the way it is done in BSD systems. /usr/bin/time (gnu time) application converts ->ru_maxrss to KBs which seems to be incorrect behavior. Maintainer of this util was notified by me with the patch which corrects it and cc'ed. To make this happen we extend struct signal_struct by two fields. The first one is ->maxrss which we use to store rss hiwater of the task. The second one is ->cmaxrss which we use to store highest rss hiwater of all task childs. These values are used in k_getrusage() to actually fill ->ru_maxrss. k_getrusage() uses current rss hiwater value directly if mm struct exists. Note: exec() clear mm->hiwater_rss, but doesn't clear sig->maxrss. it is intetionally behavior. *BSD getrusage have exec() inheriting. test programs ======================================================== getrusage.c =========== #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/time.h> #include <sys/resource.h> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #include <signal.h> #include <sys/mman.h> #include "common.h" #define err(str) perror(str), exit(1) int main(int argc, char** argv) { int status; printf("allocate 100MB\n"); consume(100); printf("testcase1: fork inherit? \n"); printf(" expect: initial.self ~= child.self\n"); show_rusage("initial"); if (__fork()) { wait(&status); } else { show_rusage("fork child"); _exit(0); } printf("\n"); printf("testcase2: fork inherit? (cont.) \n"); printf(" expect: initial.children ~= 100MB, but child.children = 0\n"); show_rusage("initial"); if (__fork()) { wait(&status); } else { show_rusage("child"); _exit(0); } printf("\n"); printf("testcase3: fork + malloc \n"); printf(" expect: child.self ~= initial.self + 50MB\n"); show_rusage("initial"); if (__fork()) { wait(&status); } else { printf("allocate +50MB\n"); consume(50); show_rusage("fork child"); _exit(0); } printf("\n"); printf("testcase4: grandchild maxrss\n"); printf(" expect: post_wait.children ~= 300MB\n"); show_rusage("initial"); if (__fork()) { wait(&status); show_rusage("post_wait"); } else { system("./child -n 0 -g 300"); _exit(0); } printf("\n"); printf("testcase5: zombie\n"); printf(" expect: pre_wait ~= initial, IOW the zombie process is not accounted.\n"); printf(" post_wait ~= 400MB, IOW wait() collect child's max_rss. \n"); show_rusage("initial"); if (__fork()) { sleep(1); /* children become zombie */ show_rusage("pre_wait"); wait(&status); show_rusage("post_wait"); } else { system("./child -n 400"); _exit(0); } printf("\n"); printf("testcase6: SIG_IGN\n"); printf(" expect: initial ~= after_zombie (child's 500MB alloc should be ignored).\n"); show_rusage("initial"); signal(SIGCHLD, SIG_IGN); if (__fork()) { sleep(1); /* children become zombie */ show_rusage("after_zombie"); } else { system("./child -n 500"); _exit(0); } printf("\n"); signal(SIGCHLD, SIG_DFL); printf("testcase7: exec (without fork) \n"); printf(" expect: initial ~= exec \n"); show_rusage("initial"); execl("./child", "child", "-v", NULL); return 0; } child.c ======= #include <sys/types.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/time.h> #include <sys/resource.h> #include "common.h" int main(int argc, char** argv) { int status; int c; long consume_size = 0; long grandchild_consume_size = 0; int show = 0; while ((c = getopt(argc, argv, "n:g:v")) != -1) { switch (c) { case 'n': consume_size = atol(optarg); break; case 'v': show = 1; break; case 'g': grandchild_consume_size = atol(optarg); break; default: break; } } if (show) show_rusage("exec"); if (consume_size) { printf("child alloc %ldMB\n", consume_size); consume(consume_size); } if (grandchild_consume_size) { if (fork()) { wait(&status); } else { printf("grandchild alloc %ldMB\n", grandchild_consume_size); consume(grandchild_consume_size); exit(0); } } return 0; } common.c ======== #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/time.h> #include <sys/resource.h> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #include <signal.h> #include <sys/mman.h> #include "common.h" #define err(str) perror(str), exit(1) void show_rusage(char *prefix) { int err, err2; struct rusage rusage_self; struct rusage rusage_children; printf("%s: ", prefix); err = getrusage(RUSAGE_SELF, &rusage_self); if (!err) printf("self %ld ", rusage_self.ru_maxrss); err2 = getrusage(RUSAGE_CHILDREN, &rusage_children); if (!err2) printf("children %ld ", rusage_children.ru_maxrss); printf("\n"); } /* Some buggy OS need this worthless CPU waste. */ void make_pagefault(void) { void *addr; int size = getpagesize(); int i; for (i=0; i<1000; i++) { addr = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); if (addr == MAP_FAILED) err("make_pagefault"); memset(addr, 0, size); munmap(addr, size); } } void consume(int mega) { size_t sz = mega * 1024 * 1024; void *ptr; ptr = malloc(sz); memset(ptr, 0, sz); make_pagefault(); } pid_t __fork(void) { pid_t pid; pid = fork(); make_pagefault(); return pid; } common.h ======== void show_rusage(char *prefix); void make_pagefault(void); void consume(int mega); pid_t __fork(void); FreeBSD result (expected result) ======================================================== allocate 100MB testcase1: fork inherit? expect: initial.self ~= child.self initial: self 103492 children 0 fork child: self 103540 children 0 testcase2: fork inherit? (cont.) expect: initial.children ~= 100MB, but child.children = 0 initial: self 103540 children 103540 child: self 103564 children 0 testcase3: fork + malloc expect: child.self ~= initial.self + 50MB initial: self 103564 children 103564 allocate +50MB fork child: self 154860 children 0 testcase4: grandchild maxrss expect: post_wait.children ~= 300MB initial: self 103564 children 154860 grandchild alloc 300MB post_wait: self 103564 children 308720 testcase5: zombie expect: pre_wait ~= initial, IOW the zombie process is not accounted. post_wait ~= 400MB, IOW wait() collect child's max_rss. initial: self 103564 children 308720 child alloc 400MB pre_wait: self 103564 children 308720 post_wait: self 103564 children 411312 testcase6: SIG_IGN expect: initial ~= after_zombie (child's 500MB alloc should be ignored). initial: self 103564 children 411312 child alloc 500MB after_zombie: self 103624 children 411312 testcase7: exec (without fork) expect: initial ~= exec initial: self 103624 children 411312 exec: self 103624 children 411312 Linux result (actual test result) ======================================================== allocate 100MB testcase1: fork inherit? expect: initial.self ~= child.self initial: self 102848 children 0 fork child: self 102572 children 0 testcase2: fork inherit? (cont.) expect: initial.children ~= 100MB, but child.children = 0 initial: self 102876 children 102644 child: self 102572 children 0 testcase3: fork + malloc expect: child.self ~= initial.self + 50MB initial: self 102876 children 102644 allocate +50MB fork child: self 153804 children 0 testcase4: grandchild maxrss expect: post_wait.children ~= 300MB initial: self 102876 children 153864 grandchild alloc 300MB post_wait: self 102876 children 307536 testcase5: zombie expect: pre_wait ~= initial, IOW the zombie process is not accounted. post_wait ~= 400MB, IOW wait() collect child's max_rss. initial: self 102876 children 307536 child alloc 400MB pre_wait: self 102876 children 307536 post_wait: self 102876 children 410076 testcase6: SIG_IGN expect: initial ~= after_zombie (child's 500MB alloc should be ignored). initial: self 102876 children 410076 child alloc 500MB after_zombie: self 102880 children 410076 testcase7: exec (without fork) expect: initial ~= exec initial: self 102880 children 410076 exec: self 102880 children 410076 Signed-off-by: Jiri Pirko <jpirko@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-21perf: Do the big rename: Performance Counters -> Performance EventsIngo Molnar
Bye-bye Performance Counters, welcome Performance Events! In the past few months the perfcounters subsystem has grown out its initial role of counting hardware events, and has become (and is becoming) a much broader generic event enumeration, reporting, logging, monitoring, analysis facility. Naming its core object 'perf_counter' and naming the subsystem 'perfcounters' has become more and more of a misnomer. With pending code like hw-breakpoints support the 'counter' name is less and less appropriate. All in one, we've decided to rename the subsystem to 'performance events' and to propagate this rename through all fields, variables and API names. (in an ABI compatible fashion) The word 'event' is also a bit shorter than 'counter' - which makes it slightly more convenient to write/handle as well. Thanks goes to Stephane Eranian who first observed this misnomer and suggested a rename. User-space tooling and ABI compatibility is not affected - this patch should be function-invariant. (Also, defconfigs were not touched to keep the size down.) This patch has been generated via the following script: FILES=$(find * -type f | grep -vE 'oprofile|[^K]config') sed -i \ -e 's/PERF_EVENT_/PERF_RECORD_/g' \ -e 's/PERF_COUNTER/PERF_EVENT/g' \ -e 's/perf_counter/perf_event/g' \ -e 's/nb_counters/nb_events/g' \ -e 's/swcounter/swevent/g' \ -e 's/tpcounter_event/tp_event/g' \ $FILES for N in $(find . -name perf_counter.[ch]); do M=$(echo $N | sed 's/perf_counter/perf_event/g') mv $N $M done FILES=$(find . -name perf_event.*) sed -i \ -e 's/COUNTER_MASK/REG_MASK/g' \ -e 's/COUNTER/EVENT/g' \ -e 's/\<event\>/event_id/g' \ -e 's/counter/event/g' \ -e 's/Counter/Event/g' \ $FILES ... to keep it as correct as possible. This script can also be used by anyone who has pending perfcounters patches - it converts a Linux kernel tree over to the new naming. We tried to time this change to the point in time where the amount of pending patches is the smallest: the end of the merge window. Namespace clashes were fixed up in a preparatory patch - and some stylistic fallout will be fixed up in a subsequent patch. ( NOTE: 'counters' are still the proper terminology when we deal with hardware registers - and these sed scripts are a bit over-eager in renaming them. I've undone some of that, but in case there's something left where 'counter' would be better than 'event' we can undo that on an individual basis instead of touching an otherwise nicely automated patch. ) Suggested-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Paul Mackerras <paulus@samba.org> Reviewed-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Howells <dhowells@redhat.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <linux-arch@vger.kernel.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-05exec: do not sleep in TASK_TRACED under ->cred_guard_mutexOleg Nesterov
Tom Horsley reports that his debugger hangs when it tries to read /proc/pid_of_tracee/maps, this happens since "mm_for_maps: take ->cred_guard_mutex to fix the race with exec" 04b836cbf19e885f8366bccb2e4b0474346c02d commit in 2.6.31. But the root of the problem lies in the fact that do_execve() path calls tracehook_report_exec() which can stop if the tracer sets PT_TRACE_EXEC. The tracee must not sleep in TASK_TRACED holding this mutex. Even if we remove ->cred_guard_mutex from mm_for_maps() and proc_pid_attr_write(), another task doing PTRACE_ATTACH should not hang until it is killed or the tracee resumes. With this patch do_execve() does not use ->cred_guard_mutex directly and we do not hold it throughout, instead: - introduce prepare_bprm_creds() helper, it locks the mutex and calls prepare_exec_creds() to initialize bprm->cred. - install_exec_creds() drops the mutex after commit_creds(), and thus before tracehook_report_exec()->ptrace_stop(). or, if exec fails, free_bprm() drops this mutex when bprm->cred != NULL which indicates install_exec_creds() was not called. Reported-by: Tom Horsley <tom.horsley@att.net> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-24kernel_read: redefine offset typeMimi Zohar
vfs_read() offset is defined as loff_t, but kernel_read() offset is only defined as unsigned long. Redefine kernel_read() offset as loff_t. Cc: stable@kernel.org Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-07-06cred_guard_mutex: do not return -EINTR to user-spaceOleg Nesterov
do_execve() and ptrace_attach() return -EINTR if mutex_lock_interruptible(->cred_guard_mutex) fails. This is not right, change the code to return ERESTARTNOINTR. Perhaps we should also change proc_pid_attr_write(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: David Howells <dhowells@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11Merge branch 'perfcounters-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perfcounters-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (574 commits) perf_counter: Turn off by default perf_counter: Add counter->id to the throttle event perf_counter: Better align code perf_counter: Rename L2 to LL cache perf_counter: Standardize event names perf_counter: Rename enums perf_counter tools: Clean up u64 usage perf_counter: Rename perf_counter_limit sysctl perf_counter: More paranoia settings perf_counter: powerpc: Implement generalized cache events for POWER processors perf_counters: powerpc: Add support for POWER7 processors perf_counter: Accurate period data perf_counter: Introduce struct for sample data perf_counter tools: Normalize data using per sample period data perf_counter: Annotate exit ctx recursion perf_counter tools: Propagate signals properly perf_counter tools: Small frequency related fixes perf_counter: More aggressive frequency adjustment perf_counter/x86: Fix the model number of Intel Core2 processors perf_counter, x86: Correct some event and umask values for Intel processors ...
2009-05-22Merge branch 'master' into nextJames Morris
Conflicts: fs/exec.c Removed IMA changes (the IMA checks are now performed via may_open()). Signed-off-by: James Morris <jmorris@namei.org>
2009-05-22integrity: path_check updateMimi Zohar
- Add support in ima_path_check() for integrity checking without incrementing the counts. (Required for nfsd.) - rename and export opencount_get to ima_counts_get - replace ima_shm_check calls with ima_counts_get - export ima_path_check Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-05-18Merge commit 'v2.6.30-rc6' into perfcounters/coreIngo Molnar
Merge reason: this branch was on an -rc4 base, merge it up to -rc6 to get the latest upstream fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-11CRED: Rename cred_exec_mutex to reflect that it's a guard against ptraceDavid Howells
Rename cred_exec_mutex to reflect that it's a guard against foreign intervention on a process's credential state, such as is made by ptrace(). The attachment of a debugger to a process affects execve()'s calculation of the new credential state - _and_ also setprocattr()'s calculation of that state. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-05-09Switch open_exec() and sys_uselib() to do_open_filp()Al Viro
... and make path_lookup_open() static Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-05-09Make open_exec() and sys_uselib() use may_open(), instead of duplicating its ↵Al Viro
parts Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-05-02alpha: binfmt_aout fixIvan Kokshaysky
This fixes the problem introduced by commit 3bfacef412 (get rid of special-casing the /sbin/loader on alpha): osf/1 ecoff binary segfaults when binfmt_aout built as module. That happens because aout binary handler gets on the top of the binfmt list due to late registration, and kernel attempts to execute the binary without preparatory work that must be done by binfmt_loader. Fixed by changing the registration order of the default binfmt handlers using list_add_tail() and introducing insert_binfmt() function which places new handler on the top of the binfmt list. This might be generally useful for installing arch-specific frontends for default handlers or just for overriding them. Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Richard Henderson <rth@twiddle.net Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-29Merge branch 'linus' into perfcounters/coreIngo Molnar
Merge reason: This brach was on -rc1, refresh it to almost-rc4 to pick up the latest upstream fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-24check_unsafe_exec: s/lock_task_sighand/rcu_read_lock/Oleg Nesterov
write_lock(&current->fs->lock) guarantees we can't wrongly miss LSM_UNSAFE_SHARE, this is what we care about. Use rcu_read_lock() instead of ->siglock to iterate over the sub-threads. We must see all CLONE_THREAD|CLONE_FS threads which didn't pass exit_fs(), it takes fs->lock too. With or without this patch we can miss the freshly cloned thread and set LSM_UNSAFE_SHARE, we don't care. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> [ Fixed lock/unlock typo - Hugh ] Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-24do_execve() must not clear fs->in_exec if it was set by another threadOleg Nesterov
If do_execve() fails after check_unsafe_exec(), it clears fs->in_exec unconditionally. This is wrong if we race with our sub-thread which also does do_execve: Two threads T1 and T2 and another process P, all share the same ->fs. T1 starts do_execve(BAD_FILE). It calls check_unsafe_exec(), since ->fs is shared, we set LSM_UNSAFE but not ->in_exec. P exits and decrements fs->users. T2 starts do_execve(), calls check_unsafe_exec(), now ->fs is not shared, we set fs->in_exec. T1 continues, open_exec(BAD_FILE) fails, we clear ->in_exec and return to the user-space. T1 does clone(CLONE_FS /* without CLONE_THREAD */). T2 continues without LSM_UNSAFE_SHARE while ->fs is shared with another process. Change check_unsafe_exec() to return res = 1 if we set ->in_exec, and change do_execve() to clear ->in_exec depending on res. When do_execve() suceeds, it is safe to clear ->in_exec unconditionally. It can be set only if we don't share ->fs with another process, and since we already killed all sub-threads either ->in_exec == 0 or we are the only user of this ->fs. Also, we do not need fs->lock to clear fs->in_exec. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-08perf_counter: track task-comm dataPeter Zijlstra
Similar to the mmap data stream, add one that tracks the task COMM field, so that the userspace reporting knows what to call a task. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> LKML-Reference: <20090408130409.127422406@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-06Merge branch 'linus' into perfcounters/core-v2Ingo Molnar
Merge reason: we have gathered quite a few conflicts, need to merge upstream Conflicts: arch/powerpc/kernel/Makefile arch/x86/ia32/ia32entry.S arch/x86/include/asm/hardirq.h arch/x86/include/asm/unistd_32.h arch/x86/include/asm/unistd_64.h arch/x86/kernel/cpu/common.c arch/x86/kernel/irq.c arch/x86/kernel/syscall_table_32.S arch/x86/mm/iomap_32.c include/linux/sched.h kernel/Makefile Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-31Get rid of indirect include of fs_struct.hAl Viro
Don't pull it in sched.h; very few files actually need it and those can include directly. sched.h itself only needs forward declaration of struct fs_struct; Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-31check_unsafe_exec() doesn't care about signal handlers sharingAl Viro
... since we'll unshare sighand anyway Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-31New locking/refcounting for fs_structAl Viro
* all changes of current->fs are done under task_lock and write_lock of old fs->lock * refcount is not atomic anymore (same protection) * its decrements are done when removing reference from current; at the same time we decide whether to free it. * put_fs_struct() is gone * new field - ->in_exec. Set by check_unsafe_exec() if we are trying to do execve() and only subthreads share fs_struct. Cleared when finishing exec (success and failure alike). Makes CLONE_FS fail with -EAGAIN if set. * check_unsafe_exec() may fail with -EAGAIN if another execve() from subthread is in progress. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-28fix setuid sometimes doesn'tHugh Dickins
Joe Malicki reports that setuid sometimes doesn't: very rarely, a setuid root program does not get root euid; and, by the way, they have a health check running lsof every few minutes. Right, check_unsafe_exec() notes whether the files_struct is being shared by more threads than will get killed by the exec, and if so sets LSM_UNSAFE_SHARE to make bprm_set_creds() careful about euid. But /proc/<pid>/fd and /proc/<pid>/fdinfo lookups make transient use of get_files_struct(), which also raises that sharing count. There's a rather simple fix for this: exec's check on files->count has been redundant ever since 2.6.1 made it unshare_files() (except while compat_do_execve() omitted to do so) - just remove that check. [Note to -stable: this patch will not apply before 2.6.29: earlier releases should just remove the files->count line from unsafe_exec().] Reported-by: Joe Malicki <jmalicki@metacarta.com> Narrowed-down-by: Michael Itz <mitz@metacarta.com> Tested-by: Joe Malicki <jmalicki@metacarta.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-03-24Merge branch 'master' into nextJames Morris
2009-02-12Add in_execve flag into task_struct.Kentaro Takeda
This patch allows LSM modules to determine whether current process is in an execve operation or not so that they can behave differently while an execve operation is in progress. This patch is needed by TOMOYO. Please see another patch titled "LSM adapter functions." for backgrounds. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
2009-02-11Merge commit 'v2.6.29-rc4' into perfcounters/coreIngo Molnar
Conflicts: arch/x86/kernel/setup_percpu.c arch/x86/mm/fault.c drivers/acpi/processor_idle.c kernel/irq/handle.c
2009-02-07CRED: Fix SUID exec regressionDavid Howells
The patch: commit a6f76f23d297f70e2a6b3ec607f7aeeea9e37e8d CRED: Make execve() take advantage of copy-on-write credentials moved the place in which the 'safeness' of a SUID/SGID exec was performed to before de_thread() was called. This means that LSM_UNSAFE_SHARE is now calculated incorrectly. This flag is set if any of the usage counts for fs_struct, files_struct and sighand_struct are greater than 1 at the time the determination is made. All of which are true for threads created by the pthread library. However, since we wish to make the security calculation before irrevocably damaging the process so that we can return it an error code in the case where we decide we want to reject the exec request on this basis, we have to make the determination before calling de_thread(). So, instead, we count up the number of threads (CLONE_THREAD) that are sharing our fs_struct (CLONE_FS), files_struct (CLONE_FILES) and sighand_structs (CLONE_SIGHAND/CLONE_THREAD) with us. These will be killed by de_thread() and so can be discounted by check_unsafe_exec(). We do have to be careful because CLONE_THREAD does not imply FS or FILES. We _assume_ that there will be no extra references to these structs held by the threads we're going to kill. This can be tested with the attached pair of programs. Build the two programs using the Makefile supplied, and run ./test1 as a non-root user. If successful, you should see something like: [dhowells@andromeda tmp]$ ./test1 --TEST1-- uid=4043, euid=4043 suid=4043 exec ./test2 --TEST2-- uid=4043, euid=0 suid=0 SUCCESS - Correct effective user ID and if unsuccessful, something like: [dhowells@andromeda tmp]$ ./test1 --TEST1-- uid=4043, euid=4043 suid=4043 exec ./test2 --TEST2-- uid=4043, euid=4043 suid=4043 ERROR - Incorrect effective user ID! The non-root user ID you see will depend on the user you run as. [test1.c] #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <pthread.h> static void *thread_func(void *arg) { while (1) {} } int main(int argc, char **argv) { pthread_t tid; uid_t uid, euid, suid; printf("--TEST1--\n"); getresuid(&uid, &euid, &suid); printf("uid=%d, euid=%d suid=%d\n", uid, euid, suid); if (pthread_create(&tid, NULL, thread_func, NULL) < 0) { perror("pthread_create"); exit(1); } printf("exec ./test2\n"); execlp("./test2", "test2", NULL); perror("./test2"); _exit(1); } [test2.c] #include <stdio.h> #include <stdlib.h> #include <unistd.h> int main(int argc, char **argv) { uid_t uid, euid, suid; getresuid(&uid, &euid, &suid); printf("--TEST2--\n"); printf("uid=%d, euid=%d suid=%d\n", uid, euid, suid); if (euid != 0) { fprintf(stderr, "ERROR - Incorrect effective user ID!\n"); exit(1); } printf("SUCCESS - Correct effective user ID\n"); exit(0); } [Makefile] CFLAGS = -D_GNU_SOURCE -Wall -Werror -Wunused all: test1 test2 test1: test1.c gcc $(CFLAGS) -o test1 test1.c -lpthread test2: test2.c gcc $(CFLAGS) -o test2 test2.c sudo chown root.root test2 sudo chmod +s test2 Reported-by: David Smith <dsmith@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: David Smith <dsmith@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>