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2009-12-17sched: Assert task state bits at build timePeter Zijlstra
Since everybody is lazy and prone to forgetting things, make the compiler help us a bit. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20091217121830.060186433@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-17sched: Update task_state_arraypwith new statesPeter Zijlstra
Neglected because its hidden... (who reads comments anyway) Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20091217121829.970166036@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-05Merge branch 'sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (35 commits) sched, cputime: Introduce thread_group_times() sched, cputime: Cleanups related to task_times() Revert "sched, x86: Optimize branch hint in __switch_to()" sched: Fix isolcpus boot option sched: Revert 498657a478c60be092208422fefa9c7b248729c2 sched, time: Define nsecs_to_jiffies() sched: Remove task_{u,s,g}time() sched: Introduce task_times() to replace task_{u,s}time() pair sched: Limit the number of scheduler debug messages sched.c: Call debug_show_all_locks() when dumping all tasks sched, x86: Optimize branch hint in __switch_to() sched: Optimize branch hint in context_switch() sched: Optimize branch hint in pick_next_task_fair() sched_feat_write(): Update ppos instead of file->f_pos sched: Sched_rt_periodic_timer vs cpu hotplug sched, kvm: Fix race condition involving sched_in_preempt_notifers sched: More generic WAKE_AFFINE vs select_idle_sibling() sched: Cleanup select_task_rq_fair() sched: Fix granularity of task_u/stime() sched: Fix/add missing update_rq_clock() calls ...
2009-12-02sched, cputime: Introduce thread_group_times()Hidetoshi Seto
This is a real fix for problem of utime/stime values decreasing described in the thread: http://lkml.org/lkml/2009/11/3/522 Now cputime is accounted in the following way: - {u,s}time in task_struct are increased every time when the thread is interrupted by a tick (timer interrupt). - When a thread exits, its {u,s}time are added to signal->{u,s}time, after adjusted by task_times(). - When all threads in a thread_group exits, accumulated {u,s}time (and also c{u,s}time) in signal struct are added to c{u,s}time in signal struct of the group's parent. So {u,s}time in task struct are "raw" tick count, while {u,s}time and c{u,s}time in signal struct are "adjusted" values. And accounted values are used by: - task_times(), to get cputime of a thread: This function returns adjusted values that originates from raw {u,s}time and scaled by sum_exec_runtime that accounted by CFS. - thread_group_cputime(), to get cputime of a thread group: This function returns sum of all {u,s}time of living threads in the group, plus {u,s}time in the signal struct that is sum of adjusted cputimes of all exited threads belonged to the group. The problem is the return value of thread_group_cputime(), because it is mixed sum of "raw" value and "adjusted" value: group's {u,s}time = foreach(thread){{u,s}time} + exited({u,s}time) This misbehavior can break {u,s}time monotonicity. Assume that if there is a thread that have raw values greater than adjusted values (e.g. interrupted by 1000Hz ticks 50 times but only runs 45ms) and if it exits, cputime will decrease (e.g. -5ms). To fix this, we could do: group's {u,s}time = foreach(t){task_times(t)} + exited({u,s}time) But task_times() contains hard divisions, so applying it for every thread should be avoided. This patch fixes the above problem in the following way: - Modify thread's exit (= __exit_signal()) not to use task_times(). It means {u,s}time in signal struct accumulates raw values instead of adjusted values. As the result it makes thread_group_cputime() to return pure sum of "raw" values. - Introduce a new function thread_group_times(*task, *utime, *stime) that converts "raw" values of thread_group_cputime() to "adjusted" values, in same calculation procedure as task_times(). - Modify group's exit (= wait_task_zombie()) to use this introduced thread_group_times(). It make c{u,s}time in signal struct to have adjusted values like before this patch. - Replace some thread_group_cputime() by thread_group_times(). This replacements are only applied where conveys the "adjusted" cputime to users, and where already uses task_times() near by it. (i.e. sys_times(), getrusage(), and /proc/<PID>/stat.) This patch have a positive side effect: - Before this patch, if a group contains many short-life threads (e.g. runs 0.9ms and not interrupted by ticks), the group's cputime could be invisible since thread's cputime was accumulated after adjusted: imagine adjustment function as adj(ticks, runtime), {adj(0, 0.9) + adj(0, 0.9) + ....} = {0 + 0 + ....} = 0. After this patch it will not happen because the adjustment is applied after accumulated. v2: - remove if()s, put new variables into signal_struct. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Spencer Candland <spencer@bluehost.com> Cc: Americo Wang <xiyou.wangcong@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> LKML-Reference: <4B162517.8040909@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-26sched: Remove task_{u,s,g}time()Hidetoshi Seto
Now all task_{u,s}time() pairs are replaced by task_times(). And task_gtime() is too simple to be an inline function. Cleanup them all. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Spencer Candland <spencer@bluehost.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Americo Wang <xiyou.wangcong@gmail.com> LKML-Reference: <4B0E16D1.70902@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-26sched: Introduce task_times() to replace task_{u,s}time() pairHidetoshi Seto
Functions task_{u,s}time() are called in pair in almost all cases. However task_stime() is implemented to call task_utime() from its inside, so such paired calls run task_utime() twice. It means we do heavy divisions (div_u64 + do_div) twice to get utime and stime which can be obtained at same time by one set of divisions. This patch introduces a function task_times(*tsk, *utime, *stime) to retrieve utime and stime at once in better, optimized way. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Spencer Candland <spencer@bluehost.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Americo Wang <xiyou.wangcong@gmail.com> LKML-Reference: <4B0E16AE.906@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-17procfs: fix /proc/<pid>/stat stack pointer for kernel threadsStefani Seibold
Fix a small issue for the stack pointer in /proc/<pid>/stat. In case of a kernel thread the value of the printed stack pointer should be 0. Signed-off-by: Stefani Seibold <stefani@seibold.net> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-10-25Merge branch 'linus' into sched/coreIngo Molnar
Conflicts: fs/proc/array.c Merge reason: resolve conflict and queue up dependent patch. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-24procfs: disable per-task stack usage on NOMMUAndrew Morton
It needs walk_page_range(). Reported-by: Michal Simek <monstr@monstr.eu> Tested-by: Michal Simek <monstr@monstr.eu> Cc: Stefani Seibold <stefani@seibold.net> Cc: David Howells <dhowells@redhat.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greg Ungerer <gerg@snapgear.com> 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>
2009-09-21sched: Always show Cpus_allowed field in /proc/<pid>/statusHeiko Carstens
The Cpus_allowed fields in /proc/<pid>/status is currently only shown in case of CONFIG_CPUSETS. However their contents are also useful for the !CONFIG_CPUSETS case. So change the current behaviour and always show these fields. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090921090627.GD4649@osiris.boeblingen.de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-04proc: avoid information leaks to non-privileged processesJake Edge
By using the same test as is used for /proc/pid/maps and /proc/pid/smaps, only allow processes that can ptrace() a given process to see information that might be used to bypass address space layout randomization (ASLR). These include eip, esp, wchan, and start_stack in /proc/pid/stat as well as the non-symbolic output from /proc/pid/wchan. ASLR can be bypassed by sampling eip as shown by the proof-of-concept code at http://code.google.com/p/fuzzyaslr/ As part of a presentation (http://www.cr0.org/paper/to-jt-linux-alsr-leak.pdf) esp and wchan were also noted as possibly usable information leaks as well. The start_stack address also leaks potentially useful information. Cc: Stable Team <stable@kernel.org> Signed-off-by: Jake Edge <jake@lwn.net> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
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 <marc.c.dionne@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
2008-10-27Switch to a valid email address...Alan Cox
Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20Merge branches 'timers/clocksource', 'timers/hrtimers', 'timers/nohz', ↵Thomas Gleixner
'timers/ntp', 'timers/posixtimers' and 'timers/debug' into v28-timers-for-linus
2008-10-10proc: remove now unneeded ADDBUF macroAlexey Dobriyan
After local seq_file conversion it was forgotten. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2008-10-10[PATCH] signal, procfs: some lock_task_sighand() users do not need ↵Lai Jiangshan
rcu_read_lock() lock_task_sighand() make sure task->sighand is being protected, so we do not need rcu_read_lock(). [ exec() will get task->sighand->siglock before change task->sighand! ] But code using rcu_read_lock() _just_ to protect lock_task_sighand() only appear in procfs. (and some code in procfs use lock_task_sighand() without such redundant protection.) Other subsystem may put lock_task_sighand() into rcu_read_lock() critical region, but these rcu_read_lock() are used for protecting "for_each_process()", "find_task_by_vpid()" etc. , not for protecting lock_task_sighand(). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> [ok from Oleg] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
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 <fmayhar@google.com> Cc: Roland McGrath <roland@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-05sched: fix process time monotonicityBalbir Singh
Spencer reported a problem where utime and stime were going negative despite the fixes in commit b27f03d4bdc145a09fb7b0c0e004b29f1ee555fa. The suspected reason for the problem is that signal_struct maintains it's own utime and stime (of exited tasks), these are not updated using the new task_utime() routine, hence sig->utime can go backwards and cause the same problem to occur (sig->utime, adds tsk->utime and not task_utime()). This patch fixes the problem TODO: using max(task->prev_utime, derived utime) works for now, but a more generic solution is to implement cputime_max() and use the cputime_gt() function for comparison. Reported-by: spencer@bluehost.com Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-26tracehook: tracehook_tracer_taskRoland McGrath
This adds the tracehook_tracer_task() hook to consolidate all forms of "Who is using ptrace on me?" logic. This is used for "TracerPid:" in /proc and for permission checks. We also clean up the selinux code the called an identical accessor. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Reviewed-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-31capabilities: remain source compatible with 32-bit raw legacy capability ↵Andrew G. Morgan
support. Source code out there hard-codes a notion of what the _LINUX_CAPABILITY_VERSION #define means in terms of the semantics of the raw capability system calls capget() and capset(). Its unfortunate, but true. Since the confusing header file has been in a released kernel, there is software that is erroneously using 64-bit capabilities with the semantics of 32-bit compatibilities. These recently compiled programs may suffer corruption of their memory when sys_getcap() overwrites more memory than they are coded to expect, and the raising of added capabilities when using sys_capset(). As such, this patch does a number of things to clean up the situation for all. It 1. forces the _LINUX_CAPABILITY_VERSION define to always retain its legacy value. 2. adopts a new #define strategy for the kernel's internal implementation of the preferred magic. 3. deprecates v2 capability magic in favor of a new (v3) magic number. The functionality of v3 is entirely equivalent to v2, the only difference being that the v2 magic causes the kernel to log a "deprecated" warning so the admin can find applications that may be using v2 inappropriately. [User space code continues to be encouraged to use the libcap API which protects the application from details like this. libcap-2.10 is the first to support v3 capabilities.] Fixes issue reported in https://bugzilla.redhat.com/show_bug.cgi?id=447518. Thanks to Bojan Smojver for the report. [akpm@linux-foundation.org: s/depreciate/deprecate/g] [akpm@linux-foundation.org: be robust about put_user size] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrew G. Morgan <morgan@kernel.org> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: Bojan Smojver <bojan@rexursive.com> Cc: stable@kernel.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
2008-05-13capabilities: add bounding set to /proc/self/statusSerge E. Hallyn
There is currently no way to query the bounding set of another task. As there appears to be no security reason not to, and as Michael Kerrisk points out the following valid reasons to do so exist: * consistency (I can see all of the other per-thread/process sets in /proc/.../status) * debugging -- I could imagine that it would make the job of debugging an application that uses capabilities a little simpler. this patch adds the bounding set to /proc/self/status right after the effective set. Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Andrew G. Morgan <morgan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-01[PATCH] split linux/file.hAl Viro
Initial splitoff of the low-level stuff; taken to fdtable.h Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-30tty_io: fix remaining pid struct lockingAlan Cox
This fixes the last couple of pid struct locking failures I know about. [oleg@tv-sign.ru: clean up do_task_stat()] Signed-off-by: Alan Cox <alan@redhat.com> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30do_task_stat: don't take rcu_read_lock()Oleg Nesterov
lock_task_sighand() was changed, and do_task_stat() doesn't need rcu_read_lock any longer. sighand->siglock protects all "interesting" fields. Except: it doesn't protect ->tty->pgrp, but neither does rcu_read_lock(), this should be fixed. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Roland McGrath <roland@redhat.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Pavel Emelyanov <xemul@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08proc: seqfile convert proc_pid_status to properly handle pid namespacesEric W. Biederman
Currently we possibly lookup the pid in the wrong pid namespace. So seq_file convert proc_pid_status which ensures the proper pid namespaces is passed in. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: another build fix] [akpm@linux-foundation.org: s390 build fix] [akpm@linux-foundation.org: fix task_name() output] [akpm@linux-foundation.org: fix nommu build] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Andrew Morgan <morgan@kernel.org> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.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>
2008-02-08seqfile convert proc_pid_statmEric W. Biederman
This conversion is just for code cleanliness, uniformity, and general safety. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-08proc: rewrite do_task_stat to correctly handle pid namespaces.Eric W. Biederman
Currently (as pointed out by Oleg) do_task_stat has a race when calling task_pid_nr_ns with the task exiting. In addition do_task_stat is not currently displaying information in the context of the pid namespace that mounted the /proc filesystem. So "cut -d' ' -f 1 /proc/<pid>/stat" may not equal <pid>. This patch fixes the problem by converting to a single_open seq_file show method. Getting the pid namespace from the filesystem superblock instead of current, and simply using the the struct pid from the inode instead of attempting to get that same pid from the task. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05Add 64-bit capability support to the kernelAndrew Morgan
The patch supports legacy (32-bit) capability userspace, and where possible translates 32-bit capabilities to/from userspace and the VFS to 64-bit kernel space capabilities. If a capability set cannot be compressed into 32-bits for consumption by user space, the system call fails, with -ERANGE. FWIW libcap-2.00 supports this change (and earlier capability formats) http://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/ [akpm@linux-foundation.org: coding-syle fixes] [akpm@linux-foundation.org: use get_task_comm()] [ezk@cs.sunysb.edu: build fix] [akpm@linux-foundation.org: do not initialise statics to 0 or NULL] [akpm@linux-foundation.org: unused var] [serue@us.ibm.com: export __cap_ symbols] Signed-off-by: Andrew G. Morgan <morgan@kernel.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: James Morris <jmorris@namei.org> Cc: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-01Merge branch 'task_killable' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc * 'task_killable' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc: (22 commits) Remove commented-out code copied from NFS NFS: Switch from intr mount option to TASK_KILLABLE Add wait_for_completion_killable Add wait_event_killable Add schedule_timeout_killable Use mutex_lock_killable in vfs_readdir Add mutex_lock_killable Use lock_page_killable Add lock_page_killable Add fatal_signal_pending Add TASK_WAKEKILL exit: Use task_is_* signal: Use task_is_* sched: Use task_contributes_to_load, TASK_ALL and TASK_NORMAL ptrace: Use task_is_* power: Use task_is_* wait: Use TASK_NORMAL proc/base.c: Use task_is_* proc/array.c: Use TASK_REPORT perfmon: Use task_is_* ... Fixed up conflicts in NFS/sunrpc manually..
2008-01-14fix the "remove task_ppid_nr_ns" commitOleg Nesterov
Commit 84427eaef1fb91704c7112bdb598c810003b99f3 (remove task_ppid_nr_ns) moved the task_tgid_nr_ns(task->real_parent) outside of lock_task_sighand(). This is wrong, ->real_parent could be freed/reused. Both ->parent/real_parent point to nothing after __exit_signal() because we remove the child from ->children list, and thus the child can't be reparented when its parent exits. rcu_read_lock() protects ->parent/real_parent, but _only_ if we know it was valid before we take rcu lock. Revert this part of the patch. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-13remove task_ppid_nr_nsRoland McGrath
task_ppid_nr_ns is called in three places. One of these should never have called it. In the other two, using it broke the existing semantics. This was presumably accidental. If the function had not been there, it would have been much more obvious to the eye that those patches were changing the behavior. We don't need this function. In task_state, the pid of the ptracer is not the ppid of the ptracer. In do_task_stat, ppid is the tgid of the real_parent, not its pid. I also moved the call outside of lock_task_sighand, since it doesn't need it. In sys_getppid, ppid is the tgid of the real_parent, not its pid. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-12-06proc/array.c: Use TASK_REPORTMatthew Wilcox
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
2007-11-26sched: fix prev_stime calculationIngo Molnar
Srivatsa Vaddagiri noticed occasionally incorrect CPU usage values in top and tracked it down to stime going below 0 in task_stime(). Negative values are possible there due to the sampled nature of stime/utime. Fix suggested by Balbir Singh. Signed-off-by: Ingo Molnar <mingo@elte.hu> Tested-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
2007-10-30sched: fix /proc/<PID>/stat stime/utime monotonicity, part 2Balbir Singh
Extend Peter's patch to fix accounting issues, by keeping stime monotonic too. Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Tested-by: Frans Pop <elendil@planet.nl>
2007-10-29sched: keep utime/stime monotonicPeter Zijlstra
keep utime/stime monotonic. cpustats use utime/stime as a ratio against sum_exec_runtime, as a consequence it can happen - when the ratio changes faster than time accumulates - that either can be appear to go backwards. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-19Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-schedLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched: sched: fix guest time accounting going faster than user time accounting
2007-10-19Fix tsk->exit_state usageEugene Teo
tsk->exit_state can only be 0, EXIT_ZOMBIE, or EXIT_DEAD. A non-zero test is the same as tsk->exit_state & (EXIT_ZOMBIE | EXIT_DEAD), so just testing tsk->exit_state is sufficient. Signed-off-by: Eugene Teo <eugeneteo@kernel.sg> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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. [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: nuther build fix] [akpm@linux-foundation.org: yet nuther build fix] [akpm@linux-foundation.org: remove unneeded casts] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Paul Menage <menage@google.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <xemul@openvz.org> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-19sched: fix guest time accounting going faster than user time accountingChristian Borntraeger
cputime_add already adds, dont do it twice. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-10-15sched: guest CPU accounting: add guest-CPU /proc/<pid>/stat fieldsLaurent Vivier
like for cpustat, introduce the "gtime" (guest time of the task) and "cgtime" (guest time of the task children) fields for the tasks. Modify signal_struct and task_struct. Modify /proc/<pid>/stat to display these new fields. Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net> Acked-by: Avi Kivity <avi@qumranet.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-08-23sched: accounting regression since rc1Christian Borntraeger
Fix the accounting regression for CONFIG_VIRT_CPU_ACCOUNTING. It reverts parts of commit b27f03d4bdc145a09fb7b0c0e004b29f1ee555fa by converting fs/proc/array.c back to cputime_t. The new functions task_utime and task_stime now return cputime_t instead of clock_t. If CONFIG_VIRT_CPU_ACCOUTING is set, task->utime and task->stime are returned directly instead of using sum_exec_runtime. Patch is tested on s390x with and without VIRT_CPU_ACCOUTING as well as on i386. [ mingo@elte.hu: cleanups, comments. ] Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-07-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-schedLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched: [PATCH] sched: fix up fs/proc/array.c whitespace problems [PATCH] sched: prettify prio_to_wmult[] [PATCH] sched: document prio_to_wmult[] [PATCH] sched: improve weight-array comments [PATCH] sched: remove dead code from task_stime() Fixed up trivial conflict in fs/proc/array.c
2007-07-16taskstats: add context-switch countersMaxim Uvarov
Make available to the user the following task and process performance statistics: * Involuntary Context Switches (task_struct->nivcsw) * Voluntary Context Switches (task_struct->nvcsw) Statistics information is available from: 1. taskstats interface (Documentation/accounting/) 2. /proc/PID/status (task only). This data is useful for detecting hyperactivity patterns between processes. [akpm@linux-foundation.org: cleanup] Signed-off-by: Maxim Uvarov <muvarov@ru.mvista.com> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Jay Lan <jlan@engr.sgi.com> Cc: Jonathan Lim <jlim@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16Use boot based time for process start time and boot time in /procTomas Janousek
Commit 411187fb05cd11676b0979d9fbf3291db69dbce2 caused boot time to move and process start times to become invalid after suspend. Using boot based time for those restores the old behaviour and fixes the issue. [akpm@linux-foundation.org: little cleanup] Signed-off-by: Tomas Janousek <tjanouse@redhat.com> Cc: Tomas Smetana <tsmetana@redhat.com> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16[PATCH] sched: fix up fs/proc/array.c whitespace problemsIngo Molnar
while changing task_stime() i noticed a whitespace style problem in array.c - fix it. While at it, fix all the other style problems too, most of them in the scheduler-stats related portions of array.c. There is no change in functionality: text data bss dec hex filename 4356 28 0 4384 1120 array.o-before 4356 28 0 4384 1120 array.o-after Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-07-16[PATCH] sched: remove dead code from task_stime()Ingo Molnar
Alexey Dobriyan noticed that task_stime() contains a piece of dead code. (which is a remnant of earlier versions of this code) Remove that code. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-07-09sched: make use of precise accounting for /proc task statsIngo Molnar
make use of CFS's precise accounting to drive /proc/<pid>/stat statistics. this code was co-authored by: Balbir Singh <balbir@linux.vnet.ibm.com> Dmitry Adamushko <dmitry.adamushko@gmail.com> Ingo Molnar <mingo@elte.hu> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>