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2012-02-27Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/events: Revert trace_sched_stat_sleeptime()
2012-02-27Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq: Handle pending irqs in irq_startup() genirq: Unmask oneshot irqs when thread was not woken
2012-02-24epoll: introduce POLLFREE to flush ->signalfd_wqh before kfree()Oleg Nesterov
This patch is intentionally incomplete to simplify the review. It ignores ep_unregister_pollwait() which plays with the same wqh. See the next change. epoll assumes that the EPOLL_CTL_ADD'ed file controls everything f_op->poll() needs. In particular it assumes that the wait queue can't go away until eventpoll_release(). This is not true in case of signalfd, the task which does EPOLL_CTL_ADD uses its ->sighand which is not connected to the file. This patch adds the special event, POLLFREE, currently only for epoll. It expects that init_poll_funcptr()'ed hook should do the necessary cleanup. Perhaps it should be defined as EPOLLFREE in eventpoll. __cleanup_sighand() is changed to do wake_up_poll(POLLFREE) if ->signalfd_wqh is not empty, we add the new signalfd_cleanup() helper. ep_poll_callback(POLLFREE) simply does list_del_init(task_list). This make this poll entry inconsistent, but we don't care. If you share epoll fd which contains our sigfd with another process you should blame yourself. signalfd is "really special". I simply do not know how we can define the "right" semantics if it used with epoll. The main problem is, epoll calls signalfd_poll() once to establish the connection with the wait queue, after that signalfd_poll(NULL) returns the different/inconsistent results depending on who does EPOLL_CTL_MOD/signalfd_read/etc. IOW: apart from sigmask, signalfd has nothing to do with the file, it works with the current thread. In short: this patch is the hack which tries to fix the symptoms. It also assumes that nobody can take tasklist_lock under epoll locks, this seems to be true. Note: - we do not have wake_up_all_poll() but wake_up_poll() is fine, poll/epoll doesn't use WQ_FLAG_EXCLUSIVE. - signalfd_cleanup() uses POLLHUP along with POLLFREE, we need a couple of simple changes in eventpoll.c to make sure it can't be "lost". Reported-by: Maxime Bizon <mbizon@freebox.fr> Cc: <stable@kernel.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-22sched/events: Revert trace_sched_stat_sleeptime()Peter Zijlstra
Commit 1ac9bc69 ("sched/tracing: Add a new tracepoint for sleeptime") added a new sched:sched_stat_sleeptime tracepoint. It's broken: the first sample we get on a task might be bad because of a stale sleep_start value that wasn't reset at the last task switch because the tracepoint was not active. It also breaks the existing schedstat samples due to the side effects of: - se->statistics.sleep_start = 0; ... - se->statistics.block_start = 0; Nor do I see means to fix it without adding overhead to the scheduler fast path, which I'm not willing to for the sake of redundant instrumentation. Most importantly, sleep time information can already be constructed by tracing context switches and wakeups, and taking the timestamp difference between the schedule-out, the wakeup and the schedule-in. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Vagin <avagin@openvz.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/n/tip-pc4c9qhl8q6vg3bs4j6k0rbd@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-20Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Assorted fixes, sat in -next for a week or so... * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: ocfs2: deal with wraparounds of i_nlink in ocfs2_rename() vfs: fix compat_sys_stat() handling of overflows in st_nlink quota: Fix deadlock with suspend and quotas vfs: Provide function to get superblock and wait for it to thaw vfs: fix panic in __d_lookup() with high dentry hashtable counts autofs4 - fix lockdep splat in autofs vfs: fix d_inode_lookup() dentry ref leak
2012-02-15genirq: Handle pending irqs in irq_startup()Thomas Gleixner
An interrupt might be pending when irq_startup() is called, but the startup code does not invoke the resend logic. In some cases this prevents the device from issuing another interrupt which renders the device non functional. Call the resend function in irq_startup() to keep things going. Reported-and-tested-by: Russell King <rmk+kernel@arm.linux.org.uk> Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-15genirq: Unmask oneshot irqs when thread was not wokenThomas Gleixner
When the primary handler of an interrupt which is marked IRQ_ONESHOT returns IRQ_HANDLED or IRQ_NONE, then the interrupt thread is not woken and the unmask logic of the interrupt line is never invoked. This keeps the interrupt masked forever. This was not noticed as most IRQ_ONESHOT users wake the thread unconditionally (usually because they cannot access the underlying device from hard interrupt context). Though this behaviour was nowhere documented and not necessarily intentional. Some drivers can avoid the thread wakeup in certain cases and run into the situation where the interrupt line s kept masked. Handle it gracefully. Reported-and-tested-by: Lothar Wassmann <lw@karo-electronics.de> Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-02-13vfs: fix panic in __d_lookup() with high dentry hashtable countsDimitri Sivanich
When the number of dentry cache hash table entries gets too high (2147483648 entries), as happens by default on a 16TB system, use of a signed integer in the dcache_init() initialization loop prevents the dentry_hashtable from getting initialized, causing a panic in __d_lookup(). Fix this in dcache_init() and similar areas. Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-02-13Merge tag 'for-linus' of git://github.com/rustyrussell/linuxLinus Torvalds
* tag 'for-linus' of git://github.com/rustyrussell/linux: module: fix broken isapnp handling in file2alias module: make module param bint handle nul value
2012-02-14module: make module param bint handle nul valueDave Young
Allow bint param accept nul values, just do same as bool param. Signed-off-by: Dave Young <dyoung@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-02-11Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds
Says Jens: "Time to push off some of the pending items. I really wanted to wait until we had the regression nailed, but alas it's not quite there yet. But I'm very confident that it's "just" a missing expire on exit, so fix from Tejun should be fairly trivial. I'm headed out for a week on the slopes. - Killing the barrier part of mtip32xx. It doesn't really support barriers, and it doesn't need them (writes are fully ordered). - A few fixes from Dan Carpenter, preventing overflows of integer multiplication. - A fixup for loop, fixing a previous commit that didn't quite solve the partial read problem from Dave Young. - A bio integer overflow fix from Kent Overstreet. - Improvement/fix of the door "keep locked" part of the cdrom shared code from Paolo Benzini. - A few cfq fixes from Shaohua Li. - A fix for bsg sysfs warning when removing a file it did not create from Stanislaw Gruszka. - Two fixes for floppy from Vivek, preventing a crash. - A few block core fixes from Tejun. One killing the over-optimized ioc exit path, cleaning that up nicely. Two others fixing an oops on elevator switch, due to calling into the scheduler merge check code without holding the queue lock." * 'for-linus' of git://git.kernel.dk/linux-block: block: fix lockdep warning on io_context release put_io_context() relay: prevent integer overflow in relay_open() loop: zero fill bio instead of return -EIO for partial read bio: don't overflow in bio_get_nr_vecs() floppy: Fix a crash during rmmod floppy: Cleanup disk->queue before caling put_disk() if add_disk() was never called cdrom: move shared static to cdrom_device_info bsg: fix sysfs link remove warning block: don't call elevator callbacks for plug merges block: separate out blk_rq_merge_ok() and blk_try_merge() from elevator functions mtip32xx: removed the irrelevant argument of mtip_hw_submit_io() and the unused member of struct driver_data block: strip out locking optimization in put_io_context() cdrom: use copy_to_user() without the underscores block: fix ioc locking warning block: fix NULL icq_cache reference block,cfq: change code order
2012-02-10Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix double start/stop in x86_pmu_start() perf evsel: Fix an issue where perf report fails to show the proper percentage perf tools: Fix prefix matching for kernel maps perf tools: Fix perf stack to non executable on x86_64 perf: Remove deprecated WARN_ON_ONCE()
2012-02-10relay: prevent integer overflow in relay_open()Dan Carpenter
"subbuf_size" and "n_subbufs" come from the user and they need to be capped to prevent an integer overflow. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-02-07perf: Fix double start/stop in x86_pmu_start()Stephane Eranian
The following patch fixes a bug introduced by the following commit: e050e3f0a71b ("perf: Fix broken interrupt rate throttling") The patch caused the following warning to pop up depending on the sampling frequency adjustments: ------------[ cut here ]------------ WARNING: at arch/x86/kernel/cpu/perf_event.c:995 x86_pmu_start+0x79/0xd4() It was caused by the following call sequence: perf_adjust_freq_unthr_context.part() { stop() if (delta > 0) { perf_adjust_period() { if (period > 8*...) { stop() ... start() } } } start() } Which caused a double start and a double stop, thus triggering the assert in x86_pmu_start(). The patch fixes the problem by avoiding the double calls. We pass a new argument to perf_adjust_period() to indicate whether or not the event is already stopped. We can't just remove the start/stop from that function because it's called from __perf_event_overflow where the event needs to be reloaded via a stop/start back-toback call. The patch reintroduces the assertion in x86_pmu_start() which was removed by commit: 84f2b9b ("perf: Remove deprecated WARN_ON_ONCE()") In this second version, we've added calls to disable/enable PMU during unthrottling or frequency adjustment based on bug report of spurious NMI interrupts from Eric Dumazet. Reported-and-tested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: markus@trippelsdorf.de Cc: paulus@samba.org Link: http://lkml.kernel.org/r/20120207133956.GA4932@quad [ Minor edits to the changelog and to the code ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-07block: strip out locking optimization in put_io_context()Tejun Heo
put_io_context() performed a complex trylock dancing to avoid deferring ioc release to workqueue. It was also broken on UP because trylock was always assumed to succeed which resulted in unbalanced preemption count. While there are ways to fix the UP breakage, even the most pathological microbench (forced ioc allocation and tight fork/exit loop) fails to show any appreciable performance benefit of the optimization. Strip it out. If there turns out to be workloads which are affected by this change, simpler optimization from the discussion thread can be applied later. Signed-off-by: Tejun Heo <tj@kernel.org> LKML-Reference: <1328514611.21268.66.camel@sli10-conroe> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-02-04Merge tag 'pm-fixes-for-3.3-rc3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Power management fixes for 3.3-rc3 Three power management regression fixes, one for a recent regression introcuded by the freezer changes during the 3.3 merge window and two for regressions in cpuidle (resulting from PM QoS changes) and in the hibernate user space interface, both introduced during the 3.2 development cycle. They include: * Two hibernate (s2disk) regression fixes from Srivatsa S. Bhat (for regressions introduced during the 3.3 merge window and during the 3.2 development cycle). * A cpuidle fix from Venki Pallipadi for a regression resulting from PM QoS changes during the 3.2 development cycle causing cpuidle to work incorrectly for CONFIG_PM unset. * tag 'pm-fixes-for-3.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PM / QoS: CPU C-state breakage with PM Qos change PM / Freezer: Thaw only kernel threads if freezing of kernel threads fails PM / Hibernate: Thaw kernel threads in SNAPSHOT_CREATE_IMAGE ioctl path
2012-02-04PM / Freezer: Thaw only kernel threads if freezing of kernel threads failsSrivatsa S. Bhat
If freezing of kernel threads fails, we are expected to automatically thaw tasks in the error recovery path. However, at times, we encounter situations in which we would like the automatic error recovery path to thaw only the kernel threads, because we want to be able to do some more cleanup before we thaw userspace. Something like: error = freeze_kernel_threads(); if (error) { /* Do some cleanup */ /* Only then thaw userspace tasks*/ thaw_processes(); } An example of such a situation is where we freeze/thaw filesystems during suspend/hibernation. There, if freezing of kernel threads fails, we would like to thaw the frozen filesystems before thawing the userspace tasks. So, modify freeze_kernel_threads() to thaw only kernel threads in case of freezing failure. And change suspend_freeze_processes() accordingly. (At the same time, let us also get rid of the rather cryptic usage of the conditional operator (:?) in that function.) [rjw: In fact, this patch fixes a regression introduced during the 3.3 merge window, because without it thaw_processes() may be called before swsusp_free() in some situations and that may lead to massive memory allocation failures.] Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Nigel Cunningham <nigel@tuxonice.net> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-02-03kprobes: fix a memory leak in function pre_handler_kretprobe()Jiang Liu
In function pre_handler_kretprobe(), the allocated kretprobe_instance object will get leaked if the entry_handler callback returns non-zero. This may cause all the preallocated kretprobe_instance objects exhausted. This issue can be reproduced by changing samples/kprobes/kretprobe_example.c to probe "mutex_unlock". And the fix is straightforward: just put the allocated kretprobe_instance object back onto the free_instances list. [akpm@linux-foundation.org: use raw_spin_lock/unlock] Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-02Fix race in process_vm_rw_coreChristopher Yeoh
This fixes the race in process_vm_core found by Oleg (see http://article.gmane.org/gmane.linux.kernel/1235667/ for details). This has been updated since I last sent it as the creation of the new mm_access() function did almost exactly the same thing as parts of the previous version of this patch did. In order to use mm_access() even when /proc isn't enabled, we move it to kernel/fork.c where other related process mm access functions already are. Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-02Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus', ↵Linus Torvalds
'sched-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: bugs, x86: Fix printk levels for panic, softlockups and stack dumps * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf top: Fix number of samples displayed perf tools: Fix strlen() bug in perf_event__synthesize_event_type() perf tools: Fix broken build by defining _GNU_SOURCE in Makefile x86/dumpstack: Remove unneeded check in dump_trace() perf: Fix broken interrupt rate throttling * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/rt: Fix task stack corruption under __ARCH_WANT_INTERRUPTS_ON_CTXSW sched: Fix ancient race in do_exit() sched/nohz: Fix nohz cpu idle load balancing state with cpu hotplug sched/s390: Fix compile error in sched/core.c sched: Fix rq->nr_uninterruptible update race * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/reboot: Remove VersaLogic Menlow reboot quirk x86/reboot: Skip DMI checks if reboot set by user x86: Properly parenthesize cmpxchg() macro arguments
2012-02-01PM / Hibernate: Thaw kernel threads in SNAPSHOT_CREATE_IMAGE ioctl pathSrivatsa S. Bhat
In the SNAPSHOT_CREATE_IMAGE ioctl, if the call to hibernation_snapshot() fails, the frozen tasks are not thawed. And in the case of success, if we happen to exit due to a successful freezer test, all tasks (including those of userspace) are thawed, whereas actually we should have thawed only the kernel threads at that point. Fix both these issues. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: stable@vger.kernel.org
2012-01-29PM / Hibernate: Fix s2disk regression related to freezing workqueuesRafael J. Wysocki
Commit 2aede851ddf08666f68ffc17be446420e9d2a056 PM / Hibernate: Freeze kernel threads after preallocating memory introduced a mechanism by which kernel threads were frozen after the preallocation of hibernate image memory to avoid problems with frozen kernel threads not responding to memory freeing requests. However, it overlooked the s2disk code path in which the SNAPSHOT_CREATE_IMAGE ioctl was run directly after SNAPSHOT_FREE, which caused freeze_workqueues_begin() to BUG(), because it saw that worqueues had been already frozen. Although in principle this issue might be addressed by removing the relevant BUG_ON() from freeze_workqueues_begin(), that would reintroduce the very problem that commit 2aede851ddf08666f68ffc17be4 attempted to avoid into that particular code path. For this reason, to fix the issue at hand, introduce thaw_kernel_threads() and make the SNAPSHOT_FREE ioctl execute it. Special thanks to Srivatsa S. Bhat for detailed analysis of the problem. Reported-and-tested-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: stable@kernel.org
2012-01-27sched/rt: Fix task stack corruption under __ARCH_WANT_INTERRUPTS_ON_CTXSWChanho Min
This issue happens under the following conditions: 1. preemption is off 2. __ARCH_WANT_INTERRUPTS_ON_CTXSW is defined 3. RT scheduling class 4. SMP system Sequence is as follows: 1.suppose current task is A. start schedule() 2.task A is enqueued pushable task at the entry of schedule() __schedule prev = rq->curr; ... put_prev_task put_prev_task_rt enqueue_pushable_task 4.pick the task B as next task. next = pick_next_task(rq); 3.rq->curr set to task B and context_switch is started. rq->curr = next; 4.At the entry of context_swtich, release this cpu's rq->lock. context_switch prepare_task_switch prepare_lock_switch raw_spin_unlock_irq(&rq->lock); 5.Shortly after rq->lock is released, interrupt is occurred and start IRQ context 6.try_to_wake_up() which called by ISR acquires rq->lock try_to_wake_up ttwu_remote rq = __task_rq_lock(p) ttwu_do_wakeup(rq, p, wake_flags); task_woken_rt 7.push_rt_task picks the task A which is enqueued before. task_woken_rt push_rt_tasks(rq) next_task = pick_next_pushable_task(rq) 8.At find_lock_lowest_rq(), If double_lock_balance() returns 0, lowest_rq can be the remote rq. (But,If preemption is on, double_lock_balance always return 1 and it does't happen.) push_rt_task find_lock_lowest_rq if (double_lock_balance(rq, lowest_rq)).. 9.find_lock_lowest_rq return the available rq. task A is migrated to the remote cpu/rq. push_rt_task ... deactivate_task(rq, next_task, 0); set_task_cpu(next_task, lowest_rq->cpu); activate_task(lowest_rq, next_task, 0); 10. But, task A is on irq context at this cpu. So, task A is scheduled by two cpus at the same time until restore from IRQ. Task A's stack is corrupted. To fix it, don't migrate an RT task if it's still running. Signed-off-by: Chanho Min <chanho.min@lge.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/r/CAOAMb1BHA=5fm7KTewYyke6u-8DP0iUuJMpgQw54vNeXFsGpoQ@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-27perf: Fix broken interrupt rate throttlingStephane Eranian
This patch fixes the sampling interrupt throttling mechanism. It was broken in v3.2. Events were not being unthrottled. The unthrottling mechanism required that events be checked at each timer tick. This patch solves this problem and also separates: - unthrottling - multiplexing - frequency-mode period adjustments Not all of them need to be executed at each timer tick. This third version of the patch is based on my original patch + PeterZ proposal (https://lkml.org/lkml/2012/1/7/87). At each timer tick, for each context: - if the current CPU has throttled events, we unthrottle events - if context has frequency-based events, we adjust sampling periods - if we have reached the jiffies interval, we multiplex (rotate) We decoupled rotation (multiplexing) from frequency-mode sampling period adjustments. They should not necessarily happen at the same rate. Multiplexing is subject to jiffies_interval (currently at 1 but could be higher once the tunable is exposed via sysfs). We have grouped frequency-mode adjustment and unthrottling into the same routine to minimize code duplication. When throttled while in frequency mode, we scan the events only once. We have fixed the threshold enforcement code in __perf_event_overflow(). There was a bug whereby it would allow more than the authorized rate because an increment of hwc->interrupts was not executed at the right place. The patch was tested with low sampling limit (2000) and fixed periods, frequency mode, overcommitted PMU. On a 2.1GHz AMD CPU: $ cat /proc/sys/kernel/perf_event_max_sample_rate 2000 We set a rate of 3000 samples/sec (2.1GHz/3000 = 700000): $ perf record -e cycles,cycles -c 700000 noploop 10 $ perf report -D | tail -21 Aggregated stats: TOTAL events: 80086 MMAP events: 88 COMM events: 2 EXIT events: 4 THROTTLE events: 19996 UNTHROTTLE events: 19996 SAMPLE events: 40000 cycles stats: TOTAL events: 40006 MMAP events: 5 COMM events: 1 EXIT events: 4 THROTTLE events: 9998 UNTHROTTLE events: 9998 SAMPLE events: 20000 cycles stats: TOTAL events: 39996 THROTTLE events: 9998 UNTHROTTLE events: 9998 SAMPLE events: 20000 For 10s, the cap is 2x2000x10 = 40000 samples. We get exactly that: 20000 samples/event. Signed-off-by: Stephane Eranian <eranian@google.com> Cc: <stable@kernel.org> # v3.2+ Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120126160319.GA5655@quad Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-27sched: Fix ancient race in do_exit()Yasunori Goto
try_to_wake_up() has a problem which may change status from TASK_DEAD to TASK_RUNNING in race condition with SMI or guest environment of virtual machine. As a result, exited task is scheduled() again and panic occurs. Here is the sequence how it occurs: ----------------------------------+----------------------------- | CPU A | CPU B ----------------------------------+----------------------------- TASK A calls exit().... do_exit() exit_mm() down_read(mm->mmap_sem); rwsem_down_failed_common() set TASK_UNINTERRUPTIBLE set waiter.task <= task A list_add to sem->wait_list : raw_spin_unlock_irq() (I/O interruption occured) __rwsem_do_wake(mmap_sem) list_del(&waiter->list); waiter->task = NULL wake_up_process(task A) try_to_wake_up() (task is still TASK_UNINTERRUPTIBLE) p->on_rq is still 1.) ttwu_do_wakeup() (*A) : (I/O interruption handler finished) if (!waiter.task) schedule() is not called due to waiter.task is NULL. tsk->state = TASK_RUNNING : check_preempt_curr(); : task->state = TASK_DEAD (*B) <--- set TASK_RUNNING (*C) schedule() (exit task is running again) BUG_ON() is called! -------------------------------------------------------- The execution time between (*A) and (*B) is usually very short, because the interruption is disabled, and setting TASK_RUNNING at (*C) must be executed before setting TASK_DEAD. HOWEVER, if SMI is interrupted between (*A) and (*B), (*C) is able to execute AFTER setting TASK_DEAD! Then, exited task is scheduled again, and BUG_ON() is called.... If the system works on guest system of virtual machine, the time between (*A) and (*B) may be also long due to scheduling of hypervisor, and same phenomenon can occur. By this patch, do_exit() waits for releasing task->pi_lock which is used in try_to_wake_up(). It guarantees the task becomes TASK_DEAD after waking up. Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20120117174031.3118.E1E9C6FF@jp.fujitsu.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-26Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Call perf_cgroup_event_time() directly perf: Don't call release_callchain_buffers() if allocation fails
2012-01-26Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: rcu: Add missing __cpuinit annotation in rcutorture code sched: Add "const" to is_idle_task() parameter rcu: Make rcutorture bool parameters really bool (core code) memblock: Fix alloc failure due to dumb underflow protection in memblock_find_in_range_node()
2012-01-26bugs, x86: Fix printk levels for panic, softlockups and stack dumpsPrarit Bhargava
rsyslog will display KERN_EMERG messages on a connected terminal. However, these messages are useless/undecipherable for a general user. For example, after a softlockup we get: Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ... kernel:Stack: Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ... kernel:Call Trace: Message from syslogd@intel-s3e37-04 at Jan 25 14:18:06 ... kernel:Code: ff ff a8 08 75 25 31 d2 48 8d 86 38 e0 ff ff 48 89 d1 0f 01 c8 0f ae f0 48 8b 86 38 e0 ff ff a8 08 75 08 b1 01 4c 89 e0 0f 01 c9 <e8> ea 69 dd ff 4c 29 e8 48 89 c7 e8 0f bc da ff 49 89 c4 49 89 This happens because the printk levels for these messages are incorrect. Only an informational message should be displayed on a terminal. I modified the printk levels for various messages in the kernel and tested the output by using the drivers/misc/lkdtm.c kernel modules (ie, softlockups, panics, hard lockups, etc.) and confirmed that the console output was still the same and that the output to the terminals was correct. For example, in the case of a softlockup we now see the much more informative: Message from syslogd@intel-s3e37-04 at Jan 25 10:18:06 ... BUG: soft lockup - CPU4 stuck for 60s! instead of the above confusing messages. AFAICT, the messages no longer have to be KERN_EMERG. In the most important case of a panic we set console_verbose(). As for the other less severe cases the correct data is output to the console and /var/log/messages. Successfully tested by me using the drivers/misc/lkdtm.c module. Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: dzickus@redhat.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1327586134-11926-1-git-send-email-prarit@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-26sched/nohz: Fix nohz cpu idle load balancing state with cpu hotplugSuresh Siddha
With the recent nohz scheduler changes, rq's nohz flag 'NOHZ_TICK_STOPPED' and its associated state doesn't get cleared immediately after the cpu exits idle. This gets cleared as part of the next tick seen on that cpu. For the cpu offline support, we need to clear this state manually. Fix it by registering a cpu notifier, which clears the nohz idle load balance state for this rq explicitly during the CPU_DYING notification. There won't be any nohz updates for that cpu, after the CPU_DYING notification. But lets be extra paranoid and skip updating the nohz state in the select_nohz_load_balancer() if the cpu is not in active state anymore. Reported-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Reviewed-and-tested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1327026538.16150.40.camel@sbsiddha-desk.sc.intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-26sched/s390: Fix compile error in sched/core.cChristian Borntraeger
Commit 029632fbb7b7c9d85063cc9eb470de6c54873df3 ("sched: Make separate sched*.c translation units") removed the include of asm/mutex.h from sched.c. This breaks the combination of: CONFIG_MUTEX_SPIN_ON_OWNER=yes CONFIG_HAVE_ARCH_MUTEX_CPU_RELAX=yes like s390 without mutex debugging: CC kernel/sched/core.o kernel/sched/core.c: In function ‘mutex_spin_on_owner’: kernel/sched/core.c:3287: error: implicit declaration of function ‘arch_mutex_cpu_relax’ Lets re-add the include to kernel/sched/core.c Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1326268696-30904-1-git-send-email-borntraeger@de.ibm.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-26sched: Fix rq->nr_uninterruptible update racePeter Zijlstra
KOSAKI Motohiro noticed the following race: > CPU0 CPU1 > -------------------------------------------------------- > deactivate_task() > task->state = TASK_UNINTERRUPTIBLE; > activate_task() > rq->nr_uninterruptible--; > > schedule() > deactivate_task() > rq->nr_uninterruptible++; > Kosaki-San's scenario is possible when CPU0 runs __sched_setscheduler() against CPU1's current @task. __sched_setscheduler() does a dequeue/enqueue in order to move the task to its new queue (position) to reflect the newly provided scheduling parameters. However it should be completely invariant to nr_uninterruptible accounting, sched_setscheduler() doesn't affect readyness to run, merely policy on when to run. So convert the inappropriate activate/deactivate_task usage to enqueue/dequeue_task, which avoids the nr_uninterruptible accounting. Also convert the two other sites: __migrate_task() and normalize_task() that still use activate/deactivate_task. These sites aren't really a problem since __migrate_task() will only be called on non-running task (and therefore are immume to the described problem) and normalize_task() isn't ever used on regular systems. Also remove the comments from activate/deactivate_task since they're misleading at best. Reported-by: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1327486224.2614.45.camel@laptop Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Davem says: 1) Fix JIT code generation on x86-64 for divide by zero, from Eric Dumazet. 2) tg3 header length computation correction from Eric Dumazet. 3) More build and reference counting fixes for socket memory cgroup code from Glauber Costa. 4) module.h snuck back into a core header after all the hard work we did to remove that, from Paul Gortmaker and Jesper Dangaard Brouer. 5) Fix PHY naming regression and add some new PCI IDs in stmmac, from Alessandro Rubini. 6) Netlink message generation fix in new team driver, should only advertise the entries that changed during events, from Jiri Pirko. 7) SRIOV VF registration and unregistration fixes, and also add a missing PCI ID, from Roopa Prabhu. 8) Fix infinite loop in tx queue flush code of brcmsmac, from Stanislaw Gruszka. 9) ftgmac100/ftmac100 build fix, missing interrupt.h include. 10) Memory leak fix in net/hyperv do_set_mutlicast() handling, from Wei Yongjun. 11) Off by one fix in netem packet scheduler, from Vijay Subramanian. 12) TCP loss detection fix from Yuchung Cheng. 13) TCP reset packet MD5 calculation uses wrong address, fix from Shawn Lu. 14) skge carrier assertion and DMA mapping fixes from Stephen Hemminger. 15) Congestion recovery undo performed at the wrong spot in BIC and CUBIC congestion control modules, fix from Neal Cardwell. 16) Ethtool ETHTOOL_GSSET_INFO is unnecessarily restrictive, from Michał Mirosław. 17) Fix triggerable race in ipv6 sysctl handling, from Francesco Ruggeri. 18) Statistics bug fixes in mlx4 from Eugenia Emantayev. 19) rds locking bug fix during info dumps, from your's truly. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (67 commits) rds: Make rds_sock_lock BH rather than IRQ safe. netprio_cgroup.h: dont include module.h from other includes net: flow_dissector.c missing include linux/export.h team: send only changed options/ports via netlink net/hyperv: fix possible memory leak in do_set_multicast() drivers/net: dsa/mv88e6xxx.c files need linux/module.h stmmac: added PCI identifiers llc: Fix race condition in llc_ui_recvmsg stmmac: fix phy naming inconsistency dsa: Add reporting of silicon revision for Marvell 88E6123/88E6161/88E6165 switches. tg3: fix ipv6 header length computation skge: add byte queue limit support mv643xx_eth: Add Rx Discard and Rx Overrun statistics bnx2x: fix compilation error with SOE in fw_dump bnx2x: handle CHIP_REVISION during init_one bnx2x: allow user to change ring size in ISCSI SD mode bnx2x: fix Big-Endianess in ethtool -t bnx2x: fixed ethtool statistics for MF modes bnx2x: credit-leakage fixup on vlan_mac_del_all macvlan: fix a possible use after free ...
2012-01-23Merge tag 'pm-fixes-for-3.3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Power management fixes for 3.3 Two fixes for regressions introduced during the merge window, one fix for a long-standing obscure issue in the computation of hibernate image size and two small PM documentation fixes. * tag 'pm-fixes-for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PM / Sleep: Fix read_unlock_usermodehelper() call. PM / Hibernate: Rewrite unlock_system_sleep() to fix s2disk regression PM / Hibernate: Correct additional pages number calculation PM / Documentation: Fix minor issue in freezing_of_tasks.txt PM / Documentation: Fix spelling mistake in basic-pm-debugging.txt
2012-01-23Merge branch 'kernel-doc' from Randy DunlapLinus Torvalds
The usual kernel-doc fixups from Randy. Some of them David acked as merged in his tree, this is the random left-overs. * kernel-doc: docbook: fix sched source file names in device-drivers book docbook: change iomap source filename in deviceiobook docbook: don't use serial_core.h in device-drivers book kernel-doc: fix kernel-doc warnings in sched kernel-doc: fix new warnings in cfg80211.h kernel-doc: fix new warning in usb.h kernel-doc: fix new warnings in device.h kernel-doc: fix new warnings in debugfs kernel-doc: fix new warning in regulator core kernel-doc: fix new warnings in pci kernel-doc: fix new warnings in driver-core kernel-doc: fix new warnings in auditsc.c scripts/kernel-doc: fix fatal error caused by cfg80211.h
2012-01-23kernel-doc: fix kernel-doc warnings in schedRandy Dunlap
Fix new kernel-doc notation warnings: Warning(include/linux/sched.h:2094): No description found for parameter 'p' Warning(include/linux/sched.h:2094): Excess function parameter 'tsk' description in 'is_idle_task' Warning(kernel/sched/cpupri.c:139): No description found for parameter 'newpri' Warning(kernel/sched/cpupri.c:139): Excess function parameter 'pri' description in 'cpupri_set' Warning(kernel/sched/cpupri.c:208): Excess function parameter 'bootmem' description in 'cpupri_init' Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23kernel-doc: fix new warnings in auditsc.cRandy Dunlap
Fix new kernel-doc warnings in auditsc.c: Warning(kernel/auditsc.c:1875): No description found for parameter 'success' Warning(kernel/auditsc.c:1875): No description found for parameter 'return_code' Warning(kernel/auditsc.c:1875): Excess function parameter 'pt_regs' description in '__audit_syscall_exit' Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Eric Paris <eparis@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23kprobes: initialize before using a hlistAnanth N Mavinakayanahalli
Commit ef53d9c5e ("kprobes: improve kretprobe scalability with hashed locking") introduced a bug where we can potentially leak kretprobe_instances since we initialize a hlist head after having used it. Initialize the hlist head before using it. Reported by: Jim Keniston <jkenisto@us.ibm.com> Acked-by: Jim Keniston <jkenisto@us.ibm.com> Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Srinivasa D S <srinivasa@in.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-22net: introduce res_counter_charge_nofail() for socket allocationsGlauber Costa
There is a case in __sk_mem_schedule(), where an allocation is beyond the maximum, but yet we are allowed to proceed. It happens under the following condition: sk->sk_wmem_queued + size >= sk->sk_sndbuf The network code won't revert the allocation in this case, meaning that at some point later it'll try to do it. Since this is never communicated to the underlying res_counter code, there is an inbalance in res_counter uncharge operation. I see two ways of fixing this: 1) storing the information about those allocations somewhere in memcg, and then deducting from that first, before we start draining the res_counter, 2) providing a slightly different allocation function for the res_counter, that matches the original behavior of the network code more closely. I decided to go for #2 here, believing it to be more elegant, since #1 would require us to do basically that, but in a more obscure way. Signed-off-by: Glauber Costa <glommer@parallels.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> CC: Tejun Heo <tj@kernel.org> CC: Li Zefan <lizf@cn.fujitsu.com> CC: Laurent Chavey <chavey@google.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-01-21perf: Call perf_cgroup_event_time() directlyNamhyung Kim
The perf_event_time() will call perf_cgroup_event_time() if @event is a cgroup event. Just do it directly and avoid the extra check.. Signed-off-by: Namhyung Kim <namhyung.kim@lge.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Link: http://lkml.kernel.org/r/1327021966-27688-2-git-send-email-namhyung.kim@lge.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-21perf: Don't call release_callchain_buffers() if allocation failsNamhyung Kim
When alloc_callchain_buffers() fails, it frees all of entries before return. In addition, calling the release_callchain_buffers() will cause a NULL pointer dereference since callchain_cpu_entries is not set. Signed-off-by: Namhyung Kim <namhyung.kim@lge.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Link: http://lkml.kernel.org/r/1327021966-27688-1-git-send-email-namhyung.kim@lge.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-19Merge branches 'sched-urgent-for-linus', 'perf-urgent-for-linus' and ↵Linus Torvalds
'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/accounting, proc: Fix /proc/stat interrupts sum * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: tracepoints/module: Fix disabling tracepoints with taint CRAP or OOT x86/kprobes: Add arch/x86/tools/insn_sanity to .gitignore x86/kprobes: Fix typo transferred from Intel manual * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, syscall: Need __ARCH_WANT_SYS_IPC for 32 bits x86, tsc: Fix SMI induced variation in quick_pit_calibrate() x86, opcode: ANDN and Group 17 in x86-opcode-map.txt x86/kconfig: Move the ZONE_DMA entry under a menu x86/UV2: Add accounting for BAU strong nacks x86/UV2: Ack BAU interrupt earlier x86/UV2: Remove stale no-resources test for UV2 BAU x86/UV2: Work around BAU bug x86/UV2: Fix BAU destination timeout initialization x86/UV2: Fix new UV2 hardware by using native UV2 broadcast mode x86: Get rid of dubious one-bit signed bitfield
2012-01-19PM / Hibernate: Correct additional pages number calculationNamhyung Kim
The struct bm_block is allocated by chain_alloc(), so it'd better counting it in LINKED_PAGE_DATA_SIZE. Signed-off-by: Namhyung Kim <namhyung.kim@lge.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-01-17Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit: (29 commits) audit: no leading space in audit_log_d_path prefix audit: treat s_id as an untrusted string audit: fix signedness bug in audit_log_execve_info() audit: comparison on interprocess fields audit: implement all object interfield comparisons audit: allow interfield comparison between gid and ogid audit: complex interfield comparison helper audit: allow interfield comparison in audit rules Kernel: Audit Support For The ARM Platform audit: do not call audit_getname on error audit: only allow tasks to set their loginuid if it is -1 audit: remove task argument to audit_set_loginuid audit: allow audit matching on inode gid audit: allow matching on obj_uid audit: remove audit_finish_fork as it can't be called audit: reject entry,always rules audit: inline audit_free to simplify the look of generic code audit: drop audit_set_macxattr as it doesn't do anything audit: inline checks for not needing to collect aux records audit: drop some potentially inadvisable likely notations ... Use evil merge to fix up grammar mistakes in Kconfig file. Bad speling and horrible grammar (and copious swearing) is to be expected, but let's keep it to commit messages and comments, rather than expose it to users in config help texts or printouts.
2012-01-17audit: no leading space in audit_log_d_path prefixKees Cook
audit_log_d_path() injects an additional space before the prefix, which serves no purpose and doesn't mix well with other audit_log*() functions that do not sneak extra characters into the log. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Eric Paris <eparis@redhat.com>
2012-01-17audit: fix signedness bug in audit_log_execve_info()Xi Wang
In the loop, a size_t "len" is used to hold the return value of audit_log_single_execve_arg(), which returns -1 on error. In that case the error handling (len <= 0) will be bypassed since "len" is unsigned, and the loop continues with (p += len) being wrapped. Change the type of "len" to signed int to fix the error handling. size_t len; ... for (...) { len = audit_log_single_execve_arg(...); if (len <= 0) break; p += len; } Signed-off-by: Xi Wang <xi.wang@gmail.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2012-01-17audit: comparison on interprocess fieldsPeter Moody
This allows audit to specify rules in which we compare two fields of a process. Such as is the running process uid != to the running process euid? Signed-off-by: Peter Moody <pmoody@google.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2012-01-17audit: implement all object interfield comparisonsPeter Moody
This completes the matrix of interfield comparisons between uid/gid information for the current task and the uid/gid information for inodes. aka I can audit based on differences between the euid of the process and the uid of fs objects. Signed-off-by: Peter Moody <pmoody@google.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2012-01-17audit: allow interfield comparison between gid and ogidEric Paris
Allow audit rules to compare the gid of the running task to the gid of the inode in question. Signed-off-by: Eric Paris <eparis@redhat.com>
2012-01-17audit: complex interfield comparison helperEric Paris
Rather than code the same loop over and over implement a helper function which uses some pointer magic to make it generic enough to be used numerous places as we implement more audit interfield comparisons Signed-off-by: Eric Paris <eparis@redhat.com>
2012-01-17audit: allow interfield comparison in audit rulesEric Paris
We wish to be able to audit when a uid=500 task accesses a file which is uid=0. Or vice versa. This patch introduces a new audit filter type AUDIT_FIELD_COMPARE which takes as an 'enum' which indicates which fields should be compared. At this point we only define the task->uid vs inode->uid, but other comparisons can be added. Signed-off-by: Eric Paris <eparis@redhat.com>