aboutsummaryrefslogtreecommitdiffstats
path: root/kernel
Commit message (Collapse)AuthorAge
* Merge branch 'perf/urgent' into perf/coreIngo Molnar2012-03-05
|\ | | | | | | | | | | | | | | | | | | | | | | Conflicts: tools/perf/builtin-record.c tools/perf/builtin-top.c tools/perf/perf.h tools/perf/util/top.h Merge reason: resolve these cherry-picking conflicts. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * perf/hwbp: Fix a possible memory leakNamhyung Kim2012-02-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If kzalloc() for TYPE_DATA failed on a given cpu, previous chunk of TYPE_INST will be leaked. Fix it. Thanks to Peter Zijlstra for suggesting this better solution. It should work as long as the initial value of the region is all 0's and that's the case of static (per-cpu) memory allocation. Signed-off-by: Namhyung Kim <namhyung.kim@lge.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: 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/1330391978-28070-1-git-send-email-namhyung.kim@lge.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds2012-02-27
| |\ | | | | | | | | | | | | | | | | | | 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()
| | * sched/events: Revert trace_sched_stat_sleeptime()Peter Zijlstra2012-02-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds2012-02-27
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| | * | genirq: Handle pending irqs in irq_startup()Thomas Gleixner2012-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| | * | genirq: Unmask oneshot irqs when thread was not wokenThomas Gleixner2012-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | epoll: introduce POLLFREE to flush ->signalfd_wqh before kfree()Oleg Nesterov2012-02-24
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | Merge branch 'for-linus' of ↵Linus Torvalds2012-02-20
| |\ \ | | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| | * vfs: fix panic in __d_lookup() with high dentry hashtable countsDimitri Sivanich2012-02-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | Merge tag 'for-linus' of git://github.com/rustyrussell/linuxLinus Torvalds2012-02-13
| |\ \ | | |/ | |/| | | | | | | | | | * tag 'for-linus' of git://github.com/rustyrussell/linux: module: fix broken isapnp handling in file2alias module: make module param bint handle nul value
| | * module: make module param bint handle nul valueDave Young2012-02-13
| | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds2012-02-11
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| | * | relay: prevent integer overflow in relay_open()Dan Carpenter2012-02-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | "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>
| | * | block: strip out locking optimization in put_io_context()Tejun Heo2012-02-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds2012-02-10
| |\ \ \ | | |_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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()
| | * | perf: Fix double start/stop in x86_pmu_start()Stephane Eranian2012-02-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | Merge tag 'pm-fixes-for-3.3-rc3' of ↵Linus Torvalds2012-02-04
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| | * | | PM / Freezer: Thaw only kernel threads if freezing of kernel threads failsSrivatsa S. Bhat2012-02-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| | * | | PM / Hibernate: Thaw kernel threads in SNAPSHOT_CREATE_IMAGE ioctl pathSrivatsa S. Bhat2012-02-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
| * | | | kprobes: fix a memory leak in function pre_handler_kretprobe()Jiang Liu2012-02-03
| | |/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | | | static keys: Inline the static_key_enabled() functionJason Baron2012-02-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the jump label enabled case, calling static_key_enabled() results in a function call. The function returns the results of a compare, so it really doesn't need the overhead of a full function call. Let's make it 'static inline' for both the jump label enabled and disabled cases. Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: a.p.zijlstra@chello.nl Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@polymtl.ca Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/201202281849.q1SIn1p2023270@int-mx10.intmail.prod.int.phx2.redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | Merge branch 'perf/jump-labels' into perf/coreIngo Molnar2012-02-28
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge reason: After much naming discussion, there seems to be consensus now - queue it up for v3.4. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | static keys: Introduce 'struct static_key', static_key_true()/false() and ↵Ingo Molnar2012-02-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | static_key_slow_[inc|dec]() So here's a boot tested patch on top of Jason's series that does all the cleanups I talked about and turns jump labels into a more intuitive to use facility. It should also address the various misconceptions and confusions that surround jump labels. Typical usage scenarios: #include <linux/static_key.h> struct static_key key = STATIC_KEY_INIT_TRUE; if (static_key_false(&key)) do unlikely code else do likely code Or: if (static_key_true(&key)) do likely code else do unlikely code The static key is modified via: static_key_slow_inc(&key); ... static_key_slow_dec(&key); The 'slow' prefix makes it abundantly clear that this is an expensive operation. I've updated all in-kernel code to use this everywhere. Note that I (intentionally) have not pushed through the rename blindly through to the lowest levels: the actual jump-label patching arch facility should be named like that, so we want to decouple jump labels from the static-key facility a bit. On non-jump-label enabled architectures static keys default to likely()/unlikely() branches. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jason Baron <jbaron@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: a.p.zijlstra@chello.nl Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.hu Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | jump label: Fix compiler warningJason Baron2012-02-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While cross-compiling on sparc64, I found: kernel/jump_label.c: In function 'jump_label_update': kernel/jump_label.c:447:40: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] Fix by casting to 'unsigned long'. Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: a.p.zijlstra@chello.nl Link: http://lkml.kernel.org/r/08026cbc6df80619cae833ef1ebbbc43efab69ab.1329851692.git.jbaron@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | jump label: Add a WARN() if jump label key count goes negativeJason Baron2012-02-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The count on a jump label key should never go negative. Add a WARN() to check for this condition. Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: rostedt@goodmis.org Cc: mathieu.desnoyers@efficios.com Cc: davem@davemloft.net Cc: ddaney.cavm@gmail.com Cc: a.p.zijlstra@chello.nl Link: http://lkml.kernel.org/r/3c68556121be4d1920417a3fe367da1ec38246b4.1329851692.git.jbaron@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | ftrace, perf: Add filter support for function trace eventJiri Olsa2012-02-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adding support to filter function trace event via perf interface. It is now possible to use filter interface in the perf tool like: perf record -e ftrace:function --filter="(ip == mm_*)" ls The filter syntax is restricted to the the 'ip' field only, and following operators are accepted '==' '!=' '||', ending up with the filter strings like: ip == f1[, ]f2 ... || ip != f3[, ]f4 ... with comma ',' or space ' ' as a function separator. If the space ' ' is used as a separator, the right side of the assignment needs to be enclosed in double quotes '"', e.g.: perf record -e ftrace:function --filter '(ip == do_execve,sys_*,ext*)' ls perf record -e ftrace:function --filter '(ip == "do_execve,sys_*,ext*")' ls perf record -e ftrace:function --filter '(ip == "do_execve sys_* ext*")' ls The '==' operator adds trace filter with same effect as would be added via set_ftrace_filter file. The '!=' operator adds trace filter with same effect as would be added via set_ftrace_notrace file. The right side of the '!=', '==' operators is list of functions or regexp. to be added to filter separated by space. The '||' operator is used for connecting multiple filter definitions together. It is possible to have more than one '==' and '!=' operators within one filter string. Link: http://lkml.kernel.org/r/1329317514-8131-8-git-send-email-jolsa@redhat.com Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | | ftrace: Allow to specify filter field type for ftrace eventsJiri Olsa2012-02-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adding FILTER_TRACE_FN event field type for function tracepoint event, so it can be properly recognized within filtering code. Currently all fields of ftrace subsystem events share the common field type FILTER_OTHER. Since the function trace fields need special care within the filtering code we need to recognize it properly, hence adding the FILTER_TRACE_FN event type. Adding filter parameter to the FTRACE_ENTRY macro, to specify the filter field type for the event. Link: http://lkml.kernel.org/r/1329317514-8131-7-git-send-email-jolsa@redhat.com Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | | ftrace, perf: Add support to use function tracepoint in perfJiri Olsa2012-02-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adding perf registration support for the ftrace function event, so it is now possible to register it via perf interface. The perf_event struct statically contains ftrace_ops as a handle for function tracer. The function tracer is registered/unregistered in open/close actions. To be efficient, we enable/disable ftrace_ops each time the traced process is scheduled in/out (via TRACE_REG_PERF_(ADD|DELL) handlers). This way tracing is enabled only when the process is running. Intentionally using this way instead of the event's hw state PERF_HES_STOPPED, which would not disable the ftrace_ops. It is now possible to use function trace within perf commands like: perf record -e ftrace:function ls perf stat -e ftrace:function ls Allowed only for root. Link: http://lkml.kernel.org/r/1329317514-8131-6-git-send-email-jolsa@redhat.com Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | | ftrace: Add FTRACE_ENTRY_REG macro to allow event registrationJiri Olsa2012-02-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adding FTRACE_ENTRY_REG macro so particular ftrace entries could specify registration function and thus become accesible via perf. This will be used in upcomming patch for function trace. Link: http://lkml.kernel.org/r/1329317514-8131-5-git-send-email-jolsa@redhat.com Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | | ftrace, perf: Add add/del tracepoint perf registration actionsJiri Olsa2012-02-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adding TRACE_REG_PERF_ADD and TRACE_REG_PERF_DEL to handle perf event schedule in/out actions. The add action is invoked for when the perf event is scheduled in, while the del action is invoked when the event is scheduled out. Link: http://lkml.kernel.org/r/1329317514-8131-4-git-send-email-jolsa@redhat.com Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | | ftrace, perf: Add open/close tracepoint perf registration actionsJiri Olsa2012-02-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adding TRACE_REG_PERF_OPEN and TRACE_REG_PERF_CLOSE to differentiate register/unregister from open/close actions. The register/unregister actions are invoked for the first/last tracepoint user when opening/closing the event. The open/close actions are invoked for each tracepoint user when opening/closing the event. Link: http://lkml.kernel.org/r/1329317514-8131-3-git-send-email-jolsa@redhat.com Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | | ftrace: Add enable/disable ftrace_ops control interfaceJiri Olsa2012-02-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adding a way to temporarily enable/disable ftrace_ops. The change follows the same way as 'global' ftrace_ops are done. Introducing 2 global ftrace_ops - control_ops and ftrace_control_list which take over all ftrace_ops registered with FTRACE_OPS_FL_CONTROL flag. In addition new per cpu flag called 'disabled' is also added to ftrace_ops to provide the control information for each cpu. When ftrace_ops with FTRACE_OPS_FL_CONTROL is registered, it is set as disabled for all cpus. The ftrace_control_list contains all the registered 'control' ftrace_ops. The control_ops provides function which iterates ftrace_control_list and does the check for 'disabled' flag on current cpu. Adding 3 inline functions: ftrace_function_local_disable/ftrace_function_local_enable - enable/disable the ftrace_ops on current cpu ftrace_function_local_disabled - get disabled ftrace_ops::disabled value for current cpu Link: http://lkml.kernel.org/r/1329317514-8131-2-git-send-email-jolsa@redhat.com Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | | tracing: Don't use p->len field to determine output in __print_*() functionsSteven Rostedt2012-02-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If more than one __print_*() function is used in a tracepoint (__print_flags(), __print_symbols(), etc), then the temp seq buffer will not be zero on entry. Using the temp seq buffer's length to know if data has been printed or not in the current function is incorrect and may produce incorrect results. Currently, no in-tree tracepoint causes this bug, but new ones may be created. Cc: Andrew Vagin <avagin@openvz.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | | tracing: Don't print an extra separator of flagsAndrey Vagin2012-02-20
|/ / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If __print_flags() is used after another __print_*() function, the temp seq_file buffer will not be empty on entry, and the delimiter will be printed even though there's just one field. We get something like: |S instead of just: S This is because the length of the temp seq buffer is used to determine if the delimiter is printed or not. But this algorithm fails when the seq buffer is not empty on entry, and the delimiter will be printed because it thinks that a previous field was already printed. Link: http://lkml.kernel.org/r/1329650167-480655-1-git-send-email-avagin@openvz.org Signed-off-by: Andrew Vagin <avagin@openvz.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | Merge branch 'tip/perf/core' of ↵Ingo Molnar2012-02-17
|\ \ \ \ | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/core
| * | | | tracing/trivial: Use kcalloc instead of kzalloc to allocate arrayThomas Meyer2012-02-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The advantage of kcalloc is, that will prevent integer overflows which could result from the multiplication of number of elements and size and it is also a bit nicer to read. The semantic patch that makes this change is available in https://lkml.org/lkml/2011/11/25/107 Link: http://lkml.kernel.org/r/1322600880.1534.347.camel@localhost.localdomain Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | printk/tracing: Add console output tracingJohannes Berg2012-02-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a printk.console trace point to record any printk messages into the trace, regardless of the current console loglevel. This can help correlate (existing) printk debugging with other tracing. Link: http://lkml.kernel.org/r/1322161388.5366.54.camel@jlt3.sipsolutions.net Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | ftrace: sched_switch plugin is deprecatedGeunsik Lim2012-02-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Actually, sched_switch function tracer is merged into wakeup/wakeup_rt Update 'mini-HOWTO' for ftrace(Kernel function tracer). If we want to trace "sched:sched_switch" to trace sched_switch func, We may utilize event option.(e.g: trace-cmd list -e | grep sched) This patch is based on Linux-3.3.rc2-SMP-PREEMPT Link: http://lkml.kernel.org/r/1328695537-15081-1-git-send-email-geunsik.lim@gmail.com Cc: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Geunsik Lim <geunsik.lim@samsung.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | tracing/softirq: Move __raise_softirq_irqoff() out of headerSteven Rostedt2012-02-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The __raise_softirq_irqoff() contains a tracepoint. As tracepoints in headers can cause issues, and not to mention, bloats the kernel when they are in a static inline, it is best to move the function that contains the tracepoint out of the header and into softirq.c. Link: http://lkml.kernel.org/r/20120118120711.GB14863@elte.hu Suggested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | | | ftrace: Change filter/notrace set functions to return exit codeJiri Olsa2012-02-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the ftrace_set_filter and ftrace_set_notrace functions do not return any return code. So there's no way for ftrace_ops user to tell wether the filter was correctly applied. The set_ftrace_filter interface returns error in case the filter did not match: # echo krava > set_ftrace_filter bash: echo: write error: Invalid argument Changing both ftrace_set_filter and ftrace_set_notrace functions to return zero if the filter was applied correctly or -E* values in case of error. Link: http://lkml.kernel.org/r/1325495060-6402-2-git-send-email-jolsa@redhat.com Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | | | watchdog: Fix code/comments mismatchesFernando Luis Vázquez Cao2012-02-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reflect the change in the soft and hard lockup thresholds and their relation to the frequency of the hrtimer and NMI events in the code comments. While at it, remove references to files that do not exist anymore. Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> Signed-off-by: Don Zickus <dzickus@redhat.com> Link: http://lkml.kernel.org/r/1328827342-6253-3-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | Merge branch 'perf/urgent' into perf/coreArnaldo Carvalho de Melo2012-02-06
|\ \ \ \ \ | |/ / / / |/| / / / | |/ / / | | | | | | | | | | | | So that we can get the perf bench exec stack fixes and then apply the remaining fix for the files added after what is in perf/urgent. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| * | | Fix race in process_vm_rw_coreChristopher Yeoh2012-02-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| | | |
| | \ \
| | \ \
| | \ \
| | \ \
| | \ \
| *-----. \ \ Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus', ↵Linus Torvalds2012-02-02
| |\ \ \ \ \ \ | | |_|_|_|/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | '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
| | | | * | | sched/rt: Fix task stack corruption under __ARCH_WANT_INTERRUPTS_ON_CTXSWChanho Min2012-01-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| | | | * | | sched: Fix ancient race in do_exit()Yasunori Goto2012-01-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| | | | * | | sched/nohz: Fix nohz cpu idle load balancing state with cpu hotplugSuresh Siddha2012-01-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| | | | * | | sched/s390: Fix compile error in sched/core.cChristian Borntraeger2012-01-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| | | | * | | sched: Fix rq->nr_uninterruptible update racePeter Zijlstra2012-01-26
| | | | |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
generated by cgit v1.2.2 (git 2.25.0) at 2025-02-25 11:31:07 -0500