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| | * hrtimer: Fix extra wakeups from __remove_hrtimer()Jeff Ohlstein2011-12-091-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 27c9cd7e601632b3794e1c3344d37b86917ffb43 upstream. __remove_hrtimer() attempts to reprogram the clockevent device when the timer being removed is the next to expire. However, __remove_hrtimer() reprograms the clockevent *before* removing the timer from the timerqueue and thus when hrtimer_force_reprogram() finds the next timer to expire it finds the timer we're trying to remove. This is especially noticeable when the system switches to NOHz mode and the system tick is removed. The timer tick is removed from the system but the clockevent is programmed to wakeup in another HZ anyway. Silence the extra wakeup by removing the timer from the timerqueue before calling hrtimer_force_reprogram() so that we actually program the clockevent for the next timer to expire. This was broken by 998adc3 "hrtimers: Convert hrtimers to use timerlist infrastructure". Signed-off-by: Jeff Ohlstein <johlstei@codeaurora.org> Link: http://lkml.kernel.org/r/1321660030-8520-1-git-send-email-johlstei@codeaurora.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * timekeeping: add arch_offset hook to ktime_get functionsHector Palacios2011-12-091-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit d004e024058a0eaca097513ce62cbcf978913e0a upstream. ktime_get and ktime_get_ts were calling timekeeping_get_ns() but later they were not calling arch_gettimeoffset() so architectures using this mechanism returned 0 ns when calling these functions. This happened for example when running Busybox's ping which calls syscall(__NR_clock_gettime, CLOCK_MONOTONIC, ts) which eventually calls ktime_get. As a result the returned ping travel time was zero. Signed-off-by: Hector Palacios <hector.palacios@digi.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * cgroup_freezer: fix freezing groups with stopped tasksMichal Hocko2011-12-091-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 884a45d964dd395eda945842afff5e16bcaedf56 upstream. 2d3cbf8b (cgroup_freezer: update_freezer_state() does incorrect state transitions) removed is_task_frozen_enough and replaced it with a simple frozen call. This, however, breaks freezing for a group with stopped tasks because those cannot be frozen and so the group remains in CGROUP_FREEZING state (update_if_frozen doesn't count stopped tasks) and never reaches CGROUP_FROZEN. Let's add is_task_frozen_enough back and use it at the original locations (update_if_frozen and try_to_freeze_cgroup). Semantically we consider stopped tasks as frozen enough so we should consider both cases when testing frozen tasks. Testcase: mkdir /dev/freezer mount -t cgroup -o freezer none /dev/freezer mkdir /dev/freezer/foo sleep 1h & pid=$! kill -STOP $pid echo $pid > /dev/freezer/foo/tasks echo FROZEN > /dev/freezer/foo/freezer.state while true do cat /dev/freezer/foo/freezer.state [ "`cat /dev/freezer/foo/freezer.state`" = "FROZEN" ] && break sleep 1 done echo OK Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Tomasz Buchert <tomasz.buchert@inria.fr> Cc: Paul Menage <paul@paulmenage.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Tejun Heo <htejun@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * genirq: fix regression in irqfixup, irqpollEdward Donovan2011-12-091-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 52553ddffad76ccf192d4dd9ce88d5818f57f62a upstream. Commit fa27271bc8d2("genirq: Fixup poll handling") introduced a regression that broke irqfixup/irqpoll for some hardware configurations. Amidst reorganizing 'try_one_irq', that patch removed a test that checked for 'action->handler' returning IRQ_HANDLED, before acting on the interrupt. Restoring this test back returns the functionality lost since 2.6.39. In the current set of tests, after 'action' is set, it must precede '!action->next' to take effect. With this and my previous patch to irq/spurious.c, c75d720fca8a, all IRQ regressions that I have encountered are fixed. Signed-off-by: Edward Donovan <edward.donovan@numble.net> Reported-and-tested-by: Rogério Brito <rbrito@ime.usp.br> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * genirq: Fix irqfixup, irqpoll regressionEdward Donovan2011-11-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit c75d720fca8a91ce99196d33adea383621027bf2 upstream. commit d05c65fff0 ("genirq: spurious: Run only one poller at a time") introduced a regression, leaving the boot options 'irqfixup' and 'irqpoll' non-functional. The patch placed tests in each function, to exit if the function is already running. The test in 'misrouted_irq' exited when it should have proceeded, effectively disabling 'misrouted_irq' and 'poll_spurious_irqs'. The check for an already running poller needs to be "!= 1" not "== 1" as "1" is the value when the first poller starts running. Signed-off-by: Edward Donovan <edward.donovan@numble.net> Cc: maciej.rutecki@gmail.com Link: http://lkml.kernel.org/r/1320175784-6745-1-git-send-email-edward.donovan@numble.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * PM / Suspend: Off by one in pm_suspend()Dan Carpenter2011-11-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 528f7ce6e439edeac38f6b3f8561f1be129b5e91 upstream. In enter_state() we use "state" as an offset for the pm_states[] array. The pm_states[] array only has PM_SUSPEND_MAX elements so this test is off by one. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * ptrace: don't clear GROUP_STOP_SIGMASK on double-stopOleg Nesterov2011-11-111-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [This does not correspond to any specific patch in the upstream tree as it was fixed accidentally by rewriting the code in the 3.1 release] https://bugzilla.redhat.com/show_bug.cgi?id=740121 1. Luke Macken triggered WARN_ON(!(group_stop & GROUP_STOP_SIGMASK)) in do_signal_stop(). This is because do_signal_stop() clears GROUP_STOP_SIGMASK part unconditionally but doesn't update it if task_is_stopped(). 2. Looking at this problem I noticed that WARN_ON_ONCE(!ptrace) is not right, a stopped-but-resumed tracee can clone the untraced thread in the SIGNAL_STOP_STOPPED group, the new thread can start another group-stop. Remove this warning, we need more fixes to make it true. Reported-by: Luke Macken <lmacken@redhat.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * genirq: Add IRQF_RESUME_EARLY and resume such IRQs earlierIan Campbell2011-11-111-7/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 9bab0b7fbaceec47d32db51cd9e59c82fb071f5a upstream. This adds a mechanism to resume selected IRQs during syscore_resume instead of dpm_resume_noirq. Under Xen we need to resume IRQs associated with IPIs early enough that the resched IPI is unmasked and we can therefore schedule ourselves out of the stop_machine where the suspend/resume takes place. This issue was introduced by 676dc3cf5bc3 "xen: Use IRQF_FORCE_RESUME". Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Jeremy Fitzhardinge <Jeremy.Fitzhardinge@citrix.com> Cc: xen-devel <xen-devel@lists.xensource.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1318713254.11016.52.camel@dagon.hellion.org.uk Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * tracing: Fix returning of duplicate data after EOF in trace_pipe_rawSteven Rostedt2011-11-111-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 436fc280261dcfce5af38f08b89287750dc91cd2 upstream. The trace_pipe_raw handler holds a cached page from the time the file is opened to the time it is closed. The cached page is used to handle the case of the user space buffer being smaller than what was read from the ring buffer. The left over buffer is held in the cache so that the next read will continue where the data left off. After EOF is returned (no more data in the buffer), the index of the cached page is set to zero. If a user app reads the page again after EOF, the check in the buffer will see that the cached page is less than page size and will return the cached page again. This will cause reading the trace_pipe_raw again after EOF to return duplicate data, making the output look like the time went backwards but instead data is just repeated. The fix is to not reset the index right after all data is read from the cache, but to reset it after all data is read and more data exists in the ring buffer. Reported-by: Jeremy Eder <jeder@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * time: Change jiffies_to_clock_t() argument type to unsigned longhank2011-11-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit cbbc719fccdb8cbd87350a05c0d33167c9b79365 upstream. The parameter's origin type is long. On an i386 architecture, it can easily be larger than 0x80000000, causing this function to convert it to a sign-extended u64 type. Change the type to unsigned long so we get the correct result. Signed-off-by: hank <pyu@redhat.com> Cc: John Stultz <john.stultz@linaro.org> [ build fix ] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * kmod: prevent kmod_loop_msg overflow in __request_module()Jiri Kosina2011-11-111-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 37252db6aa576c34fd794a5a54fb32d7a8b3a07a upstream. Due to post-increment in condition of kmod_loop_msg in __request_module(), the system log can be spammed by much more than 5 instances of the 'runaway loop' message if the number of events triggering it makes the kmod_loop_msg to overflow. Fix that by making sure we never increment it past the threshold. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | | Added support for ariesPawit Pornkitprasan2011-12-241-0/+86
|/ / | | | | | | | | Reverts "S5PC11X : FIMC apply v4l2 standard for asynchronous dequeue/queue" 5f4b037e6ebb18d65a3ac896032eb559d7fe2baf
* | Fix "time: Catch invalid timespec sleep values in ↵Arve Hjønnevåg2011-11-221-1/+1
| | | | | | | | | | | | __timekeeping_inject_sleeptime" to compile on 3.0 Change-Id: I1225f279cda04dedbfb7f853f6b58f1032bd6d2b
* | time: Catch invalid timespec sleep values in __timekeeping_inject_sleeptimeJohn Stultz2011-11-221-0/+6
| | | | | | | | | | | | | | | | | | Arve suggested making sure we catch possible negative sleep time intervals that could be passed into timekeeping_inject_sleeptime. CC: Arve Hjønnevåg <arve@android.com> CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
* | Merge commit 'v3.0.8' into android-3.0Colin Cross2011-10-2713-81/+172
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| * cputimer: Cure lock inversionPeter Zijlstra2011-10-251-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit bcd5cff7216f9b2de0a148cc355eac199dc6f1cf upstream. There's a lock inversion between the cputimer->lock and rq->lock; notably the two callchains involved are: update_rlimit_cpu() sighand->siglock set_process_cpu_timer() cpu_timer_sample_group() thread_group_cputimer() cputimer->lock thread_group_cputime() task_sched_runtime() ->pi_lock rq->lock scheduler_tick() rq->lock task_tick_fair() update_curr() account_group_exec() cputimer->lock Where the first one is enabling a CLOCK_PROCESS_CPUTIME_ID timer, and the second one is keeping up-to-date. This problem was introduced by e8abccb7193 ("posix-cpu-timers: Cure SMP accounting oddities"). Cure the problem by removing the cputimer->lock and rq->lock nesting, this leaves concurrent enablers doing duplicate work, but the time wasted should be on the same order otherwise wasted spinning on the lock and the greater-than assignment filter should ensure we preserve monotonicity. Reported-by: Dave Jones <davej@redhat.com> Reported-by: Simon Kirby <sim@hostway.ca> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Link: http://lkml.kernel.org/r/1318928713.21167.4.camel@twins Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * Avoid using variable-length arrays in kernel/sys.cLinus Torvalds2011-10-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit a84a79e4d369a73c0130b5858199e949432da4c6 upstream. The size is always valid, but variable-length arrays generate worse code for no good reason (unless the function happens to be inlined and the compiler sees the length for the simple constant it is). Also, there seems to be some code generation problem on POWER, where Henrik Bakken reports that register r28 can get corrupted under some subtle circumstances (interrupt happening at the wrong time?). That all indicates some seriously broken compiler issues, but since variable length arrays are bad regardless, there's little point in trying to chase it down. "Just don't do that, then". Reported-by: Henrik Grindal Bakken <henribak@cisco.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * ftrace: Fix regression where ftrace breaks when modules are loadedSteven Rostedt2011-10-161-2/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit f7bc8b61f65726ff98f52e286b28e294499d7a08 upstream. Enabling function tracer to trace all functions, then load a module and then disable function tracing will cause ftrace to fail. This can also happen by enabling function tracing on the command line: ftrace=function and during boot up, modules are loaded, then you disable function tracing with 'echo nop > current_tracer' you will trigger a bug in ftrace that will shut itself down. The reason is, the new ftrace code keeps ref counts of all ftrace_ops that are registered for tracing. When one or more ftrace_ops are registered, all the records that represent the functions that the ftrace_ops will trace have a ref count incremented. If this ref count is not zero, when the code modification runs, that function will be enabled for tracing. If the ref count is zero, that function will be disabled from tracing. To make sure the accounting was working, FTRACE_WARN_ON()s were added to updating of the ref counts. If the ref count hits its max (> 2^30 ftrace_ops added), or if the ref count goes below zero, a FTRACE_WARN_ON() is triggered which disables all modification of code. Since it is common for ftrace_ops to trace all functions in the kernel, instead of creating > 20,000 hash items for the ftrace_ops, the hash count is just set to zero, and it represents that the ftrace_ops is to trace all functions. This is where the issues arrise. If you enable function tracing to trace all functions, and then add a module, the modules function records do not get the ref count updated. When the function tracer is disabled, all function records ref counts are subtracted. Since the modules never had their ref counts incremented, they go below zero and the FTRACE_WARN_ON() is triggered. The solution to this is rather simple. When modules are loaded, and their functions are added to the the ftrace pool, look to see if any ftrace_ops are registered that trace all functions. And for those, update the ref count for the module function records. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * ftrace: Fix regression of :mod:module function enablingSteven Rostedt2011-10-162-10/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 43dd61c9a09bd413e837df829e6bfb42159be52a upstream. The new code that allows different utilities to pick and choose what functions they trace broke the :mod: hook that allows users to trace only functions of a particular module. The reason is that the :mod: hook bypasses the hash that is setup to allow individual users to trace their own functions and uses the global hash directly. But if the global hash has not been set up, it will cause a bug: echo '*:mod:radeon' > /sys/kernel/debug/set_ftrace_filter produces: [drm:drm_mode_getfb] *ERROR* invalid framebuffer id [drm:radeon_crtc_page_flip] *ERROR* failed to reserve new rbo buffer before flip BUG: unable to handle kernel paging request at ffffffff8160ec90 IP: [<ffffffff810d9136>] add_hash_entry+0x66/0xd0 PGD 1a05067 PUD 1a09063 PMD 80000000016001e1 Oops: 0003 [#1] SMP Jul 7 04:02:28 phyllis kernel: [55303.858604] CPU 1 Modules linked in: cryptd aes_x86_64 aes_generic binfmt_misc rfcomm bnep ip6table_filter hid radeon r8169 ahci libahci mii ttm drm_kms_helper drm video i2c_algo_bit intel_agp intel_gtt Pid: 10344, comm: bash Tainted: G WC 3.0.0-rc5 #1 Dell Inc. Inspiron N5010/0YXXJJ RIP: 0010:[<ffffffff810d9136>] [<ffffffff810d9136>] add_hash_entry+0x66/0xd0 RSP: 0018:ffff88003a96bda8 EFLAGS: 00010246 RAX: ffff8801301735c0 RBX: ffffffff8160ec80 RCX: 0000000000306ee0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880137c92940 RBP: ffff88003a96bdb8 R08: ffff880137c95680 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff81c9df78 R13: ffff8801153d1000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f329c18a700(0000) GS:ffff880137c80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffff8160ec90 CR3: 000000003002b000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process bash (pid: 10344, threadinfo ffff88003a96a000, task ffff88012fcfc470) Stack: 0000000000000fd0 00000000000000fc ffff88003a96be38 ffffffff810d92f5 ffff88011c4c4e00 ffff880000000000 000000000b69f4d0 ffffffff8160ec80 ffff8800300e6f06 0000000081130295 0000000000000282 ffff8800300e6f00 Call Trace: [<ffffffff810d92f5>] match_records+0x155/0x1b0 [<ffffffff810d940c>] ftrace_mod_callback+0xbc/0x100 [<ffffffff810dafdf>] ftrace_regex_write+0x16f/0x210 [<ffffffff810db09f>] ftrace_filter_write+0xf/0x20 [<ffffffff81166e48>] vfs_write+0xc8/0x190 [<ffffffff81167001>] sys_write+0x51/0x90 [<ffffffff815c7e02>] system_call_fastpath+0x16/0x1b Code: 48 8b 33 31 d2 48 85 f6 75 33 49 89 d4 4c 03 63 08 49 8b 14 24 48 85 d2 48 89 10 74 04 48 89 42 08 49 89 04 24 4c 89 60 08 31 d2 RIP [<ffffffff810d9136>] add_hash_entry+0x66/0xd0 RSP <ffff88003a96bda8> CR2: ffffffff8160ec90 ---[ end trace a5d031828efdd88e ]--- Reported-by: Brian Marete <marete@toshnix.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * posix-cpu-timers: Cure SMP wobblesPeter Zijlstra2011-10-162-26/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit d670ec13178d0fd8680e6742a2bc6e04f28f87d8 upstream. David reported: Attached below is a watered-down version of rt/tst-cpuclock2.c from GLIBC. Just build it with "gcc -o test test.c -lpthread -lrt" or similar. Run it several times, and you will see cases where the main thread will measure a process clock difference before and after the nanosleep which is smaller than the cpu-burner thread's individual thread clock difference. This doesn't make any sense since the cpu-burner thread is part of the top-level process's thread group. I've reproduced this on both x86-64 and sparc64 (using both 32-bit and 64-bit binaries). For example: [davem@boricha build-x86_64-linux]$ ./test process: before(0.001221967) after(0.498624371) diff(497402404) thread: before(0.000081692) after(0.498316431) diff(498234739) self: before(0.001223521) after(0.001240219) diff(16698) [davem@boricha build-x86_64-linux]$ The diff of 'process' should always be >= the diff of 'thread'. I make sure to wrap the 'thread' clock measurements the most tightly around the nanosleep() call, and that the 'process' clock measurements are the outer-most ones. --- #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <time.h> #include <fcntl.h> #include <string.h> #include <errno.h> #include <pthread.h> static pthread_barrier_t barrier; static void *chew_cpu(void *arg) { pthread_barrier_wait(&barrier); while (1) __asm__ __volatile__("" : : : "memory"); return NULL; } int main(void) { clockid_t process_clock, my_thread_clock, th_clock; struct timespec process_before, process_after; struct timespec me_before, me_after; struct timespec th_before, th_after; struct timespec sleeptime; unsigned long diff; pthread_t th; int err; err = clock_getcpuclockid(0, &process_clock); if (err) return 1; err = pthread_getcpuclockid(pthread_self(), &my_thread_clock); if (err) return 1; pthread_barrier_init(&barrier, NULL, 2); err = pthread_create(&th, NULL, chew_cpu, NULL); if (err) return 1; err = pthread_getcpuclockid(th, &th_clock); if (err) return 1; pthread_barrier_wait(&barrier); err = clock_gettime(process_clock, &process_before); if (err) return 1; err = clock_gettime(my_thread_clock, &me_before); if (err) return 1; err = clock_gettime(th_clock, &th_before); if (err) return 1; sleeptime.tv_sec = 0; sleeptime.tv_nsec = 500000000; nanosleep(&sleeptime, NULL); err = clock_gettime(th_clock, &th_after); if (err) return 1; err = clock_gettime(my_thread_clock, &me_after); if (err) return 1; err = clock_gettime(process_clock, &process_after); if (err) return 1; diff = process_after.tv_nsec - process_before.tv_nsec; printf("process: before(%lu.%.9lu) after(%lu.%.9lu) diff(%lu)\n", process_before.tv_sec, process_before.tv_nsec, process_after.tv_sec, process_after.tv_nsec, diff); diff = th_after.tv_nsec - th_before.tv_nsec; printf("thread: before(%lu.%.9lu) after(%lu.%.9lu) diff(%lu)\n", th_before.tv_sec, th_before.tv_nsec, th_after.tv_sec, th_after.tv_nsec, diff); diff = me_after.tv_nsec - me_before.tv_nsec; printf("self: before(%lu.%.9lu) after(%lu.%.9lu) diff(%lu)\n", me_before.tv_sec, me_before.tv_nsec, me_after.tv_sec, me_after.tv_nsec, diff); return 0; } This is due to us using p->se.sum_exec_runtime in thread_group_cputime() where we iterate the thread group and sum all data. This does not take time since the last schedule operation (tick or otherwise) into account. We can cure this by using task_sched_runtime() at the cost of having to take locks. This also means we can (and must) do away with thread_group_sched_runtime() since the modified thread_group_cputime() is now more accurate and would deadlock when called from thread_group_sched_runtime(). Aside of that it makes the function safe on 32 bit systems. The old code added t->se.sum_exec_runtime unprotected. sum_exec_runtime is a 64bit value and could be changed on another cpu at the same time. Reported-by: David Miller <davem@davemloft.net> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1314874459.7945.22.camel@twins Tested-by: David Miller <davem@davemloft.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * sched: Fix up wchan borkageSimon Kirby2011-10-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 6ebbe7a07b3bc40b168d2afc569a6543c020d2e3 upstream. Commit c259e01a1ec ("sched: Separate the scheduler entry for preemption") contained a boo-boo wrecking wchan output. It forgot to put the new schedule() function in the __sched section and thereby doesn't get properly ignored for things like wchan. Tested-by: Simon Kirby <sim@hostway.ca> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110923000346.GA25425@hostway.ca Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * sched/rt: Migrate equal priority tasks to available CPUsShawn Bohrer2011-10-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 3be209a8e22cedafc1b6945608b7bb8d9887ab61 upstream. Commit 43fa5460fe60dea5c610490a1d263415419c60f6 ("sched: Try not to migrate higher priority RT tasks") also introduced a change in behavior which keeps RT tasks on the same CPU if there is an equal priority RT task currently running even if there are empty CPUs available. This can cause unnecessary wakeup latencies, and can prevent the scheduler from balancing all RT tasks across available CPUs. This change causes an RT task to search for a new CPU if an equal priority RT task is already running on wakeup. Lower priority tasks will still have to wait on higher priority tasks, but the system should still balance out because there is always the possibility that if there are both a high and low priority RT tasks on a given CPU that the high priority task could wakeup while the low priority task is running and force it to search for a better runqueue. Signed-off-by: Shawn Bohrer <sbohrer@rgmadvisors.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Tested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1315837684-18733-1-git-send-email-sbohrer@rgmadvisors.com Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * workqueue: lock cwq access in drain_workqueueThomas Tuttle2011-10-031-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit fa2563e41c3d6d6e8af437643981ed28ae0cb56d upstream. Take cwq->gcwq->lock to avoid racing between drain_workqueue checking to make sure the workqueues are empty and cwq_dec_nr_in_flight decrementing and then incrementing nr_active when it activates a delayed work. We discovered this when a corner case in one of our drivers resulted in us trying to destroy a workqueue in which the remaining work would always requeue itself again in the same workqueue. We would hit this race condition and trip the BUG_ON on workqueue.c:3080. Signed-off-by: Thomas Tuttle <ttuttle@chromium.org> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * genirq: Make irq_shutdown() symmetric vs. irq_startup againGeert Uytterhoeven2011-10-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit ed585a651681e822089087b426e6ebfb6d3d9873 upstream. If an irq_chip provides .irq_shutdown(), but neither of .irq_disable() or .irq_mask(), free_irq() crashes when jumping to NULL. Fix this by only trying .irq_disable() and .irq_mask() if there's no .irq_shutdown() provided. This revives the symmetry with irq_startup(), which tries .irq_startup(), .irq_enable(), and irq_unmask(), and makes it consistent with the comment for irq_chip.irq_shutdown() in <linux/irq.h>, which says: * @irq_shutdown: shut down the interrupt (defaults to ->disable if NULL) This is also how __free_irq() behaved before the big overhaul, cfr. e.g. 3b56f0585fd4c02d047dc406668cb40159b2d340 ("genirq: Remove bogus conditional"), where the core interrupt code always overrode .irq_shutdown() to .irq_disable() if .irq_shutdown() was NULL. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: linux-m68k@lists.linux-m68k.org Link: http://lkml.kernel.org/r/1315742394-16036-2-git-send-email-geert@linux-m68k.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * sched: Fix a memory leak in __sdt_free()WANG Cong2011-10-031-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit feff8fa0075bdfd43c841e9d689ed81adda988d6 upstream. This patch fixes the following memory leak: unreferenced object 0xffff880107266800 (size 512): comm "sched-powersave", pid 3718, jiffies 4323097853 (age 27495.450s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff81133940>] create_object+0x187/0x28b [<ffffffff814ac103>] kmemleak_alloc+0x73/0x98 [<ffffffff811232ba>] __kmalloc_node+0x104/0x159 [<ffffffff81044b98>] kzalloc_node.clone.97+0x15/0x17 [<ffffffff8104cb90>] build_sched_domains+0xb7/0x7f3 [<ffffffff8104d4df>] partition_sched_domains+0x1db/0x24a [<ffffffff8109ee4a>] do_rebuild_sched_domains+0x3b/0x47 [<ffffffff810a00c7>] rebuild_sched_domains+0x10/0x12 [<ffffffff8104d5ba>] sched_power_savings_store+0x6c/0x7b [<ffffffff8104d5df>] sched_mc_power_savings_store+0x16/0x18 [<ffffffff8131322c>] sysdev_class_store+0x20/0x22 [<ffffffff81193876>] sysfs_write_file+0x108/0x144 [<ffffffff81135b10>] vfs_write+0xaf/0x102 [<ffffffff81135d23>] sys_write+0x4d/0x74 [<ffffffff814c8a42>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff Signed-off-by: WANG Cong <amwang@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1313671017-4112-1-git-send-email-amwang@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * sched: Move blk_schedule_flush_plug() out of __schedule()Thomas Gleixner2011-10-031-10/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 9c40cef2b799f9b5e7fa5de4d2ad3a0168ba118c upstream. There is no real reason to run blk_schedule_flush_plug() with interrupts and preemption disabled. Move it into schedule() and call it when the task is going voluntarily to sleep. There might be false positives when the task is woken between that call and actually scheduling, but that's not really different from being woken immediately after switching away. This fixes a deadlock in the scheduler where the blk_schedule_flush_plug() callchain enables interrupts and thereby allows a wakeup to happen of the task that's going to sleep. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-dwfxtra7yg1b5r65m32ywtct@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * sched: Separate the scheduler entry for preemptionThomas Gleixner2011-10-031-5/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit c259e01a1ec90063042f758e409cd26b2a0963c8 upstream. Block-IO and workqueues call into notifier functions from the scheduler core code with interrupts and preemption disabled. These calls should be made before entering the scheduler core. To simplify this, separate the scheduler core code into __schedule(). __schedule() is directly called from the places which set PREEMPT_ACTIVE and from schedule(). This allows us to add the work checks into schedule(), so they are only called when a task voluntary goes to sleep. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20110622174918.813258321@linutronix.de Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * alarmtimers: Avoid possible denial of service with high freq periodic timersJohn Stultz2011-10-031-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 6af7e471e5a7746b8024d70b4363d3dfe41d36b8 upstream. Its possible to jam up the alarm timers by setting very small interval timers, which will cause the alarmtimer subsystem to spend all of its time firing and restarting timers. This can effectivly lock up a box. A deeper fix is needed, closely mimicking the hrtimer code, but for now just cap the interval to 100us to avoid userland hanging the system. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * alarmtimers: Memset itimerspec passed into alarm_timer_getJohn Stultz2011-10-031-0/+2
| | | | | | | | | | | | | | | | | | | | | | commit ea7802f630d356acaf66b3c0b28c00a945fc35dc upstream. Following common_timer_get, zero out the itimerspec passed in. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * alarmtimers: Avoid possible null pointer traversalJohn Stultz2011-10-031-5/+2
| | | | | | | | | | | | | | | | | | | | | | | | commit 971c90bfa2f0b4fe52d6d9002178d547706f1343 upstream. We don't check if old_setting is non null before assigning it, so correct this. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * kernel/printk: do not turn off bootconsole in printk_late_init() if keep_bootconNishanth Aravamudan2011-10-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 4c30c6f566c0989ddaee3407da44751e340a63ed upstream. It seems that 7bf693951a8e ("console: allow to retain boot console via boot option keep_bootcon") doesn't always achieve what it aims, as when printk_late_init() runs it unconditionally turns off all boot consoles. With this patch, I am able to see more messages on the boot console in KVM guests than I can without, when keep_bootcon is specified. I think it is appropriate for the relevant -stable trees. However, it's more of an annoyance than a serious bug (ideally you don't need to keep the boot console around as console handover should be working -- I was encountering a situation where the console handover wasn't working and not having the boot console available meant I couldn't see why). Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Greg KH <gregkh@suse.de> Acked-by: Fabio M. Di Nitto <fdinitto@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * Add a personality to report 2.6.x version numbersAndi Kleen2011-08-291-0/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit be27425dcc516fd08245b047ea57f83b8f6f0903 upstream. I ran into a couple of programs which broke with the new Linux 3.0 version. Some of those were binary only. I tried to use LD_PRELOAD to work around it, but it was quite difficult and in one case impossible because of a mix of 32bit and 64bit executables. For example, all kind of management software from HP doesnt work, unless we pretend to run a 2.6 kernel. $ uname -a Linux svivoipvnx001 3.0.0-08107-g97cd98f #1062 SMP Fri Aug 12 18:11:45 CEST 2011 i686 i686 i386 GNU/Linux $ hpacucli ctrl all show Error: No controllers detected. $ rpm -qf /usr/sbin/hpacucli hpacucli-8.75-12.0 Another notable case is that Python now reports "linux3" from sys.platform(); which in turn can break things that were checking sys.platform() == "linux2": https://bugzilla.mozilla.org/show_bug.cgi?id=664564 It seems pretty clear to me though it's a bug in the apps that are using '==' instead of .startswith(), but this allows us to unbreak broken programs. This patch adds a UNAME26 personality that makes the kernel report a 2.6.40+x version number instead. The x is the x in 3.x. I know this is somewhat ugly, but I didn't find a better workaround, and compatibility to existing programs is important. Some programs also read /proc/sys/kernel/osrelease. This can be worked around in user space with mount --bind (and a mount namespace) To use: wget ftp://ftp.kernel.org/pub/linux/kernel/people/ak/uname26/uname26.c gcc -o uname26 uname26.c ./uname26 program Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * x86, mtrr: lock stop machine during MTRR rendezvous sequenceSuresh Siddha2011-08-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 6d3321e8e2b3bf6a5892e2ef673c7bf536e3f904 upstream. MTRR rendezvous sequence using stop_one_cpu_nowait() can potentially happen in parallel with another system wide rendezvous using stop_machine(). This can lead to deadlock (The order in which works are queued can be different on different cpu's. Some cpu's will be running the first rendezvous handler and others will be running the second rendezvous handler. Each set waiting for the other set to join for the system wide rendezvous, leading to a deadlock). MTRR rendezvous sequence is not implemented using stop_machine() as this gets called both from the process context aswell as the cpu online paths (where the cpu has not come online and the interrupts are disabled etc). stop_machine() works with only online cpus. For now, take the stop_machine mutex in the MTRR rendezvous sequence that gets called from an online cpu (here we are in the process context and can potentially sleep while taking the mutex). And the MTRR rendezvous that gets triggered during cpu online doesn't need to take this stop_machine lock (as the stop_machine() already ensures that there is no cpu hotplug going on in parallel by doing get_online_cpus()) TBD: Pursue a cleaner solution of extending the stop_machine() infrastructure to handle the case where the calling cpu is still not online and use this for MTRR rendezvous sequence. fixes: https://bugzilla.novell.com/show_bug.cgi?id=672008 Reported-by: Vadim Kotelnikov <vadimuzzz@inbox.ru> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Link: http://lkml.kernel.org/r/20110623182056.807230326@sbsiddha-MOBL3.sc.intel.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * genirq: Fix wrong bit operationjhbird.choi@samsung.com2011-08-291-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | commit 1dd75f91ae713049eb6baaa640078f3a6549e522 upstream. (!msk & 0x01) should be !(msk & 0x01) Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com> Link: http://lkml.kernel.org/r/1311229754-6003-1-git-send-email-jhbird.choi@samsung.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * futex: Fix regression with read only mappingsShawn Bohrer2011-08-151-12/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae upstream. commit 7485d0d3758e8e6491a5c9468114e74dc050785d (futexes: Remove rw parameter from get_futex_key()) in 2.6.33 fixed two problems: First, It prevented a loop when encountering a ZERO_PAGE. Second, it fixed RW MAP_PRIVATE futex operations by forcing the COW to occur by unconditionally performing a write access get_user_pages_fast() to get the page. The commit also introduced a user-mode regression in that it broke futex operations on read-only memory maps. For example, this breaks workloads that have one or more reader processes doing a FUTEX_WAIT on a futex within a read only shared file mapping, and a writer processes that has a writable mapping issuing the FUTEX_WAKE. This fixes the regression for valid futex operations on RO mappings by trying a RO get_user_pages_fast() when the RW get_user_pages_fast() fails. This change makes it necessary to also check for invalid use cases, such as anonymous RO mappings (which can never change) and the ZERO_PAGE which the commit referenced above was written to address. This patch does restore the original behavior with RO MAP_PRIVATE mappings, which have inherent user-mode usage problems and don't really make sense. With this patch performing a FUTEX_WAIT within a RO MAP_PRIVATE mapping will be successfully woken provided another process updates the region of the underlying mapped file. However, the mmap() man page states that for a MAP_PRIVATE mapping: It is unspecified whether changes made to the file after the mmap() call are visible in the mapped region. So user-mode users attempting to use futex operations on RO MAP_PRIVATE mappings are depending on unspecified behavior. Additionally a RO MAP_PRIVATE mapping could fail to wake up in the following case. Thread-A: call futex(FUTEX_WAIT, memory-region-A). get_futex_key() return inode based key. sleep on the key Thread-B: call mprotect(PROT_READ|PROT_WRITE, memory-region-A) Thread-B: write memory-region-A. COW happen. This process's memory-region-A become related to new COWed private (ie PageAnon=1) page. Thread-B: call futex(FUETX_WAKE, memory-region-A). get_futex_key() return mm based key. IOW, we fail to wake up Thread-A. Once again doing something like this is just silly and users who do something like this get what they deserve. While RO MAP_PRIVATE mappings are nonsensical, checking for a private mapping requires walking the vmas and was deemed too costly to avoid a userspace hang. This Patch is based on Peter Zijlstra's initial patch with modifications to only allow RO mappings for futex operations that need VERIFY_READ access. Reported-by: David Oliver <david@rgmadvisors.com> Signed-off-by: Shawn Bohrer <sbohrer@rgmadvisors.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Darren Hart <dvhart@linux.intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: peterz@infradead.org Cc: eric.dumazet@gmail.com Cc: zvonler@rgmadvisors.com Cc: hughd@google.com Link: http://lkml.kernel.org/r/1309450892-30676-1-git-send-email-sbohrer@rgmadvisors.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | PM: Backoff suspend if repeated attempts failTodd Poynor2011-09-061-4/+35
| | | | | | | | | | Change-Id: I32289676d95a307ea3aa5e78f6c126ca979c0fec Signed-off-by: Todd Poynor <toddpoynor@google.com>
* | panic: Add board ID to panic outputNishanth Menon2011-08-191-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | At times, it is necessary for boards to provide some additional information as part of panic logs. Provide information on the board hardware as part of panic logs. It is safer to print this information at the very end in case something bad happens as part of the information retrieval itself. To use this, set global mach_panic_string to an appropriate string in the board file. Change-Id: Id12cdda87b0cd2940dd01d52db97e6162f671b4d Signed-off-by: Nishanth Menon <nm@ti.com>
* | Merge commit 'v3.0.1' into android-3.0Colin Cross2011-08-105-25/+106
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| * mm/futex: fix futex writes on archs with SW tracking of dirty & youngBenjamin Herrenschmidt2011-08-041-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 2efaca927f5cd7ecd0f1554b8f9b6a9a2c329c03 upstream. I haven't reproduced it myself but the fail scenario is that on such machines (notably ARM and some embedded powerpc), if you manage to hit that futex path on a writable page whose dirty bit has gone from the PTE, you'll livelock inside the kernel from what I can tell. It will go in a loop of trying the atomic access, failing, trying gup to "fix it up", getting succcess from gup, go back to the atomic access, failing again because dirty wasn't fixed etc... So I think you essentially hang in the kernel. The scenario is probably rare'ish because affected architecture are embedded and tend to not swap much (if at all) so we probably rarely hit the case where dirty is missing or young is missing, but I think Shan has a piece of SW that can reliably reproduce it using a shared writable mapping & fork or something like that. On archs who use SW tracking of dirty & young, a page without dirty is effectively mapped read-only and a page without young unaccessible in the PTE. Additionally, some architectures might lazily flush the TLB when relaxing write protection (by doing only a local flush), and expect a fault to invalidate the stale entry if it's still present on another processor. The futex code assumes that if the "in_atomic()" access -EFAULT's, it can "fix it up" by causing get_user_pages() which would then be equivalent to taking the fault. However that isn't the case. get_user_pages() will not call handle_mm_fault() in the case where the PTE seems to have the right permissions, regardless of the dirty and young state. It will eventually update those bits ... in the struct page, but not in the PTE. Additionally, it will not handle the lazy TLB flushing that can be required by some architectures in the fault case. Basically, gup is the wrong interface for the job. The patch provides a more appropriate one which boils down to just calling handle_mm_fault() since what we are trying to do is simulate a real page fault. The futex code currently attempts to write to user memory within a pagefault disabled section, and if that fails, tries to fix it up using get_user_pages(). This doesn't work on archs where the dirty and young bits are maintained by software, since they will gate access permission in the TLB, and will not be updated by gup(). In addition, there's an expectation on some archs that a spurious write fault triggers a local TLB flush, and that is missing from the picture as well. I decided that adding those "features" to gup() would be too much for this already too complex function, and instead added a new simpler fixup_user_fault() which is essentially a wrapper around handle_mm_fault() which the futex code can call. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix some nits Darren saw, fiddle comment layout] Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reported-by: Shan Hai <haishan.bai@gmail.com> Tested-by: Shan Hai <haishan.bai@gmail.com> Cc: David Laight <David.Laight@ACULAB.COM> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Darren Hart <darren.hart@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * tracing: Have "enable" file use refcounts like the "filter" fileSteven Rostedt2011-08-041-9/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 40ee4dffff061399eb9358e0c8fcfbaf8de4c8fe upstream. The "enable" file for the event system can be removed when a module is unloaded and the event system only has events from that module. As the event system nr_events count goes to zero, it may be freed if its ref_count is also set to zero. Like the "filter" file, the "enable" file may be opened by a task and referenced later, after a module has been unloaded and the events for that event system have been removed. Although the "filter" file referenced the event system structure, the "enable" file only references a pointer to the event system name. Since the name is freed when the event system is removed, it is possible that an access to the "enable" file may reference a freed pointer. Update the "enable" file to use the subsystem_open() routine that the "filter" file uses, to keep a reference to the event system structure while the "enable" file is opened. Reported-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * tracing: Fix bug when reading system filters on module removalSteven Rostedt2011-08-043-11/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit e9dbfae53eeb9fc3d4bb7da3df87fa9875f5da02 upstream. The event system is freed when its nr_events is set to zero. This happens when a module created an event system and then later the module is removed. Modules may share systems, so the system is allocated when it is created and freed when the modules are unloaded and all the events under the system are removed (nr_events set to zero). The problem arises when a task opened the "filter" file for the system. If the module is unloaded and it removed the last event for that system, the system structure is freed. If the task that opened the filter file accesses the "filter" file after the system has been freed, the system will access an invalid pointer. By adding a ref_count, and using it to keep track of what is using the event system, we can free it after all users are finished with the event system. Reported-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * perf: Fix software event overflowPeter Zijlstra2011-08-041-5/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The below patch is for -stable only, upstream has a much larger patch that contains the below hunk in commit a8b0ca17b80e92faab46ee7179ba9e99ccb61233 Vince found that under certain circumstances software event overflows go wrong and deadlock. Avoid trying to delete a timer from the timer callback. Reported-by: Vince Weaver <vweaver1@eecs.utk.edu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | Merge commit 'v3.0' into android-3.0Colin Cross2011-08-108-92/+335
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| * Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds2011-07-204-28/+100
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: signal: align __lock_task_sighand() irq disabling and RCU softirq,rcu: Inform RCU of irq_exit() activity sched: Add irq_{enter,exit}() to scheduler_ipi() rcu: protect __rcu_read_unlock() against scheduler-using irq handlers rcu: Streamline code produced by __rcu_read_unlock() rcu: Fix RCU_BOOST race handling current->rcu_read_unlock_special rcu: decrease rcu_report_exp_rnp coupling with scheduler
| | * Merge branch 'rcu/urgent' of ↵Ingo Molnar2011-07-204-28/+100
| | |\ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu into core/urgent
| | | * signal: align __lock_task_sighand() irq disabling and RCUPaul E. McKenney2011-07-201-6/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The __lock_task_sighand() function calls rcu_read_lock() with interrupts and preemption enabled, but later calls rcu_read_unlock() with interrupts disabled. It is therefore possible that this RCU read-side critical section will be preempted and later RCU priority boosted, which means that rcu_read_unlock() will call rt_mutex_unlock() in order to deboost itself, but with interrupts disabled. This results in lockdep splats, so this commit nests the RCU read-side critical section within the interrupt-disabled region of code. This prevents the RCU read-side critical section from being preempted, and thus prevents the attempt to deboost with interrupts disabled. It is quite possible that a better long-term fix is to make rt_mutex_unlock() disable irqs when acquiring the rt_mutex structure's ->wait_lock. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | | * softirq,rcu: Inform RCU of irq_exit() activityPeter Zijlstra2011-07-202-3/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rcu_read_unlock_special() function relies on in_irq() to exclude scheduler activity from interrupt level. This fails because exit_irq() can invoke the scheduler after clearing the preempt_count() bits that in_irq() uses to determine that it is at interrupt level. This situation can result in failures as follows: $task IRQ SoftIRQ rcu_read_lock() /* do stuff */ <preempt> |= UNLOCK_BLOCKED rcu_read_unlock() --t->rcu_read_lock_nesting irq_enter(); /* do stuff, don't use RCU */ irq_exit(); sub_preempt_count(IRQ_EXIT_OFFSET); invoke_softirq() ttwu(); spin_lock_irq(&pi->lock) rcu_read_lock(); /* do stuff */ rcu_read_unlock(); rcu_read_unlock_special() rcu_report_exp_rnp() ttwu() spin_lock_irq(&pi->lock) /* deadlock */ rcu_read_unlock_special(t); Ed can simply trigger this 'easy' because invoke_softirq() immediately does a ttwu() of ksoftirqd/# instead of doing the in-place softirq stuff first, but even without that the above happens. Cure this by also excluding softirqs from the rcu_read_unlock_special() handler and ensuring the force_irqthreads ksoftirqd/# wakeup is done from full softirq context. [ Alternatively, delaying the ->rcu_read_lock_nesting decrement until after the special handling would make the thing more robust in the face of interrupts as well. And there is a separate patch for that. ] Cc: Thomas Gleixner <tglx@linutronix.de> Reported-and-tested-by: Ed Tomlinson <edt@aei.ca> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | | * sched: Add irq_{enter,exit}() to scheduler_ipi()Peter Zijlstra2011-07-201-6/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ensure scheduler_ipi() calls irq_{enter,exit} when it does some actual work. Traditionally we never did any actual work from the resched IPI and all magic happened in the return from interrupt path. Now that we do do some work, we need to ensure irq_{enter,exit} are called so that we don't confuse things. This affects things like timekeeping, NO_HZ and RCU, basically everything with a hook in irq_enter/exit. Explicit examples of things going wrong are: sched_clock_cpu() -- has a callback when leaving NO_HZ state to take a new reading from GTOD and TSC. Without this callback, time is stuck in the past. RCU -- needs in_irq() to work in order to avoid some nasty deadlocks Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | | * rcu: protect __rcu_read_unlock() against scheduler-using irq handlersPaul E. McKenney2011-07-201-5/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The addition of RCU read-side critical sections within runqueue and priority-inheritance lock critical sections introduced some deadlock cycles, for example, involving interrupts from __rcu_read_unlock() where the interrupt handlers call wake_up(). This situation can cause the instance of __rcu_read_unlock() invoked from interrupt to do some of the processing that would otherwise have been carried out by the task-level instance of __rcu_read_unlock(). When the interrupt-level instance of __rcu_read_unlock() is called with a scheduler lock held from interrupt-entry/exit situations where in_irq() returns false, deadlock can result. This commit resolves these deadlocks by using negative values of the per-task ->rcu_read_lock_nesting counter to indicate that an instance of __rcu_read_unlock() is in flight, which in turn prevents instances from interrupt handlers from doing any special processing. This patch is inspired by Steven Rostedt's earlier patch that similarly made __rcu_read_unlock() guard against interrupt-mediated recursion (see https://lkml.org/lkml/2011/7/15/326), but this commit refines Steven's approach to avoid the need for preemption disabling on the __rcu_read_unlock() fastpath and to also avoid the need for manipulating a separate per-CPU variable. This patch avoids need for preempt_disable() by instead using negative values of the per-task ->rcu_read_lock_nesting counter. Note that nested rcu_read_lock()/rcu_read_unlock() pairs are still permitted, but they will never see ->rcu_read_lock_nesting go to zero, and will therefore never invoke rcu_read_unlock_special(), thus preventing them from seeing the RCU_READ_UNLOCK_BLOCKED bit should it be set in ->rcu_read_unlock_special. This patch also adds a check for ->rcu_read_unlock_special being negative in rcu_check_callbacks(), thus preventing the RCU_READ_UNLOCK_NEED_QS bit from being set should a scheduling-clock interrupt occur while __rcu_read_unlock() is exiting from an outermost RCU read-side critical section. Of course, __rcu_read_unlock() can be preempted during the time that ->rcu_read_lock_nesting is negative. This could result in the setting of the RCU_READ_UNLOCK_BLOCKED bit after __rcu_read_unlock() checks it, and would also result it this task being queued on the corresponding rcu_node structure's blkd_tasks list. Therefore, some later RCU read-side critical section would enter rcu_read_unlock_special() to clean up -- which could result in deadlock if that critical section happened to be in the scheduler where the runqueue or priority-inheritance locks were held. This situation is dealt with by making rcu_preempt_note_context_switch() check for negative ->rcu_read_lock_nesting, thus refraining from queuing the task (and from setting RCU_READ_UNLOCK_BLOCKED) if we are already exiting from the outermost RCU read-side critical section (in other words, we really are no longer actually in that RCU read-side critical section). In addition, rcu_preempt_note_context_switch() invokes rcu_read_unlock_special() to carry out the cleanup in this case, which clears out the ->rcu_read_unlock_special bits and dequeues the task (if necessary), in turn avoiding needless delay of the current RCU grace period and needless RCU priority boosting. It is still illegal to call rcu_read_unlock() while holding a scheduler lock if the prior RCU read-side critical section has ever had either preemption or irqs enabled. However, the common use case is legal, namely where then entire RCU read-side critical section executes with irqs disabled, for example, when the scheduler lock is held across the entire lifetime of the RCU read-side critical section. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| | | * rcu: Streamline code produced by __rcu_read_unlock()Paul E. McKenney2011-07-191-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Given some common flag combinations, particularly -Os, gcc will inline rcu_read_unlock_special() despite its being in an unlikely() clause. Use noinline to prohibit this misoptimization. In addition, move the second barrier() in __rcu_read_unlock() so that it is not on the common-case code path. This will allow the compiler to generate better code for the common-case path through __rcu_read_unlock(). Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
generated by cgit v1.1 at 2024-12-24 00:01:07 +0000