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* genirq: prevent wakeup of freed irq threadLinus Torvalds2009-08-13
| | | | | | | | | | | | | | | | | | | | free_irq() can remove an irqaction while the corresponding interrupt is in progress, but free_irq() sets action->thread to NULL unconditionally, which might lead to a NULL pointer dereference in handle_IRQ_event() when the hard interrupt context tries to wake up the handler thread. Prevent this by moving the thread stop after synchronize_irq(). No need to set action->thread to NULL either as action is going to be freed anyway. This fixes a boot crash reported against preempt-rt which uses the mainline irq threads code to implement full irq threading. [ tglx: removed local irqthread variable ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Merge branch 'perfcounters-fixes-for-linus' of ↵Linus Torvalds2009-08-13
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf_counter: Report the cloning task as parent on perf_counter_fork() perf_counter: Fix an ipi-deadlock perf: Rework/fix the whole read vs group stuff perf_counter: Fix swcounter context invariance perf report: Don't show unresolved DSOs and symbols when -S/-d is used perf tools: Add a general option to enable raw sample records perf tools: Add a per tracepoint counter attribute to get raw sample perf_counter: Provide hw_perf_counter_setup_online() APIs perf list: Fix large list output by using the pager perf_counter, x86: Fix/improve apic fallback perf record: Add missing -C option support for specifying profile cpu perf tools: Fix dso__new handle() to handle deleted DSOs perf tools: Fix fallback to cplus_demangle() when bfd_demangle() is not available perf report: Show the tid too in -D perf record: Fix .tid and .pid fill-in when synthesizing events perf_counter, x86: Fix generic cache events on P6-mobile CPUs perf_counter, x86: Fix lapic printk message
| * perf_counter: Report the cloning task as parent on perf_counter_fork()Peter Zijlstra2009-08-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A bug in (9f498cc: perf_counter: Full task tracing) makes profiling multi-threaded apps it go belly up. [ output as: (PID:TID):(PPID:PTID) ] # ./perf report -D | grep FORK 0x4b0 [0x18]: PERF_EVENT_FORK: (3237:3237):(3236:3236) 0xa10 [0x18]: PERF_EVENT_FORK: (3237:3238):(3236:3236) 0xa70 [0x18]: PERF_EVENT_FORK: (3237:3239):(3236:3236) 0xad0 [0x18]: PERF_EVENT_FORK: (3237:3240):(3236:3236) 0xb18 [0x18]: PERF_EVENT_FORK: (3237:3241):(3236:3236) Shows us that the test (27d028d perf report: Update for the new FORK/EXIT events) in builtin-report.c: /* * A thread clone will have the same PID for both * parent and child. */ if (thread == parent) return 0; Will clearly fail. The problem is that perf_counter_fork() reports the actual parent, instead of the cloning thread. Fixing that (with the below patch), yields: # ./perf report -D | grep FORK 0x4c8 [0x18]: PERF_EVENT_FORK: (1590:1590):(1589:1589) 0xbd8 [0x18]: PERF_EVENT_FORK: (1590:1591):(1590:1590) 0xc80 [0x18]: PERF_EVENT_FORK: (1590:1592):(1590:1590) 0x3338 [0x18]: PERF_EVENT_FORK: (1590:1593):(1590:1590) 0x66b0 [0x18]: PERF_EVENT_FORK: (1590:1594):(1590:1590) Which both makes more sense and doesn't confuse perf report anymore. Reported-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: paulus@samba.org Cc: Anton Blanchard <anton@samba.org> Cc: Arjan van de Ven <arjan@infradead.org> LKML-Reference: <1250172882.5241.62.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * perf_counter: Fix an ipi-deadlockPeter Zijlstra2009-08-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | perf_pending_counter() is called from IRQ context and will call perf_counter_disable(), however perf_counter_disable() uses smp_call_function_single() which doesn't fancy being used with IRQs disabled due to IPI deadlocks. Fix this by making it use the local __perf_counter_disable() call and teaching the counter_sched_out() code about pending disables as well. This should cover the case where a counter migrates before the pending queue gets processed. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey J Ashford <cjashfor@us.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: stephane eranian <eranian@googlemail.com> LKML-Reference: <20090813103655.244097721@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * perf: Rework/fix the whole read vs group stuffPeter Zijlstra2009-08-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace PERF_SAMPLE_GROUP with PERF_SAMPLE_READ and introduce PERF_FORMAT_GROUP to deal with group reads in a more generic way. This allows you to get group reads out of read() as well. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey J Ashford <cjashfor@us.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: stephane eranian <eranian@googlemail.com> LKML-Reference: <20090813103655.117411814@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * perf_counter: Fix swcounter context invariancePeter Zijlstra2009-08-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | perf_swcounter_is_counting() uses a lock, which means we cannot use swcounters from NMI or when holding that particular lock, this is unintended. The below removes the lock, this opens up race window, but not worse than the swcounters already experience due to RCU traversal of the context in perf_swcounter_ctx_event(). This also fixes the hard lockups while opening a lockdep tracepoint counter. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: stephane eranian <eranian@googlemail.com> Cc: Corey J Ashford <cjashfor@us.ibm.com> LKML-Reference: <1250149915.10001.66.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * perf_counter: Provide hw_perf_counter_setup_online() APIsIngo Molnar2009-08-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Provide weak aliases for hw_perf_counter_setup_online(). This is used by the BTS patches (for v2.6.32), but it interacts with fixes so propagate this upstream. (it has no effect as of yet) Also export perf_counter_output() to architecture code. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds2009-08-13
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futex: Fix handling of bad requeue syscall pairing futex: Fix compat_futex to be same as futex for REQUEUE_PI locking, sched: Give waitqueue spinlocks their own lockdep classes futex: Update futex_q lock_ptr on requeue proxy lock
| * | futex: Fix handling of bad requeue syscall pairingDarren Hart2009-08-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If futex_requeue(requeue_pi=1) finds a futex_q that was created by a call other the futex_wait_requeue_pi(), the q.rt_waiter may be null. If so, this will result in an oops from the following call graph: futex_requeue() rt_mutex_start_proxy_lock() task_blocks_on_rt_mutex() waiter->task dereference OOPS We currently WARN_ON() if this is detected, clearly this is inadequate. If we detect a mispairing in futex_requeue(), bail out, seding -EINVAL to user-space. V2: Fix parenthesis warnings. Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: John Kacur <jkacur@redhat.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Dinakar Guniguntala <dino@in.ibm.com> Cc: John Stultz <johnstul@linux.vnet.ibm.com> LKML-Reference: <4A7CA8C0.7010809@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | futex: Fix compat_futex to be same as futex for REQUEUE_PIDinakar Guniguntala2009-08-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Need to add the REQUEUE_PI checks to the compat_sys_futex API as well to ensure 32 bit requeue's work fine on a 64 bit system. Patch is against latest tip Signed-off-by: Dinakar Guniguntala <dino@in.ibm.com> Cc: Darren Hart <dvhltc@us.ibm.com> LKML-Reference: <20090810130142.GA23619@in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | locking, sched: Give waitqueue spinlocks their own lockdep classesPeter Zijlstra2009-08-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Give waitqueue spinlocks their own lockdep classes when they are initialised from init_waitqueue_head(). This means that struct wait_queue::func functions can operate other waitqueues. This is used by CacheFiles to catch the page from a backing fs being unlocked and to wake up another thread to take a copy of it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Takashi Iwai <tiwai@suse.de> Cc: linux-cachefs@redhat.com Cc: torvalds@osdl.org Cc: akpm@linux-foundation.org LKML-Reference: <20090810113305.17284.81508.stgit@warthog.procyon.org.uk> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | futex: Update futex_q lock_ptr on requeue proxy lockDarren Hart2009-08-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | futex_requeue() can acquire the lock on behalf of a waiter early on or during the requeue loop if it is uncontended or in the event of a lock steal or owner died. On wakeup, the waiter (in futex_wait_requeue_pi()) cleans up the pi_state owner using the lock_ptr to protect against concurrent access to the pi_state. The pi_state is hung off futex_q's on the requeue target futex hash bucket so the lock_ptr needs to be updated accordingly. The problem manifested by triggering the WARN_ON in lookup_pi_state() about the pid != pi_state->owner->pid. With this patch, the pi_state is properly guarded against concurrent access via the requeue target hb lock. The astute reviewer may notice that there is a window of time between when futex_requeue() unlocks the hb locks and when futex_wait_requeue_pi() will acquire hb2->lock. During this time the pi_state and uval are not in sync with the underlying rtmutex owner (but the uval does indicate there are waiters, so no atomic changes will occur in userspace). However, this is not a problem. Should a contending thread enter lookup_pi_state() and acquire hb2->lock before the ownership is fixed up, it will find the pi_state hung off a waiter's (possibly the pending owner's) futex_q and block on the rtmutex. Once futex_wait_requeue_pi() fixes up the owner, it will also move the pi_state from the old owner's task->pi_state_list to its own. v3: Fix plist lock name for application to mainline (rather than -rt) Compile tested against tip/v2.6.31-rc5. Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Dinakar Guniguntala <dino@in.ibm.com> Cc: John Stultz <johnstul@linux.vnet.ibm.com> LKML-Reference: <4A7F4EFF.6090903@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Remove double removal of blktrace directoryAlan D. Brunelle2009-08-12
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit fd51d251e4cdb21f68e9dbc4336514d64a105a79 Author: Stefan Raspl <raspl@linux.vnet.ibm.com> Date: Tue May 19 09:59:08 2009 +0200 blktrace: remove debugfs entries on bad path added in an explicit invocation of debugfs_remove for bt->dir, in blk_remove_buf_file_callback we are also getting the directory removed. On occasion I am seeing memory corruption that I have bisected down to this commit. [The testing involves a (long) series of I/O benchmarks with blktrace invoked around the actual runs.] I believe that this committed patch is correct, but the problem actually lies in the code in blk_remove_buf_file_callback. With this patch I am able to consistently get complete runs whereas previously I could not get a single run to complete. The first part of the patch simply moves the debugfs_remove below the relay_close: the relay_close call will remove files under bt->dir, and so we should not remove the directory until all the files we created have been removed. (Note: This is not sufficient to fix the problem - the file system code has ref counts on the directoy, so our invocation does not cause the directory to actually be removed. Nonetheless, we should not rely upon that feature.) Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | Merge branch 'perfcounters-fixes-for-linus' of ↵Linus Torvalds2009-08-10
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (27 commits) perf_counter: Zero dead bytes from ftrace raw samples size alignment perf_counter: Subtract the buffer size field from the event record size perf_counter: Require CAP_SYS_ADMIN for raw tracepoint data perf_counter: Correct PERF_SAMPLE_RAW output perf tools: callchain: Fix bad rounding of minimum rate perf_counter tools: Fix libbfd detection for systems with libz dependency perf: "Longum est iter per praecepta, breve et efficax per exempla" perf_counter: Fix a race on perf_counter_ctx perf_counter: Fix tracepoint sampling to be part of generic sampling perf_counter: Work around gcc warning by initializing tracepoint record unconditionally perf tools: callchain: Fix sum of percentages to be 100% by displaying amount of ignored chains in fractal mode perf tools: callchain: Fix 'perf report' display to be callchain by default perf tools: callchain: Fix spurious 'perf report' warnings: ignore empty callchains perf record: Fix the -A UI for empty or non-existent perf.data perf util: Fix do_read() to fail on EOF instead of busy-looping perf list: Fix the output to not include tracepoints without an id perf_counter/powerpc: Fix oops on cpus without perf_counter hardware support perf stat: Fix tool option consistency: rename -S/--scale to -c/--scale perf report: Add debug help for the finding of symbol bugs - show the symtab origin (DSO, build-id, kernel, etc) perf report: Fix per task mult-counter stat reporting ...
| * | perf_counter: Require CAP_SYS_ADMIN for raw tracepoint dataPeter Zijlstra2009-08-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Raw tracepoint data contains various kernel internals and data from other users, so restrict this to CAP_SYS_ADMIN. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1249896452.17467.75.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | perf_counter: Correct PERF_SAMPLE_RAW outputPeter Zijlstra2009-08-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PERF_SAMPLE_* output switches should unconditionally output the correct format, as they are the only way to unambiguously parse the PERF_EVENT_SAMPLE data. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1249896447.17467.74.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | perf_counter: Fix a race on perf_counter_ctxPeter Zijlstra2009-08-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While extending perfcounters with BTS hw-tracing, Markus Metzger managed to trigger this warning: [ 995.557128] WARNING: at kernel/perf_counter.c:1191 __perf_counter_task_sched_out+0x48/0x6b() triggers because commit 9f498cc5be7e013d8d6e4c616980ed0ffc8680d2 (perf_counter: Full task tracing) removed clearing of tsk->perf_counter_ctxp out from under ctx->lock which introduced a race (against perf_lock_task_context). Move it back and deal with the exit notification by explicitly passing along the former task context. Reported-by: Markus T Metzger <markus.t.metzger@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1249667341.17467.5.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | perf_counter: Fix tracepoint sampling to be part of generic samplingFrederic Weisbecker2009-08-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on Peter's comments, make tracepoint sampling generic just like all the other sampling bits are. This is a rename with no code changes: - PERF_SAMPLE_TP_RECORD to PERF_SAMPLE_RAW - struct perf_tracepoint_record to perf_raw_record We want the system in place that transport tracepoints raw samples events into the perf ring buffer to be generalized and usable by any type of counter. Reported-by; Peter Zijlstra <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1249698400-5441-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | perf_counter: Work around gcc warning by initializing tracepoint record ↵Frederic Weisbecker2009-08-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | unconditionally Despite that the tracepoint record is always present when the PERF_SAMPLE_TP_RECORD flag is set, gcc raises a warning, thinking it might not be initialized: kernel/perf_counter.c: In function ‘perf_counter_output’: kernel/perf_counter.c:2650: warning: ‘tp’ may be used uninitialized in this function Then, initialize it to NULL and always check if it's not NULL before dereference it. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1249698400-5441-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | perf_counter: Fix software counters for fast moving event sourcesPeter Zijlstra2009-08-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reimplement the software counters to deal with fast moving event sources (such as tracepoints). This means being able to generate multiple overflows from a single 'event' as well as support throttling. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'irq-fixes-for-linus' of ↵Linus Torvalds2009-08-10
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'irq-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86/irq: Fix move_irq_desc() for nodes without ram
| * | x86/irq: Fix move_irq_desc() for nodes without ramYinghai Lu2009-08-08
| | | | | | | | | | | | | | | | | | | | | | | | Don't move it if target node is -1. Signed-off-by: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <4A785B5D.4070702@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds2009-08-09
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: posix_cpu_timers_exit_group(): Do not use thread_group_cputimer()
| * | | posix_cpu_timers_exit_group(): Do not use thread_group_cputimer()Stanislaw Gruszka2009-08-08
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the process exits we don't have to run new cputimer nor use running one (as it not accounts when tsk->exit_state != 0) to get process CPU times. As there is only one thread we can just use CPU times fields from task and signal structs. Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Roland McGrath <roland@redhat.com> Cc: Vitaly Mayatskikh <vmayatsk@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'tracing-fixes-for-linus' of ↵Linus Torvalds2009-08-09
|\ \ \ | | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf_counter: Fix/complete ftrace event records sampling perf_counter, ftrace: Fix perf_counter integration tracing/filters: Always free pred on filter_add_subsystem_pred() failure tracing/filters: Don't use pred on alloc failure ring-buffer: Fix memleak in ring_buffer_free() tracing: Fix recordmcount.pl to handle sections with only weak functions ring-buffer: Fix advance of reader in rb_buffer_peek() tracing: do not use functions starting with .L in recordmcount.pl ring-buffer: do not disable ring buffer on oops_in_progress ring-buffer: fix check of try_to_discard result
| * | perf_counter: Fix/complete ftrace event records samplingFrederic Weisbecker2009-08-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements the kernel side support for ftrace event record sampling. A new counter sampling attribute is added: PERF_SAMPLE_TP_RECORD which requests ftrace events record sampling. In this case if a PERF_TYPE_TRACEPOINT counter is active and a tracepoint fires, we emit the tracepoint binary record to the perfcounter event buffer, as a sample. Result, after setting PERF_SAMPLE_TP_RECORD attribute from perf record: perf record -f -F 1 -a -e workqueue:workqueue_execution perf report -D 0x21e18 [0x48]: event: 9 . . ... raw event: size 72 bytes . 0000: 09 00 00 00 01 00 48 00 d0 c7 00 81 ff ff ff ff ......H........ . 0010: 0a 00 00 00 0a 00 00 00 21 00 00 00 00 00 00 00 ........!...... . 0020: 2b 00 01 02 0a 00 00 00 0a 00 00 00 65 76 65 6e +...........eve . 0030: 74 73 2f 31 00 00 00 00 00 00 00 00 0a 00 00 00 ts/1........... . 0040: e0 b1 31 81 ff ff ff ff ....... . 0x21e18 [0x48]: PERF_EVENT_SAMPLE (IP, 1): 10: 0xffffffff8100c7d0 period: 33 The raw ftrace binary record starts at offset 0020. Translation: struct trace_entry { type = 0x2b = 43; flags = 1; preempt_count = 2; pid = 0xa = 10; tgid = 0xa = 10; } thread_comm = "events/1" thread_pid = 0xa = 10; func = 0xffffffff8131b1e0 = flush_to_ldisc() What will come next? - Userspace support ('perf trace'), 'flight data recorder' mode for perf trace, etc. - The unconditional copy from the profiling callback brings some costs however if someone wants no such sampling to occur, and needs to be fixed in the future. For that we need to have an instant access to the perf counter attribute. This is a matter of a flag to add in the struct ftrace_event. - Take care of the events recursivity! Don't ever try to record a lock event for example, it seems some locking is used in the profiling fast path and lead to a tracing recursivity. That will be fixed using raw spinlock or recursivity protection. - [...] - Profit! :-) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Gabriel Munteanu <eduard.munteanu@linux360.ro> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | perf_counter, ftrace: Fix perf_counter integrationPeter Zijlstra2009-08-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adds possible second part to the assign argument of TP_EVENT(). TP_perf_assign( __perf_count(foo); __perf_addr(bar); ) Which, when specified make the swcounter increment with @foo instead of the usual 1, and report @bar for PERF_SAMPLE_ADDR (data address associated with the event) when this triggers a counter overflow. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | Merge branch 'linus' into tracing/urgentIngo Molnar2009-08-09
| |\| | | | | | | | | | | | | | | | | | | Merge reason: Merge up to almost-rc6 to pick up latest perfcounters (on which we'll queue up a dependent fix) Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | tracing/filters: Always free pred on filter_add_subsystem_pred() failureTom Zanussi2009-08-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If filter_add_subsystem_pred() fails due to ENOSPC or ENOMEM, the pred doesn't get freed, while as a side effect it does for other errors. Make it so the caller always frees the pred for any error. Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <1249746593.6453.32.camel@tropicana> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | tracing/filters: Don't use pred on alloc failureTom Zanussi2009-08-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dan Carpenter sent me a fix to prevent pred from being used if it couldn't be allocated. I noticed the same problem also existed for the create_pred() case and added a fix for that. Reported-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <1249746549.6453.29.camel@tropicana> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | ring-buffer: Fix memleak in ring_buffer_free()Eric Dumazet2009-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I noticed oprofile memleaked in linux-2.6 current tree, and tracked this ring-buffer leak. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> LKML-Reference: <4A7C06B9.2090302@gmail.com> Cc: stable@kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | ring-buffer: Fix advance of reader in rb_buffer_peek()Robert Richter2009-08-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When calling rb_buffer_peek() from ring_buffer_consume() and a padding event is returned, the function rb_advance_reader() is called twice. This may lead to missing samples or under high workloads to the warning below. This patch fixes this. If a padding event is returned by rb_buffer_peek() it will be consumed by the calling function now. Also, I simplified some code in ring_buffer_consume(). ------------[ cut here ]------------ WARNING: at /dev/shm/.source/linux/kernel/trace/ring_buffer.c:2289 rb_advance_reader+0x2e/0xc5() Hardware name: Anaheim Modules linked in: Pid: 29, comm: events/2 Tainted: G W 2.6.31-rc3-oprofile-x86_64-standard-00059-g5050dc2 #1 Call Trace: [<ffffffff8106776f>] ? rb_advance_reader+0x2e/0xc5 [<ffffffff81039ffe>] warn_slowpath_common+0x77/0x8f [<ffffffff8103a025>] warn_slowpath_null+0xf/0x11 [<ffffffff8106776f>] rb_advance_reader+0x2e/0xc5 [<ffffffff81068bda>] ring_buffer_consume+0xa0/0xd2 [<ffffffff81326933>] op_cpu_buffer_read_entry+0x21/0x9e [<ffffffff810be3af>] ? __find_get_block+0x4b/0x165 [<ffffffff8132749b>] sync_buffer+0xa5/0x401 [<ffffffff810be3af>] ? __find_get_block+0x4b/0x165 [<ffffffff81326c1b>] ? wq_sync_buffer+0x0/0x78 [<ffffffff81326c76>] wq_sync_buffer+0x5b/0x78 [<ffffffff8104aa30>] worker_thread+0x113/0x1ac [<ffffffff8104dd95>] ? autoremove_wake_function+0x0/0x38 [<ffffffff8104a91d>] ? worker_thread+0x0/0x1ac [<ffffffff8104dc9a>] kthread+0x88/0x92 [<ffffffff8100bdba>] child_rip+0xa/0x20 [<ffffffff8104dc12>] ? kthread+0x0/0x92 [<ffffffff8100bdb0>] ? child_rip+0x0/0x20 ---[ end trace f561c0a58fcc89bd ]--- Cc: Steven Rostedt <rostedt@goodmis.org> Cc: <stable@kernel.org> Signed-off-by: Robert Richter <robert.richter@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | ring-buffer: do not disable ring buffer on oops_in_progressSteven Rostedt2009-08-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The commit: commit e0fdace10e75dac67d906213b780ff1b1a4cc360 Author: David Miller <davem@davemloft.net> Date: Fri Aug 1 01:11:22 2008 -0700 debug_locks: set oops_in_progress if we will log messages. Otherwise lock debugging messages on runqueue locks can deadlock the system due to the wakeups performed by printk(). Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> Will permanently set oops_in_progress on any lockdep failure. When this triggers it will cause any read from the ring buffer to permanently disable the ring buffer (not to mention no locking of printk). This patch removes the check. It keeps the print in NMI which makes sense. This is probably OK, since the ring buffer should not cause something to set oops_in_progress anyway. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * | ring-buffer: fix check of try_to_discard resultSteven Rostedt2009-08-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function ring_buffer_discard_commit inversed the code path of the result of try_to_discard. It should skip incrementing the entry counter if try_to_discard succeeded. But instead, it increments the entry conder if it succeeded to discard, and does not increment it if it fails. The result of this bug is that filtering will make the stat counters incorrect. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | Merge branch 'core-fixes-for-linus-2' of ↵Linus Torvalds2009-08-09
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: lockdep: Fix typos in documentation lockdep: Fix file mode of lock_stat rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock()
| * | lockdep: Fix file mode of lock_statLi Zefan2009-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | /proc/lock_stat is writable. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <4A7BE7B6.10904@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock()Darren Hart2009-08-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the event of a lock steal or owner died, rt_mutex_start_proxy_lock() will give the rt_mutex to the waiting task, but it fails to release the wait_lock. This leads to subsequent deadlocks when other tasks try to acquire the rt_mutex. I also removed a few extra blank lines that really spaced this routine out. I must have been high on the \n when I wrote this originally... Signed-off-by: Darren Hart <dvhltc@us.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Dinakar Guniguntala <dino@in.ibm.com> Cc: John Stultz <johnstul@linux.vnet.ibm.com> LKML-Reference: <4A79D7F1.4000405@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'perfcounters-fixes-for-linus' of ↵Linus Torvalds2009-08-07
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf_counter: Fix double list iteration in per task precise stats perf: Auto-detect libelf perf symbol: Fix symbol parsing in certain cases: use the build-id as a symlink perf_counter/powerpc: Check oprofile_cpu_type for NULL before using it ftrace: Fix perf-tracepoint OOPS perf report: Add missing command line options to man page perf: Auto-detect libbfd perf report: Make --sort comm,dso,symbol the default
| * | | perf_counter: Fix double list iteration in per task precise statsPeter Zijlstra2009-08-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Brice Goglin reported this crash with per task precise stats: > I finally managed to test the threaded perfcounter statistics (thanks a > lot for implementing it). I am running 2.6.31-rc5 (with the AMD > magny-cours patches but I don't think they matter here). I am trying to > measure local/remote memory accesses per thread during the well-known > stream benchmark. It's compiled with OpenMP using 16 threads on a > quad-socket quad-core barcelona machine. > > Command line is: > /mnt/scratch/bgoglin/cpunode/linux-2.6.31/tools/perf/perf record -f -s > -e r1000001e0 -e r1000002e0 -e r1000004e0 -e r1000008e0 ./stream > > It seems to work fine with a single -e <counter> on the command line > while it crashes when there are at least 2 of them. > It seems to work fine without -s as well. A silly copy-paste resulted in a messed up iteration which would cause the OOPS. Reported-by: Brice Goglin <Brice.Goglin@inria.fr> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Brice Goglin <Brice.Goglin@inria.fr> LKML-Reference: <1249574786.32113.550.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | ftrace: Fix perf-tracepoint OOPSPeter Zijlstra2009-08-06
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Not all tracepoints are created equal, in specific the ftrace tracepoints are created with TRACE_EVENT_FORMAT() which does not generate the needed bits to tie them into perf counters. For those events, don't create the 'id' file and fail ->profile_enable when their ID is specified through other means. Reported-by: Chris Mason <chris.mason@oracle.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1249497664.5890.4.camel@laptop> [ v2: fix build error in the !CONFIG_EVENT_PROFILE case ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | execve: must clear current->clear_child_tidEric Dumazet2009-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While looking at Jens Rosenboom bug report (http://lkml.org/lkml/2009/7/27/35) about strange sys_futex call done from a dying "ps" program, we found following problem. clone() syscall has special support for TID of created threads. This support includes two features. One (CLONE_CHILD_SETTID) is to set an integer into user memory with the TID value. One (CLONE_CHILD_CLEARTID) is to clear this same integer once the created thread dies. The integer location is a user provided pointer, provided at clone() time. kernel keeps this pointer value into current->clear_child_tid. At execve() time, we should make sure kernel doesnt keep this user provided pointer, as full user memory is replaced by a new one. As glibc fork() actually uses clone() syscall with CLONE_CHILD_SETTID and CLONE_CHILD_CLEARTID set, chances are high that we might corrupt user memory in forked processes. Following sequence could happen: 1) bash (or any program) starts a new process, by a fork() call that glibc maps to a clone( ... CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID ...) syscall 2) When new process starts, its current->clear_child_tid is set to a location that has a meaning only in bash (or initial program) context (&THREAD_SELF->tid) 3) This new process does the execve() syscall to start a new program. current->clear_child_tid is left unchanged (a non NULL value) 4) If this new program creates some threads, and initial thread exits, kernel will attempt to clear the integer pointed by current->clear_child_tid from mm_release() : if (tsk->clear_child_tid && !(tsk->flags & PF_SIGNALED) && atomic_read(&mm->mm_users) > 1) { u32 __user * tidptr = tsk->clear_child_tid; tsk->clear_child_tid = NULL; /* * We don't check the error code - if userspace has * not set up a proper pointer then tough luck. */ << here >> put_user(0, tidptr); sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL, 0); } 5) OR : if new program is not multi-threaded, but spied by /proc/pid users (ps command for example), mm_users > 1, and the exiting program could corrupt 4 bytes in a persistent memory area (shm or memory mapped file) If current->clear_child_tid points to a writeable portion of memory of the new program, kernel happily and silently corrupts 4 bytes of memory, with unexpected effects. Fix is straightforward and should not break any sane program. Reported-by: Jens Rosenboom <jens@mcbone.net> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sonny Rao <sonnyrao@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | generic-ipi: fix hotplug_cfd()Xiao Guangrong2009-08-07
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use CONFIG_HOTPLUG_CPU, not CONFIG_CPU_HOTPLUG When hot-unpluging a cpu, it will leak memory allocated at cpu hotplug, but only if CPUMASK_OFFSTACK=y, which is default to n. The bug was introduced by 8969a5ede0f9e17da4b943712429aef2c9bcd82b ("generic-ipi: remove kmalloc()"). Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'perfcounters-fixes-for-linus' of ↵Linus Torvalds2009-08-04
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf_counter: Set the CONFIG_PERF_COUNTERS default to y if CONFIG_PROFILING=y perf: Fix read buffer overflow perf top: Add mwait_idle_with_hints to skip_symbols[] perf tools: Fix faulty check perf report: Update for the new FORK/EXIT events perf_counter: Full task tracing perf_counter: Collapse inherit on read() tracing, perf_counter: Add help text to CONFIG_EVENT_PROFILE perf_counter tools: Fix link errors with older toolchains
| * | perf_counter: Full task tracingPeter Zijlstra2009-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to be able to distinguish between no samples due to inactivity and no samples due to task ended, Arjan asked for PERF_EVENT_EXIT events. This is useful to the boot delay instrumentation (bootchart) app. This patch changes the PERF_EVENT_FORK to be emitted on every clone, and adds PERF_EVENT_EXIT to be emitted on task exit, after the task's counters have been closed. This task tracing is controlled through: attr.comm || attr.mmap and through the new attr.task field. Suggested-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> [ cleaned up perf_counter.h a bit ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | perf_counter: Collapse inherit on read()Peter Zijlstra2009-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the counter value returned by read() is the value of the parent counter, to which child counters are only fed back on child exit. Thus read() can return rather erratic (and meaningless) numbers depending on the state of the child processes. Change this by always iterating the full child hierarchy on read() and sum all counters. Suggested-by: Corey Ashford <cjashfor@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds2009-08-04
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: Fix race in cpupri introduced by cpumask_var changes sched: Fix latencytop and sleep profiling vs group scheduling
| * | | sched: Fix race in cpupri introduced by cpumask_var changesGregory Haskins2009-08-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Background: Several race conditions in the scheduler have cropped up recently, which Steven and I have tracked down using ftrace. The most recent one turns out to be a race in how the scheduler determines a suitable migration target for RT tasks, introduced recently with commit: commit 68e74568fbe5854952355e942acca51f138096d9 Date: Tue Nov 25 02:35:13 2008 +1030 sched: convert struct cpupri_vec cpumask_var_t. The original design of cpupri allowed lockless readers to quickly determine a best-estimate target. Races between the pri_active bitmap and the vec->mask were handled in the original code because we would detect and return "0" when this occured. The design was predicated on the *effective* atomicity (*) of caching the result of cpus_and() between the cpus_allowed and the vec->mask. Commit 68e74568 changed the behavior such that vec->mask is accessed multiple times. This introduces a subtle race, the result of which means we can have a result that returns "1", but with an empty bitmap. *) yes, we know cpus_and() is not a locked operator across the entire composite array, but it is implicitly atomic on a per-word basis which is all the design required to work. Implementation: Rather than forgoing the lockless design, or reverting to a stack-based cpumask_t, we simply check for when the race has been encountered and continue processing in the event that the race is hit. This renders the removal race as if the priority bit had been atomically cleared as well, and allows the algorithm to execute correctly. Signed-off-by: Gregory Haskins <ghaskins@novell.com> CC: Rusty Russell <rusty@rustcorp.com.au> CC: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20090730145728.25226.92769.stgit@dev.haskins.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | sched: Fix latencytop and sleep profiling vs group schedulingPeter Zijlstra2009-08-02
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | The latencytop and sleep accounting code assumes that any scheduler entity represents a task, this is not so. Cc: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds2009-08-04
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: posix-timers: Fix oops in clock_nanosleep() with CLOCK_MONOTONIC_RAW
| * | | posix-timers: Fix oops in clock_nanosleep() with CLOCK_MONOTONIC_RAWHiroshi Shimamoto2009-08-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Prevent calling do_nanosleep() with clockid CLOCK_MONOTONIC_RAW, it may cause oops, such as NULL pointer dereference. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <johnstul@us.ibm.com> Cc: <stable@kernel.org> LKML-Reference: <4A764FF3.50607@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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