user/sven/linux.git/kernel/events, branch v3.10.42

list: introduce list_next_entry() and list_prev_entry()

2014-05-31T04:52:14Z

[ Upstream commit 008208c6b26f21c2648c250a09c55e737c02c5f8 ] Add two trivial helpers list_next_entry() and list_prev_entry(), they can have a lot of users including list.h itself. In fact the 1st one is already defined in events/core.c and bnx2x_sp.c, so the patch simply moves the definition to list.h. Signed-off-by: Oleg Nesterov Cc: Eilon Greenstein Cc: Greg Kroah-Hartman Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

perf: Fix hotplug splat

2014-03-07T05:30:11Z

commit e3703f8cdfcf39c25c4338c3ad8e68891cca3731 upstream. Drew Richardson reported that he could make the kernel go *boom* when hotplugging while having perf events active. It turned out that when you have a group event, the code in __perf_event_exit_context() fails to remove the group siblings from the context. We then proceed with destroying and freeing the event, and when you re-plug the CPU and try and add another event to that CPU, things go *boom* because you've still got dead entries there. Reported-by: Drew Richardson Signed-off-by: Peter Zijlstra Cc: Will Deacon Link: http://lkml.kernel.org/n/tip-k6v5wundvusvcseqj1si0oz0@git.kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

perf: Fix perf ring buffer memory ordering

2013-11-20T20:27:47Z

commit bf378d341e4873ed928dc3c636252e6895a21f50 upstream. The PPC64 people noticed a missing memory barrier and crufty old comments in the perf ring buffer code. So update all the comments and add the missing barrier. When the architecture implements local_t using atomic_long_t there will be double barriers issued; but short of introducing more conditional barrier primitives this is the best we can do. Reported-by: Victor Kaplansky Tested-by: Victor Kaplansky Signed-off-by: Peter Zijlstra Cc: Mathieu Desnoyers Cc: michael@ellerman.id.au Cc: Paul McKenney Cc: Michael Neuling Cc: Frederic Weisbecker Cc: anton@samba.org Cc: benh@kernel.crashing.org Link: http://lkml.kernel.org/r/20131025173749.GG19466@laptop.lan Signed-off-by: Ingo Molnar Cc: Michael Neuling Signed-off-by: Greg Kroah-Hartman

uprobes: Fix utask->depth accounting in handle_trampoline()

2013-09-27T00:18:27Z

commit 878b5a6efd38030c7a90895dc8346e8fb1e09b4c upstream. Currently utask->depth is simply the number of allocated/pending return_instance's in uprobe_task->return_instances list. handle_trampoline() should decrement this counter every time we handle/free an instance, but due to typo it does this only if ->chained == T. This means that in the likely case this counter is never decremented and the probed task can't report more than MAX_URETPROBE_DEPTH events. Reported-by: Mikhail Kulemin Reported-by: Hemant Kumar Shaw Signed-off-by: Oleg Nesterov Acked-by: Anton Arapov Cc: masami.hiramatsu.pt@hitachi.com Cc: srikar@linux.vnet.ibm.com Cc: systemtap@sourceware.org Link: http://lkml.kernel.org/r/20130911154726.GA8093@redhat.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

perf: Fix perf_lock_task_context() vs RCU

2013-07-25T21:07:43Z

commit 058ebd0eba3aff16b144eabf4510ed9510e1416e upstream. Jiri managed to trigger this warning: [] ====================================================== [] [ INFO: possible circular locking dependency detected ] [] 3.10.0+ #228 Tainted: G W [] ------------------------------------------------------- [] p/6613 is trying to acquire lock: [] (rcu_node_0){..-...}, at: [] rcu_read_unlock_special+0xa7/0x250 [] [] but task is already holding lock: [] (&ctx->lock){-.-...}, at: [] perf_lock_task_context+0xd9/0x2c0 [] [] which lock already depends on the new lock. [] [] the existing dependency chain (in reverse order) is: [] [] -> #4 (&ctx->lock){-.-...}: [] -> #3 (&rq->lock){-.-.-.}: [] -> #2 (&p->pi_lock){-.-.-.}: [] -> #1 (&rnp->nocb_gp_wq[1]){......}: [] -> #0 (rcu_node_0){..-...}: Paul was quick to explain that due to preemptible RCU we cannot call rcu_read_unlock() while holding scheduler (or nested) locks when part of the read side critical section was preemptible. Therefore solve it by making the entire RCU read side non-preemptible. Also pull out the retry from under the non-preempt to play nice with RT. Reported-by: Jiri Olsa Helped-out-by: Paul E. McKenney Signed-off-by: Peter Zijlstra Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

perf: Remove WARN_ON_ONCE() check in __perf_event_enable() for valid scenario

2013-07-25T21:07:42Z

commit 06f417968beac6e6b614e17b37d347aa6a6b1d30 upstream. The '!ctx->is_active' check has a valid scenario, so there's no need for the warning. The reason is that there's a time window between the 'ctx->is_active' check in the perf_event_enable() function and the __perf_event_enable() function having: - IRQs on - ctx->lock unlocked where the task could be killed and 'ctx' deactivated by perf_event_exit_task(), ending up with the warning below. So remove the WARN_ON_ONCE() check and add comments to explain it all. This addresses the following warning reported by Vince Weaver: [ 324.983534] ------------[ cut here ]------------ [ 324.984420] WARNING: at kernel/events/core.c:1953 __perf_event_enable+0x187/0x190() [ 324.984420] Modules linked in: [ 324.984420] CPU: 19 PID: 2715 Comm: nmi_bug_snb Not tainted 3.10.0+ #246 [ 324.984420] Hardware name: Supermicro X8DTN/X8DTN, BIOS 4.6.3 01/08/2010 [ 324.984420] 0000000000000009 ffff88043fce3ec8 ffffffff8160ea0b ffff88043fce3f00 [ 324.984420] ffffffff81080ff0 ffff8802314fdc00 ffff880231a8f800 ffff88043fcf7860 [ 324.984420] 0000000000000286 ffff880231a8f800 ffff88043fce3f10 ffffffff8108103a [ 324.984420] Call Trace: [ 324.984420] [] dump_stack+0x19/0x1b [ 324.984420] [] warn_slowpath_common+0x70/0xa0 [ 324.984420] [] warn_slowpath_null+0x1a/0x20 [ 324.984420] [] __perf_event_enable+0x187/0x190 [ 324.984420] [] remote_function+0x40/0x50 [ 324.984420] [] generic_smp_call_function_single_interrupt+0xbe/0x130 [ 324.984420] [] smp_call_function_single_interrupt+0x27/0x40 [ 324.984420] [] call_function_single_interrupt+0x6f/0x80 [ 324.984420] [] ? _raw_spin_unlock_irqrestore+0x41/0x70 [ 324.984420] [] perf_event_exit_task+0x14d/0x210 [ 324.984420] [] ? switch_task_namespaces+0x24/0x60 [ 324.984420] [] do_exit+0x2b6/0xa40 [ 324.984420] [] ? _raw_spin_unlock_irq+0x2c/0x30 [ 324.984420] [] do_group_exit+0x49/0xc0 [ 324.984420] [] get_signal_to_deliver+0x254/0x620 [ 324.984420] [] do_signal+0x57/0x5a0 [ 324.984420] [] ? __do_page_fault+0x2a4/0x4e0 [ 324.984420] [] ? retint_restore_args+0xe/0xe [ 324.984420] [] ? retint_signal+0x11/0x84 [ 324.984420] [] do_notify_resume+0x65/0x80 [ 324.984420] [] retint_signal+0x46/0x84 [ 324.984420] ---[ end trace 442ec2f04db3771a ]--- Reported-by: Vince Weaver Signed-off-by: Jiri Olsa Suggested-by: Peter Zijlstra Cc: Corey Ashford Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Namhyung Kim Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1373384651-6109-2-git-send-email-jolsa@redhat.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

perf: Clone child context from parent context pmu

2013-07-25T21:07:42Z

commit 734df5ab549ca44f40de0f07af1c8803856dfb18 upstream. Currently when the child context for inherited events is created, it's based on the pmu object of the first event of the parent context. This is wrong for the following scenario: - HW context having HW and SW event - HW event got removed (closed) - SW event stays in HW context as the only event and its pmu is used to clone the child context The issue starts when the cpu context object is touched based on the pmu context object (__get_cpu_context). In this case the HW context will work with SW cpu context ending up with following WARN below. Fixing this by using parent context pmu object to clone from child context. Addresses the following warning reported by Vince Weaver: [ 2716.472065] ------------[ cut here ]------------ [ 2716.476035] WARNING: at kernel/events/core.c:2122 task_ctx_sched_out+0x3c/0x) [ 2716.476035] Modules linked in: nfsd auth_rpcgss oid_registry nfs_acl nfs locn [ 2716.476035] CPU: 0 PID: 3164 Comm: perf_fuzzer Not tainted 3.10.0-rc4 #2 [ 2716.476035] Hardware name: AOpen DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BI2 [ 2716.476035] 0000000000000000 ffffffff8102e215 0000000000000000 ffff88011fc18 [ 2716.476035] ffff8801175557f0 0000000000000000 ffff880119fda88c ffffffff810ad [ 2716.476035] ffff880119fda880 ffffffff810af02a 0000000000000009 ffff880117550 [ 2716.476035] Call Trace: [ 2716.476035] [] ? warn_slowpath_common+0x5b/0x70 [ 2716.476035] [] ? task_ctx_sched_out+0x3c/0x5f [ 2716.476035] [] ? perf_event_exit_task+0xbf/0x194 [ 2716.476035] [] ? do_exit+0x3e7/0x90c [ 2716.476035] [] ? __do_fault+0x359/0x394 [ 2716.476035] [] ? do_group_exit+0x66/0x98 [ 2716.476035] [] ? get_signal_to_deliver+0x479/0x4ad [ 2716.476035] [] ? __perf_event_task_sched_out+0x230/0x2d1 [ 2716.476035] [] ? do_signal+0x3c/0x432 [ 2716.476035] [] ? ctx_sched_in+0x43/0x141 [ 2716.476035] [] ? perf_event_context_sched_in+0x7a/0x90 [ 2716.476035] [] ? __perf_event_task_sched_in+0x31/0x118 [ 2716.476035] [] ? mmdrop+0xd/0x1c [ 2716.476035] [] ? finish_task_switch+0x7d/0xa6 [ 2716.476035] [] ? do_notify_resume+0x20/0x5d [ 2716.476035] [] ? retint_signal+0x3d/0x78 [ 2716.476035] ---[ end trace 827178d8a5966c3d ]--- Reported-by: Vince Weaver Signed-off-by: Jiri Olsa Cc: Corey Ashford Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Namhyung Kim Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1373384651-6109-1-git-send-email-jolsa@redhat.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot()

2013-06-20T15:57:01Z

fetch_bp_busy_slots() and toggle_bp_slot() use for_each_online_cpu(), this is obviously wrong wrt cpu_up() or cpu_down(), we can over/under account the per-cpu numbers. For example: # echo 0 >> /sys/devices/system/cpu/cpu1/online # perf record -e mem:0x10 -p 1 & # echo 1 >> /sys/devices/system/cpu/cpu1/online # perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10 -C1 -a & # taskset -p 0x2 1 triggers the same WARN_ONCE("Can't find any breakpoint slot") in arch_install_hw_breakpoint(). Reported-by: Vince Weaver Signed-off-by: Oleg Nesterov Acked-by: Frederic Weisbecker Cc: Link: http://lkml.kernel.org/r/20130620155009.GA6327@redhat.com Signed-off-by: Ingo Molnar

hw_breakpoint: Fix cpu check in task_bp_pinned(cpu)

2013-06-20T15:57:00Z

trinity fuzzer triggered WARN_ONCE("Can't find any breakpoint slot") in arch_install_hw_breakpoint() but the problem is not arch-specific. The problem is, task_bp_pinned(cpu) checks "cpu == iter->cpu" but this doesn't account the "all cpus" events with iter->cpu < 0. This means that, say, register_user_hw_breakpoint(tsk) can happily create the arbitrary number > HBP_NUM of breakpoints which can not be activated. toggle_bp_task_slot() is equally wrong by the same reason and nr_task_bp_pinned[] can have negative entries. Simple test: # perl -e 'sleep 1 while 1' & # perf record -e mem:0x10,mem:0x10,mem:0x10,mem:0x10,mem:0x10 -p `pidof perl` Before this patch this triggers the same problem/WARN_ON(), after the patch it correctly fails with -ENOSPC. Reported-by: Vince Weaver Signed-off-by: Oleg Nesterov Acked-by: Frederic Weisbecker Cc: Link: http://lkml.kernel.org/r/20130620155006.GA6324@redhat.com Signed-off-by: Ingo Molnar

perf: Fix mmap() accounting hole

2013-06-19T10:44:13Z

Vince's fuzzer once again found holes. This time it spotted a leak in the locked page accounting. When an event had redirected output and its close() was the last reference to the buffer we didn't have a vm context to undo accounting. Change the code to destroy the buffer on the last munmap() and detach all redirected events at that time. This provides us the right context to undo the vm accounting. Reported-and-tested-by: Vince Weaver Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20130604084421.GI8923@twins.programming.kicks-ass.net Cc: Signed-off-by: Ingo Molnar