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2013-07-12perf: Fix perf_lock_task_context() vs RCUPeter Zijlstra
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: [<ffffffff810ca797>] rcu_read_unlock_special+0xa7/0x250 [] [] but task is already holding lock: [] (&ctx->lock){-.-...}, at: [<ffffffff810f2879>] 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 <jolsa@redhat.com> Helped-out-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-07-12perf: Remove WARN_ON_ONCE() check in __perf_event_enable() for valid scenarioJiri Olsa
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] <IRQ> [<ffffffff8160ea0b>] dump_stack+0x19/0x1b [ 324.984420] [<ffffffff81080ff0>] warn_slowpath_common+0x70/0xa0 [ 324.984420] [<ffffffff8108103a>] warn_slowpath_null+0x1a/0x20 [ 324.984420] [<ffffffff81134437>] __perf_event_enable+0x187/0x190 [ 324.984420] [<ffffffff81130030>] remote_function+0x40/0x50 [ 324.984420] [<ffffffff810e51de>] generic_smp_call_function_single_interrupt+0xbe/0x130 [ 324.984420] [<ffffffff81066a47>] smp_call_function_single_interrupt+0x27/0x40 [ 324.984420] [<ffffffff8161fd2f>] call_function_single_interrupt+0x6f/0x80 [ 324.984420] <EOI> [<ffffffff816161a1>] ? _raw_spin_unlock_irqrestore+0x41/0x70 [ 324.984420] [<ffffffff8113799d>] perf_event_exit_task+0x14d/0x210 [ 324.984420] [<ffffffff810acd04>] ? switch_task_namespaces+0x24/0x60 [ 324.984420] [<ffffffff81086946>] do_exit+0x2b6/0xa40 [ 324.984420] [<ffffffff8161615c>] ? _raw_spin_unlock_irq+0x2c/0x30 [ 324.984420] [<ffffffff81087279>] do_group_exit+0x49/0xc0 [ 324.984420] [<ffffffff81096854>] get_signal_to_deliver+0x254/0x620 [ 324.984420] [<ffffffff81043057>] do_signal+0x57/0x5a0 [ 324.984420] [<ffffffff8161a164>] ? __do_page_fault+0x2a4/0x4e0 [ 324.984420] [<ffffffff8161665c>] ? retint_restore_args+0xe/0xe [ 324.984420] [<ffffffff816166cd>] ? retint_signal+0x11/0x84 [ 324.984420] [<ffffffff81043605>] do_notify_resume+0x65/0x80 [ 324.984420] [<ffffffff81616702>] retint_signal+0x46/0x84 [ 324.984420] ---[ end trace 442ec2f04db3771a ]--- Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Suggested-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1373384651-6109-2-git-send-email-jolsa@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-07-12perf: Clone child context from parent context pmuJiri Olsa
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] [<ffffffff8102e215>] ? warn_slowpath_common+0x5b/0x70 [ 2716.476035] [<ffffffff810ab2bd>] ? task_ctx_sched_out+0x3c/0x5f [ 2716.476035] [<ffffffff810af02a>] ? perf_event_exit_task+0xbf/0x194 [ 2716.476035] [<ffffffff81032a37>] ? do_exit+0x3e7/0x90c [ 2716.476035] [<ffffffff810cd5ab>] ? __do_fault+0x359/0x394 [ 2716.476035] [<ffffffff81032fe6>] ? do_group_exit+0x66/0x98 [ 2716.476035] [<ffffffff8103dbcd>] ? get_signal_to_deliver+0x479/0x4ad [ 2716.476035] [<ffffffff810ac05c>] ? __perf_event_task_sched_out+0x230/0x2d1 [ 2716.476035] [<ffffffff8100205d>] ? do_signal+0x3c/0x432 [ 2716.476035] [<ffffffff810abbf9>] ? ctx_sched_in+0x43/0x141 [ 2716.476035] [<ffffffff810ac2ca>] ? perf_event_context_sched_in+0x7a/0x90 [ 2716.476035] [<ffffffff810ac311>] ? __perf_event_task_sched_in+0x31/0x118 [ 2716.476035] [<ffffffff81050dd9>] ? mmdrop+0xd/0x1c [ 2716.476035] [<ffffffff81051a39>] ? finish_task_switch+0x7d/0xa6 [ 2716.476035] [<ffffffff81002473>] ? do_notify_resume+0x20/0x5d [ 2716.476035] [<ffffffff813654f5>] ? retint_signal+0x3d/0x78 [ 2716.476035] ---[ end trace 827178d8a5966c3d ]--- Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1373384651-6109-1-git-send-email-jolsa@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-07-05perf: Fix interrupt handler timing harnessStephane Eranian
This patch fixes a serious bug in: 14c63f17b1fd perf: Drop sample rate when sampling is too slow There was an misunderstanding on the API of the do_div() macro. It returns the remainder of the division and this was not what the function expected leading to disabling the interrupt latency watchdog. This patch also remove a duplicate assignment in perf_sample_event_took(). Signed-off-by: Stephane Eranian <eranian@google.com> Cc: peterz@infradead.org Cc: dave.hansen@linux.intel.com Cc: ak@linux.intel.com Cc: jolsa@redhat.com Link: http://lkml.kernel.org/r/20130704223010.GA30625@quad Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-23perf: Drop sample rate when sampling is too slowDave Hansen
This patch keeps track of how long perf's NMI handler is taking, and also calculates how many samples perf can take a second. If the sample length times the expected max number of samples exceeds a configurable threshold, it drops the sample rate. This way, we don't have a runaway sampling process eating up the CPU. This patch can tend to drop the sample rate down to level where perf doesn't work very well. *BUT* the alternative is that my system hangs because it spends all of its time handling NMIs. I'll take a busted performance tool over an entire system that's busted and undebuggable any day. BTW, my suspicion is that there's still an underlying bug here. Using the HPET instead of the TSC is definitely a contributing factor, but I suspect there are some other things going on. But, I can't go dig down on a bug like that with my machine hanging all the time. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: paulus@samba.org Cc: acme@ghostprotocols.net Cc: Dave Hansen <dave@sr71.net> [ Prettified it a bit. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-20hw_breakpoint: Introduce "struct bp_cpuinfo"Oleg Nesterov
This patch simply moves all per-cpu variables into the new single per-cpu "struct bp_cpuinfo". To me this looks more logical and clean, but this can also simplify the further potential changes. In particular, I do not think this memory should be per-cpu, it is never used "locally". After this change it is trivial to turn it into, say, bootmem[nr_cpu_ids]. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20130620155020.GA6350@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-20hw_breakpoint: Simplify *register_wide_hw_breakpoint()Oleg Nesterov
1. register_wide_hw_breakpoint() can use unregister_ if failure, no need to duplicate the code. 2. "struct perf_event **pevent" adds the unnecesary lever of indirection and complication, use per_cpu(*cpu_events, cpu). Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20130620155018.GA6347@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-20hw_breakpoint: Introduce cpumask_of_bp()Oleg Nesterov
Add the trivial helper which simply returns cpumask_of() or cpu_possible_mask depending on bp->cpu. Change fetch_bp_busy_slots() and toggle_bp_slot() to always do for_each_cpu(cpumask_of_bp) to simplify the code and avoid the code duplication. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20130620155015.GA6340@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-20hw_breakpoint: Simplify the "weight" usage in toggle_bp_slot() pathsOleg Nesterov
Change toggle_bp_slot() to make "weight" negative if !enable. This way we can always use "+ weight" without additional "if (enable)" check and toggle_bp_task_slot() no longer needs this arg. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20130620155013.GA6337@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-20hw_breakpoint: Simplify list/idx mess in toggle_bp_slot() pathsOleg Nesterov
The enable/disable logic in toggle_bp_slot() is not symmetrical and imho very confusing. "old_count" in toggle_bp_task_slot() is actually new_count because this bp was already removed from the list. Change toggle_bp_slot() to always call list_add/list_del after toggle_bp_task_slot(). This way old_idx is task_bp_pinned() and this entry should be decremented, new_idx is +/-weight and we need to increment this element. The code/logic looks obvious. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20130620155011.GA6330@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-20Merge branch 'perf/urgent' into perf/coreIngo Molnar
Merge in two hw_breakpoint fixes, before applying another 5. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-20hw_breakpoint: Use cpu_possible_mask in {reserve,release}_bp_slot()Oleg Nesterov
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 <vincent.weaver@maine.edu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20130620155009.GA6327@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-20hw_breakpoint: Fix cpu check in task_bp_pinned(cpu)Oleg Nesterov
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 <vincent.weaver@maine.edu> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20130620155006.GA6324@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-19perf: Add const qualifier to perf_pmu_register's 'name' argMischa Jonker
This allows us to use pdev->name for registering a PMU device. IMO the name is not supposed to be changed anyway. Signed-off-by: Mischa Jonker <mjonker@synopsys.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1370339148-5566-1-git-send-email-mjonker@synopsys.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-19perf: Fix hypervisor branch sampling permission checkStephane Eranian
Commit 2b923c8 perf/x86: Check branch sampling priv level in generic code was missing the check for the hypervisor (HV) priv level, so add it back. With this patch, we get the following correct behavior: # echo 2 >/proc/sys/kernel/perf_event_paranoid $ perf record -j any,k noploop 1 Error: You may not have permission to collect stats. Consider tweaking /proc/sys/kernel/perf_event_paranoid: -1 - Not paranoid at all 0 - Disallow raw tracepoint access for unpriv 1 - Disallow cpu events for unpriv 2 - Disallow kernel profiling for unpriv $ perf record -j any,hv noploop 1 Error: You may not have permission to collect stats. Consider tweaking /proc/sys/kernel/perf_event_paranoid: -1 - Not paranoid at all 0 - Disallow raw tracepoint access for unpriv 1 - Disallow cpu events for unpriv 2 - Disallow kernel profiling for unpriv Signed-off-by: Stephane Eranian <eranian@google.com> Acked-by: Petr Matousek <pmatouse@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20130606090204.GA3725@quad Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-19Merge branch 'perf/urgent' into perf/coreIngo Molnar
Merge in the latest fixes, to avoid conflicts with ongoing work. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-06-19perf: Fix mmap() accounting holePeter Zijlstra
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 <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20130604084421.GI8923@twins.programming.kicks-ass.net Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-05-28perf: Fix perf mmap bugsPeter Zijlstra
Vince reported a problem found by his perf specific trinity fuzzer. Al noticed 2 problems with perf's mmap(): - it has issues against fork() since we use vma->vm_mm for accounting. - it has an rb refcount leak on double mmap(). We fix the issues against fork() by using VM_DONTCOPY; I don't think there's code out there that uses this; we didn't hear about weird accounting problems/crashes. If we do need this to work, the previously proposed VM_PINNED could make this work. Aside from the rb reference leak spotted by Al, Vince's example prog was indeed doing a double mmap() through the use of perf_event_set_output(). This exposes another problem, since we now have 2 events with one buffer, the accounting gets screwy because we account per event. Fix this by making the buffer responsible for its own accounting. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Link: http://lkml.kernel.org/r/20130528085548.GA12193@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-05-28perf/x86: Check branch sampling priv level in generic codeStephane Eranian
This patch moves commit 7cc23cd to the generic code: perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNEL The check is now implemented in generic code instead of x86 specific code. That way we do not have to repeat the test in each arch supporting branch sampling. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Link: http://lkml.kernel.org/r/20130521105337.GA2879@quad Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-05-28perf: Add sysfs entry to adjust multiplexing interval per PMUStephane Eranian
This patch adds /sys/device/xxx/perf_event_mux_interval_ms to ajust the multiplexing interval per PMU. The unit is milliseconds. Value has to be >= 1. In the 4th version, we renamed the sysfs file to be more consistent with the other /proc/sys/kernel entries for perf_events. In the 5th version, we handle the reprogramming of the hrtimer using hrtimer_forward_now(). That way, we sync up to new timer value quickly (suggested by Jiri Olsa). Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Link: http://lkml.kernel.org/r/1364991694-5876-3-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-05-28perf: Use hrtimers for event multiplexingStephane Eranian
The current scheme of using the timer tick was fine for per-thread events. However, it was causing bias issues in system-wide mode (including for uncore PMUs). Event groups would not get their fair share of runtime on the PMU. With tickless kernels, if a core is idle there is no timer tick, and thus no event rotation (multiplexing). However, there are events (especially uncore events) which do count even though cores are asleep. This patch changes the timer source for multiplexing. It introduces a per-PMU per-cpu hrtimer. The advantage is that even when a core goes idle, it will come back to service the hrtimer, thus multiplexing on system-wide events works much better. The per-PMU implementation (suggested by PeterZ) enables adjusting the multiplexing interval per PMU. The preferred interval is stashed into the struct pmu. If not set, it will be forced to the default interval value. In order to minimize the impact of the hrtimer, it is turned on and off on demand. When the PMU on a CPU is overcommited, the hrtimer is activated. It is stopped when the PMU is not overcommitted. In order for this to work properly, we had to change the order of initialization in start_kernel() such that hrtimer_init() is run before perf_event_init(). The default interval in milliseconds is set to a timer tick just like with the old code. We will provide a sysctl to tune this in another patch. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Link: http://lkml.kernel.org/r/1364991694-5876-2-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-05-28perf: Fix hw breakpoints overflow period samplingJiri Olsa
The hw breakpoint pmu 'add' function is missing the period_left update needed for SW events. The perf HW breakpoint events use the SW events framework to process the overflow, so it needs to be properly initialized in the PMU 'add' method. Signed-off-by: Jiri Olsa <jolsa@redhat.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1367421944-19082-5-git-send-email-jolsa@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-05-07perf: Factor out auxiliary events notificationJiri Olsa
Add perf_event_aux() function to send out all types of auxiliary events - mmap, task, comm events. For each type there's match and output functions defined and used as callbacks during perf_event_aux processing. This way we can centralize the pmu/context iterating and event matching logic. Also since lot of the code was duplicated, this patch reduces the .text size about 2kB on my setup: snipped output from 'objdump -x kernel/events/core.o' before: Idx Name Size 0 .text 0000d313 after: Idx Name Size 0 .text 0000cad3 Signed-off-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/1367857638-27631-3-git-send-email-jolsa@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-05-07perf: Fix EXIT event notificationJiri Olsa
The perf_event_task_ctx() function needs to be called with preemption disabled, since it's checking for currently scheduled cpu against event cpu. We disable preemption for task related perf event context if there's one defined, leaving up to the chance which cpu it gets scheduled in. Signed-off-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/1367857638-27631-2-git-send-email-jolsa@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-05-05Merge branch 'timers-nohz-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull 'full dynticks' support from Ingo Molnar: "This tree from Frederic Weisbecker adds a new, (exciting! :-) core kernel feature to the timer and scheduler subsystems: 'full dynticks', or CONFIG_NO_HZ_FULL=y. This feature extends the nohz variable-size timer tick feature from idle to busy CPUs (running at most one task) as well, potentially reducing the number of timer interrupts significantly. This feature got motivated by real-time folks and the -rt tree, but the general utility and motivation of full-dynticks runs wider than that: - HPC workloads get faster: CPUs running a single task should be able to utilize a maximum amount of CPU power. A periodic timer tick at HZ=1000 can cause a constant overhead of up to 1.0%. This feature removes that overhead - and speeds up the system by 0.5%-1.0% on typical distro configs even on modern systems. - Real-time workload latency reduction: CPUs running critical tasks should experience as little jitter as possible. The last remaining source of kernel-related jitter was the periodic timer tick. - A single task executing on a CPU is a pretty common situation, especially with an increasing number of cores/CPUs, so this feature helps desktop and mobile workloads as well. The cost of the feature is mainly related to increased timer reprogramming overhead when a CPU switches its tick period, and thus slightly longer to-idle and from-idle latency. Configuration-wise a third mode of operation is added to the existing two NOHZ kconfig modes: - CONFIG_HZ_PERIODIC: [formerly !CONFIG_NO_HZ], now explicitly named as a config option. This is the traditional Linux periodic tick design: there's a HZ tick going on all the time, regardless of whether a CPU is idle or not. - CONFIG_NO_HZ_IDLE: [formerly CONFIG_NO_HZ=y], this turns off the periodic tick when a CPU enters idle mode. - CONFIG_NO_HZ_FULL: this new mode, in addition to turning off the tick when a CPU is idle, also slows the tick down to 1 Hz (one timer interrupt per second) when only a single task is running on a CPU. The .config behavior is compatible: existing !CONFIG_NO_HZ and CONFIG_NO_HZ=y settings get translated to the new values, without the user having to configure anything. CONFIG_NO_HZ_FULL is turned off by default. This feature is based on a lot of infrastructure work that has been steadily going upstream in the last 2-3 cycles: related RCU support and non-periodic cputime support in particular is upstream already. This tree adds the final pieces and activates the feature. The pull request is marked RFC because: - it's marked 64-bit only at the moment - the 32-bit support patch is small but did not get ready in time. - it has a number of fresh commits that came in after the merge window. The overwhelming majority of commits are from before the merge window, but still some aspects of the tree are fresh and so I marked it RFC. - it's a pretty wide-reaching feature with lots of effects - and while the components have been in testing for some time, the full combination is still not very widely used. That it's default-off should reduce its regression abilities and obviously there are no known regressions with CONFIG_NO_HZ_FULL=y enabled either. - the feature is not completely idempotent: there is no 100% equivalent replacement for a periodic scheduler/timer tick. In particular there's ongoing work to map out and reduce its effects on scheduler load-balancing and statistics. This should not impact correctness though, there are no known regressions related to this feature at this point. - it's a pretty ambitious feature that with time will likely be enabled by most Linux distros, and we'd like you to make input on its design/implementation, if you dislike some aspect we missed. Without flaming us to crisp! :-) Future plans: - there's ongoing work to reduce 1Hz to 0Hz, to essentially shut off the periodic tick altogether when there's a single busy task on a CPU. We'd first like 1 Hz to be exposed more widely before we go for the 0 Hz target though. - once we reach 0 Hz we can remove the periodic tick assumption from nr_running>=2 as well, by essentially interrupting busy tasks only as frequently as the sched_latency constraints require us to do - once every 4-40 msecs, depending on nr_running. I am personally leaning towards biting the bullet and doing this in v3.10, like the -rt tree this effort has been going on for too long - but the final word is up to you as usual. More technical details can be found in Documentation/timers/NO_HZ.txt" * 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits) sched: Keep at least 1 tick per second for active dynticks tasks rcu: Fix full dynticks' dependency on wide RCU nocb mode nohz: Protect smp_processor_id() in tick_nohz_task_switch() nohz_full: Add documentation. cputime_nsecs: use math64.h for nsec resolution conversion helpers nohz: Select VIRT_CPU_ACCOUNTING_GEN from full dynticks config nohz: Reduce overhead under high-freq idling patterns nohz: Remove full dynticks' superfluous dependency on RCU tree nohz: Fix unavailable tick_stop tracepoint in dynticks idle nohz: Add basic tracing nohz: Select wide RCU nocb for full dynticks nohz: Disable the tick when irq resume in full dynticks CPU nohz: Re-evaluate the tick for the new task after a context switch nohz: Prepare to stop the tick on irq exit nohz: Implement full dynticks kick nohz: Re-evaluate the tick from the scheduler IPI sched: New helper to prevent from stopping the tick in full dynticks sched: Kick full dynticks CPU that have more than one task enqueued. perf: New helper to prevent full dynticks CPUs from stopping tick perf: Kick full dynticks CPU if events rotation is needed ...
2013-05-05Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "Misc fixes plus a small hw-enablement patch for Intel IB model 58 uncore events" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86/intel/lbr: Demand proper privileges for PERF_SAMPLE_BRANCH_KERNEL perf/x86/intel/lbr: Fix LBR filter perf/x86: Blacklist all MEM_*_RETIRED events for Ivy Bridge perf: Fix vmalloc ring buffer pages handling perf/x86/intel: Fix unintended variable name reuse perf/x86/intel: Add support for IvyBridge model 58 Uncore perf/x86/intel: Fix typo in perf_event_intel_uncore.c x86: Eliminate irq_mis_count counted in arch_irq_stat
2013-05-02Merge commit '8700c95adb03' into timers/nohzFrederic Weisbecker
The full dynticks tree needs the latest RCU and sched upstream updates in order to fix some dependencies. Merge a common upstream merge point that has these updates. Conflicts: include/linux/perf_event.h kernel/rcutree.h kernel/rcutree_plugin.h Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2013-05-01perf: Fix vmalloc ring buffer pages handlingJiri Olsa
If we allocate perf ring buffer with the size of single (user) page, we will get memory corruption when releasing itin rb_free_work function (for CONFIG_PERF_USE_VMALLOC option). For single page sized ring buffer the page_order is -1 (because nr_pages is 0). This needs to be recognized in the rb_free_work function to release proper amount of pages. Adding data_page_nr function that returns number of allocated data pages. Customizing the rest of the code to use it. Reported-by: Jan Stancek <jstancek@redhat.com> Original-patch-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Jiri Olsa <jolsa@redhat.com> Link: http://lkml.kernel.org/r/20130319143509.GA1128@krava.brq.redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-30Merge branch 'perf-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf updates from Ingo Molnar: "Features: - Add "uretprobes" - an optimization to uprobes, like kretprobes are an optimization to kprobes. "perf probe -x file sym%return" now works like kretprobes. By Oleg Nesterov. - Introduce per core aggregation in 'perf stat', from Stephane Eranian. - Add memory profiling via PEBS, from Stephane Eranian. - Event group view for 'annotate' in --stdio, --tui and --gtk, from Namhyung Kim. - Add support for AMD NB and L2I "uncore" counters, by Jacob Shin. - Add Ivy Bridge-EP uncore support, by Zheng Yan - IBM zEnterprise EC12 oprofile support patchlet from Robert Richter. - Add perf test entries for checking breakpoint overflow signal handler issues, from Jiri Olsa. - Add perf test entry for for checking number of EXIT events, from Namhyung Kim. - Add perf test entries for checking --cpu in record and stat, from Jiri Olsa. - Introduce perf stat --repeat forever, from Frederik Deweerdt. - Add --no-demangle to report/top, from Namhyung Kim. - PowerPC fixes plus a couple of cleanups/optimizations in uprobes and trace_uprobes, by Oleg Nesterov. Various fixes and refactorings: - Fix dependency of the python binding wrt libtraceevent, from Naohiro Aota. - Simplify some perf_evlist methods and to allow 'stat' to share code with 'record' and 'trace', by Arnaldo Carvalho de Melo. - Remove dead code in related to libtraceevent integration, from Namhyung Kim. - Revert "perf sched: Handle PERF_RECORD_EXIT events" to get 'perf sched lat' back working, by Arnaldo Carvalho de Melo - We don't use Newt anymore, just plain libslang, by Arnaldo Carvalho de Melo. - Kill a bunch of die() calls, from Namhyung Kim. - Fix build on non-glibc systems due to libio.h absence, from Cody P Schafer. - Remove some perf_session and tracing dead code, from David Ahern. - Honor parallel jobs, fix from Borislav Petkov - Introduce tools/lib/lk library, initially just removing duplication among tools/perf and tools/vm. from Borislav Petkov ... and many more I missed to list, see the shortlog and git log for more details." * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (136 commits) perf/x86/intel/P4: Robistify P4 PMU types perf/x86/amd: Fix AMD NB and L2I "uncore" support perf/x86/amd: Remove old-style NB counter support from perf_event_amd.c perf/x86: Check all MSRs before passing hw check perf/x86/amd: Add support for AMD NB and L2I "uncore" counters perf/x86/intel: Add Ivy Bridge-EP uncore support perf/x86/intel: Fix SNB-EP CBO and PCU uncore PMU filter management perf/x86: Avoid kfree() in CPU_{STARTING,DYING} uprobes/perf: Avoid perf_trace_buf_prepare/submit if ->perf_events is empty uprobes/tracing: Don't pass addr=ip to perf_trace_buf_submit() uprobes/tracing: Change create_trace_uprobe() to support uretprobes uprobes/tracing: Make seq_printf() code uretprobe-friendly uprobes/tracing: Make register_uprobe_event() paths uretprobe-friendly uprobes/tracing: Make uprobe_{trace,perf}_print() uretprobe-friendly uprobes/tracing: Introduce is_ret_probe() and uretprobe_dispatcher() uprobes/tracing: Introduce uprobe_{trace,perf}_print() helpers uprobes/tracing: Generalize struct uprobe_trace_entry_head uprobes/tracing: Kill the pointless local_save_flags/preempt_count calls uprobes/tracing: Kill the pointless seq_print_ip_sym() call uprobes/tracing: Kill the pointless task_pt_regs() calls ...
2013-04-29Merge branch 'for-3.10' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: - Fixes and a lot of cleanups. Locking cleanup is finally complete. cgroup_mutex is no longer exposed to individual controlelrs which used to cause nasty deadlock issues. Li fixed and cleaned up quite a bit including long standing ones like racy cgroup_path(). - device cgroup now supports proper hierarchy thanks to Aristeu. - perf_event cgroup now supports proper hierarchy. - A new mount option "__DEVEL__sane_behavior" is added. As indicated by the name, this option is to be used for development only at this point and generates a warning message when used. Unfortunately, cgroup interface currently has too many brekages and inconsistencies to implement a consistent and unified hierarchy on top. The new flag is used to collect the behavior changes which are necessary to implement consistent unified hierarchy. It's likely that this flag won't be used verbatim when it becomes ready but will be enabled implicitly along with unified hierarchy. The option currently disables some of broken behaviors in cgroup core and also .use_hierarchy switch in memcg (will be routed through -mm), which can be used to make very unusual hierarchy where nesting is partially honored. It will also be used to implement hierarchy support for blk-throttle which would be impossible otherwise without introducing a full separate set of control knobs. This is essentially versioning of interface which isn't very nice but at this point I can't see any other options which would allow keeping the interface the same while moving towards hierarchy behavior which is at least somewhat sane. The planned unified hierarchy is likely to require some level of adaptation from userland anyway, so I think it'd be best to take the chance and update the interface such that it's supportable in the long term. Maintaining the existing interface does complicate cgroup core but shouldn't put too much strain on individual controllers and I think it'd be manageable for the foreseeable future. Maybe we'll be able to drop it in a decade. Fix up conflicts (including a semantic one adding a new #include to ppc that was uncovered by header the file changes) as per Tejun. * 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (45 commits) cpuset: fix compile warning when CONFIG_SMP=n cpuset: fix cpu hotplug vs rebuild_sched_domains() race cpuset: use rebuild_sched_domains() in cpuset_hotplug_workfn() cgroup: restore the call to eventfd->poll() cgroup: fix use-after-free when umounting cgroupfs cgroup: fix broken file xattrs devcg: remove parent_cgroup. memcg: force use_hierarchy if sane_behavior cgroup: remove cgrp->top_cgroup cgroup: introduce sane_behavior mount option move cgroupfs_root to include/linux/cgroup.h cgroup: convert cgroupfs_root flag bits to masks and add CGRP_ prefix cgroup: make cgroup_path() not print double slashes Revert "cgroup: remove bind() method from cgroup_subsys." perf: make perf_event cgroup hierarchical cgroup: implement cgroup_is_descendant() cgroup: make sure parent won't be destroyed before its children cgroup: remove bind() method from cgroup_subsys. devcg: remove broken_hierarchy tag cgroup: remove cgroup_lock_is_held() ...
2013-04-22perf: New helper to prevent full dynticks CPUs from stopping tickFrederic Weisbecker
Provide a new helper that help full dynticks CPUs to prevent from stopping their tick in case there are events in the local rotation list. This way we make sure that perf_event_task_tick() is serviced on demand. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Stephane Eranian <eranian@google.com> Cc: Jiri Olsa <jolsa@redhat.com>
2013-04-22perf: Kick full dynticks CPU if events rotation is neededFrederic Weisbecker
Kick the current CPU's tick by sending it a self IPI when an event is queued on the rotation list and it is the first element inserted. This makes sure that perf_event_task_tick() works on full dynticks CPUs. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Stephane Eranian <eranian@google.com> Cc: Jiri Olsa <jolsa@redhat.com>
2013-04-21events: Protect access via task_subsys_state_check()Paul E. McKenney
The following RCU splat indicates lack of RCU protection: [ 953.267649] =============================== [ 953.267652] [ INFO: suspicious RCU usage. ] [ 953.267657] 3.9.0-0.rc6.git2.4.fc19.ppc64p7 #1 Not tainted [ 953.267661] ------------------------------- [ 953.267664] include/linux/cgroup.h:534 suspicious rcu_dereference_check() usage! [ 953.267669] [ 953.267669] other info that might help us debug this: [ 953.267669] [ 953.267675] [ 953.267675] rcu_scheduler_active = 1, debug_locks = 0 [ 953.267680] 1 lock held by glxgears/1289: [ 953.267683] #0: (&sig->cred_guard_mutex){+.+.+.}, at: [<c00000000027f884>] .prepare_bprm_creds+0x34/0xa0 [ 953.267700] [ 953.267700] stack backtrace: [ 953.267704] Call Trace: [ 953.267709] [c0000001f0d1b6e0] [c000000000016e30] .show_stack+0x130/0x200 (unreliable) [ 953.267717] [c0000001f0d1b7b0] [c0000000001267f8] .lockdep_rcu_suspicious+0x138/0x180 [ 953.267724] [c0000001f0d1b840] [c0000000001d43a4] .perf_event_comm+0x4c4/0x690 [ 953.267731] [c0000001f0d1b950] [c00000000027f6e4] .set_task_comm+0x84/0x1f0 [ 953.267737] [c0000001f0d1b9f0] [c000000000280414] .setup_new_exec+0x94/0x220 [ 953.267744] [c0000001f0d1ba70] [c0000000002f665c] .load_elf_binary+0x58c/0x19b0 ... This commit therefore adds the required RCU read-side critical section to perf_event_comm(). Reported-by: Adam Jackson <ajax@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: a.p.zijlstra@chello.nl Cc: paulus@samba.org Cc: acme@ghostprotocols.net Link: http://lkml.kernel.org/r/20130419190124.GA8638@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Gustavo Luiz Duarte <gusld@br.ibm.com>
2013-04-21Merge branch 'perf/urgent' into perf/coreIngo Molnar
Conflicts: arch/x86/kernel/cpu/perf_event_intel.c Merge in the latest fixes before applying new patches, resolve the conflict. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-15perf: Treat attr.config as u64 in perf_swevent_init()Tommi Rantala
Trinity discovered that we fail to check all 64 bits of attr.config passed by user space, resulting to out-of-bounds access of the perf_swevent_enabled array in sw_perf_event_destroy(). Introduced in commit b0a873ebb ("perf: Register PMU implementations"). Signed-off-by: Tommi Rantala <tt.rantala@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: davej@redhat.com Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Link: http://lkml.kernel.org/r/1365882554-30259-1-git-send-email-tt.rantala@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-13uretprobes: Remove -ENOSYS as return probes implementedAnton Arapov
Enclose return probes implementation. Signed-off-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13uretprobes: Limit the depth of return probe nestednessAnton Arapov
Unlike the kretprobes we can't trust userspace, thus must have protection from user space attacks. User-space have "unlimited" stack, and this patch limits the return probes nestedness as a simple remedy for it. Note that this implementation leaks return_instance on siglongjmp until exit()/exec(). The intention is to have KISS and bare minimum solution for the initial implementation in order to not complicate the uretprobes code. In the future we may come up with more sophisticated solution that remove this depth limitation. It is not easy task and lays beyond this patchset. Signed-off-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13uretprobes: Return probe exit, invoke handlersAnton Arapov
Uretprobe handlers are invoked when the trampoline is hit, on completion the trampoline is replaced with the saved return address and the uretprobe instance deleted. TODO: handle_trampoline() assumes that ->return_instances is always valid. We should teach it to handle longjmp() which can invalidate the pending return_instance's. This is nontrivial, we will try to do this in a separate series. Signed-off-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13uretprobes: Return probe entry, prepare_uretprobe()Anton Arapov
When a uprobe with return probe consumer is hit, prepare_uretprobe() function is invoked. It creates return_instance, hijacks return address and replaces it with the trampoline. * Return instances are kept as stack per uprobed task. * Return instance is chained, when the original return address is trampoline's page vaddr (e.g. recursive call of the probed function). Signed-off-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13uretprobes: Reserve the first slot in xol_vma for trampolineAnton Arapov
Allocate trampoline page, as the very first one in uprobed task xol area, and fill it with breakpoint opcode. Also introduce get_trampoline_vaddr() helper, to wrap the trampoline address extraction from area->vaddr. That removes confusion and eases the debug experience in case ->vaddr notion will be changed. Signed-off-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13uretprobes: Introduce uprobe_consumer->ret_handler()Anton Arapov
Enclose return probes implementation, introduce ->ret_handler() and update existing code to rely on ->handler() *and* ->ret_handler() for uprobe and uretprobe respectively. Signed-off-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-12perf: Fix error return codeWei Yongjun
Fix to return -ENOMEM in the allocation error case instead of 0 (if pmu_bus_running == 1), as done elsewhere in this function. Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Cc: a.p.zijlstra@chello.nl Cc: paulus@samba.org Cc: acme@ghostprotocols.net Link: http://lkml.kernel.org/r/CAPgLHd8j_fWcgqe%3DKLWjpBj%2B%3Do0Pw6Z-SEq%3DNTPU08c2w1tngQ@mail.gmail.com [ Tweaked the error code setting placement and the changelog. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10perf: make perf_event cgroup hierarchicalTejun Heo
perf_event is one of a couple remaining cgroup controllers with broken hierarchy support. Converting it to support hierarchy is almost trivial. The only thing necessary is to consider a task belonging to a descendant cgroup as a match. IOW, if the cgroup of the currently executing task (@cpuctx->cgrp) equals or is a descendant of the event's cgroup (@event->cgrp), then the event should be enabled. Implement hierarchy support and remove .broken_hierarchy tag along with the incorrect comment on what needs to be done for hierarchy support. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Stephane Eranian <eranian@google.com> Cc: Namhyung Kim <namhyung.kim@lge.com>
2013-04-08perf: Fix strncpy() use, always make sure it's NUL terminatedChen Gang
For NUL terminated string, always make sure that there's '\0' at the end. In our case we need a return value, so still use strncpy() and fix up the tail explicitly. (strlcpy() returns the size, not the pointer) Signed-off-by: Chen Gang <gang.chen@asianux.com> Cc: a.p.zijlstra@chello.nl <a.p.zijlstra@chello.nl> Cc: paulus@samba.org <paulus@samba.org> Cc: acme@ghostprotocols.net <acme@ghostprotocols.net> Link: http://lkml.kernel.org/r/51623E0B.7070101@asianux.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-04uprobes: Change write_opcode() to use copy_*page()Oleg Nesterov
Change write_opcode() to use copy_highpage() + copy_to_page() and simplify the code. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04uprobes: Introduce copy_to_page()Oleg Nesterov
Extract the kmap_atomic/memcpy/kunmap_atomic code from xol_get_insn_slot() into the new simple helper, copy_to_page(). It will have more users soon. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04uprobes: Kill the unnecesary filp != NULL check in __copy_insn()Oleg Nesterov
__copy_insn(filp) can only be called after valid_vma() returns T, vma->vm_file passed as "filp" can not be NULL. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04uprobes: Change __copy_insn() to use copy_from_page()Oleg Nesterov
Change __copy_insn() to use copy_from_page() and simplify the code. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04uprobes: Turn copy_opcode() into copy_from_page()Oleg Nesterov
No functional changes. Rename copy_opcode() into copy_from_page() and add the new "int len" argument to make it more more generic for the new users. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Anton Arapov <anton@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04uprobes: Add trap variant helperAnanth N Mavinakayanahalli
Some architectures like powerpc have multiple variants of the trap instruction. Introduce an additional helper is_trap_insn() for run-time handling of non-uprobe traps on such architectures. While there, change is_swbp_at_addr() to is_trap_at_addr() for reading clarity. With this change, the uprobe registration path will supercede any trap instruction inserted at the requested location, while taking care of delivering the SIGTRAP for cases where the trap notification came in for an address without a uprobe. See [1] for a more detailed explanation. [1] https://lists.ozlabs.org/pipermail/linuxppc-dev/2013-March/104771.html This change was suggested by Oleg Nesterov. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
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