Messages in this thread | | | From | "Liang, Kan" <> | Subject | RE: perf: fuzzer triggered warning in intel_pmu_drain_pebs_nhm() | Date | Mon, 6 Jul 2015 16:23:56 +0000 |
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> On Mon, 6 Jul 2015, Liang, Kan wrote: > > > > > > On Fri, Jul 03, 2015 at 08:08:27PM +0000, Liang, Kan wrote: > > > > If we cleared the last bit, we not only drain the buffer but also > > > > decrease the event->ctx->pmu, which is used to flush the PEBS > > > > buffer during context switches. > > > > We need to disable cpuc->pebs_enabled before changing > > > > event->ctx->pmu as below. > > > > > > > > > > Indeed, mind sending a proper patch so I can press 'A' on it? > > > > Sure, I will do that. > > But I didn't verify the patch, since I cannot reproduce the issue. > > > > Vince, would you mind testing the patch? > > If the issue is gone, I will send a proper patch then. > > I've got too many patches floating around so I forget what this one is trying > to fix. The pebs related lockup? Or the warning? >
It's trying to fix the warning issue as below. For the test result, it looks the patch doesn't help, does it?
> > WARN_ON_ONCE(!event->attr.precise_ip); > > > > [ 584.352324] WARNING: CPU: 2 PID: 18924 at > > arch/x86/kernel/cpu/perf_event_intel_ds.c:1198 > > intel_pmu_drain_pebs_nhm+0x283/0x2e0()
> Was this patch meant to be in addition to PeterZ's, or standalone? >
Standalone.
> Also please send proper patches in the future, this one was whitespace > damaged and a pain to get applied. > > With just this patch applied (without PeterZ's) I still managed to trigger the > following warning.
Thanks for the test.
> > [ 1328.103920] ------------[ cut here ]------------ [ 1328.109367] WARNING: > CPU: 0 PID: 0 at arch/x86/kernel/cpu/perf_event_intel_ds.c:1199 > intel_pmu_drain_pebs_nhm+0x283/0x2e0() > [ 1328.199193] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 4.2.0- > rc1+ #166 > [ 1328.207955] Hardware name: LENOVO 10AM000AUS/SHARKBAY, BIOS > FBKT72AUS 01/26/2014 [ 1328.216461] ffffffff81a10f88 ffff88011ea05b10 > ffffffff816a10a3 0000000000000000 [ 1328.225043] 0000000000000000 > ffff88011ea05b50 ffffffff8106ec8a ffff88011ea05ba0 [ 1328.233654] > 0000000000000000 0000000000000001 ffff88011ea0bd80 ffff8801190000c0 > [ 1328.242260] Call Trace: > [ 1328.245452] <NMI> [<ffffffff816a10a3>] dump_stack+0x45/0x57 > [ 1328.252243] [<ffffffff8106ec8a>] warn_slowpath_common+0x8a/0xc0 > [ 1328.259212] [<ffffffff8106ed7a>] warn_slowpath_null+0x1a/0x20 > [ 1328.266000] [<ffffffff8102f783>] > intel_pmu_drain_pebs_nhm+0x283/0x2e0 > [ 1328.273551] [<ffffffff81032235>] intel_pmu_handle_irq+0x255/0x440 > [ 1328.280742] [<ffffffff811574bf>] ? __perf_event_enable+0x1f/0x2a0 > [ 1328.287887] [<ffffffff8114b19d>] ? irq_work_queue+0x5d/0x80 > [ 1328.294500] [<ffffffff81028e76>] perf_event_nmi_handler+0x26/0x40 > [ 1328.301659] [<ffffffff810181ad>] nmi_handle+0x9d/0x140 [ 1328.307783] > [<ffffffff81018115>] ? nmi_handle+0x5/0x140 [ 1328.314010] > [<ffffffff8101843a>] default_do_nmi+0x4a/0x120 [ 1328.320495] > [<ffffffff8101859d>] do_nmi+0x8d/0xc0 [ 1328.326053] [<ffffffff816ab01f>] > end_repeat_nmi+0x1e/0x2e [ 1328.332405] [<ffffffff810309ba>] ? > __intel_pmu_enable_all+0x5a/0xc0 [ 1328.339627] [<ffffffff810309ba>] ? > __intel_pmu_enable_all+0x5a/0xc0 [ 1328.346894] [<ffffffff810309ba>] ? > __intel_pmu_enable_all+0x5a/0xc0 [ 1328.354130] <<EOE>> <IRQ> > [<ffffffff81030a30>] intel_pmu_enable_all+0x10/0x20 [ 1328.362556] > [<ffffffff8102a95c>] x86_pmu_enable+0x25c/0x2e0 [ 1328.369079] > [<ffffffff81156202>] perf_pmu_enable+0x22/0x30 [ 1328.375447] > [<ffffffff81157da1>] __perf_install_in_context+0x131/0x1d0 > [ 1328.382936] [<ffffffff811533b0>] ? cpu_clock_event_start+0x40/0x40 > [ 1328.390106] [<ffffffff811533f2>] remote_function+0x42/0x50 > [ 1328.396525] [<ffffffff810f0e9b>] > flush_smp_call_function_queue+0x7b/0x170 > [ 1328.404360] [<ffffffff810f1883>] > generic_smp_call_function_single_interrupt+0x13/0x60 > [ 1328.413345] [<ffffffff81049217>] > smp_call_function_single_interrupt+0x27/0x40 > [ 1328.421544] [<ffffffff816aa1ab>] > call_function_single_interrupt+0x6b/0x70 > [ 1328.429358] <EOI> [<ffffffff81545454>] ? > cpuidle_enter_state+0xf4/0x220 [ 1328.437120] [<ffffffff81545430>] ? > cpuidle_enter_state+0xd0/0x220 [ 1328.444210] [<ffffffff815455b7>] > cpuidle_enter+0x17/0x20 [ 1328.450491] [<ffffffff810b06eb>] > call_cpuidle+0x3b/0x70 [ 1328.456680] [<ffffffff81545593>] ? > cpuidle_select+0x13/0x20 [ 1328.463196] [<ffffffff810b0965>] > cpu_startup_entry+0x245/0x310 [ 1328.469992] [<ffffffff81695b3b>] > rest_init+0xbb/0xd0 [ 1328.475860] [<ffffffff81d4af8b>] > start_kernel+0x460/0x46d [ 1328.482154] [<ffffffff81d4a120>] ? > early_idt_handler_array+0x120/0x120 > [ 1328.489661] [<ffffffff81d4a4d7>] x86_64_start_reservations+0x2a/0x2c > [ 1328.496974] [<ffffffff81d4a614>] x86_64_start_kernel+0x13b/0x14a > [ 1328.503905] ---[ end trace a75b257dea18211b ]---
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