perf_event, x86: Fix 'perf sched record' crashing the machine
Chris Malley reported that 'perf sched record' sometimes
crashes his box with:
[ 389.272175] BUG: unable to handle kernel paging request at ffffb300
[ 389.272294] IP: [<c011b0bd>] default_send_IPI_self+0x1d/0x50
[ 389.272366] *pde = 0073f067 *pte = 00000000
[ 389.274708] Call Trace:
[ 389.274752] [<c010e3b4>] ? set_perf_event_pending+0x14/0x20
[ 389.274801] [<c01b9751>] ? perf_output_unlock+0x121/0x1a0
[ 389.274848] [<c01b981a>] ? perf_output_end+0x4a/0x70
[ 389.274893] [<c01ba690>] ? __perf_event_overflow+0x240/0x2f0
[ 389.274942] [<c030963e>] ? atomic64_cmpxchg+0x1e/0x30
[ 389.274988] [<c01ba8f4>] ? perf_swevent_ctx_event+0x1b4/0x1c0
[ 389.275035] [<c01ba773>] ? perf_swevent_ctx_event+0x33/0x1c0
[ 389.275081] [<c01ba9a7>] ? do_perf_sw_event+0xa7/0x160
[ 389.275127] [<c01baae2>] ? perf_tp_event+0x82/0xa0
[ 389.275174] [<c012e9c6>] ? ftrace_profile_sched_stat_runtime+0xe6/0x120
[ 389.275224] [<c012e8e0>] ? ftrace_profile_sched_stat_runtime+0x0/0x120
[ 389.275273] [<c013c85a>] ? update_curr+0x18a/0x230
[ 389.275318] [<c013cdc5>] ? put_prev_task_fair+0x155/0x160
[ 389.275366] [<c01618b5>] ? sched_clock_cpu+0xd5/0x110
[ 389.275413] [<c04e7525>] ? _spin_lock_irq+0x45/0x50
[ 389.275458] [<c04e424e>] ? schedule+0x20e/0xb10
The problem is that the box has no lapic enabled:
[ 0.042445] Local APIC not detected. Using dummy APIC emulation.
The below seems like the best fix. We disabled all lapic bits, except
the self-IPI-resend logic.
Reported-by: Chris Malley <mail@chrismalley.co.uk>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <7863dc4c0909221409v7893bfd3o4b590d5951a233ba@mail.gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
1 file changed