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Date: Tue, 5 Sep 2017 14:59:24 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
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Subject: Re: [RFC][PATCH] perf: Rewrite enabled/running timekeeping
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On Tue, Sep 05, 2017 at 03:06:26PM +0300, Alexey Budankov wrote:
> [ 6614.226305] WARNING: CPU: 45 PID: 43385 at kernel/events/core.c:239 event_function+0xb3/0xe0

> [ 6614.226563] Call Trace:
> [ 6614.226577]  remote_function+0x3b/0x50
> [ 6614.226585]  generic_exec_single+0x9a/0xd0
> [ 6614.226592]  smp_call_function_single+0xc8/0x100
> [ 6614.226599]  cpu_function_call+0x43/0x60
> [ 6614.226606]  ? cpu_clock_event_read+0x10/0x10
> [ 6614.226612]  perf_event_read+0xc7/0xe0
> [ 6614.226619]  ? perf_install_in_context+0xf0/0xf0
> [ 6614.226625]  __perf_read_group_add+0x25/0x180
> [ 6614.226632]  perf_read+0xcb/0x2b0
> [ 6614.226640]  __vfs_read+0x37/0x160
> [ 6614.226648]  ? security_file_permission+0x9d/0xc0
> [ 6614.226655]  vfs_read+0x8c/0x130
> [ 6614.226661]  SyS_read+0x55/0xc0
> [ 6614.226670]  do_syscall_64+0x67/0x180
> [ 6614.226678]  entry_SYSCALL64_slow_path+0x25/0x25


Hmm.. must be the perf_event_read() rewrite, let me stare at that.

Thanks for testing.