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Message-Id: <3ysJcJ3ygHz9sRV@ozlabs.org>
Date: Wed, 6 Dec 2017 23:59:59 +1100 (AEDT)
From: Michael Ellerman <patch-notifications@...erman.id.au>
To: Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>
Cc: maddy@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>,
paulus@...ba.org, kan.liang@...el.com, tglx@...utronix.de,
sukadev@...ux.vnet.ibm.com, linuxppc-dev@...ts.ozlabs.org
Subject: Re: powerpc/perf: Fix oops when grouping different pmu events
On Thu, 2017-11-30 at 08:33:22 UTC, Ravi Bangoria wrote:
> When user tries to group imc (In-Memory Collections) event with
> normal event, (sometime) kernel crashes with following log:
>
> Faulting instruction address: 0x00000000
> [link register ] c00000000010ce88 power_check_constraints+0x128/0x980
> ...
> c00000000010e238 power_pmu_event_init+0x268/0x6f0
> c0000000002dc60c perf_try_init_event+0xdc/0x1a0
> c0000000002dce88 perf_event_alloc+0x7b8/0xac0
> c0000000002e92e0 SyS_perf_event_open+0x530/0xda0
> c00000000000b004 system_call+0x38/0xe0
>
> 'event_base' field of 'struct hw_perf_event' is used as flags for
> normal hw events and used as memory address for imc events. While
> grouping these two types of events, collect_events() tries to
> interpret imc 'event_base' as a flag, which causes a corruption
> resulting in a crash.
>
> Consider only those events which belongs to 'perf_hw_context' in
> collect_events().
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>
> Reviewed-By: Madhavan Srinivasan <maddy@...ux.vnet.ibm.com>
Applied to powerpc fixes, thanks.
https://git.kernel.org/powerpc/c/5aa04b3eb6fca63d2e9827be656dca
cheers
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