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From: CAI Qian <caiqian@redhat.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Rob Herring <robh@kernel.org>, Kan Liang <kan.liang@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH] perf: Protect pmu device removal with pmu_bus_running check CONFIG_DEBUG_TEST_DRIVER_REMOVE kernel panic
Date: Thu, 20 Oct 2016 10:30:29 -0400 (EDT)	[thread overview]
Message-ID: <1110984561.1204029.1476973829969.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <20161020111011.GA13361@krava>


> CAI Qian reported crash [1] in uncore device removal related
> to CONFIG_DEBUG_TEST_DRIVER_REMOVE option.
> 
> The reason for crash is that  perf_pmu_unregister tries to remove
> pmu device which is not added at this point. We add pmu devices
> only after pmu_bus is registered which happens in perf_event_sysfs_init
> init call and sets pmu_bus_running flag.
> 
> The fix is to get the pmu_bus_running flag state at the point
> the pmu is taken  out of the pmus list and  remove the device
> later only if it's set.
> 
> [1] https://marc.info/?l=linux-kernel&m=147688837328451
> 
> Reported-by: CAI Qian <caiqian@redhat.com>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>

Tested-by: CAI Qian <caiqian@redhat.com>

  reply	other threads:[~2016-10-20 14:31 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <907882571.66590.1476113724660.JavaMail.zimbra@redhat.com>
2016-10-10 15:37 ` kasan inline + CONFIG_DEBUG_TEST_DRIVER_REMOVE kernel panic CAI Qian
2016-10-10 17:09   ` Rob Herring
2016-10-10 18:25     ` CAI Qian
2016-10-10 17:20   ` Greg Kroah-Hartman
2016-10-10 18:15     ` Rob Herring
2016-10-10 18:22       ` CAI Qian
2016-10-10 19:34         ` Rob Herring
2016-10-10 20:09           ` CAI Qian
2016-10-19 14:45       ` [4.9-rc1+] intel_uncore builtin " CAI Qian
2016-10-19 19:19         ` Jiri Olsa
2016-10-19 20:18           ` CAI Qian
2016-10-20  5:39           ` Peter Zijlstra
2016-10-20  8:58             ` Jiri Olsa
2016-10-20  9:04               ` Peter Zijlstra
2016-10-20  9:42                 ` Jiri Olsa
2016-10-20 11:10                   ` [PATCH] perf: Protect pmu device removal with pmu_bus_running check " Jiri Olsa
2016-10-20 14:30                     ` CAI Qian [this message]
2016-10-28 10:10                     ` [tip:perf/urgent] perf/core: Protect PMU device removal with a 'pmu_bus_running' check, to fix CONFIG_DEBUG_TEST_DRIVER_REMOVE=y " tip-bot for Jiri Olsa

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