From: tip-bot for Jiri Olsa <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: peterz@infradead.org, mingo@kernel.org, jolsa@redhat.com,
kan.liang@intel.com, caiqian@redhat.com,
gregkh@linuxfoundation.org, tglx@linutronix.de, robh@kernel.org,
torvalds@linux-foundation.org,
alexander.shishkin@linux.intel.com, acme@redhat.com,
linux-kernel@vger.kernel.org, jolsa@kernel.org, hpa@zytor.com
Subject: [tip:perf/urgent] perf/core: Protect PMU device removal with a 'pmu_bus_running' check, to fix CONFIG_DEBUG_TEST_DRIVER_REMOVE=y kernel panic
Date: Fri, 28 Oct 2016 03:10:03 -0700 [thread overview]
Message-ID: <tip-0933840acf7b65d6d30a5b6089d882afea57aca3@git.kernel.org> (raw)
In-Reply-To: <20161020111011.GA13361@krava>
Commit-ID: 0933840acf7b65d6d30a5b6089d882afea57aca3
Gitweb: http://git.kernel.org/tip/0933840acf7b65d6d30a5b6089d882afea57aca3
Author: Jiri Olsa <jolsa@redhat.com>
AuthorDate: Thu, 20 Oct 2016 13:10:11 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 28 Oct 2016 11:06:25 +0200
perf/core: Protect PMU device removal with a 'pmu_bus_running' check, to fix CONFIG_DEBUG_TEST_DRIVER_REMOVE=y kernel panic
CAI Qian reported a crash in the PMU uncore device removal code,
enabled by the CONFIG_DEBUG_TEST_DRIVER_REMOVE=y option:
https://marc.info/?l=linux-kernel&m=147688837328451
The reason for the crash is that perf_pmu_unregister() tries to remove
a PMU device which is not added at this point. We add PMU devices
only after pmu_bus is registered, which happens in the
perf_event_sysfs_init() call and sets the '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 PMU list and remove the device
later only if it's set.
Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161020111011.GA13361@krava
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/events/core.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c6e47e9..a5d2e62 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8855,7 +8855,10 @@ EXPORT_SYMBOL_GPL(perf_pmu_register);
void perf_pmu_unregister(struct pmu *pmu)
{
+ int remove_device;
+
mutex_lock(&pmus_lock);
+ remove_device = pmu_bus_running;
list_del_rcu(&pmu->entry);
mutex_unlock(&pmus_lock);
@@ -8869,10 +8872,12 @@ void perf_pmu_unregister(struct pmu *pmu)
free_percpu(pmu->pmu_disable_count);
if (pmu->type >= PERF_TYPE_MAX)
idr_remove(&pmu_idr, pmu->type);
- if (pmu->nr_addr_filters)
- device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
- device_del(pmu->dev);
- put_device(pmu->dev);
+ if (remove_device) {
+ if (pmu->nr_addr_filters)
+ device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
+ device_del(pmu->dev);
+ put_device(pmu->dev);
+ }
free_pmu_context(pmu);
}
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
prev parent reply other threads:[~2016-10-28 10:10 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
2016-10-28 10:10 ` tip-bot for Jiri Olsa [this message]
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