From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
To: Greg KH <greg@kroah.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>,
Chunyan Zhang <zhang.chunyan@linaro.org>,
laurent.fert@intel.com, yann.fouassier@intel.com,
linux-kernel@vger.kernel.org,
Alexander Shishkin <alexander.shishkin@linux.intel.com>
Subject: [QUEUED v20160212 14/19] stm class: Fix unlocking braino in the error path
Date: Fri, 12 Feb 2016 19:00:30 +0200 [thread overview]
Message-ID: <1455296435-17362-15-git-send-email-alexander.shishkin@linux.intel.com> (raw)
In-Reply-To: <1455296435-17362-1-git-send-email-alexander.shishkin@linux.intel.com>
If an illegal attempt is made to unlink stm source device from an
stm device, the stm device's link spinlock mistakenly remains locked.
While this really shouldn't happen (there's a warning in place), the
locking should remain in order so that we can still recover from this
situation if it indeed does happen.
This patch unifies the unlocking in the exit path of
__stm_source_link_drop() to fix this.
Reported-by: Laurent Fert <laurent.fert@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
---
drivers/hwtracing/stm/core.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
index 385db65994..fb5a6a582b 100644
--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -816,10 +816,8 @@ static void __stm_source_link_drop(struct stm_source_device *src,
spin_lock(&stm->link_lock);
spin_lock(&src->link_lock);
link = srcu_dereference_check(src->link, &stm_source_srcu, 1);
- if (WARN_ON_ONCE(link != stm)) {
- spin_unlock(&src->link_lock);
- return;
- }
+ if (WARN_ON_ONCE(link != stm))
+ goto unlock;
stm_output_free(link, &src->output);
list_del_init(&src->link_entry);
@@ -827,6 +825,7 @@ static void __stm_source_link_drop(struct stm_source_device *src,
stm_put_device(link);
rcu_assign_pointer(src->link, NULL);
+unlock:
spin_unlock(&src->link_lock);
spin_unlock(&stm->link_lock);
}
--
2.7.0
next prev parent reply other threads:[~2016-02-12 17:10 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-12 17:00 [QUEUED v20160212 00/19] stm class/intel_th: Patches in my queue Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 01/19] stm class: Use a signed return type for stm_find_master_chan Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 02/19] intel_th: Depend on HAS_IOMEM Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 03/19] intel_th: gth: Remove commented-out code Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 04/19] intel_th: Update scratchpad bits according to enabled output activity Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 05/19] intel_th: msu: Fix offset for wrapped block Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 06/19] intel_th: msu: Release resources on read error Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 07/19] intel_th: sth: Sanitize packet callback's return values Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 08/19] intel_th: Set root device's drvdata early Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 09/19] intel_th: Use real device index in the node names Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 10/19] stm class: Use driver's packet callback return value Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 11/19] stm class: Support devices with multiple instances Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 12/19] stm class: dummy_stm: Create multiple devices Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 13/19] stm class: Add heartbeat stm source device Alexander Shishkin
2016-02-12 17:00 ` Alexander Shishkin [this message]
2016-02-12 17:00 ` [QUEUED v20160212 15/19] stm class: Guard output assignment against concurrency Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 16/19] stm class: Fix unbalanced module/device refcounting Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 17/19] stm class: Fix a race in unlinking Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 18/19] stm class: Plug stm device's unlink callback Alexander Shishkin
2016-02-12 17:00 ` [QUEUED v20160212 19/19] stm class: dummy_stm: Add link callback for fault injection Alexander Shishkin
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