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Groups > linux.kernel > #1332949
| From | Alexander Shishkin <alexander.shishkin@linux.intel.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [QUEUED v20160212 14/19] stm class: Fix unlocking braino in the error path |
| Date | 2016-02-12 18:20 +0100 |
| Message-ID | <r1pxW-1vA-53@gated-at.bofh.it> (permalink) |
| References | <r1poe-1rA-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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
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[QUEUED v20160212 00/19] stm class/intel_th: Patches in my queue Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:10 +0100 [QUEUED v20160212 01/19] stm class: Use a signed return type for stm_find_master_chan Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:10 +0100 [QUEUED v20160212 04/19] intel_th: Update scratchpad bits according to enabled output activity Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:10 +0100 [QUEUED v20160212 02/19] intel_th: Depend on HAS_IOMEM Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:10 +0100 [QUEUED v20160212 07/19] intel_th: sth: Sanitize packet callback's return values Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:10 +0100 [QUEUED v20160212 08/19] intel_th: Set root device's drvdata early Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:10 +0100 [QUEUED v20160212 11/19] stm class: Support devices with multiple instances Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:10 +0100 [QUEUED v20160212 03/19] intel_th: gth: Remove commented-out code Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:10 +0100 [QUEUED v20160212 18/19] stm class: Plug stm device's unlink callback Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:20 +0100 [QUEUED v20160212 16/19] stm class: Fix unbalanced module/device refcounting Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:20 +0100 [QUEUED v20160212 19/19] stm class: dummy_stm: Add link callback for fault injection Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:20 +0100 [QUEUED v20160212 12/19] stm class: dummy_stm: Create multiple devices Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:20 +0100 [QUEUED v20160212 17/19] stm class: Fix a race in unlinking Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:20 +0100 [QUEUED v20160212 15/19] stm class: Guard output assignment against concurrency Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:20 +0100 [QUEUED v20160212 14/19] stm class: Fix unlocking braino in the error path Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:20 +0100 [QUEUED v20160212 13/19] stm class: Add heartbeat stm source device Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-02-12 18:20 +0100
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