Unlocking a mutex twice is wrong. Hence modify blkcg_policy_register()
such that blkcg_pol_mutex is unlocked once if cpd == NULL. This patch
avoids that smatch reports the following error:
block/blk-cgroup.c:1378: blkcg_policy_register() error: double unlock 'mutex:&blkcg_pol_mutex'
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
---
block/blk-cgroup.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index dd38e5c..cdbca1c 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1327,8 +1327,10 @@ int blkcg_policy_register(struct blkcg_policy *pol)
for (i = 0; i < BLKCG_MAX_POLS; i++)
if (!blkcg_policy[i])
break;
- if (i >= BLKCG_MAX_POLS)
+ if (i >= BLKCG_MAX_POLS) {
+ mutex_unlock(&blkcg_pol_mutex);
goto err_unlock;
+ }
/* register @pol */
pol->plid = i;
@@ -1374,8 +1376,8 @@ err_free_cpds:
}
}
blkcg_policy[pol->plid] = NULL;
+
err_unlock:
- mutex_unlock(&blkcg_pol_mutex);
mutex_unlock(&blkcg_pol_register_mutex);
return ret;
}
--
2.10.0
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