On 09/29/2016 03:03 AM, Tejun Heo wrote:
Hello,
On Mon, Sep 26, 2016 at 03:36:25PM -0700, Bart Van Assche wrote:
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 <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: <[email protected]>
---
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;
+ }
Wouldn't it be better to drop explicit mutx_unlock(&blkcg_pol_mutex)
on "if (!cpd)"?
Agreed. I will rework this patch accordingly. Thanks for the feedback.
Bart.
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