[PATCH] workqueue: Fix an use after free in init_rescuer()

[Dan Carpenter]

We need to preserve error code before freeing "rescuer".

Fixes: f187b6974f6df ("workqueue: Use IS_ERR and PTR_ERR instead of 
PTR_ERR_OR_ZERO.")
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
---
Another option would be to just revert the original commit.

 kernel/workqueue.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index ddf0537dce140..10ed8d761e0b7 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4197,6 +4197,7 @@ static int wq_clamp_max_active(int max_active, unsigned 
int flags,
 static int init_rescuer(struct workqueue_struct *wq)
 {
        struct worker *rescuer;
+       int ret;
 
        if (!(wq->flags & WQ_MEM_RECLAIM))
                return 0;
@@ -4208,8 +4209,9 @@ static int init_rescuer(struct workqueue_struct *wq)
        rescuer->rescue_wq = wq;
        rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", wq->name);
        if (IS_ERR(rescuer->task)) {
+               ret = PTR_ERR(rescuer->task);
                kfree(rescuer);
-               return PTR_ERR(rescuer->task);
+               return ret;
        }
 
        wq->rescuer = rescuer;
-- 
2.26.2