On 3/7/19 11:37 PM, Kefeng Wang wrote:
syzkaller report an issue "KASAN: use-after-free Read in alloc_workqueue",
alloc_workqueue
- kzalloc wq
- wq_init_lockdep(wq);
- lockdep_register_key(&wq->key); // add to hlist
- kfree wq
But forget to call wq_unregister_lockdep()->lockdep_unregister_key(), it
will delete the entry from hlist.
Reported-by: syzbot+17335689e239ce135...@syzkaller.appspotmail.com
Fixes: 669de8bda87b ("kernel/workqueue: Use dynamic lockdep keys for
workqueues")
Signed-off-by: Kefeng Wang <wangkefeng.w...@huawei.com>
---
kernel/workqueue.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 7abbeed13421..9209d25dfade 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4291,6 +4291,7 @@ struct workqueue_struct *alloc_workqueue(const char *fmt,
return wq;
err_free_wq:
+ wq_unregister_lockdep(wq);
free_workqueue_attrs(wq->unbound_attrs);
kfree(wq);
return NULL;
Hi Kefeng,
Five days ago I had posted a similar but slightly different patch. Can
you have a look at it? See also
https://lore.kernel.org/lkml/20190303220046.29448-1-bvanass...@acm.org/
Thanks,
Bart.
