Messages in this thread | | | Subject | Re: [PATCH] workqueue: unregister wq lockdep on error path in alloc_workqueue() | From | Kefeng Wang <> | Date | Sat, 9 Mar 2019 12:13:30 +0800 |
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On 2019/3/8 22:45, Bart Van Assche wrote: > 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+17335689e239ce135d8b@syzkaller.appspotmail.com >> Fixes: 669de8bda87b ("kernel/workqueue: Use dynamic lockdep keys for workqueues") >> Signed-off-by: Kefeng Wang <wangkefeng.wang@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-bvanassche@acm.org/ I don't notice your patch due to no subscribe lkml, that is better, wq->lock_name should be freed too; ) > > Thanks, > > Bart. > > > > . >
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