* [PATCH] workqueue: unregister wq lockdep on error path in alloc_workqueue()
@ 2019-03-08 7:37 Kefeng Wang
2019-03-08 14:45 ` Bart Van Assche
0 siblings, 1 reply; 3+ messages in thread
From: Kefeng Wang @ 2019-03-08 7:37 UTC (permalink / raw)
To: Bart Van Assche, Ingo Molnar, Tejun Heo, linux-kernel
Cc: Kefeng Wang, syzbot+17335689e239ce135d8b
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;
--
2.20.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] workqueue: unregister wq lockdep on error path in alloc_workqueue()
2019-03-08 7:37 [PATCH] workqueue: unregister wq lockdep on error path in alloc_workqueue() Kefeng Wang
@ 2019-03-08 14:45 ` Bart Van Assche
2019-03-09 4:13 ` Kefeng Wang
0 siblings, 1 reply; 3+ messages in thread
From: Bart Van Assche @ 2019-03-08 14:45 UTC (permalink / raw)
To: Kefeng Wang, Ingo Molnar, Tejun Heo, linux-kernel
Cc: syzbot+17335689e239ce135d8b
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/
Thanks,
Bart.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] workqueue: unregister wq lockdep on error path in alloc_workqueue()
2019-03-08 14:45 ` Bart Van Assche
@ 2019-03-09 4:13 ` Kefeng Wang
0 siblings, 0 replies; 3+ messages in thread
From: Kefeng Wang @ 2019-03-09 4:13 UTC (permalink / raw)
To: Bart Van Assche, Ingo Molnar, Tejun Heo, linux-kernel
Cc: syzbot+17335689e239ce135d8b
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.
>
>
>
> .
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-03-09 4:13 UTC | newest]
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2019-03-08 7:37 [PATCH] workqueue: unregister wq lockdep on error path in alloc_workqueue() Kefeng Wang
2019-03-08 14:45 ` Bart Van Assche
2019-03-09 4:13 ` Kefeng Wang
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