* [PATCH] nbd: make the config put is called before the notifying the waiter
@ 2020-10-14 2:45 xiubli
2020-10-14 17:33 ` Josef Bacik
2020-10-14 18:30 ` Jens Axboe
0 siblings, 2 replies; 3+ messages in thread
From: xiubli @ 2020-10-14 2:45 UTC (permalink / raw)
To: josef, axboe; +Cc: linux-block, nbd, Xiubo Li
From: Xiubo Li <xiubli@redhat.com>
There has one race case for ceph's rbd-nbd tool. When do mapping
it may fail with EBUSY from ioctl(nbd, NBD_DO_IT), but actually
the nbd device has already unmaped.
It dues to if just after the wake_up(), the recv_work() is scheduled
out and defers calling the nbd_config_put(), though the map process
has exited the "nbd->recv_task" is not cleared.
Signed-off-by: Xiubo Li <xiubli@redhat.com>
---
drivers/block/nbd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index edf8b632e3d2..f46e26c9d9b3 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -801,9 +801,9 @@ static void recv_work(struct work_struct *work)
if (likely(!blk_should_fake_timeout(rq->q)))
blk_mq_complete_request(rq);
}
+ nbd_config_put(nbd);
atomic_dec(&config->recv_threads);
wake_up(&config->recv_wq);
- nbd_config_put(nbd);
kfree(args);
}
--
2.18.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] nbd: make the config put is called before the notifying the waiter
2020-10-14 2:45 [PATCH] nbd: make the config put is called before the notifying the waiter xiubli
@ 2020-10-14 17:33 ` Josef Bacik
2020-10-14 18:30 ` Jens Axboe
1 sibling, 0 replies; 3+ messages in thread
From: Josef Bacik @ 2020-10-14 17:33 UTC (permalink / raw)
To: xiubli, axboe; +Cc: linux-block, nbd
On 10/13/20 10:45 PM, xiubli@redhat.com wrote:
> From: Xiubo Li <xiubli@redhat.com>
>
> There has one race case for ceph's rbd-nbd tool. When do mapping
> it may fail with EBUSY from ioctl(nbd, NBD_DO_IT), but actually
> the nbd device has already unmaped.
>
> It dues to if just after the wake_up(), the recv_work() is scheduled
> out and defers calling the nbd_config_put(), though the map process
> has exited the "nbd->recv_task" is not cleared.
>
> Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Thanks,
Josef
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] nbd: make the config put is called before the notifying the waiter
2020-10-14 2:45 [PATCH] nbd: make the config put is called before the notifying the waiter xiubli
2020-10-14 17:33 ` Josef Bacik
@ 2020-10-14 18:30 ` Jens Axboe
1 sibling, 0 replies; 3+ messages in thread
From: Jens Axboe @ 2020-10-14 18:30 UTC (permalink / raw)
To: xiubli, josef; +Cc: linux-block, nbd
On 10/13/20 8:45 PM, xiubli@redhat.com wrote:
> From: Xiubo Li <xiubli@redhat.com>
>
> There has one race case for ceph's rbd-nbd tool. When do mapping
> it may fail with EBUSY from ioctl(nbd, NBD_DO_IT), but actually
> the nbd device has already unmaped.
>
> It dues to if just after the wake_up(), the recv_work() is scheduled
> out and defers calling the nbd_config_put(), though the map process
> has exited the "nbd->recv_task" is not cleared.
Applied, thanks.
--
Jens Axboe
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-10-14 18:31 UTC | newest]
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2020-10-14 17:33 ` Josef Bacik
2020-10-14 18:30 ` Jens Axboe
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