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| author | Shigeru Yoshida <syoshida@redhat.com> | 2022-09-08 01:35:02 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-26 13:19:40 +0200 |
| commit | c7b4641bd2395c2f3cd3b0a0cbf292ed9d489398 (patch) | |
| tree | d3debacebfe285d9ca73225ceeb32e06271ff376 | |
| parent | 37b679f8b5387a7d7bfbf30bec21c0f38da3abcc (diff) | |
| download | linux-stable-c7b4641bd2395c2f3cd3b0a0cbf292ed9d489398.tar.gz linux-stable-c7b4641bd2395c2f3cd3b0a0cbf292ed9d489398.tar.bz2 linux-stable-c7b4641bd2395c2f3cd3b0a0cbf292ed9d489398.zip | |
nbd: Fix hung when signal interrupts nbd_start_device_ioctl()
[ Upstream commit 1de7c3cf48fc41cd95adb12bd1ea9033a917798a ]
syzbot reported hung task [1]. The following program is a simplified
version of the reproducer:
int main(void)
{
int sv[2], fd;
if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) < 0)
return 1;
if ((fd = open("/dev/nbd0", 0)) < 0)
return 1;
if (ioctl(fd, NBD_SET_SIZE_BLOCKS, 0x81) < 0)
return 1;
if (ioctl(fd, NBD_SET_SOCK, sv[0]) < 0)
return 1;
if (ioctl(fd, NBD_DO_IT) < 0)
return 1;
return 0;
}
When signal interrupt nbd_start_device_ioctl() waiting the condition
atomic_read(&config->recv_threads) == 0, the task can hung because it
waits the completion of the inflight IOs.
This patch fixes the issue by clearing queue, not just shutdown, when
signal interrupt nbd_start_device_ioctl().
Link: https://syzkaller.appspot.com/bug?id=7d89a3ffacd2b83fdd39549bc4d8e0a89ef21239 [1]
Reported-by: syzbot+38e6c55d4969a14c1534@syzkaller.appspotmail.com
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20220907163502.577561-1-syoshida@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/block/nbd.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 2ef7eec6461c..cc66983e8b6a 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1271,10 +1271,12 @@ static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *b mutex_unlock(&nbd->config_lock); ret = wait_event_interruptible(config->recv_wq, atomic_read(&config->recv_threads) == 0); - if (ret) + if (ret) { sock_shutdown(nbd); - flush_workqueue(nbd->recv_workq); + nbd_clear_que(nbd); + } + flush_workqueue(nbd->recv_workq); mutex_lock(&nbd->config_lock); nbd_bdev_reset(bdev); /* user requested, ignore socket errors */ |