Messages in this thread | | | Subject | Re: [PATCH] nbd: add a flush_workqueue in nbd_start_device | From | Josef Bacik <> | Date | Tue, 21 Jan 2020 09:00:35 -0500 |
| |
On 1/21/20 7:48 AM, Sun Ke wrote: > When kzalloc fail, may cause trying to destroy the > workqueue from inside the workqueue. > > If num_connections is m (2 < m), and NO.1 ~ NO.n > (1 < n < m) kzalloc are successful. The NO.(n + 1) > failed. Then, nbd_start_device will return ENOMEM > to nbd_start_device_ioctl, and nbd_start_device_ioctl > will return immediately without running flush_workqueue. > However, we still have n recv threads. If nbd_release > run first, recv threads may have to drop the last > config_refs and try to destroy the workqueue from > inside the workqueue. > > To fix it, add a flush_workqueue in nbd_start_device. > > Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") > Signed-off-by: Sun Ke <sunke32@huawei.com> > --- > drivers/block/nbd.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c > index b4607dd96185..dd1f8c2c6169 100644 > --- a/drivers/block/nbd.c > +++ b/drivers/block/nbd.c > @@ -1264,7 +1264,12 @@ static int nbd_start_device(struct nbd_device *nbd) > > args = kzalloc(sizeof(*args), GFP_KERNEL); > if (!args) { > - sock_shutdown(nbd); > + if (i == 0) > + sock_shutdown(nbd); > + else { > + sock_shutdown(nbd); > + flush_workqueue(nbd->recv_workq); > + }
Just for readability sake why don't we just flush_workqueue() unconditionally, and add a comment so we know why in the future. Thanks,
Josef
| |