On Wed, Oct 04, 2017 at 09:33:18AM +0800, Jia-Ju Bai wrote: > The driver may sleep under a RCU lock, and the function call path is: > drbd_sync_handshake (acquire the RCU lock) > drbd_asb_recover_1p > drbd_khelper > drbd_bcast_event > genlmsg_new(GFP_NOIO) --> may sleep > > To fix it, GFP_NOIO is replaced with GFP_ATOMIC. > This bug is found by my static analysis tool and my code review. > > > Signed-off-by: Jia-Ju Bai <baijiaju1...@163.com> > --- > drivers/block/drbd/drbd_nl.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c > index a12f77e..713c965 100644 > --- a/drivers/block/drbd/drbd_nl.c > +++ b/drivers/block/drbd/drbd_nl.c > @@ -4537,7 +4537,7 @@ void drbd_bcast_event(struct drbd_device *device, const > struct sib_info *sib) > int err = -ENOMEM; > > seq = atomic_inc_return(&drbd_genl_seq); > - msg = genlmsg_new(NLMSG_GOODSIZE, GFP_NOIO); > + msg = genlmsg_new(NLMSG_GOODSIZE, GFP_ATOMIC); > if (!msg) > goto failed;
Hi Jia-Ju, thanks for reporting that. I fixed that by narrowing the scope of the rcu_lock in drbd_sync_handshake() while keeping the code down the rabbit hole untouched. This has the benefit that it fixes all your 3 cases. As usual, we will send that upstream soon. Thanks, rck