| Message ID | alpine.LRH.2.02.2208100858130.19047@file01.intranet.prod.int.rdu2.redhat.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | rds: add missing barrier to release_refill | expand |
Hello: This patch was applied to netdev/net.git (master) by David S. Miller <davem@davemloft.net>: On Wed, 10 Aug 2022 09:00:42 -0400 (EDT) you wrote: > The functions clear_bit and set_bit do not imply a memory barrier, thus it > may be possible that the waitqueue_active function (which does not take > any locks) is moved before clear_bit and it could miss a wakeup event. > > Fix this bug by adding a memory barrier after clear_bit. > > Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> > Cc: stable@vger.kernel.org Here is the summary with links: - rds: add missing barrier to release_refill https://git.kernel.org/netdev/net/c/9f414eb409da You are awesome, thank you!
Index: linux-2.6/net/rds/ib_recv.c =================================================================== --- linux-2.6.orig/net/rds/ib_recv.c +++ linux-2.6/net/rds/ib_recv.c @@ -363,6 +363,7 @@ static int acquire_refill(struct rds_con static void release_refill(struct rds_connection *conn) { clear_bit(RDS_RECV_REFILL, &conn->c_flags); + smp_mb__after_atomic(); /* We don't use wait_on_bit()/wake_up_bit() because our waking is in a * hot path and finding waiters is very rare. We don't want to walk
The functions clear_bit and set_bit do not imply a memory barrier, thus it may be possible that the waitqueue_active function (which does not take any locks) is moved before clear_bit and it could miss a wakeup event. Fix this bug by adding a memory barrier after clear_bit. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org