diff options
| author | David Howells <dhowells@redhat.com> | 2022-04-13 11:16:25 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-27 13:50:46 +0200 |
| commit | f10e5c9f226cf90fcf796e590b75dea85d3bdfd8 (patch) | |
| tree | 4bf8e4c8e539c90ee1ac94bf2405d28730c09b89 /net | |
| parent | 9a9c481593650bbe4066e2185de6b68a82a4110f (diff) | |
rxrpc: Restore removed timer deletion
[ Upstream commit ee3b0826b4764f6c13ad6db67495c5a1c38e9025 ]
A recent patch[1] from Eric Dumazet flipped the order in which the
keepalive timer and the keepalive worker were cancelled in order to fix a
syzbot reported issue[2]. Unfortunately, this enables the mirror image bug
whereby the timer races with rxrpc_exit_net(), restarting the worker after
it has been cancelled:
CPU 1 CPU 2
=============== =====================
if (rxnet->live)
<INTERRUPT>
rxnet->live = false;
cancel_work_sync(&rxnet->peer_keepalive_work);
rxrpc_queue_work(&rxnet->peer_keepalive_work);
del_timer_sync(&rxnet->peer_keepalive_timer);
Fix this by restoring the removed del_timer_sync() so that we try to remove
the timer twice. If the timer runs again, it should see ->live == false
and not restart the worker.
Fixes: 1946014ca3b1 ("rxrpc: fix a race in rxrpc_exit_net()")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Dumazet <edumazet@google.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/20220404183439.3537837-1-eric.dumazet@gmail.com/ [1]
Link: https://syzkaller.appspot.com/bug?extid=724378c4bb58f703b09a [2]
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/rxrpc/net_ns.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/net/rxrpc/net_ns.c b/net/rxrpc/net_ns.c index 9a76b74af37b..91a503871116 100644 --- a/net/rxrpc/net_ns.c +++ b/net/rxrpc/net_ns.c @@ -116,7 +116,9 @@ static __net_exit void rxrpc_exit_net(struct net *net) struct rxrpc_net *rxnet = rxrpc_net(net); rxnet->live = false; + del_timer_sync(&rxnet->peer_keepalive_timer); cancel_work_sync(&rxnet->peer_keepalive_work); + /* Remove the timer again as the worker may have restarted it. */ del_timer_sync(&rxnet->peer_keepalive_timer); rxrpc_destroy_all_calls(rxnet); rxrpc_destroy_all_connections(rxnet); |