This is a note to let you know that I've just added the patch titled net: tun: unlink NAPI from device on destruction to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-tun-unlink-napi-from-device-on-destruction.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 3b9bc84d311104906d2b4995a9a02d7b7ddab2db Mon Sep 17 00:00:00 2001 From: Jakub Kicinski <kuba@xxxxxxxxxx> Date: Wed, 22 Jun 2022 21:20:39 -0700 Subject: net: tun: unlink NAPI from device on destruction From: Jakub Kicinski <kuba@xxxxxxxxxx> commit 3b9bc84d311104906d2b4995a9a02d7b7ddab2db upstream. Syzbot found a race between tun file and device destruction. NAPIs live in struct tun_file which can get destroyed before the netdev so we have to del them explicitly. The current code is missing deleting the NAPI if the queue was detached first. Fixes: 943170998b20 ("tun: enable NAPI for TUN/TAP driver") Reported-by: syzbot+b75c138e9286ac742647@xxxxxxxxxxxxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/20220623042039.2274708-1-kuba@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/tun.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -783,6 +783,7 @@ static void tun_detach_all(struct net_de sock_put(&tfile->sk); } list_for_each_entry_safe(tfile, tmp, &tun->disabled, next) { + tun_napi_del(tfile); tun_enable_queue(tfile); tun_queue_purge(tfile); xdp_rxq_info_unreg(&tfile->xdp_rxq); Patches currently in stable-queue which might be from kuba@xxxxxxxxxx are queue-5.4/selftests-net-pass-ipv6_args-to-udpgso_bench-s-ipv6-tcp-test.patch queue-5.4/ipv6-take-care-of-disable_policy-when-restoring-routes.patch queue-5.4/net-tun-unlink-napi-from-device-on-destruction.patch queue-5.4/usbnet-fix-memory-allocation-in-helpers.patch queue-5.4/net-tun-stop-napi-when-detaching-queues.patch