This is a note to let you know that I've just added the patch titled net: tun: stop NAPI when detaching queues to the 5.10-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-stop-napi-when-detaching-queues.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a8fc8cb5692aebb9c6f7afd4265366d25dcd1d01 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski <kuba@xxxxxxxxxx> Date: Wed, 22 Jun 2022 21:21:05 -0700 Subject: net: tun: stop NAPI when detaching queues From: Jakub Kicinski <kuba@xxxxxxxxxx> commit a8fc8cb5692aebb9c6f7afd4265366d25dcd1d01 upstream. While looking at a syzbot report I noticed the NAPI only gets disabled before it's deleted. I think that user can detach the queue before destroying the device and the NAPI will never be stopped. Fixes: 943170998b20 ("tun: enable NAPI for TUN/TAP driver") Acked-by: Petar Penkov <ppenkov@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220623042105.2274812-1-kuba@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/tun.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -279,6 +279,12 @@ static void tun_napi_init(struct tun_str } } +static void tun_napi_enable(struct tun_file *tfile) +{ + if (tfile->napi_enabled) + napi_enable(&tfile->napi); +} + static void tun_napi_disable(struct tun_file *tfile) { if (tfile->napi_enabled) @@ -659,8 +665,10 @@ static void __tun_detach(struct tun_file if (clean) { RCU_INIT_POINTER(tfile->tun, NULL); sock_put(&tfile->sk); - } else + } else { tun_disable_queue(tun, tfile); + tun_napi_disable(tfile); + } synchronize_net(); tun_flow_delete_by_queue(tun, tun->numqueues + 1); @@ -814,6 +822,7 @@ static int tun_attach(struct tun_struct if (tfile->detached) { tun_enable_queue(tfile); + tun_napi_enable(tfile); } else { sock_hold(&tfile->sk); tun_napi_init(tun, tfile, napi, napi_frags); Patches currently in stable-queue which might be from kuba@xxxxxxxxxx are queue-5.10/selftests-net-pass-ipv6_args-to-udpgso_bench-s-ipv6-tcp-test.patch queue-5.10/net-dp83822-disable-false-carrier-interrupt.patch queue-5.10/ipv6-take-care-of-disable_policy-when-restoring-routes.patch queue-5.10/net-tun-unlink-napi-from-device-on-destruction.patch queue-5.10/usbnet-fix-memory-allocation-in-helpers.patch queue-5.10/net-tun-stop-napi-when-detaching-queues.patch queue-5.10/net-dp83822-disable-rx-error-interrupt.patch queue-5.10/net-dsa-bcm_sf2-force-pause-link-settings.patch