From: Jakub Kicinski <kuba@kernel.org> stable inclusion from stable-4.19.251 commit a12fae7621434d0360202156e13969874e002661 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5I4FP CVE: NA -------------------------------- commit ff1fa2081d173b01cebe2fbf0a2d0f1cee9ce4b5 upstream. Eric reports that syzbot made short work out of my speculative fix. Indeed when queue gets detached its tfile->tun remains, so we would try to stop NAPI twice with a detach(), close() sequence. Alternative fix would be to move tun_napi_disable() to tun_detach_all() and let the NAPI run after the queue has been detached. Fixes: a8fc8cb5692a ("net: tun: stop NAPI when detaching queues") Reported-by: syzbot <syzkaller@googlegroups.com> Reported-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20220629181911.372047-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- drivers/net/tun.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index d2ec3c987f0f..a772ceff9c1f 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -702,7 +702,8 @@ static void __tun_detach(struct tun_file *tfile, bool clean) tun = rtnl_dereference(tfile->tun); if (tun && clean) { - tun_napi_disable(tfile); + if (!tfile->detached) + tun_napi_disable(tfile); tun_napi_del(tfile); } -- 2.25.1