From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D1EA83CB565; Fri, 31 Jul 2026 10:06:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785492403; cv=none; b=LwoD3wJpHVuA/hjg8V0IRN/7WU+aasc/drQCWoGSlqv58A4LCeSr99TIzBFdLcgiJn/vlijRT1/rFu8OWXarmjgAhrpFqs0QmmbNRqLI1Dfe5sJYnTZbC5GK8aLxEc2Aox8XKiW5TUBPfijWffyGjAJCWLm3UqBTSslE/r63whM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785492403; c=relaxed/simple; bh=wx4kngmNrTo/NSw75ebXXyzUURVJejqXFLaIDkBKXqo=; h=From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type:Date; b=i7zjbN4PrEI5gb2/uPU9DmfbkxUp6bdi987SemI67TiuoFBRwIS1oH8+lXbrbaro9CuqqHuvojoENBhsJcQnO+veDKESPOEVzt3nZXAvs+mcHFKj8xjuvMhSo/iYJUYdOFXkUhpveOYJcjitNgSqzttQam7khj8+6mVTMnGW9tM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Rou5vz6Q; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Rou5vz6Q" Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id A05E41F00A3A; Fri, 31 Jul 2026 10:06:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785492381; bh=1PAjhfiJGNKE7o1Y+80U2ZTuRF/fFH0ZTMJo/XOsbh8=; h=From:To:Cc:Subject:Date; b=Rou5vz6QmgO1xtAD5B/GAXzPW0AYW7cXXf8RLp7YJhnwmBkEBE1AA/SopkBs2gCEL PPQ2NXzRhrN9VfLOqQONHzQ/+9YDKUlkC69+FZbw4VSekfQFlk5+66meWCR3qeP9i0 9OYzLSfiTtn9UTf9DmD0ozYPJe5xmqlKJsy5ygdDZMYt82ElsGzIf4+pjBci6FOZ0I m5jXSbn5bLeQYcaS5sWIQyJZPKwwPQ6t+NqRE92FzmWOctC/8TQOqw12s8D9EdYPig /NEzggSmpW6d+HHZXw9BSHXTZC5qOec8yNRlU8uXN2Or5VpYPfxHPjAGfwzu77hTJ0 Yvsn6NFUcRR+Q== From: "syzbot" To: syzkaller-bugs@googlegroups.com, Aleksandr Nogikh , "David S. Miller" , "Eric Dumazet" , "Herbert Xu" , "Jakub Kicinski" , , "Paolo Abeni" , "Steffen Klassert" , "Antony Antony" Cc: horms@kernel.org, linux-kernel@vger.kernel.org, syzbot@lists.linux.dev Subject: [PATCH] xfrm: add missing RCU read lock in xfrm_send_migrate_state() Message-ID: <2f866679-25c2-4b17-9fa6-086d4c3b593f@mail.kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Date: Fri, 31 Jul 2026 10:06:20 +0000 (UTC) From: Aleksandr Nogikh xfrm_nlmsg_multicast() requires the RCU read lock to be held because it safely dereferences the net->xfrm.nlsk pointer using rcu_dereference(). When it is called from xfrm_send_migrate_state(), the RCU read lock is not held, which triggers a suspicious RCU usage warning: WARNING: suspicious RCU usage net/xfrm/xfrm_user.c:1630 suspicious rcu_dereference_check() usage! Call Trace: lockdep_rcu_suspicious+0x13f/0x1d0 kernel/locking/lockdep.c:6876 xfrm_nlmsg_multicast+0x1d8/0x1f0 net/xfrm/xfrm_user.c:1630 xfrm_send_migrate_state+0x870/0xae0 net/xfrm/xfrm_user.c:3340 xfrm_do_migrate_state+0x1749/0x1e90 net/xfrm/xfrm_user.c:3507 xfrm_user_rcv_msg+0x7a8/0xf30 net/xfrm/xfrm_user.c:3907 Fix this by wrapping the xfrm_nlmsg_multicast() call in xfrm_send_migrate_state() with rcu_read_lock() and rcu_read_unlock(). Fixes: a9d155ea9b44 ("xfrm: add XFRM_MSG_MIGRATE_STATE for single SA migration") Assisted-by: Gemini:gemini-3.5-flash Gemini:gemini-3.1-pro-preview syzbot Reported-by: syzbot+c0e99a1aa85a286d7a3b@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=c0e99a1aa85a286d7a3b Link: https://syzkaller.appspot.com/ai_job?id=8977f559-3a7e-4bb5-b4d6-1196956260b6 Signed-off-by: Aleksandr Nogikh --- diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index d6db63304..0ba0614d6 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -3337,7 +3337,11 @@ static int xfrm_send_migrate_state(struct net *net, return err; } - return xfrm_nlmsg_multicast(net, skb, 0, XFRMNLGRP_MIGRATE); + rcu_read_lock(); + err = xfrm_nlmsg_multicast(net, skb, 0, XFRMNLGRP_MIGRATE); + rcu_read_unlock(); + + return err; } static int xfrm_do_migrate_state(struct sk_buff *skb, struct nlmsghdr *nlh, base-commit: f5098b6bae761e346ebcd9da7f95622c04733cff -- See https://goo.gle/syzbot-ai-patches for information about AI-generated patches. You can comment on the patch as usual, syzbot will try to address the comments and send a new version of the patch if necessary. syzbot engineers can be reached at syzkaller@googlegroups.com.