From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from r3-18.sinamail.sina.com.cn (r3-18.sinamail.sina.com.cn [202.108.3.18]) (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 3449FF9D6 for ; Wed, 27 Aug 2025 00:40:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.108.3.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756255256; cv=none; b=CBr6VUQSNhkQQq0B7DnW8mTKQ0jBW+nszCcrXFu2voiMQhiupeQhWTl8ZuLD7m5U30BZ5j4kOc423RYWB363QGvWC3RcavYLp7ULwuaiDtp2uv4Z5hxvpz2l/uNRNb5By3JekMxBrbsn+Nc5Qp5d40VUl8rV48vF5CeI4t3Lc9o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756255256; c=relaxed/simple; bh=ZIP8hF44M6IJGIjSSyGjYXXnwuLdQmO35En6HJGa/XY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FhRqN/Xg6rS2TIhI1bAKThWZ/BSNhEtu9USRWBVEXFC36ZQaF8T+OBkMmmRJ0QTWqwa3yGMyP0K6C/4xju0rinBVkkeoBxaV84sxDpJ1hplrgRrN6ueWX//gGCEDp0FBiZ5atlHi9q0ckDd0SjLJ9Tu/HgcjvNhaeZlCjO1Wlds= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b=JktGW+kl; arc=none smtp.client-ip=202.108.3.18 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b="JktGW+kl" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sina.com; s=201208; t=1756255251; bh=Gl6tAbUq+DzbydUTHpVw8ebckTFWUFP6T43SjEnyiKU=; h=From:Subject:Date:Message-ID; b=JktGW+klaIKEaACDrVfNASGPTCtgEBgfG4HzpKDOslAhCWHTGVWGzubfgdgvi2rog /Vp4CeLpAJuP11yPROWSm7HuVSUkux8j+OZBuY7Gc3BxAUOQuRZgfXqVyZbfbtN4ix FccT9H9f67o75YmecMddTH44CmYnDQxyMNrC7WmA= X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([114.249.58.236]) by sina.com (10.54.253.32) with ESMTP id 68AE540E00007EC1; Wed, 27 Aug 2025 08:40:48 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 6469054456922 X-SMAIL-UIID: 754A451A8BA24684912915226A503815-20250827-084048-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [net?] KASAN: slab-use-after-free Write in __xfrm_state_delete Date: Wed, 27 Aug 2025 08:40:36 +0800 Message-ID: <20250827004037.5728-1-hdanton@sina.com> In-Reply-To: <68ab6633.050a0220.37038e.0079.GAE@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > Date: Sun, 24 Aug 2025 12:21:23 -0700 [thread overview] > syzbot has found a reproducer for the following issue on: > > HEAD commit: b1c92cdf5af3 Merge branch 'net-wangxun-complete-ethtool-co.. > git tree: net-next > console output: https://syzkaller.appspot.com/x/log.txt?x=1411b062580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=67b99ceb67d33475 > dashboard link: https://syzkaller.appspot.com/bug?extid=a25ee9d20d31e483ba7b > compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14221862580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=159fba34580000 #syz test --- x/include/net/xfrm.h +++ y/include/net/xfrm.h @@ -202,6 +202,7 @@ struct xfrm_state { refcount_t refcnt; spinlock_t lock; + int deleted; u32 pcpu_num; struct xfrm_id id; --- x/net/xfrm/xfrm_state.c +++ y/net/xfrm/xfrm_state.c @@ -615,6 +615,7 @@ static void xfrm_state_gc_destroy(struct put_page(x->xfrag.page); xfrm_dev_state_free(x); security_xfrm_state_free(x); + xfrm_state_delete(x); xfrm_state_free(x); } @@ -812,10 +813,16 @@ int __xfrm_state_delete(struct xfrm_stat struct net *net = xs_net(x); int err = -ESRCH; - if (x->km.state != XFRM_STATE_DEAD) { - x->km.state = XFRM_STATE_DEAD; + for (;;) { + if (x->km.state != XFRM_STATE_DEAD) + x->km.state = XFRM_STATE_DEAD; spin_lock(&net->xfrm.xfrm_state_lock); + if (x->deleted) { + spin_unlock(&net->xfrm.xfrm_state_lock); + return 0; + } + x->deleted++; list_del(&x->km.all); hlist_del_rcu(&x->bydst); hlist_del_rcu(&x->bysrc); --