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 5596A281369; Fri, 7 Aug 2026 15:22:10 +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=1786116131; cv=none; b=ksNWx6dQ0SsNJbEZQnNPefD3Sw2zC3v4rIFzYhyVFImo5O/VJoPOGMldozkhPtZkhOLs7wj6GsTeDAUFswJZ2W8zW6k039ZfWfdmUvpycXhjFloWVnaZJIyIMiopGer0lreXeoad9tTGETswgsqytPmMeGd9P7rgbnv0vpSijn4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786116131; c=relaxed/simple; bh=/Xd03DyMAXOYMKA4wLNU+W0RCCpFzeaJIux7b28BAyo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oh+kv1FkA2YbRM/pDWqY5rbAU4OGRj7pyQ2SdfHfg9t0OIWlRwf3hNIiDGoElmRtBBESBYPanOvZwydezxLYDpN5oEWyOmsD2c6xWfBVpiG3Bt2oX9Shvv4vvF8yRLzj7DQXO63y4x93XpTejtbPhwbe+WEs3PnphsbRgidlTFU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qDPiSgkk; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qDPiSgkk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A94931F000E9; Fri, 7 Aug 2026 15:22:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786116130; bh=eWhR3xdZNPxyd2DRdZ8hQvbJIKZBA839cTEvoreZVPo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=qDPiSgkkW8NcN7LY0VVEBhX9+TCNAYEvyP1jqffD8O8/4rgUgdPoP//U1Pqa56BGd lCbrpD8u9aNwk71LPefZ//9wV7HNnKNQ74hIh/zbJYoH4ZqFWj52LWYYtWTiQ2+Ity 5ZEbLGGwxLZwXSyktqraycTUGo6hDqfIAW7BRgRY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xuanqiang Luo , Mahanta Jambigi , Paolo Abeni Subject: [PATCH 6.6 124/261] net/smc: fix socket use-after-free during link group termination Date: Fri, 7 Aug 2026 16:38:01 +0200 Message-ID: <20260807143418.044442300@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143415.358597922@linuxfoundation.org> References: <20260807143415.358597922@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xuanqiang Luo commit f621d6ebeebb6374342571e4ddf45fdbc420f6cd upstream. __smc_lgr_terminate() drops conns_lock after finding a connection in lgr->conns_all, but before taking a reference on its socket. The connection is embedded in the socket, and its registration reference protects it only while the connection remains in the tree. A concurrent close can unregister the connection and drop that reference, freeing the socket before the termination worker reaches sock_hold(). The race is reachable when close overlaps link group termination. Local stress testing reproduced the use-after-free and KASAN reported: BUG: KASAN: slab-use-after-free in __smc_lgr_terminate.part.0 [smc] Write of size 4 by task kworker/3:3 Workqueue: events smc_lgr_terminate_work [smc] __smc_lgr_terminate.part.0 [smc] The socket was allocated by smc_create(), freed through slab_free_after_rcu_debug(), and was followed by: refcount_t: addition on 0; use-after-free. __smc_lgr_terminate.part.0 [smc] Take the socket reference while conns_lock still protects the tree entry. The unregister path then cannot drop the last reference until termination has finished using the socket. Fixes: 69318b5215f2 ("net/smc: improve abnormal termination locking") Cc: stable@vger.kernel.org Signed-off-by: Xuanqiang Luo Reviewed-by: Mahanta Jambigi Link: https://patch.msgid.link/20260723105454.87016-1-xuanqiang.luo@linux.dev Signed-off-by: Paolo Abeni Signed-off-by: Greg Kroah-Hartman --- net/smc/smc_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -1502,10 +1502,10 @@ static void __smc_lgr_terminate(struct s read_lock_bh(&lgr->conns_lock); node = rb_first(&lgr->conns_all); while (node) { - read_unlock_bh(&lgr->conns_lock); conn = rb_entry(node, struct smc_connection, alert_node); smc = container_of(conn, struct smc_sock, conn); sock_hold(&smc->sk); /* sock_put below */ + read_unlock_bh(&lgr->conns_lock); lock_sock(&smc->sk); smc_conn_kill(conn, soft); release_sock(&smc->sk);