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 2F3F94B7164 for ; Thu, 3 Sep 2026 14:30:44 +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=1788445853; cv=none; b=TaB9aGfBsxMD6znBt7kPjRu133ouNr1QMkGBIcvYK/qAdXXGA0dVNZMns4rxqzMX0I1FxyN6DMmWQHG7VZS4BbQUfHn7ldD1mBwzIM+oJ5cDsABkod9aC1JU1BeRl3P/cFNFVs1hlBXyz9PCvOsnDUHMpRf63sOI3O7b5RSMX5s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788445853; c=relaxed/simple; bh=1cVfT7HBCn1hnP0vdibj4PvM5A7TEVbWCoc8Arj/jcE=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=LT28qDbmaspk/D94WX/+O9nq8nUe8J8ZLRsJ9hDdid5F5OimOhgMD7FL2I4JjW5WY2lAidkQzsca7mdHtkhjNm3nyRvgm7NUWMD7quesTmXPF1YhYtnq0eljhFlaONcMC3iR11kMQ6EN894CkZB3nLwfyAHB673TdF99cqmSkv0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IA6rm6Tb; 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="IA6rm6Tb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A06CF1F000E9; Thu, 3 Sep 2026 14:30:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788445841; bh=4LjRMVMe2fRRXVIeL79JpoXbc0LN0w+oh3PwprhkWNI=; h=Subject:To:Cc:From:Date; b=IA6rm6TbEF+yQd13SKiojCCPyKnPFkG3fnHw/gcUwuM3Z8lRfm+Xoj0nkwnFMtcNJ 2GOjVxxCPaq06cxdPQexmJjJP7PCJBhXPon3QYWS0L21E2K3FoFequkcBNASEVhKXA H7ehA+DyU+8PXJlkOwn2GJdBDjbphKZ0P+Eje8oQ= Subject: FAILED: patch "[PATCH] sunrpc: fix use-after-free in __rpc_clnt_handle_event and" failed to apply to 5.15-stable tree To: rakukuip@gmail.com,dstsmallbird@foxmail.com,enjou1224z@gmail.com,trond.myklebust@hammerspace.com,yuantan098@gmail.com Cc: From: Date: Thu, 03 Sep 2026 16:07:18 +0200 Message-ID: <2026090318-squad-abnormal-f798@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 932a8cf6abb2b2f8677b79153a823108d8861fe2 # git commit -s git send-email --to '' --in-reply-to '2026090318-squad-abnormal-f798@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 932a8cf6abb2b2f8677b79153a823108d8861fe2 Mon Sep 17 00:00:00 2001 From: Luxiao Xu Date: Tue, 7 Jul 2026 13:20:47 +0800 Subject: [PATCH] sunrpc: fix use-after-free in __rpc_clnt_handle_event and __rpc_clnt_remove_pipedir Normal client creation goes through rpc_setup_pipedir(), which records clnt->pipefs_sb, but the mount-event path in __rpc_clnt_handle_event() calls rpc_setup_pipedir_sb() directly and never refreshes that field. The umount path also removes the directory without clearing clnt->pipefs_sb. After a late pipefs mount or any remount, rpc_clnt_remove_pipedir() compares the current superblock against a stale pipefs_sb pointer and skips cleanup, leaving pipefs dentries whose inode private data still points at a freed rpc_clnt, leading to a potential use-after-free during subsequent rpc_info_open() or rpc_show_info() calls. Fix this by properly updating clnt->pipefs_sb upon mount events and clearing it during unmount or failure paths. Fixes: bfca5fb4e97c ("SUNRPC: Fix RPC client cleaned up the freed pipefs dentries") Cc: stable@vger.kernel.org Reported-by: Yuan Tan Reported-by: Xin Liu Reviewed-by: Ren Wei Assisted-by: Codex:gpt-5.4 Signed-off-by: Luxiao Xu Signed-off-by: Trond Myklebust diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index efa26899bc7d..6cedc824cf82 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -96,7 +96,10 @@ static void rpc_unregister_client(struct rpc_clnt *clnt) static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt) { - rpc_remove_client_dir(clnt); + if (clnt->pipefs_sb) { + rpc_remove_client_dir(clnt); + clnt->pipefs_sb = NULL; + } } static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt) @@ -177,19 +180,28 @@ static int rpc_clnt_skip_event(struct rpc_clnt *clnt, unsigned long event) } static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event, - struct super_block *sb) + struct super_block *sb) { + int err = 0; + switch (event) { case RPC_PIPEFS_MOUNT: - return rpc_setup_pipedir_sb(sb, clnt); + clnt->pipefs_sb = sb; + err = rpc_setup_pipedir_sb(sb, clnt); + if (err) + clnt->pipefs_sb = NULL; + break; case RPC_PIPEFS_UMOUNT: - __rpc_clnt_remove_pipedir(clnt); + if (clnt->pipefs_sb == sb) { + __rpc_clnt_remove_pipedir(clnt); + clnt->pipefs_sb = NULL; + } break; default: printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event); return -ENOTSUPP; } - return 0; + return err; } static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,