From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 411182E7621 for ; Fri, 20 Mar 2026 08:46:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773996407; cv=none; b=VPbO74GCmRG5Mj4v2vzTfDIB/5Jgo8yfBEeKDMoD5titYl0FSvczy2FPmUfB3h9XlAeiVMdxco1Z0oCenE14Uib1I4CgisFdvQCWZ+/zkDvvUGbap8VrY3rBuvVan/DYXryh0XVKfIy8QTuE/6nqvJM/1riE1T/aLi4ryTb4jpM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773996407; c=relaxed/simple; bh=AH40O0t1/vMPd3oZiGySUrusO8SWxog1svs3SpIwlfQ=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=RX5RaTD9BXajGnGygZd7PtRrPApjakIePjQ/3lqOrJ4gtvoNoiSPZXDswdEFT8WfGi4ciEgFux1N+ew0jY9AP/wi7jfjbFMmtiuStzZpxduehwPIjT1LjGi/CGCE97XlY5Nq7rvwVj2oB/ozTcDDK1GXl938UnGz7iiF+fE0MCA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dFqjNQcy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="dFqjNQcy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77639C4CEF7; Fri, 20 Mar 2026 08:46:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1773996406; bh=AH40O0t1/vMPd3oZiGySUrusO8SWxog1svs3SpIwlfQ=; h=Subject:To:Cc:From:Date:From; b=dFqjNQcya7qCLqiG+cfP3exMHtKaKgFHQz4Adrlx0ydCYSgbQVU9jPs83wdge4W5O SZTfeg99+KcqY8m2TSSkwpZ5sFh8s2aOpM4ThNxTbLa1SgwRDkCsRmSFSFS1bed/kd lq+f4Ur1bHeuRaQ12IEcgUcWAgNrCrYJRYnIqQfU= Subject: FAILED: patch "[PATCH] NFSD: Hold net reference for the lifetime of" failed to apply to 5.15-stable tree To: chuck.lever@oracle.com,jlayton@kernel.org,misanjum@linux.ibm.com,neil@brown.name,okorniev@redhat.com Cc: From: Date: Fri, 20 Mar 2026 09:46:39 +0100 Message-ID: <2026032038-dimly-tiring-d92b@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 e7fcf179b82d3a3730fd8615da01b087cc654d0b # git commit -s git send-email --to '' --in-reply-to '2026032038-dimly-tiring-d92b@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From e7fcf179b82d3a3730fd8615da01b087cc654d0b Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Thu, 19 Feb 2026 16:50:17 -0500 Subject: [PATCH] NFSD: Hold net reference for the lifetime of /proc/fs/nfs/exports fd The /proc/fs/nfs/exports proc entry is created at module init and persists for the module's lifetime. exports_proc_open() captures the caller's current network namespace and stores its svc_export_cache in seq->private, but takes no reference on the namespace. If the namespace is subsequently torn down (e.g. container destruction after the opener does setns() to a different namespace), nfsd_net_exit() calls nfsd_export_shutdown() which frees the cache. Subsequent reads on the still-open fd dereference the freed cache_detail, walking a freed hash table. Hold a reference on the struct net for the lifetime of the open file descriptor. This prevents nfsd_net_exit() from running -- and thus prevents nfsd_export_shutdown() from freeing the cache -- while any exports fd is open. cache_detail already stores its net pointer (cd->net, set by cache_create_net()), so exports_release() can retrieve it without additional per-file storage. Reported-by: Misbah Anjum N Closes: https://lore.kernel.org/linux-nfs/dcd371d3a95815a84ba7de52cef447b8@linux.ibm.com/ Fixes: 96d851c4d28d ("nfsd: use proper net while reading "exports" file") Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Reviewed-by: NeilBrown Tested-by: Olga Kornievskaia Signed-off-by: Chuck Lever diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index fe3b3f206aa9..d67c169526d0 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -149,9 +149,19 @@ static int exports_net_open(struct net *net, struct file *file) seq = file->private_data; seq->private = nn->svc_export_cache; + get_net(net); return 0; } +static int exports_release(struct inode *inode, struct file *file) +{ + struct seq_file *seq = file->private_data; + struct cache_detail *cd = seq->private; + + put_net(cd->net); + return seq_release(inode, file); +} + static int exports_nfsd_open(struct inode *inode, struct file *file) { return exports_net_open(inode->i_sb->s_fs_info, file); @@ -161,7 +171,7 @@ static const struct file_operations exports_nfsd_operations = { .open = exports_nfsd_open, .read = seq_read, .llseek = seq_lseek, - .release = seq_release, + .release = exports_release, }; static int export_features_show(struct seq_file *m, void *v) @@ -1376,7 +1386,7 @@ static const struct proc_ops exports_proc_ops = { .proc_open = exports_proc_open, .proc_read = seq_read, .proc_lseek = seq_lseek, - .proc_release = seq_release, + .proc_release = exports_release, }; static int create_proc_exports_entry(void)