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 BB9787D3FE; Mon, 8 Apr 2024 14:00:44 +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=1712584844; cv=none; b=XQfyVowq/q1QocBWdparxWoKrcBXXUattZMPvjV3XHHCXMsXmO9moAA62+B0zTWxJt7lXH9Sz/TcdFBCmzu8yMwdAkC0ahXjxk2BroNT16S26w4M/FgFNXDYPkSf+V0e5jPlPXIdMsIaW90PiqFsEhj4x8YSag5E+NviQt6Bd58= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712584844; c=relaxed/simple; bh=ea8aiDlL4oIE2vsqvWd1mxRa6jomX9pvUdgOEUiFRWw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rWidVUwLKpJTyI4K7aN8jnb/bVnpibs70O6Y6Szn14W5mwZfLDDyfgSmWOHJSCDwIRrm1G/8pOdgouuqz56SZJ3mpIF/WEp2ejo2wRjYasdRyj9k3IRoDZQ/Sz/XhXF/a5KDqyrxrr+qCIesTmpZSYVDt/alKghhm0NnUzTWsCI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=vgWvmD3Q; 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="vgWvmD3Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 45039C433F1; Mon, 8 Apr 2024 14:00:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1712584844; bh=ea8aiDlL4oIE2vsqvWd1mxRa6jomX9pvUdgOEUiFRWw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=vgWvmD3QHqV84/KypMUCeZMCUpTi4Rs4sa9Xrcs3nZeQQYjOWvqOChjVtfK8uTzxG x7z4hDkXrsUfsOGGpsZrh9LYgVneAAfa4GpXomywjYaFeAja2wlMT0qlwYzaPUwXfh ReDKAimif5T8hC15vUtUMCyDwqNLjJgIY8DDGrgY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, NeilBrown , Jeff Layton , Chuck Lever Subject: [PATCH 5.15 549/690] NFSD: fix possible oops when nfsd/pool_stats is closed. Date: Mon, 8 Apr 2024 14:56:55 +0200 Message-ID: <20240408125419.518748990@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240408125359.506372836@linuxfoundation.org> References: <20240408125359.506372836@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown [ Upstream commit 88956eabfdea7d01d550535af120d4ef265b1d02 ] If /proc/fs/nfsd/pool_stats is open when the last nfsd thread exits, then when the file is closed a NULL pointer is dereferenced. This is because nfsd_pool_stats_release() assumes that the pointer to the svc_serv cannot become NULL while a reference is held. This used to be the case but a recent patch split nfsd_last_thread() out from nfsd_put(), and clearing the pointer is done in nfsd_last_thread(). This is easily reproduced by running rpc.nfsd 8 ; ( rpc.nfsd 0;true) < /proc/fs/nfsd/pool_stats Fortunately nfsd_pool_stats_release() has easy access to the svc_serv pointer, and so can call svc_put() on it directly. Fixes: 9f28a971ee9f ("nfsd: separate nfsd_last_thread() from nfsd_put()") Signed-off-by: NeilBrown Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever --- fs/nfsd/nfssvc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index ee5713fca1870..2a1dd580dfb94 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -1084,11 +1084,12 @@ int nfsd_pool_stats_open(struct inode *inode, struct file *file) int nfsd_pool_stats_release(struct inode *inode, struct file *file) { + struct seq_file *seq = file->private_data; + struct svc_serv *serv = seq->private; int ret = seq_release(inode, file); - struct net *net = inode->i_sb->s_fs_info; mutex_lock(&nfsd_mutex); - nfsd_put(net); + svc_put(serv); mutex_unlock(&nfsd_mutex); return ret; } -- 2.43.0