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 838DD2DBF75; Tue, 21 Jul 2026 18:51:48 +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=1784659909; cv=none; b=iC3jrq3jTmXtB7U9c8CDZmOfIm6Mp83qFTrUpLiMOW8ieb9m4EiktqV4i4FFvwGkyNI1XHF6feqgv4cqGjXJBvCtdLzgF3cqKwnTPB/ljubH0M+g0ecsHSgOrGNBFolSaMofM5M2e6m+S2pDmu6gBH4/YR777sGfut2mRGqsT7A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784659909; c=relaxed/simple; bh=nhkcZYjtFzee47wNsLFqd3V73uuLEFtLj+WAK5np9Is=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NfBdMhrAoUyKP7f8OM+oiVqq2R2I/wL46WHLtpvAZtPuEP5Yadx8KRowFHM8fwYq5NN3jU6ErPXR/mZlrzVz+LcCmFdy8FieSUQlaE2xvRiQkpP26c8aQVfGa7cBCKgD6xqRlOt9AWBKtuB4LkjdtIqp7vWOnwE58vsnR7xiJZ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fQnjkIQy; 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="fQnjkIQy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EADD11F000E9; Tue, 21 Jul 2026 18:51:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784659908; bh=5iZr5vdTsEetZwe/jidW7IOGl+Fy9ZgFQf70S4qNfSE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fQnjkIQyfxOOsrLPXI5UO+/6OUEGCj36FxX7/TfeDVIgsfIPxBIGQ6xvZeWO4oBEH 6WuhRj4uruu/SW9yx38RWTa5poYuPkodl1/7lJ74FYAlqyPI201LH/KugqRLDhKEHT /BRU6J+pYh8V+pYrQl5ASbbL/fnjFRpJuS0zIgJk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jian Zhang , Steve French , Sasha Levin Subject: [PATCH 7.1 0777/2077] cifs: remove all cifs files before kill super Date: Tue, 21 Jul 2026 17:07:30 +0200 Message-ID: <20260721152611.124874436@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152552.646164743@linuxfoundation.org> References: <20260721152552.646164743@linuxfoundation.org> User-Agent: quilt/0.69 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 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jian Zhang [ Upstream commit 6d9a4aaaa8b2612b5ef9d581e2f286a458b71ee1 ] Cifs files may be put into fileinfo_put_wq during umounting cifs. After umount done, cifsFileInfo_put_final is called, which cause following BUG: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... [ 134.222152] list_lru_add+0x64/0x1a0 [ 134.222399] ? cifs_put_tcon+0x171/0x340 [cifs] [ 134.222772] d_lru_add+0x44/0x60 [ 134.222997] dput+0x1fc/0x210 [ 134.223213] cifsFileInfo_put_final+0x11a/0x140 [cifs] [ 134.223576] process_one_work+0x17c/0x320 [ 134.223843] worker_thread+0x188/0x280 [ 134.224084] ? __pfx_worker_thread+0x10/0x10 [ 134.224366] kthread+0xcc/0x100 [ 134.224576] ? __pfx_kthread+0x10/0x10 [ 134.224827] ret_from_fork+0x30/0x50 [ 134.225063] ? __pfx_kthread+0x10/0x10 [ 134.225328] ret_from_fork_asm+0x1b/0x30 This can be reproduce by following: unshare -n bash -c " mkdir -p ${CIFS_MNT} ip netns attach root 1 ip link add eth0 type veth peer veth0 netns root ip link set eth0 up ip -n root link set veth0 up ip addr add 192.168.0.2/24 dev eth0 ip -n root addr add 192.168.0.1/24 dev veth0 ip route add default via 192.168.0.1 dev eth0 ip netns exec root sysctl net.ipv4.ip_forward=1 ip netns exec root iptables -t nat -A POSTROUTING -s 192.168.0.2 -o ${DEV} -j MASQUERADE mount -t cifs ${CIFS_PATH} ${CIFS_MNT} -o vers=3.0,sec=ntlmssp,credentials=${CIFS_CRED},rsize=65536,wsize=65536,cache=none,echo_interval=1 touch ${CIFS_MNT}/a.txt ip netns exec root iptables -t nat -D POSTROUTING -s 192.168.0.2 -o ${DEV} -j MASQUERADE " umount ${CIFS_MNT} Fixes: 340cea84f691 ("cifs: open files should not hold ref on superblock") Signed-off-by: Jian Zhang Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/smb/client/connect.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index dcde25da468dfb..cbeb5637eeb925 100644 --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -3996,6 +3996,9 @@ cifs_umount(struct cifs_sb_info *cifs_sb) } spin_unlock(&cifs_sb->tlink_tree_lock); + flush_workqueue(serverclose_wq); + flush_workqueue(fileinfo_put_wq); + kfree(cifs_sb->prepath); call_rcu(&cifs_sb->rcu, delayed_free); } -- 2.53.0