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| author | Jian Zhang <zhangjian496@huawei.com> | 2026-05-19 18:44:22 +0800 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2026-05-27 17:17:02 -0500 |
| commit | 8704b5aa179ae57c3169aacc63868c459bb4316e (patch) | |
| tree | 0e760c85a517d172cbe5c692d0273e918d546b84 /fs | |
| parent | 76efb52e058d4fccd44e4d9efa334cb1ff71f4b8 (diff) | |
| download | linux-next-history-8704b5aa179ae57c3169aacc63868c459bb4316e.tar.gz | |
cifs: remove all cifs files before kill super
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 <zhangjian496@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/smb/client/connect.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index dcde25da468df..cbeb5637eeb92 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); } |