commit bc8dedae02 upstream.
This fixes a kernel oops when reading ceph snapshot directories (.snap),
for example by simply running `ls /mnt/my_ceph/.snap`.
The variable str is guarded by __free(kfree), but advanced by one for
skipping the initial '_' in snapshot names. Thus, kfree() is called
with an invalid pointer. This patch removes the need for advancing the
pointer so kfree() is called with correct memory pointer.
Steps to reproduce:
1. Create snapshots on a cephfs volume (I've 63 snaps in my testcase)
2. Add cephfs mount to fstab
$ echo "samba-fileserver@.files=/volumes/datapool/stuff/3461082b-ecc9-4e82-8549-3fd2590d3fb6 /mnt/test/stuff ceph acl,noatime,_netdev 0 0" >> /etc/fstab
3. Reboot the system
$ systemctl reboot
4. Check if it's really mounted
$ mount | grep stuff
5. List snapshots (expected 63 snapshots on my system)
$ ls /mnt/test/stuff/.snap
Now ls hangs forever and the kernel log shows the oops.
Cc: stable@vger.kernel.org
Fixes: 101841c383 ("[ceph] parse_longname(): strrchr() expects NUL-terminated string")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220807
Suggested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Daniel Vogelbacher <daniel@chaospixel.com>
Reviewed-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
8c9af7339d