You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
xfs: XFS_IS_REALTIME_INODE() should be false if no rt device present
If using a kernel with CONFIG_XFS_RT=y and we set the RHINHERIT flag on
a directory in a filesystem that does not have a realtime device and
create a new file in that directory, it gets marked as a real time file.
When data is written and a fsync is issued, the filesystem attempts to
flush a non-existent rt device during the fsync process.
This results in a crash dereferencing a null buftarg pointer in
xfs_blkdev_issue_flush():
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: xfs_blkdev_issue_flush+0xd/0x20
.....
Call Trace:
xfs_file_fsync+0x188/0x1c0
vfs_fsync_range+0x3b/0xa0
do_fsync+0x3d/0x70
SyS_fsync+0x10/0x20
do_syscall_64+0x4d/0xb0
entry_SYSCALL64_slow_path+0x25/0x25
Setting RT inode flags does not require special privileges so any
unprivileged user can cause this oops to occur. To reproduce, confirm
kernel is compiled with CONFIG_XFS_RT=y and run:
# mkfs.xfs -f /dev/pmem0
# mount /dev/pmem0 /mnt/test
# mkdir /mnt/test/foo
# xfs_io -c 'chattr +t' /mnt/test/foo
# xfs_io -f -c 'pwrite 0 5m' -c fsync /mnt/test/foo/bar
Or just run xfstests with MKFS_OPTIONS="-d rtinherit=1" and wait.
Kernels built with CONFIG_XFS_RT=n are not exposed to this bug.
Fixes: f538d4d ("[XFS] write barrier support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Richard Wareing <rwareing@fb.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
0 commit comments