commit d8189834d4 upstream.
butt3rflyh4ck reports a bug as below:
When a thread always calls F2FS_IOC_RESIZE_FS to resize fs, if resize fs is
failed, f2fs kernel thread would invoke callback function to update f2fs io
info, it would call f2fs_write_end_io and may trigger null-ptr-deref in
NODE_MAPPING.
general protection fault, probably for non-canonical address
KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
RIP: 0010:NODE_MAPPING fs/f2fs/f2fs.h:1972 [inline]
RIP: 0010:f2fs_write_end_io+0x727/0x1050 fs/f2fs/data.c:370
<TASK>
bio_endio+0x5af/0x6c0 block/bio.c:1608
req_bio_endio block/blk-mq.c:761 [inline]
blk_update_request+0x5cc/0x1690 block/blk-mq.c:906
blk_mq_end_request+0x59/0x4c0 block/blk-mq.c:1023
lo_complete_rq+0x1c6/0x280 drivers/block/loop.c:370
blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1101
__do_softirq+0x1d4/0x8ef kernel/softirq.c:571
run_ksoftirqd kernel/softirq.c:939 [inline]
run_ksoftirqd+0x31/0x60 kernel/softirq.c:931
smpboot_thread_fn+0x659/0x9e0 kernel/smpboot.c:164
kthread+0x33e/0x440 kernel/kthread.c:379
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
The root cause is below race case can cause leaving dirty metadata
in f2fs after filesystem is remount as ro:
Thread A Thread B
- f2fs_ioc_resize_fs
- f2fs_readonly --- return false
- f2fs_resize_fs
- f2fs_remount
- write_checkpoint
- set f2fs as ro
- free_segment_range
- update meta_inode's data
Then, if f2fs_put_super() fails to write_checkpoint due to readonly
status, and meta_inode's dirty data will be writebacked after node_inode
is put, finally, f2fs_write_end_io will access NULL pointer on
sbi->node_inode.
Thread A IRQ context
- f2fs_put_super
- write_checkpoint fails
- iput(node_inode)
- node_inode = NULL
- iput(meta_inode)
- write_inode_now
- f2fs_write_meta_page
- f2fs_write_end_io
- NODE_MAPPING(sbi)
: access NULL pointer on node_inode
Fixes: b4b10061ef ("f2fs: refactor resize_fs to avoid meta updates in progress")
Reported-by: butt3rflyh4ck <butterflyhuangxx@gmail.com>
Closes: https://lore.kernel.org/r/1684480657-2375-1-git-send-email-yangtiezhu@loongson.cn
Tested-by: butt3rflyh4ck <butterflyhuangxx@gmail.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Stefan Ghinea <stefan.ghinea@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
982c29e0d2