f2fs: fix to avoid panic in dec_valid_block_count()
As Jungyeon reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=203209
- Overview
When mounting the attached crafted image and running program, I got this error.
Additionally, it hangs on sync after the this script.
The image is intentionally fuzzed from a normal f2fs image for testing and I enabled option CONFIG_F2FS_CHECK_FS on.
- Reproduces
cc poc_01.c
./run.sh f2fs
sync
kernel BUG at fs/f2fs/f2fs.h:1788!
RIP: 0010:f2fs_truncate_data_blocks_range+0x342/0x350
Call Trace:
f2fs_truncate_blocks+0x36d/0x3c0
f2fs_truncate+0x88/0x110
f2fs_setattr+0x3e1/0x460
notify_change+0x2da/0x400
do_truncate+0x6d/0xb0
do_sys_ftruncate+0xf1/0x160
do_syscall_64+0x43/0xf0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The reason is dec_valid_block_count() will trigger kernel panic due to
inconsistent count in between inode.i_blocks and actual block.
To avoid panic, let's just print debug message and set SBI_NEED_FSCK to
give a hint to fsck for latter repairing.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: fix build warning and add unlikely]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
1 file changed