Re: [PATCH] udf: Check return code from udf_update_extents

From: Ефанов Владислав Александрович
Date: Tue Jan 24 2023 - 11:42:44 EST


Thank you for information.


Vlad.

On 24.01.2023 11:47, Jan Kara wrote:
On Fri 20-01-23 12:10:28, Vladislav Efanov wrote:
udf_add_aext() does not create new extent and returns ENOSPC if new
block was not created by udf_bitmap_new_block(). The caller,
udf_insert_aext(), does not check this return code and returns OK to
its caller(udf_update_extents). Finally the error is being lost. So
an inconsistency in inode.i_size and extents length becomes.

Later this inconsistency leads to WARNING:

WARNING: CPU: 3 PID: 1104 at fs/udf/truncate.c:226
udf_truncate_extents+0x7e0/0x8e0 fs/udf/truncate.c:226

RIP: 0010:udf_truncate_extents+0x7e0/0x8e0 fs/udf/truncate.c:226
Call Trace:
udf_write_failed.isra.0+0x173/0x1c0 fs/udf/inode.c:179
udf_write_begin+0x8d/0xb0 fs/udf/inode.c:214
generic_perform_write+0x20a/0x4e0 mm/filemap.c:3333
__generic_file_write_iter+0x252/0x610 mm/filemap.c:3462
udf_file_write_iter+0x2cc/0x4e0 fs/udf/file.c:168
call_write_iter include/linux/fs.h:1904 [inline]
new_sync_write+0x42c/0x660 fs/read_write.c:518
vfs_write+0x75b/0xa40 fs/read_write.c:605

Found by Linux Verification Center (linuxtesting.org) with syzkaller.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Vladislav Efanov <VEfanov@xxxxxxxxx>

Thanks for the fix but I have a very similar fix already queued in my tree
in linux-next: 19fd80de0a8 ("udf: Handle error when adding extent to a
file").

Honza