High · published October 4, 2025
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to avoid use-after-free for cached IPU bio
xfstest generic/019 reports a bug:
kernel BUG at mm/filemap.c:1619!
RIP: 0010:folio_end_writeback+0x8a/0x90
Call Trace:
end_page_writeback+0x1c/0x60
f2fs_write_end_io+0x199/0x420
bio_endio+0x104/0x180
submit_bio_noacct+0xa5/0x510
submit_bio+0x48/0x80
f2fs_submit_write_bio+0x35/0x300
f2fs_submit_merged_ipu_write+0x2a0/0x2b0
f2fs_write_single_data_page+0x838/0x8b0
f2fs_write_cache_pages+0x379/0xa30
f2fs_write_data_pages+0x30c/0x340
do_writepages+0xd8/0x1b0
__writeback_single_inode+0x44/0x370
writeback_sb_inodes+0x233/0x4d0
__writeback_inodes_wb+0x56/0xf0
wb_writeback+0x1dd/0x2d0
wb_workfn+0x367/0x4a0
process_one_work+0x21d/0x430
worker_thread+0x4e/0x3c0
kthread+0x103/0x130
ret_from_fork+0x2c/0x50
The root cause is: after cp_error is set, f2fs_submit_merged_ipu_write()
in f2fs_write_single_data_page() tries to flush IPU bio in cache, however
f2fs_submit_merged_ipu_write() missed to check validity of @bio parameter,
result in submitting random cached bio which belong to other IO context,
then it will cause use-after-free issue, fix it by adding additional
validity check.
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | ≥ 5.5, < 5.10.180 | 5.10.180 |
| linux/linux_kernel | ≥ 5.11, < 5.15.111 | 5.15.111 |
| linux/linux_kernel | ≥ 5.16, < 6.1.28 | 6.1.28 |
| linux/linux_kernel | ≥ 6.2, < 6.2.15 | 6.2.15 |
| linux/linux_kernel | ≥ 6.3, < 6.3.2 | 6.3.2 |