CVE-2025-38626

f2fs: fix to trigger foreground gc during f2fs_map_blocks() in lfs mode

State: Published
Severity: Not scored
Published: Aug 22, 2025
Updated: Jun 1, 2026
Reserved: Apr 16, 2025

Description

In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to trigger foreground gc during f2fs_map_blocks() in lfs mode

w/ "mode=lfs" mount option, generic/299 will cause system panic as below:

------------[ cut here ]------------ kernel BUG at fs/f2fs/segment.c:2835! Call Trace: <TASK> f2fs_allocate_data_block+0x6f4/0xc50 f2fs_map_blocks+0x970/0x1550 f2fs_iomap_begin+0xb2/0x1e0 iomap_iter+0x1d6/0x430 __iomap_dio_rw+0x208/0x9a0 f2fs_file_write_iter+0x6b3/0xfa0 aio_write+0x15d/0x2e0 io_submit_one+0x55e/0xab0 __x64_sys_io_submit+0xa5/0x230 do_syscall_64+0x84/0x2f0 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0010:new_curseg+0x70f/0x720

The root cause of we run out-of-space is: in f2fs_map_blocks(), f2fs may trigger foreground gc only if it allocates any physical block, it will be a little bit later when there is multiple threads writing data w/ aio/dio/bufio method in parallel, since we always use OPU in lfs mode, so f2fs_map_blocks() does block allocations aggressively.

In order to fix this issue, let's give a chance to trigger foreground gc in prior to block allocation in f2fs_map_blocks().

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	36abef4e796d382e81a0c2d21ea5327481dd7154 to before c737047f4665232d1e26b3620bc62df334545451Affected 36abef4e796d382e81a0c2d21ea5327481dd7154 to before d2f280f43a2a9d918fd23169ff3a6f3b65c7cec5Affected 36abef4e796d382e81a0c2d21ea5327481dd7154 to before f289690f50a01c3e085d87853392d5b7436a4ceeAffected 36abef4e796d382e81a0c2d21ea5327481dd7154 to before 82765ce5c7a56f9309ee45328e763610eaf11253Affected 36abef4e796d382e81a0c2d21ea5327481dd7154 to before 264ede8a52f18647ed5bb5f2bd9bf54f556ad8f5Affected 36abef4e796d382e81a0c2d21ea5327481dd7154 to before 385e64a0744584397b4b52b27c96703516f39968Affected 36abef4e796d382e81a0c2d21ea5327481dd7154 to before 1005a3ca28e90c7a64fa43023f866b960a60f791Affected
LinuxLinux	4.8Affected before 4.8Not affected 5.15.209 through 5.15.Not affected 6.1.167 through 6.1.Not affected 6.6.102 through 6.6.Not affected 6.12.42 through 6.12.Not affected 6.15.10 through 6.15.Not affected 6.16.1 through 6.16.Not affected 6.17 and laterNot affected

Product

Versions

LinuxLinux

36abef4e796d382e81a0c2d21ea5327481dd7154 to before c737047f4665232d1e26b3620bc62df334545451Affected
36abef4e796d382e81a0c2d21ea5327481dd7154 to before d2f280f43a2a9d918fd23169ff3a6f3b65c7cec5Affected
36abef4e796d382e81a0c2d21ea5327481dd7154 to before f289690f50a01c3e085d87853392d5b7436a4ceeAffected
36abef4e796d382e81a0c2d21ea5327481dd7154 to before 82765ce5c7a56f9309ee45328e763610eaf11253Affected
36abef4e796d382e81a0c2d21ea5327481dd7154 to before 264ede8a52f18647ed5bb5f2bd9bf54f556ad8f5Affected
36abef4e796d382e81a0c2d21ea5327481dd7154 to before 385e64a0744584397b4b52b27c96703516f39968Affected
36abef4e796d382e81a0c2d21ea5327481dd7154 to before 1005a3ca28e90c7a64fa43023f866b960a60f791Affected

LinuxLinux

4.8Affected
before 4.8Not affected
5.15.209 through 5.15.*Not affected
6.1.167 through 6.1.*Not affected
6.6.102 through 6.6.*Not affected
6.12.42 through 6.12.*Not affected
6.15.10 through 6.15.*Not affected
6.16.1 through 6.16.*Not affected
6.17 and laterNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.