Vulnerability Database

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Total vulnerabilities in the database

CVE-2025-38626 — linux / linux_kernel

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().

  • Published: Aug 22, 2025
  • Updated: Nov 27, 2025
  • CVE: CVE-2025-38626
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 5.5
  • AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

No CWE or OWASP classifications available.

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