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CVE-2025-38626

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

Description (CNA)

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().

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 36abef4e796d382e81a0c2d21ea5327481dd7154 before c737047f4665232d1e26b3620bc62df334545451; affected 36abef4e796d382e81a0c2d21ea5327481dd7154 before d2f280f43a2a9d918fd23169ff3a6f3b65c7cec5; affected 36abef4e796d382e81a0c2d21ea5327481dd7154 before f289690f50a01c3e085d87853392d5b7436a4cee; affected 36abef4e796d382e81a0c2d21ea5327481dd7154 before 82765ce5c7a56f9309ee45328e763610eaf11253; affected 36abef4e796d382e81a0c2d21ea5327481dd7154 before 264ede8a52f18647ed5bb5f2bd9bf54f556ad8f5; affected 36abef4e796d382e81a0c2d21ea5327481dd7154 before 385e64a0744584397b4b52b27c96703516f39968; affected 36abef4e796d382e81a0c2d21ea5327481dd7154 before 1005a3ca28e90c7a64fa43023f866b960a60f791
Linux / Linuxaffected 4.8; unaffected 0 before 4.8; unaffected 5.15.209 through 5.15.*; unaffected 6.1.167 through 6.1.*; unaffected 6.6.102 through 6.6.*; unaffected 6.12.42 through 6.12.*; unaffected 6.15.10 through 6.15.*; unaffected 6.16.1 through 6.16.*; unaffected 6.17 through *

CWE

No CWE identifiers supplied.

References