CVE-2026-46175

Summary

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

f2fs: fix fsck inconsistency caused by FGGC of node block

During FGGC node block migration, fsck may incorrectly treat the migrated node block as fsync-written data.

The reproduction scenario: root@vm:/mnt/f2fs# seq 1 2048 | xargs -n 1 ./test_sync // write inline inode and sync root@vm:/mnt/f2fs# rm -f 1 root@vm:/mnt/f2fs# sync root@vm:/mnt/f2fs# f2fs_io gc_range // move data block in sync mode and not write CP SPO, "fsck –dry-run" find inode has already checkpointed but still with DENT_BIT_SHIFT set

The root cause is that GC does not clear the dentry mark and fsync mark during node block migration, leading fsck to misinterpret them as user-issued fsync writes.

In BGGC mode, node block migration is handled by f2fs_sync_node_pages(), which guarantees the dentry and fsync marks are cleared before writing.

This patch move the set/clear of the fsync|dentry marks into __write_node_folio to make the logic clearer, and ensures the fsync|dentry mark is cleared in FGGC.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/8be551f538dc5b64183e27bd45a7a0795263f760
• https://git.kernel.org/stable/c/e7c6d30169b03307d27c4479563df79c08f3a746
• https://git.kernel.org/stable/c/c3e238bd1f56993f205ef83889d406dfeaf717a8

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