Bug 2425105 (CVE-2023-54124)

Summary: CVE-2023-54124 kernel: f2fs: fix to drop all dirty pages during umount() if cp_error is set
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-12-24 14:03:14 UTC 
In the Linux kernel, the following vulnerability has been resolved:

f2fs: fix to drop all dirty pages during umount() if cp_error is set

xfstest generic/361 reports a bug as below:

f2fs_bug_on(sbi, sbi->fsync_node_num);

kernel BUG at fs/f2fs/super.c:1627!
RIP: 0010:f2fs_put_super+0x3a8/0x3b0
Call Trace:
 generic_shutdown_super+0x8c/0x1b0
 kill_block_super+0x2b/0x60
 kill_f2fs_super+0x87/0x110
 deactivate_locked_super+0x39/0x80
 deactivate_super+0x46/0x50
 cleanup_mnt+0x109/0x170
 __cleanup_mnt+0x16/0x20
 task_work_run+0x65/0xa0
 exit_to_user_mode_prepare+0x175/0x190
 syscall_exit_to_user_mode+0x25/0x50
 do_syscall_64+0x4c/0x90
 entry_SYSCALL_64_after_hwframe+0x72/0xdc

During umount(), if cp_error is set, f2fs_wait_on_all_pages() should
not stop waiting all F2FS_WB_CP_DATA pages to be writebacked, otherwise,
fsync_node_num can be non-zero after f2fs_wait_on_all_pages() causing
this bug.

In this case, to avoid deadloop in f2fs_wait_on_all_pages(), it needs
to drop all dirty pages rather than redirtying them.
Comment 1 Alexander B 2025-12-25 02:17:04 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025122417-CVE-2023-54124-d6ac@gregkh/T