CVE-2025-38163f2fs: fix to do sanity check on sbi->total_valid_block_count

Official description

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to do sanity check on sbi->total_valid_block_count syzbot reported a f2fs bug as below: ------------[ cut here ]------------ kernel BUG at fs/f2fs/f2fs.h:2521! RIP: 0010:dec_valid_block_count+0x3b2/0x3c0 fs/f2fs/f2fs.h:2521 Call Trace: f2fs_truncate_data_blocks_range+0xc8c/0x11a0 fs/f2fs/file.c:695 truncate_dnode+0x417/0x740 fs/f2fs/node.c:973 truncate_nodes+0x3ec/0xf50 fs/f2fs/node.c:1014 f2fs_truncate_inode_blocks+0x8e3/0x1370 fs/f2fs/node.c:1197 f2fs_do_truncate_blocks+0x840/0x12b0 fs/f2fs/file.c:810 f2fs_truncate_blocks+0x10d/0x300 fs/f2fs/file.c:838 f2fs_truncate+0x417/0x720 fs/f2fs/file.c:888 f2fs_setattr+0xc4f/0x12f0 fs/f2fs/file.c:1112 notify_change+0xbca/0xe90 fs/attr.c:552 do_truncate+0x222/0x310 fs/open.c:65 handle_truncate fs/namei.c:3466 [inline] do_open fs/namei.c:3849 [inline] path_openat+0x2e4f/0x35d0 fs/namei.c:4004 do_filp_open+0x284/0x4e0 fs/namei.c:4031 do_sys_openat2+0x12b/0x1d0 fs/open.c:1429 do_sys_open fs/open.c:1444 [inline] __do_sys_creat fs/open.c:1522 [inline] __se_sys_creat fs/open.c:1516 [inline] __x64_sys_creat+0x124/0x170 fs/open.c:1516 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/syscall_64.c:94 The reason is: in fuzzed image, sbi->total_valid_block_count is inconsistent w/ mapped blocks indexed by inode, so, we should not trigger panic for such case, instead, let's print log and set fsck flag.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/49bc7bf38e42cfa642787e947f5721696ea73ac3
• https://git.kernel.org/stable/c/f1b743c1955151bd392539b739a3ad155296be13
• https://git.kernel.org/stable/c/6a324d77f7ea1a91d55c4b6ad970e3ac9ab6a20d
• https://git.kernel.org/stable/c/25f3776b58c1c45ad2e50ab4b263505b4d2378ca
• https://git.kernel.org/stable/c/a39cc43efc1bca74ed9d6cf9e60b995071f7d178
• https://git.kernel.org/stable/c/65b3f76592aed5a43c4d79375ac097acf975972b
• https://git.kernel.org/stable/c/ccc28c0397f75a3ec9539cceed9db014d7b73869
• https://git.kernel.org/stable/c/05872a167c2cab80ef186ef23cc34a6776a1a30c
• https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
• https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html