From: Chao Yu <chao@kernel.org> stable inclusion from stable-v6.6.94 commit a39cc43efc1bca74ed9d6cf9e60b995071f7d178 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ICJT6T CVE: CVE-2025-38163 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 05872a167c2cab80ef186ef23cc34a6776a1a30c ] 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. Fixes: 39a53e0ce0df ("f2fs: add superblock and major in-memory structure") Reported-by: syzbot+8b376a77b2f364097fbe@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-f2fs-devel/67f3c0b2.050a0220.396535.0547.GAE@g... Signed-off-by: Chao Yu <chao@kernel.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> --- fs/f2fs/f2fs.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index c5297bb8968d..c47243818ef1 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -2445,8 +2445,14 @@ static inline void dec_valid_block_count(struct f2fs_sb_info *sbi, blkcnt_t sectors = count << F2FS_LOG_SECTORS_PER_BLOCK; spin_lock(&sbi->stat_lock); - f2fs_bug_on(sbi, sbi->total_valid_block_count < (block_t) count); - sbi->total_valid_block_count -= (block_t)count; + if (unlikely(sbi->total_valid_block_count < count)) { + f2fs_warn(sbi, "Inconsistent total_valid_block_count:%u, ino:%lu, count:%u", + sbi->total_valid_block_count, inode->i_ino, count); + sbi->total_valid_block_count = 0; + set_sbi_flag(sbi, SBI_NEED_FSCK); + } else { + sbi->total_valid_block_count -= count; + } if (sbi->reserved_blocks && sbi->current_reserved_blocks < sbi->reserved_blocks) sbi->current_reserved_blocks = min(sbi->reserved_blocks, -- 2.39.2