Commit 4d17e6fe authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
Browse files

f2fs: fix to avoid f2fs_bug_on() in dec_valid_node_count() 

As Yanming reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=215897



I have encountered a bug in F2FS file system in kernel v5.17.

The kernel should enable CONFIG_KASAN=y and CONFIG_KASAN_INLINE=y. You can
reproduce the bug by running the following commands:

The kernel message is shown below:

kernel BUG at fs/f2fs/f2fs.h:2511!
Call Trace:
 f2fs_remove_inode_page+0x2a2/0x830
 f2fs_evict_inode+0x9b7/0x1510
 evict+0x282/0x4e0
 do_unlinkat+0x33a/0x540
 __x64_sys_unlinkat+0x8e/0xd0
 do_syscall_64+0x3b/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae

The root cause is: .total_valid_block_count or .total_valid_node_count
could fuzzed to zero, then once dec_valid_node_count() was called, it
will cause BUG_ON(), this patch fixes to print warning info and set
SBI_NEED_FSCK into CP instead of panic.

Cc: stable@vger.kernel.org
Reported-by: default avatarMing Yan <yanming@tju.edu.cn>
Signed-off-by: default avatarChao Yu <chao.yu@oppo.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent a9163b94

fs/f2fs/f2fs.h

+10 −4
Original line number Diff line number Diff line
@@ -2605,11 +2605,17 @@ static inline void dec_valid_node_count(struct f2fs_sb_info *sbi, 
{

	spin_lock(&sbi->stat_lock);



	f2fs_bug_on(sbi, !sbi->total_valid_block_count);

	f2fs_bug_on(sbi, !sbi->total_valid_node_count);



	sbi->total_valid_node_count--;

	if (unlikely(!sbi->total_valid_block_count ||

			!sbi->total_valid_node_count)) {

		f2fs_warn(sbi, "dec_valid_node_count: inconsistent block counts, total_valid_block:%u, total_valid_node:%u",

			  sbi->total_valid_block_count,

			  sbi->total_valid_node_count);

		set_sbi_flag(sbi, SBI_NEED_FSCK);

	} else {

		sbi->total_valid_block_count--;

		sbi->total_valid_node_count--;

	}



	if (sbi->reserved_blocks &&

		sbi->current_reserved_blocks < sbi->reserved_blocks)

		sbi->current_reserved_blocks++;