f2fs: fix to avoid panic in dec_valid_block_count() (5e159cd3) · Commits · 戴 / test

As Jungyeon reported in bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203209 - Overview When mounting the attached crafted image and running program, I got this error. Additionally, it hangs on sync after the this script. The image is intentionally fuzzed from a normal f2fs image for testing and I enabled option CONFIG_F2FS_CHECK_FS on. - Reproduces cc poc_01.c ./run.sh f2fs sync kernel BUG at fs/f2fs/f2fs.h:1788! RIP: 0010:f2fs_truncate_data_blocks_range+0x342/0x350 Call Trace: f2fs_truncate_blocks+0x36d/0x3c0 f2fs_truncate+0x88/0x110 f2fs_setattr+0x3e1/0x460 notify_change+0x2da/0x400 do_truncate+0x6d/0xb0 do_sys_ftruncate+0xf1/0x160 do_syscall_64+0x43/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The reason is dec_valid_block_count() will trigger kernel panic due to inconsistent count in between inode.i_blocks and actual block. To avoid panic, let's just print debug message and set SBI_NEED_FSCK to give a hint to fsck for latter repairing. Signed-off-by:

Chao Yu <yuchao0@huawei.com> [Jaegeuk Kim: fix build warning and add unlikely] Signed-off-by:

Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/f2fs.h

+10 −2

Original line number	Diff line number	Diff line
		@@ -1789,6 +1789,7 @@ enospc:
		return -ENOSPC;
		}

		void f2fs_msg(struct super_block sb, const char level, const char *fmt, ...);
		static inline void dec_valid_block_count(struct f2fs_sb_info *sbi,
		struct inode *inode,
		block_t count)
		@@ -1797,13 +1798,21 @@ static inline void dec_valid_block_count(struct f2fs_sb_info *sbi,

		spin_lock(&sbi->stat_lock);
		f2fs_bug_on(sbi, sbi->total_valid_block_count < (block_t) count);
		f2fs_bug_on(sbi, inode->i_blocks < sectors);
		sbi->total_valid_block_count -= (block_t)count;
		if (sbi->reserved_blocks &&
		sbi->current_reserved_blocks < sbi->reserved_blocks)
		sbi->current_reserved_blocks = min(sbi->reserved_blocks,
		sbi->current_reserved_blocks + count);
		spin_unlock(&sbi->stat_lock);
		if (unlikely(inode->i_blocks < sectors)) {
		f2fs_msg(sbi->sb, KERN_WARNING,
		"Inconsistent i_blocks, ino:%lu, iblocks:%llu, sectors:%llu",
		inode->i_ino,
		(unsigned long long)inode->i_blocks,
		(unsigned long long)sectors);
		set_sbi_flag(sbi, SBI_NEED_FSCK);
		return;
		}
		f2fs_i_blocks_write(inode, count, false, true);
		}

		@@ -2819,7 +2828,6 @@ static inline void f2fs_update_iostat(struct f2fs_sb_info *sbi,

		bool f2fs_is_valid_blkaddr(struct f2fs_sb_info *sbi,
		block_t blkaddr, int type);
		void f2fs_msg(struct super_block sb, const char level, const char *fmt, ...);
		static inline void verify_blkaddr(struct f2fs_sb_info *sbi,
		block_t blkaddr, int type)
		{

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