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Commit c297bc0e authored by Chao Yu's avatar Chao Yu Committed by Jaegeuk Kim
Browse files

f2fs: fix to do sanity check on segment bitmap of LFS curseg 

As Jungyeon Reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=203233



- Reproduces
gcc poc_13.c
./run.sh f2fs

- Kernel messages
 F2FS-fs (sdb): Bitmap was wrongly set, blk:4608
 kernel BUG at fs/f2fs/segment.c:2133!
 RIP: 0010:update_sit_entry+0x35d/0x3e0
 Call Trace:
  f2fs_allocate_data_block+0x16c/0x5a0
  do_write_page+0x57/0x100
  f2fs_do_write_node_page+0x33/0xa0
  __write_node_page+0x270/0x4e0
  f2fs_sync_node_pages+0x5df/0x670
  f2fs_write_checkpoint+0x364/0x13a0
  f2fs_sync_fs+0xa3/0x130
  f2fs_do_sync_file+0x1a6/0x810
  do_fsync+0x33/0x60
  __x64_sys_fsync+0xb/0x10
  do_syscall_64+0x43/0x110
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

The testcase fails because that, in fuzzed image, current segment was
allocated with LFS type, its .next_blkoff should point to an unused
block address, but actually, its bitmap shows it's not. So during
allocation, f2fs crash when setting bitmap.

Introducing sanity_check_curseg() to check such inconsistence of
current in-used segment.

Signed-off-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 6e30778f

fs/f2fs/segment.c

+39 −0
Original line number Diff line number Diff line
@@ -4239,6 +4239,41 @@ static int build_dirty_segmap(struct f2fs_sb_info *sbi) 
	return init_victim_secmap(sbi);

}



static int sanity_check_curseg(struct f2fs_sb_info *sbi)

{

	int i;



	/*

	 * In LFS/SSR curseg, .next_blkoff should point to an unused blkaddr;

	 * In LFS curseg, all blkaddr after .next_blkoff should be unused.

	 */

	for (i = 0; i < NO_CHECK_TYPE; i++) {

		struct curseg_info *curseg = CURSEG_I(sbi, i);

		struct seg_entry *se = get_seg_entry(sbi, curseg->segno);

		unsigned int blkofs = curseg->next_blkoff;



		if (f2fs_test_bit(blkofs, se->cur_valid_map))

			goto out;



		if (curseg->alloc_type == SSR)

			continue;



		for (blkofs += 1; blkofs < sbi->blocks_per_seg; blkofs++) {

			if (!f2fs_test_bit(blkofs, se->cur_valid_map))

				continue;

out:

			f2fs_msg(sbi->sb, KERN_ERR,

				"Current segment's next free block offset is "

				"inconsistent with bitmap, logtype:%u, "

				"segno:%u, type:%u, next_blkoff:%u, blkofs:%u",

				i, curseg->segno, curseg->alloc_type,

				curseg->next_blkoff, blkofs);

			return -EINVAL;

		}

	}

	return 0;

}



/*

 * Update min, max modified time for cost-benefit GC algorithm

 */
@@ -4334,6 +4369,10 @@ int f2fs_build_segment_manager(struct f2fs_sb_info *sbi) 
	if (err)

		return err;



	err = sanity_check_curseg(sbi);

	if (err)

		return err;



	init_min_max_mtime(sbi);

	return 0;

}