w/ below testcase, resize will generate a corrupted image which
contains inconsistent metadata, so when mounting such image, it
will trigger kernel panic:
touch img
truncate -s $((512*1024*1024*1024)) img
mkfs.f2fs -f img $((256*1024*1024))
resize.f2fs -s -i img -t $((1024*1024*1024))
mount img /mnt/f2fs
------------[ cut here ]------------
kernel BUG at fs/f2fs/segment.h:863!
Oops: invalid opcode: 0000 [#1] SMP PTI
CPU: 11 UID: 0 PID: 3922 Comm: mount Not tainted 6.15.0-rc1+ #191
PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:f2fs_ra_meta_pages+0x47c/0x490
Call Trace:
f2fs_build_segment_manager+0x11c3/0x2600
f2fs_fill_super+0xe97/0x2840
mount_bdev+0xf4/0x140
legacy_get_tree+0x2b/0x50
vfs_get_tree+0x29/0xd0
path_mount+0x487/0xaf0
__x64_sys_mount+0x116/0x150
do_syscall_64+0x82/0x190
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fdbfde1bcfe
The reaseon is:
sit_i->bitmap_size is 192, so size of sit bitmap is 192*8=1536, at maximum
there are 1536 sit blocks, however MAIN_SEGS is 261893, so that sit_blk_cnt
is 4762, build_sit_entries() -> current_sit_addr() tries to access
out-of-boundary in sit_bitmap at offset from [1536, 4762), once sit_bitmap
and sit_bitmap_mirror is not the same, it will trigger f2fs_bug_on().
Let's add sanity check in f2fs_sanity_check_ckpt() to avoid panic.
Cc: sta...@vger.kernel.org
Signed-off-by: Chao Yu <c...@kernel.org>
---
fs/f2fs/super.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index eb1275616d8c..8abfbee13204 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -3716,6 +3716,7 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
block_t user_block_count, valid_user_blocks;
block_t avail_node_count, valid_node_count;
unsigned int nat_blocks, nat_bits_bytes, nat_bits_blocks;
+ unsigned int sit_blk_cnt;
int i, j;
total = le32_to_cpu(raw_super->segment_count);
@@ -3827,6 +3828,13 @@ int f2fs_sanity_check_ckpt(struct f2fs_sb_info *sbi)
return 1;
}
+ sit_blk_cnt = DIV_ROUND_UP(main_segs, SIT_ENTRY_PER_BLOCK);
+ if (sit_bitmap_size * 8 < sit_blk_cnt) {
+ f2fs_err(sbi, "Wrong bitmap size: sit: %u, sit_blk_cnt:%u",
+ sit_bitmap_size, sit_blk_cnt);
+ return 1;
+ }
+
cp_pack_start_sum = __start_sum_addr(sbi);
cp_payload = __cp_payload(sbi);
if (cp_pack_start_sum < cp_payload + 1 ||
--
2.49.0
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