Re: [PATCH v3] fsck.f2fs: check validity of nat journal

[Jaegeuk Kim <jaegeuk@kernel.org>]

On 01/14, Chao Yu wrote:
> As reported by Aravind:
> 
> I built f2fs tools from source (at tag v1.12.0) and was able to get this backtrace in gdb:
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x00007ffff7f8eb54 in f2fs_set_bit (nr=1041170432,
>     addr=0x7fffff621010 <error: Cannot access memory at address 0x7fffff621010>) at libf2fs.c:312
> 312        mask = 1 << (7 - (nr & 0x07));
> (gdb) where
>     addr=0x7fffff621010 <error: Cannot access memory at address 0x7fffff621010>) at libf2fs.c:312
> 
> > [ 5338.040024] nats:8781, sits:6
> > [ 5338.040027] F2FS-fs (sda2): Failed to initialize F2FS segment manager
> > [ 5338.128893] nats:8781, sits:6
> > [ 5338.128895] F2FS-fs (sda2): Failed to initialize F2FS segment manager
> 
> nat_count/nid/blkaddr recorded in journal may be corrupted, let's do
> sanity check on them, skip loading invalid ones during build_node_manager().

This requires the below diff.

--- a/fsck/f2fs.h
+++ b/fsck/f2fs.h
@@ -376,6 +376,9 @@ static inline bool IS_VALID_NID(struct f2fs_sb_info *sbi, u32 nid)

 static inline bool IS_VALID_BLK_ADDR(struct f2fs_sb_info *sbi, u32 addr)
 {
+       if (addr == NULL_ADDR || addr == NEW_ADDR)
+               return 1;
+
        if (addr >= le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count) ||
                                addr < SM_I(sbi)->main_blkaddr) {
                DBG(1, "block addr [0x%x]\n", addr);

> 
> Reported-by: Aravind R S <aravindet@gmail.com>
> Signed-off-by: Chao Yu <yuchao0@huawei.com>
> ---
> v3:
> - truncate nat journal table once any journalled nat entry is corrupted
>  fsck/mount.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/fsck/mount.c b/fsck/mount.c
> index 3966525104a7..51d0a09695eb 100644
> --- a/fsck/mount.c
> +++ b/fsck/mount.c
> @@ -1066,11 +1066,29 @@ static int f2fs_init_nid_bitmap(struct f2fs_sb_info *sbi)
>  			f2fs_set_bit(nid, nm_i->nid_bitmap);
>  	}
>  
> +	if (nats_in_cursum(journal) > NAT_JOURNAL_ENTRIES) {
> +		MSG(0, "\tError: f2fs_init_nid_bitmap truncate n_nats(%u) to "
> +			"NAT_JOURNAL_ENTRIES(%lu)\n",
> +			nats_in_cursum(journal), NAT_JOURNAL_ENTRIES);
> +		journal->n_nats = cpu_to_le16(NAT_JOURNAL_ENTRIES);
> +	}
> +
>  	for (i = 0; i < nats_in_cursum(journal); i++) {
>  		block_t addr;
>  
>  		addr = le32_to_cpu(nat_in_journal(journal, i).block_addr);
> +		if (!IS_VALID_BLK_ADDR(sbi, addr)) {
> +			MSG(0, "\tError: f2fs_init_nid_bitmap: addr(%u) is invalid!!!\n", addr);
> +			journal->n_nats = cpu_to_le16(i);
> +			continue;
> +		}
> +
>  		nid = le32_to_cpu(nid_in_journal(journal, i));
> +		if (!IS_VALID_NID(sbi, nid)) {
> +			MSG(0, "\tError: f2fs_init_nid_bitmap: nid(%u) is invalid!!!\n", nid);
> +			journal->n_nats = cpu_to_le16(i);
> +			continue;
> +		}
>  		if (addr != NULL_ADDR)
>  			f2fs_set_bit(nid, nm_i->nid_bitmap);
>  	}
> -- 
> 2.18.0.rc1