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![]() I hit a J_ASSERT(blocknr != 0) failure in cleanup_journal_tail() when mounting a fsfuzzed ext3 image. It turns out that the corrupted ext3 image has s_first = 0 in journal superblock, and the 0 is passed to journal->j_head in journal_reset(), then to blocknr in cleanup_journal_tail(), in the end the J_ASSERT failed. So validate s_first after reading journal superblock from disk in journal_get_superblock() to ensure s_first is valid. The following script could reproduce it: fstype=ext3 blocksize=1024 img=$fstype.img offset=0 found=0 magic="c0 3b 39 98" dd if=/dev/zero of=$img bs=1M count=8 mkfs -t $fstype -b $blocksize -F $img filesize=`stat -c %s $img` while [ $offset -lt $filesize ] do if od -j $offset -N 4 -t x1 $img | grep -i "$magic";then echo "Found journal: $offset" found=1 break fi offset=`echo "$offset+$blocksize" | bc` done if [ $found -ne 1 ];then echo "Magic \"$magic\" not found" exit 1 fi dd if=/dev/zero of=$img seek=$(($offset+23)) conv=notrunc bs=1 count=1 mkdir -p ./mnt mount -o loop $img ./mnt Cc: Jan Kara <jack@suse.cz> Signed-off-by: Eryu Guan <guaneryu@gmail.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> |
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.. | ||
checkpoint.c | ||
commit.c | ||
journal.c | ||
Kconfig | ||
Makefile | ||
recovery.c | ||
revoke.c | ||
transaction.c |