Hello, I found that the segmentation fault occurs in optimized code (-O2). It does not happen when optimization is turned off. I am not sure what exactly happened but mke2fs is now able to get past that point. The command now fails at a different point: ext2fs_mkdir: EXT2 directory corrupted while creating /lost+found Tracing from the ext2fs_mkdir() function, I found that the code returns an error here: ext2fs_read_dir_block3(): returns EXT2_ET_DIR_CORRUPTED Any thoughts or ideas on this issue will be very helpful. Thanks, Sri On Tue, Dec 10, 2013 at 5:21 PM, Srivatsan Canchivaram <crsrivatstechnical@xxxxxxxxx> wrote: > Hi, > I have built e2fsprogs-1.42.8 for a MIPS64-based board. The tools were > generated on an Intel machine with a MIPS64 cross compiler. > > MIPS64 board info: > Linux kernel: 3.4.27 > Cavium Octeon Plus MIPS64 dual core processor > 256 MB RAM > > The MIPS-based board will have a 2 TB NTFS (or VFAT) formatted > external USB hard drive connected to it. The goal is to format the 2 > TB drive from NTFS/ VFAT to EXT4 using the 'mke2fs' program. > > 'Mke2fs' results in a segmentation fault when formatting to ext4: > > mke2fs -t ext4 /dev/sda1 > mke2fs 1.42.8 (20-Jun-2013) > Segmentation fault > > As a parallel test, I tried formatting to EXT3 and this worked > correctly. The issue only seems to occur for EXT4. > > Upon further debug, I found the segmentation fault to occur in > mke2fs.c: end of the should_do_undo() function in the following call: > io_channel_close(channel); > > I tried tracing through the code in the should_do_undo() function. > The manager->open() call succeeds. > An issue of note occurs in the following line: > retval = io_channel_read_blk64(channel, 1, -SUPERBLOCK_SIZE, &super); > > The following shows the contents of the 'channel' data structure > before and after the above function call: > > Before call to io_channel_read_blk64() > ----------------------------------------------------- > should_do_undo: Channel structure address = 0x1005fd70 > should_do_undo: magic = 2133571333, name: /dev/sda1, block_size = 1024 > should_do_undo: refcount = 1, flags = 4, align = 0 > > After call to io_channel_read_blk64() > --------------------------------------------------- > After Read blk64: Channel structure address = 0x668b1e1a > Segmentation fault > > So, the io_channel_read_blk64() function somehow modifies the > "channel" structure pointer. Trying to read the structure after the > call results in a seg fault. > > In the io_channel_read_blk64() function, the code takes the following route: > if (channel->manager->read_blk64) > return (channel->manager->read_blk64)(channel, block, > count, data); > > If you have any thoughts on this issue or need additional details, > please let me know. > > Thanks, > > Sri -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
