[AT&T, Rogers, Bell, Telus Samsung Galaxy S III] polobunny:
[ 107.696963] mmc0: got_dataend=0, prog_enable=0, wait_for_auto_prog_done=1, got_auto_prog_done=0, req_tout_ms=10000
[ 107.776560] mmcblk0: timed out sending r/w cmd command, card status 0xc40
[ 107.782389] mmcblk0: not retrying timeout
[ 107.786693] end_request: I/O error, dev mmcblk0, sector 10012552
[ 107.792400] Buffer I/O error on device mmcblk0p15, logical block 839921
[ 107.799053] end_request: I/O error, dev mmcblk0, sector 10012656
[ 107.805035] Buffer I/O error on device mmcblk0p15, logical block 839934
[ 107.811658] end_request: I/O error, dev mmcblk0, sector 10014552
[ 107.817671] Buffer I/O error on device mmcblk0p15, logical block 840171
[ 107.824294] end_request: I/O error, dev mmcblk0, sector 10018144
[ 107.830154] Buffer I/O error on device mmcblk0p15, logical block 840620
[ 107.836807] end_request: I/O error, dev mmcblk0, sector 10018272
[ 107.842789] Buffer I/O error on device mmcblk0p15, logical block 840636
[ 107.849351] Buffer I/O error on device mmcblk0p15, logical block 840637
[ 107.855974] end_request: I/O error, dev mmcblk0, sector 10058704
[ 107.861925] Buffer I/O error on device mmcblk0p15, logical block 845690
[ 107.868579] end_request: I/O error, dev mmcblk0, sector 10058984
[ 107.874469] Buffer I/O error on device mmcblk0p15, logical block 845725
[ 107.881153] Buffer I/O error on device mmcblk0p15, logical block 845726
[ 107.887746] end_request: I/O error, dev mmcblk0, sector 10060200
[ 107.893636] Buffer I/O error on device mmcblk0p15, logical block 845877
[ 107.900350] end_request: I/O error, dev mmcblk0, sector 10060528
[ 107.906241] end_request: I/O error, dev mmcblk0, sector 10063632
[ 107.912620] Buffer I/O error on device mmcblk0p15, logical block 2721162
[ 107.918937] Buffer I/O error on device mmcblk0p15, logical block 2721163
[ 107.925652] Buffer I/O error on device mmcblk0p15, logical block 2721164
[ 107.932305] Buffer I/O error on device mmcblk0p15, logical block 2721165
[ 107.939050] Buffer I/O error on device mmcblk0p15, logical block 2721166
[ 107.945704] Buffer I/O error on device mmcblk0p15, logical block 2721167
[ 107.952357] Buffer I/O error on device mmcblk0p15, logical block 2721168
[ 107.959102] Buffer I/O error on device mmcblk0p15, logical block 2721169
[ 107.965695] Buffer I/O error on device mmcblk0p15, logical block 2721170
[ 107.972470] Buffer I/O error on device mmcblk0p15, logical block 2721171
[ 107.979154] Buffer I/O error on device mmcblk0p15, logical block 2721172
[ 107.985746] Buffer I/O error on device mmcblk0p15, logical block 2721173
[ 107.992522] Buffer I/O error on device mmcblk0p15, logical block 2721174
[ 107.999145] Buffer I/O error on device mmcblk0p15, logical block 2721175
[ 108.005859] Buffer I/O error on device mmcblk0p15, logical block 2721176
[ 108.012604] Buffer I/O error on device mmcblk0p15, logical block 2721177
[ 108.019197] Buffer I/O error on device mmcblk0p15, logical block 2721178
[ 108.025911] Buffer I/O error on device mmcblk0p15, logical block 2721179
[ 110.032107] EXT4-fs error (device mmcblk0p15): ext4_find_entry:932: inode #360449: comm MountService#on: reading directory lblock 0
[ 110.044010] Aborting journal on device mmcblk0p15-8.
[ 110.052464] Kernel panic - not syncing: EXT4-fs (device mmcblk0p15): panic forced after error

Answer before was short, I was on my phone and I had little time. This is the interesting part that caused a kernel panic (which sums up to big freaking error, but not necessarily related to improper kernel coding)

mmcblk0p15 corresponds to /data on your phone. It's where all userdata is stored.

Now, I don't want to be a bearer of bad news, but if you get I/O error from your internal memory, chances are it's because it's going the way of the dodo.

If you were "lucky", it could simply be the connection, but even then we're talking micro electronics.

There's a few things you could do. Try to dd it (caution! select the right partition!) and filling it with 0s, from recovery. This will erase all your user data, then you will need to re-install your rom, apps, settings etc. You can always make a titanium backup of your apps that you can drop on your computer temporarily while you do this. That's assuming dd doesn't glitch out.

You could also flag the bad blocks "try to fix them" by using fsck (e2fsck more precisely).

This is outlined here:

http://xdaforums.com/showthread.php?t=2165870

Fill in with appropriate partition information for your case. Use -c to find and flag bad blocks, -f to force and -y to agree to everything. Read up on it for more info.

http://www.delafond.org/traducmanfr/man/man8/e2fsck.8.html

Either way, good luck, not related to kernel (sadly). ;)