NULL pointer dereference in ext4_superblock_csum_set

[Michael Gissing]

Hi,

tl,dr; I have a sd card which I suspect to have a corrupted fs. When I 
insert the card into my laptop's reader, I get the following:

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff8123bb0d>] ext4_superblock_csum_set+0x4d/0xd0



Long story: It seems like i got a corrupted SD card when running one of 
my Raspberry pis in turbo mode. I wanted to check the card on my laptop, 
I got a kernel error. (please find it in the attached .txt)

The installed system is Linux Mint 14 Nadia (the one based on Ubuntu 12.10)

uname -a:
Linux x200t 3.5.0-34-generic #55-Ubuntu SMP Thu Jun 6 20:18:19 UTC 2013 
x86_64 x86_64 x86_64 GNU/Linux

Cinnamon gives me a popup too:

Error mounting /dev/sdb2 at 
/media/michael/41cd5baa-7a62-4706-b8e8-02c43ccee8d9: Command-line `mount 
-t "ext4" -o "uhelper=udisks2,nodev,nosuid" "/dev/sdb2" 
"/media/michael/41cd5baa-7a62-4706-b8e8-02c43ccee8d9"' was signaled with 
signal SIGKILL (9):

I couldn't reproduce the error, something must have changed the sd card. 
I've created a dd image of the card, but I did it after the error 
occured. I haven't tried whether the image causes the error yet, I need 
the card at the moment.

Is this something you want to look into? If so, let me know, I'll try to 
help.

Please CC me as I'm not subscribed to the list.

Michael

[32999.780051] usb 2-6: new high-speed USB device number 4 using ehci_hcd
[32999.922255] usb 2-6: New USB device found, idVendor=05ca, idProduct=1880
[32999.922261] usb 2-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[32999.922265] usb 2-6: Product: USB2.0-FLASH Media    
[32999.922268] usb 2-6: Manufacturer: RICOH             
[32999.922272] usb 2-6: SerialNumber: R5U880-00003
[32999.922763] scsi5 : usb-storage 2-6:1.0
[33000.920884] scsi 5:0:0:0: Direct-Access     RICOH    R5U880FlashMedia 0000 PQ: 0 ANSI: 2
[33000.922988] sd 5:0:0:0: Attached scsi generic sg2 type 0
[33001.118989] sd 5:0:0:0: [sdb] 31116288 512-byte logical blocks: (15.9 GB/14.8 GiB)
[33001.119621] sd 5:0:0:0: [sdb] Write Protect is off
[33001.119626] sd 5:0:0:0: [sdb] Mode Sense: 0b 00 00 08
[33001.120249] sd 5:0:0:0: [sdb] No Caching mode page present
[33001.120253] sd 5:0:0:0: [sdb] Assuming drive cache: write through
[33001.125969] sd 5:0:0:0: [sdb] No Caching mode page present
[33001.125973] sd 5:0:0:0: [sdb] Assuming drive cache: write through
[33001.127486]  sdb: sdb1 sdb2
[33001.133596] sd 5:0:0:0: [sdb] No Caching mode page present
[33001.133601] sd 5:0:0:0: [sdb] Assuming drive cache: write through
[33001.133605] sd 5:0:0:0: [sdb] Attached SCSI removable disk
[33001.708071] BUG: unable to handle kernel NULL pointer dereference at           (null)
[33001.708126] IP: [<ffffffff8123bb0d>] ext4_superblock_csum_set+0x4d/0xd0
[33001.708167] PGD 783ea067 PUD 780c3067 PMD 0 
[33001.708199] Oops: 0000 [#1] SMP 
[33001.708225] CPU 0 
[33001.708238] Modules linked in: nls_iso8859_1 usb_storage ip6table_filter ip6_tables ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack ipt_REJECT xt_CHECKSUM iptable_mangle xt_tcpudp iptable_filter ip_tables x_tables bridge stp llc parport_pc ppdev rfcomm bnep bluetooth snd_hda_codec_conexant coretemp kvm_intel kvm arc4 snd_hda_intel snd_hda_codec snd_hwdep snd_pcm thinkpad_acpi snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq microcode snd_timer uvcvideo videobuf2_core psmouse videodev videobuf2_vmalloc snd_seq_device lpc_ich iwlwifi serio_raw videobuf2_memops snd mac80211 soundcore snd_page_alloc cfg80211 tpm_tis nvram wmi i915 drm_kms_helper drm i2c_algo_bit video mei mac_hid lp parport hid_generic usbhid hid ahci libahci e1000e
[33001.708825] 
[33001.708830] Pid: 6334, comm: mount Not tainted 3.5.0-34-generic #55-Ubuntu LENOVO 7453WRK/7453WRK
[33001.708882] RIP: 0010:[<ffffffff8123bb0d>]  [<ffffffff8123bb0d>] ext4_superblock_csum_set+0x4d/0xd0
[33001.708931] RSP: 0000:ffff88001f46d6a8  EFLAGS: 00010202
[33001.708960] RAX: ffff880130d87000 RBX: ffff8800a595e400 RCX: 0000000000000002
[33001.708996] RDX: 0000000000000000 RSI: ffff8800a595e400 RDI: ffff880131528800
[33001.709032] RBP: ffff88001f46d6c8 R08: ffffffff81cd5720 R09: 0000000000000100
[33001.709068] R10: ff9fd0093bf9d402 R11: 0000000000000000 R12: ffff880042300750
[33001.709104] R13: ffff88001f46d6a8 R14: 0000000000000000 R15: ffff880131528800
[33001.709141] FS:  00007fc30280d800(0000) GS:ffff88013bc00000(0000) knlGS:0000000000000000
[33001.709183] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[33001.709213] CR2: 0000000000000000 CR3: 000000001aaa9000 CR4: 00000000000407f0
[33001.709248] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[33001.709284] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[33001.709322] Process mount (pid: 6334, threadinfo ffff88001f46c000, task ffff8800a1ea2e00)
[33001.709357] Stack:
[33001.709370]  ffffffff81140b79 00000000000e1eed ffff880042300750 ffff8800a595e400
[33001.709413]  ffff88001f46d718 ffffffff8123c333 0000000136ca0f60 000000000040b745
[33001.709456]  ffff88001f46d718 ffff880131528800 00000000000311b7 ffffffff81827bc0
[33001.709498] Call Trace:
[33001.709513]  [<ffffffff81140b79>] ? zone_statistics+0x99/0xc0
[33001.709541]  [<ffffffff8123c333>] ext4_commit_super+0x173/0x250
[33001.709568]  [<ffffffff8123c603>] save_error_info+0x23/0x30
[33001.709594]  [<ffffffff8123d7a3>] ext4_error_inode+0x63/0x120
[33001.709623]  [<ffffffff8121bdb8>] __check_block_validity.constprop.48+0x78/0x80
[33001.709656]  [<ffffffff8121d980>] ext4_map_blocks+0x190/0x250
[33001.709683]  [<ffffffff8121fcb6>] _ext4_get_block+0xa6/0x160
[33001.709712]  [<ffffffff8121fdd6>] ext4_get_block+0x16/0x20
[33001.709740]  [<ffffffff811b25cf>] generic_block_bmap+0x3f/0x50
[33001.709771]  [<ffffffff8168217e>] ? _raw_spin_lock+0xe/0x20
[33001.709799]  [<ffffffff8112ca92>] ? mapping_tagged+0x12/0x20
[33001.709826]  [<ffffffff8121cc6c>] ext4_bmap+0x6c/0xe0
[33001.709851]  [<ffffffff8119b1ae>] bmap+0x1e/0x20
[33001.709876]  [<ffffffff812731c3>] jbd2_journal_bmap+0x33/0xb0
[33001.709904]  [<ffffffff8126c4a0>] jread+0x40/0x270
[33001.709929]  [<ffffffff811b3efc>] ? __getblk+0x2c/0x2e0
[33001.709954]  [<ffffffff8168217e>] ? _raw_spin_lock+0xe/0x20
[33001.709982]  [<ffffffff81076777>] ? bit_waitqueue+0x17/0xc0
[33001.710008]  [<ffffffff8126cb0b>] do_one_pass+0x43b/0xc30
[33001.711347]  [<ffffffff8167fa2c>] ? out_of_line_wait_on_bit+0x7c/0x90
[33001.712007]  [<ffffffff8126d3d9>] jbd2_journal_recover+0xd9/0x110
[33001.712007]  [<ffffffff81272cbf>] jbd2_journal_load+0xdf/0x390
[33001.712007]  [<ffffffff8116e4c5>] ? kmem_cache_alloc_trace+0x35/0x110
[33001.712007]  [<ffffffff812411e8>] ext4_fill_super+0x1e88/0x2e10
[33001.712007]  [<ffffffff8118588b>] mount_bdev+0x1cb/0x210
[33001.712007]  [<ffffffff8123f360>] ? ext4_calculate_overhead+0x430/0x430
[33001.712007]  [<ffffffff8122e145>] ext4_mount+0x15/0x20
[33001.712007]  [<ffffffff811863c3>] mount_fs+0x43/0x1b0
[33001.712007]  [<ffffffff8119f873>] ? find_filesystem+0x63/0x80
[33001.712007]  [<ffffffff811a0734>] vfs_kern_mount+0x74/0x110
[33001.712007]  [<ffffffff811a10a4>] do_kern_mount+0x54/0x110
[33001.712007]  [<ffffffff811a29da>] do_mount+0x26a/0x890
[33001.712007]  [<ffffffff8113e32b>] ? strndup_user+0x5b/0x80
[33001.712007]  [<ffffffff811a314d>] sys_mount+0x8d/0xe0
[33001.712007]  [<ffffffff8168a429>] system_call_fastpath+0x16/0x1b
[33001.712007] Code: 58 68 f6 43 65 04 75 16 48 8b 5d e8 4c 8b 65 f0 4c 8b 6d f8 c9 c3 0f 1f 84 00 00 00 00 00 48 8b 90 a8 03 00 00 49 89 e5 48 89 de <8b> 02 48 83 c0 17 48 83 e0 f8 48 83 c0 16 48 c1 e8 04 48 c1 e0 
[33001.712007] RIP  [<ffffffff8123bb0d>] ext4_superblock_csum_set+0x4d/0xd0
[33001.712007]  RSP <ffff88001f46d6a8>
[33001.712007] CR2: 0000000000000000
[33001.747428] ---[ end trace d7c34101b04cdedd ]---