Writing large amounts of data to exFAT formatted micro sdcards with Ubuntu causes kernel errors and permanent sdcard failure.

[thump]

I've now confirmed 3 cases where writing large volumes of data causes kernel errors:

System: linux Kubuntu 12.04.5 LTS,
Package: udev 175-0ubuntu9.6

STEPS:
1) Insert new 64G microsd card (either via built-in card reader or with USB style adapter)
2) Create and write fresh partition with fdisk (full card, 1 primary partition, type 7, exFAT)
3) mkfs.exfat /dev/sdi1
4) mount partition using device manager gui (process shows as /sbin/mount.exfat /dev/sdi1 /media/<user>/6FED-20E6 -o rw,nosuid,nodev,uhelper=udisks2)
5) Attempt to copy a large amount (20G+) of data to drive using Dolphin gui, or in the most recent case, rsync.
$ rsync -rltsihv --delete --progress --stats /home/user/syncfolder/ /media/<user>/6FED-20E6/

Somewhere during the middle of the operation the process will hang and provide the dmesg output below. Once this happens, the card will go into internal failsafe mode and become permanently read-only. The card is now non-recoverable using any software method (fsck, hdpart, windows chkdsk, or the sdcard.org formatter).

This originally occurred for me on a new G.Skill 32gb card, then on a Sandisk Ultra Plus 64g card. Both cards were returned to the manufacturers which confirmed the cards as permanently failed (and replaced under warranty).

Today I tried again with the replacement Sandisk card using a micro sdcard usb adapter instead of the built in card reader, and received the same result - another failed card. This same card was able to accept a large amount of data copied on with my android phone, but is now failed after copying data under Kubuntu.

** dmesg log once the copy process hangs **
[ 8158.303149] INFO: task hald-addon-stor:2145 blocked for more than 120 seconds.
[ 8158.303154] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 8158.303157] hald-addon-stor D 0000000000000003 0 2145 1991 0x00000000
[ 8158.303163] ffff8802f740d928 0000000000000082 ffff8802f740d908 ffffffff810581db
[ 8158.303169] ffff8802f740dfd8 ffff8802f740dfd8 ffff8802f740dfd8 00000000000137c0
[ 8158.303174] ffff8802654e0000 ffff880318f95c00 0000000000000082 7fffffffffffffff
[ 8158.303179] Call Trace:
[ 8158.303189] [<ffffffff810581db>] ? check_preempt_wakeup+0x15b/0x230
[ 8158.303195] [<ffffffff816621df>] schedule+0x3f/0x60
[ 8158.303199] [<ffffffff8166281d>] schedule_timeout+0x29d/0x310
[ 8158.303204] [<ffffffff810539c6>] ? ttwu_do_activate.constprop.178+0x66/0x70
[ 8158.303209] [<ffffffff8103ec29>] ? default_spin_lock_flags+0x9/0x10
[ 8158.303213] [<ffffffff8166201f>] wait_for_common+0xdf/0x180
[ 8158.303218] [<ffffffff81060aa0>] ? try_to_wake_up+0x200/0x200
[ 8158.303222] [<ffffffff8166219d>] wait_for_completion+0x1d/0x20
[ 8158.303228] [<ffffffff8108752e>] flush_work+0x2e/0x40
[ 8158.303232] [<ffffffff81083860>] ? wake_up_worker+0x30/0x30
[ 8158.303236] [<ffffffff810875fb>] flush_delayed_work+0x4b/0x60
[ 8158.303242] [<ffffffff81301634>] disk_clear_events+0x84/0x130
[ 8158.303248] [<ffffffff811b2987>] check_disk_change+0x37/0x80
[ 8158.303254] [<ffffffff81449b3d>] sd_open+0xad/0x1e0
[ 8158.303258] [<ffffffff811b4177>] __blkdev_get+0x2f7/0x460
[ 8158.303266] [<ffffffff8118e5f0>] ? __pollwait+0xf0/0xf0
[ 8158.303268] [<ffffffff811b433e>] blkdev_get+0x5e/0x1e0
[ 8158.303271] [<ffffffff811b451d>] blkdev_open+0x5d/0x80
[ 8158.303274] [<ffffffff81178ff0>] __dentry_open+0x2b0/0x380
[ 8158.303276] [<ffffffff811b44c0>] ? blkdev_get+0x1e0/0x1e0
[ 8158.303280] [<ffffffff812a19dc>] ? security_inode_permission+0x1c/0x30
[ 8158.303283] [<ffffffff8118708a>] ? inode_permission+0x4a/0x110
[ 8158.303285] [<ffffffff8117978d>] vfs_open+0x3d/0x40
[ 8158.303288] [<ffffffff8117a850>] nameidata_to_filp+0x40/0x50
[ 8158.303290] [<ffffffff811898c8>] do_last+0x3f8/0x730
[ 8158.303292] [<ffffffff8118afa1>] path_openat+0xd1/0x3f0
[ 8158.303295] [<ffffffff81312837>] ? kobject_put+0x27/0x60
[ 8158.303318] [<ffffffff813f7907>] ? put_device+0x17/0x20
[ 8158.303321] [<ffffffff8118b3e2>] do_filp_open+0x42/0xa0
[ 8158.303324] [<ffffffff8131e9f1>] ? strncpy_from_user+0x31/0x40
[ 8158.303326] [<ffffffff8118672a>] ? do_getname+0x10a/0x180
[ 8158.303329] [<ffffffff8166413e>] ? _raw_spin_lock+0xe/0x20
[ 8158.303333] [<ffffffff81198707>] ? alloc_fd+0xf7/0x150
[ 8158.303335] [<ffffffff8117a958>] do_sys_open+0xf8/0x240
[ 8158.303337] [<ffffffff8117aac0>] sys_open+0x20/0x30
[ 8158.303341] [<ffffffff8166c782>] system_call_fastpath+0x16/0x1b
[ 8158.303374] INFO: task mount.exfat:14071 blocked for more than 120 seconds.
[ 8158.303375] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 8158.303377] mount.exfat D ffffffff81806240 0 14071 1 0x00000000
[ 8158.303380] ffff88032afbb9b8 0000000000000086 ffff88032afbb9a8 ffffffff812f8fbc
[ 8158.303383] ffff88032afbbfd8 ffff88032afbbfd8 ffff88032afbbfd8 00000000000137c0
[ 8158.303386] ffff88032b709700 ffff8802db000000 ffff88032afbb998 ffff88033fcd4080
[ 8158.303389] Call Trace:
[ 8158.303392] [<ffffffff812f8fbc>] ? blk_queue_bio+0x1bc/0x370
[ 8158.303394] [<ffffffff811ac2b0>] ? __wait_on_buffer+0x30/0x30
[ 8158.303396] [<ffffffff816621df>] schedule+0x3f/0x60
[ 8158.303398] [<ffffffff8166228f>] io_schedule+0x8f/0xd0
[ 8158.303401] [<ffffffff811ac2be>] sleep_on_buffer+0xe/0x20
[ 8158.303403] [<ffffffff81662a9f>] __wait_on_bit+0x5f/0x90
[ 8158.303405] [<ffffffff811b1c1a>] ? bio_alloc_bioset+0x5a/0xf0
[ 8158.303407] [<ffffffff811ac2b0>] ? __wait_on_buffer+0x30/0x30
[ 8158.303410] [<ffffffff81662b4c>] out_of_line_wait_on_bit+0x7c/0x90
[ 8158.303413] [<ffffffff8108c420>] ? autoremove_wake_function+0x40/0x40
[ 8158.303415] [<ffffffff811ac2ae>] __wait_on_buffer+0x2e/0x30
[ 8158.303418] [<ffffffff811af39c>] __block_write_begin+0x36c/0x520
[ 8158.303421] [<ffffffff811b3a00>] ? blkdev_get_blocks+0xd0/0xd0
[ 8158.303423] [<ffffffff811b3a00>] ? blkdev_get_blocks+0xd0/0xd0
[ 8158.303425] [<ffffffff811af7e1>] block_write_begin+0x51/0xa0
[ 8158.303429] [<ffffffff81119a5a>] ? unlock_page+0x2a/0x40
[ 8158.303432] [<ffffffff811b3063>] blkdev_write_begin+0x23/0x30
[ 8158.303434] [<ffffffff81119e1a>] generic_perform_write+0xca/0x210
[ 8158.303438] [<ffffffff812a2786>] ? security_inode_need_killpriv+0x16/0x20
[ 8158.303440] [<ffffffff81119fbd>] generic_file_buffered_write+0x5d/0x90
[ 8158.303443] [<ffffffff8111b9d9>] __generic_file_aio_write+0x229/0x440
[ 8158.303448] [<ffffffff81280050>] ? fuse_dev_read+0x70/0x80
[ 8158.303450] [<ffffffff811b36c3>] blkdev_aio_write+0x33/0x90
[ 8158.303453] [<ffffffff8117ad4a>] do_sync_write+0xda/0x120
[ 8158.303457] [<ffffffff812dc7c8>] ? apparmor_file_permission+0x18/0x20
[ 8158.303459] [<ffffffff812a1e4c>] ? security_file_permission+0x2c/0xb0
[ 8158.303462] [<ffffffff8117b2f1>] ? rw_verify_area+0x61/0xf0
[ 8158.303464] [<ffffffff8117b653>] vfs_write+0xb3/0x180
[ 8158.303466] [<ffffffff8117bb12>] sys_pwrite64+0xa2/0xb0
[ 8158.303469] [<ffffffff8166c782>] system_call_fastpath+0x16/0x1b
[ 8158.303471] INFO: task flush-8:128:14081 blocked for more than 120 seconds.
[ 8158.303473] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 8158.303474] flush-8:128 D ffffffff81806240 0 14081 2 0x00000000
[ 8158.303477] ffff88032a3b36d0 0000000000000046 ffff88032a3b3690 ffff880325751d60
[ 8158.303480] ffff88032a3b3fd8 ffff88032a3b3fd8 ffff88032a3b3fd8 00000000000137c0
[ 8158.303483] ffff88032b659700 ffff8800b0b0ae00 ffff88032a3b36a0 ffff88033fc34080
[ 8158.303486] Call Trace:
[ 8158.303488] [<ffffffff816621df>] schedule+0x3f/0x60
[ 8158.303490] [<ffffffff8166228f>] io_schedule+0x8f/0xd0
[ 8158.303492] [<ffffffff812f7f86>] get_request_wait+0xf6/0x1d0
[ 8158.303495] [<ffffffff8108c3e0>] ? add_wait_queue+0x60/0x60
[ 8158.303497] [<ffffffff812f8e7f>] blk_queue_bio+0x7f/0x370
[ 8158.303501] [<ffffffff812f5a94>] generic_make_request.part.52+0x74/0xb0
[ 8158.303504] [<ffffffff812f5ea8>] generic_make_request+0x68/0x70
[ 8158.303507] [<ffffffff812f5f35>] submit_bio+0x85/0x110
[ 8158.303509] [<ffffffff811b1c1a>] ? bio_alloc_bioset+0x5a/0xf0
[ 8158.303512] [<ffffffff811abaab>] submit_bh+0xeb/0x120
[ 8158.303514] [<ffffffff811adf30>] __block_write_full_page+0x210/0x3a0
[ 8158.303516] [<ffffffff811ad710>] ? end_buffer_async_read+0x140/0x140
[ 8158.303519] [<ffffffff811b3a00>] ? blkdev_get_blocks+0xd0/0xd0
[ 8158.303521] [<ffffffff811b3a00>] ? blkdev_get_blocks+0xd0/0xd0
[ 8158.303524] [<ffffffff811ae8bd>] block_write_full_page_endio+0xcd/0x100
[ 8158.303527] [<ffffffff8111a2c4>] ? find_get_pages_tag+0x44/0x140
[ 8158.303529] [<ffffffff811ae905>] block_write_full_page+0x15/0x20
[ 8158.303531] [<ffffffff811b30a8>] blkdev_writepage+0x18/0x20
[ 8158.303534] [<ffffffff81123997>] __writepage+0x17/0x40
[ 8158.303537] [<ffffffff811240cd>] write_cache_pages+0x20d/0x460
[ 8158.303539] [<ffffffff81123980>] ? set_page_dirty_lock+0x60/0x60
[ 8158.303542] [<ffffffff8112436a>] generic_writepages+0x4a/0x70
[ 8158.303545] [<ffffffff811252d1>] do_writepages+0x21/0x40
[ 8158.303549] [<ffffffff811a4b00>] writeback_single_inode+0x170/0x420
[ 8158.303551] [<ffffffff811a51c6>] writeback_sb_inodes+0x1b6/0x270
[ 8158.303554] [<ffffffff811a531e>] __writeback_inodes_wb+0x9e/0xd0
[ 8158.303557] [<ffffffff811a55bb>] wb_writeback+0x26b/0x310
[ 8158.303559] [<ffffffff811a6618>] wb_do_writeback+0x198/0x1d0
[ 8158.303562] [<ffffffff811a66d3>] bdi_writeback_thread+0x83/0x280
[ 8158.303565] [<ffffffff811a6650>] ? wb_do_writeback+0x1d0/0x1d0
[ 8158.303567] [<ffffffff8108b93c>] kthread+0x8c/0xa0
[ 8158.303570] [<ffffffff8166e8f4>] kernel_thread_helper+0x4/0x10
[ 8158.303573] [<ffffffff8108b8b0>] ? flush_kthread_worker+0xa0/0xa0
[ 8158.303576] [<ffffffff8166e8f0>] ? gs_change+0x13/0x13
[ 8170.090834] sd 6:0:0:4: timing out command, waited 180s
[ 8170.090846] sd 6:0:0:4: [sdi] Unhandled sense code
[ 8170.090848] sd 6:0:0:4: [sdi] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
[ 8170.090853] sd 6:0:0:4: [sdi] Sense Key : Hardware Error [current]
[ 8170.090858] sd 6:0:0:4: [sdi] Add. Sense: Data phase error
[ 8170.090864] sd 6:0:0:4: [sdi] CDB: Write(10): 2a 00 00 00 82 70 00 00 f0 00
[ 8170.090874] end_request: I/O error, dev sdi, sector 33392
[ 8170.090878] Buffer I/O error on device sdi1, logical block 3918
[ 8170.090881] lost page write due to I/O error on sdi1
[ 8170.090887] Buffer I/O error on device sdi1, logical block 3919
[ 8170.090889] lost page write due to I/O error on sdi1
[ 8170.090893] Buffer I/O error on device sdi1, logical block 3920
[ 8170.090895] lost page write due to I/O error on sdi1
[ 8170.090899] Buffer I/O error on device sdi1, logical block 3921
[ 8170.090901] lost page write due to I/O error on sdi1
[ 8170.090905] Buffer I/O error on device sdi1, logical block 3922
[ 8170.090907] lost page write due to I/O error on sdi1
[ 8170.090911] Buffer I/O error on device sdi1, logical block 3923
[ 8170.090913] lost page write due to I/O error on sdi1
[ 8170.090917] Buffer I/O error on device sdi1, logical block 3924
[ 8170.090919] lost page write due to I/O error on sdi1
[ 8170.090922] Buffer I/O error on device sdi1, logical block 3925
[ 8170.090925] lost page write due to I/O error on sdi1
[ 8170.090930] Buffer I/O error on device sdi1, logical block 3926
[ 8170.090932] lost page write due to I/O error on sdi1
[ 8170.090934] Buffer I/O error on device sdi1, logical block 3927
[ 8170.091006] lost page write due to I/O error on sdi1

** dmesg log when trying to unmount failed sdcard **
[ 8278.261364] INFO: task flush-8:128:14081 blocked for more than 120 seconds.
[ 8278.261367] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 8278.261369] flush-8:128 D ffffffff81806240 0 14081 2 0x00000000
[ 8278.261373] ffff88032a3b36d0 0000000000000046 ffff88032a3b3690 ffff880325751d60
[ 8278.261377] ffff88032a3b3fd8 ffff88032a3b3fd8 ffff88032a3b3fd8 00000000000137c0
[ 8278.261380] ffff88032b659700 ffff8800b0b0ae00 ffff88032a3b36a0 ffff88033fc34080
[ 8278.261383] Call Trace:
[ 8278.261390] [<ffffffff816621df>] schedule+0x3f/0x60
[ 8278.261393] [<ffffffff8166228f>] io_schedule+0x8f/0xd0
[ 8278.261435] [<ffffffff812f7f86>] get_request_wait+0xf6/0x1d0
[ 8278.261440] [<ffffffff8108c3e0>] ? add_wait_queue+0x60/0x60
[ 8278.261442] [<ffffffff812f8e7f>] blk_queue_bio+0x7f/0x370
[ 8278.261447] [<ffffffff812f5a94>] generic_make_request.part.52+0x74/0xb0
[ 8278.261449] [<ffffffff812f5ea8>] generic_make_request+0x68/0x70
[ 8278.261452] [<ffffffff812f5f35>] submit_bio+0x85/0x110
[ 8278.261456] [<ffffffff811b1c1a>] ? bio_alloc_bioset+0x5a/0xf0
[ 8278.261458] [<ffffffff811abaab>] submit_bh+0xeb/0x120
[ 8278.261461] [<ffffffff811adf30>] __block_write_full_page+0x210/0x3a0
[ 8278.261463] [<ffffffff811ad710>] ? end_buffer_async_read+0x140/0x140
[ 8278.261467] [<ffffffff811b3a00>] ? blkdev_get_blocks+0xd0/0xd0
[ 8278.261469] [<ffffffff811b3a00>] ? blkdev_get_blocks+0xd0/0xd0
[ 8278.261471] [<ffffffff811ae8bd>] block_write_full_page_endio+0xcd/0x100
[ 8278.261475] [<ffffffff8111a2c4>] ? find_get_pages_tag+0x44/0x140
[ 8278.261478] [<ffffffff811ae905>] block_write_full_page+0x15/0x20
[ 8278.261480] [<ffffffff811b30a8>] blkdev_writepage+0x18/0x20
[ 8278.261483] [<ffffffff81123997>] __writepage+0x17/0x40
[ 8278.261486] [<ffffffff811240cd>] write_cache_pages+0x20d/0x460
[ 8278.261488] [<ffffffff81123980>] ? set_page_dirty_lock+0x60/0x60
[ 8278.261491] [<ffffffff8112436a>] generic_writepages+0x4a/0x70
[ 8278.261494] [<ffffffff811252d1>] do_writepages+0x21/0x40
[ 8278.261497] [<ffffffff811a4b00>] writeback_single_inode+0x170/0x420
[ 8278.261500] [<ffffffff811a51c6>] writeback_sb_inodes+0x1b6/0x270
[ 8278.261503] [<ffffffff811a531e>] __writeback_inodes_wb+0x9e/0xd0
[ 8278.261505] [<ffffffff811a55bb>] wb_writeback+0x26b/0x310
[ 8278.261508] [<ffffffff811a6618>] wb_do_writeback+0x198/0x1d0
[ 8278.261511] [<ffffffff811a66d3>] bdi_writeback_thread+0x83/0x280
[ 8278.261513] [<ffffffff811a6650>] ? wb_do_writeback+0x1d0/0x1d0
[ 8278.261516] [<ffffffff8108b93c>] kthread+0x8c/0xa0
[ 8278.261520] [<ffffffff8166e8f4>] kernel_thread_helper+0x4/0x10
[ 8278.261523] [<ffffffff8108b8b0>] ? flush_kthread_worker+0xa0/0xa0
[ 8278.261525] [<ffffffff8166e8f0>] ? gs_change+0x13/0x13

The unmount process will hang as well and cannot be killed even using "kill -n 9". When doing a forced system reboot the shutdown process will hand on "udevd [xyz] timeout: killing: "udisk-part-id /dev/sdi".

Thanks.

[sillyxone (sillyxone)]

I'm getting similar symptoms on Ubuntu 14.04 64bit. A Samsung 64GB microSD card, was able to browse and delete files normally, but when copy about 48GB to it, it would hang around 10GB (my system has 16GB of RAM). The processing mount.exfat then would cause high iowait. I ejected the card, put it back in and was able to read it again, but there was only about 300MB of data written to it.

See attached log copied from dmesg.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Joseph Salisbury (jsalisbury)]

Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.1 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.1-unstable/

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Dominic Amann (dominic-amann)]

This exact same pattern occurred to me, using dd to copy a system image to an SD card.

[Dominic Amann (dominic-amann)]

Kernel version 3.19.0-32-generic.

[Bas van den Heuvel (2-bas)]

Got the same problem with Ubuntu 16.04 with 4.4.0-28 kernel (64bit).

Tried to copy about 60GB, stuck after a few minutes:

Jul 14 18:47:41 patsy kernel: [ 6840.370388] INFO: task mount.exfat:19269 blocked for more than 120 seconds.
Jul 14 18:47:41 patsy kernel: [ 6840.370392] Tainted: P OE 4.4.0-28-generic #47-Ubuntu
Jul 14 18:47:41 patsy kernel: [ 6840.370394] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
Jul 14 18:47:41 patsy kernel: [ 6840.370397] mount.exfat D ffff88080c403a08 0 19269 1 0x00000000
Jul 14 18:47:41 patsy kernel: [ 6840.370403] ffff88080c403a08 0000000000000100 ffff88080b1dac40 ffff88072da90000
Jul 14 18:47:41 patsy kernel: [ 6840.370408] ffff88080c404000 ffff880836d96d00 7fffffffffffffff ffffffff81823db0
Jul 14 18:47:41 patsy kernel: [ 6840.370413] ffff88080c403b60 ffff88080c403a20 ffffffff818235b5 0000000000000000
Jul 14 18:47:41 patsy kernel: [ 6840.370418] Call Trace:
Jul 14 18:47:41 patsy kernel: [ 6840.370425] [<ffffffff81823db0>] ? bit_wait+0x60/0x60
Jul 14 18:47:41 patsy kernel: [ 6840.370430] [<ffffffff818235b5>] schedule+0x35/0x80
Jul 14 18:47:41 patsy kernel: [ 6840.370436] [<ffffffff818266d5>] schedule_timeout+0x1b5/0x270
Jul 14 18:47:41 patsy kernel: [ 6840.370443] [<ffffffff810f597c>] ? ktime_get+0x3c/0xb0
Jul 14 18:47:41 patsy kernel: [ 6840.370449] [<ffffffff81823db0>] ? bit_wait+0x60/0x60
Jul 14 18:47:41 patsy kernel: [ 6840.370454] [<ffffffff81822ae4>] io_schedule_timeout+0xa4/0x110
Jul 14 18:47:41 patsy kernel: [ 6840.370460] [<ffffffff81823dcb>] bit_wait_io+0x1b/0x70
Jul 14 18:47:41 patsy kernel: [ 6840.370466] [<ffffffff8182395d>] __wait_on_bit+0x5d/0x90
Jul 14 18:47:41 patsy kernel: [ 6840.370471] [<ffffffff813bbba6>] ? submit_bio+0x76/0x170
Jul 14 18:47:41 patsy kernel: [ 6840.370476] [<ffffffff81823db0>] ? bit_wait+0x60/0x60
Jul 14 18:47:41 patsy kernel: [ 6840.370482] [<ffffffff81823a12>] out_of_line_wait_on_bit+0x82/0xb0
Jul 14 18:47:41 patsy kernel: [ 6840.370489] [<ffffffff810c3ce0>] ? autoremove_wake_function+0x40/0x40
Jul 14 18:47:41 patsy kernel: [ 6840.370494] [<ffffffff81245e23>] __block_write_begin+0x263/0x480
Jul 14 18:47:41 patsy kernel: [ 6840.370499] [<ffffffff81247b80>] ? I_BDEV+0x20/0x20
Jul 14 18:47:41 patsy kernel: [ 6840.370504] [<ffffffff81247b80>] ? I_BDEV+0x20/0x20
Jul 14 18:47:41 patsy kernel: [ 6840.370508] [<ffffffff81246086>] block_write_begin+0x46/0x80
Jul 14 18:47:41 patsy kernel: [ 6840.370514] [<ffffffff812486f3>] blkdev_write_begin+0x23/0x30
Jul 14 18:47:41 patsy kernel: [ 6840.370521] [<ffffffff8118dabe>] generic_perform_write+0xce/0x1c0
Jul 14 18:47:41 patsy kernel: [ 6840.370527] [<ffffffff8118f962>] __generic_file_write_iter+0x1a2/0x1e0
Jul 14 18:47:41 patsy kernel: [ 6840.370532] [<ffffffff8124891f>] blkdev_write_iter+0x8f/0x130
Jul 14 18:47:41 patsy kernel: [ 6840.370539] [<ffffffff8120c8bb>] new_sync_write+0x9b/0xe0
Jul 14 18:47:41 patsy kernel: [ 6840.370545] [<ffffffff8120c926>] __vfs_write+0x26/0x40
Jul 14 18:47:41 patsy kernel: [ 6840.370551] [<ffffffff8120d2a9>] vfs_write+0xa9/0x1a0
Jul 14 18:47:41 patsy kernel: [ 6840.370556] [<ffffffff8120d1e4>] ? vfs_read+0x114/0x130
J...