[18.04] writing on thumb drives causes hang for write op, shutdown and 'sync' command

[LGB [Gábor Lénárt]]

I've upgraded to 18.04. Since then, it's impossible to use thumb-drives. If I try, on the first write operation, that operation hangs. Trying to issue a 'sync' command that hangs too. After a while (some minutes or so?) I see the following in kernel log / dmesg (see later). It's not even possible to cleanly shut the computer down, as it also hangs then.

kernel is:

4.15.0-15-generic
Linux oxygene 4.15.0-15-generic #16-Ubuntu SMP Wed Apr 4 13:58:14 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
$ dpkg -S /boot/vmlinuz-4.15.0-15-generic
linux-image-4.15.0-15-generic: /boot/vmlinuz-4.15.0-15-generic
$ dpkg -l linux-image-4.15.0-15-generic
ii linux-image-4.15.0-15-generic 4.15.0-15.16 amd64 Linux kernel image for version 4.15.0 on 64 bit x86 SMP

dmesg:

[ 110.931501] usb 6-1: new high-speed USB device number 2 using xhci_hcd
[ 111.083432] usb 6-1: New USB device found, idVendor=13fe, idProduct=1d00
[ 111.083438] usb 6-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 111.083441] usb 6-1: Product: DataTraveler 2.0
[ 111.083444] usb 6-1: Manufacturer: Kingston
[ 111.083447] usb 6-1: SerialNumber: 5B7402949950
[ 111.157729] usb-storage 6-1:1.0: USB Mass Storage device detected
[ 111.157882] scsi host6: usb-storage 6-1:1.0
[ 111.158826] usbcore: registered new interface driver usb-storage
[ 111.174387] usbcore: registered new interface driver uas
[ 112.172295] scsi 6:0:0:0: Direct-Access Kingston DataTraveler 2.0 PMAP PQ: 0 ANSI: 0 CCS
[ 112.203451] sd 6:0:0:0: Attached scsi generic sg1 type 0
[ 112.443337] sd 6:0:0:0: [sdb] 4030464 512-byte logical blocks: (2.06 GB/1.92 GiB)
[ 112.443462] sd 6:0:0:0: [sdb] Write Protect is off
[ 112.443464] sd 6:0:0:0: [sdb] Mode Sense: 23 00 00 00
[ 112.443586] sd 6:0:0:0: [sdb] No Caching mode page found
[ 112.443591] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[ 112.447045] sd 6:0:0:0: [sdb] Attached SCSI removable disk

this was ok, the problem is from here:

[ 363.231738] INFO: task fdisk:1798 blocked for more than 120 seconds.
[ 363.231745] Tainted: G OE 4.15.0-15-generic #16-Ubuntu
[ 363.231747] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 363.231750] fdisk D 0 1798 1728 0x00000000
[ 363.231754] Call Trace:
[ 363.231764] __schedule+0x297/0x8b0
[ 363.231768] ? fdatawait_one_bdev+0x20/0x20
[ 363.231771] schedule+0x2c/0x80
[ 363.231775] io_schedule+0x16/0x40
[ 363.231779] wait_on_page_bit_common+0xd8/0x160
[ 363.231782] ? page_cache_tree_insert+0xe0/0xe0
[ 363.231785] __filemap_fdatawait_range+0xfa/0x160
[ 363.231788] ? __filemap_fdatawrite_range+0xc1/0x100
[ 363.231791] ? __filemap_fdatawrite_range+0xcd/0x100
[ 363.231794] ? __sync_filesystem+0x60/0x60
[ 363.231797] filemap_fdatawait_keep_errors+0x1e/0x40
[ 363.231799] fdatawait_one_bdev+0x16/0x20
[ 363.231802] iterate_bdevs+0xb7/0x160
[ 363.231805] sys_sync+0x7e/0xb0
[ 363.231809] do_syscall_64+0x73/0x130
[ 363.231813] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 363.231816] RIP: 0033:0x7f2fcff17287
[ 363.231817] RSP: 002b:00007fffbbea61a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a2
[ 363.231820] RAX: ffffffffffffffda RBX: 000056096b767400 RCX: 00007f2fcff17287
[ 363.231821] RDX: 0000000000000000 RSI: 000056096b766018 RDI: 000056096b767400
[ 363.231823] RBP: 00007fffbbea82d8 R08: 000000000000000a R09: 7472617020656854
[ 363.231824] R10: 0000000000000008 R11: 0000000000000202 R12: 000056096a25b198
[ 363.231825] R13: 0000000000000000 R14: 000056096a25b198 R15: 0000000000000000
[ 484.045928] INFO: task fdisk:1798 blocked for more than 120 seconds.
[ 484.045934] Tainted: G OE 4.15.0-15-generic #16-Ubuntu
[ 484.045936] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 484.045939] fdisk D 0 1798 1728 0x00000000
[ 484.045942] Call Trace:
[ 484.045950] __schedule+0x297/0x8b0
[ 484.045954] ? fdatawait_one_bdev+0x20/0x20
[ 484.045956] schedule+0x2c/0x80
[ 484.045959] io_schedule+0x16/0x40
[ 484.045962] wait_on_page_bit_common+0xd8/0x160
[ 484.045965] ? page_cache_tree_insert+0xe0/0xe0
[ 484.045967] __filemap_fdatawait_range+0xfa/0x160
[ 484.045970] ? __filemap_fdatawrite_range+0xc1/0x100
[ 484.045972] ? __filemap_fdatawrite_range+0xcd/0x100
[ 484.045975] ? __sync_filesystem+0x60/0x60
[ 484.045977] filemap_fdatawait_keep_errors+0x1e/0x40
[ 484.045979] fdatawait_one_bdev+0x16/0x20
[ 484.045981] iterate_bdevs+0xb7/0x160
[ 484.045984] sys_sync+0x7e/0xb0
[ 484.045987] do_syscall_64+0x73/0x130
[ 484.045990] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 484.045992] RIP: 0033:0x7f2fcff17287
[ 484.045994] RSP: 002b:00007fffbbea61a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a2
[ 484.045996] RAX: ffffffffffffffda RBX: 000056096b767400 RCX: 00007f2fcff17287
[ 484.045997] RDX: 0000000000000000 RSI: 000056096b766018 RDI: 000056096b767400
[ 484.045998] RBP: 00007fffbbea82d8 R08: 000000000000000a R09: 7472617020656854
[ 484.046000] R10: 0000000000000008 R11: 0000000000000202 R12: 000056096a25b198
[ 484.046001] R13: 0000000000000000 R14: 000056096a25b198 R15: 0000000000000000
[ 484.046024] INFO: task sync:2149 blocked for more than 120 seconds.
[ 484.046026] Tainted: G OE 4.15.0-15-generic #16-Ubuntu
[ 484.046028] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 484.046030] sync D 0 2149 1821 0x00000004
[ 484.046032] Call Trace:
[ 484.046035] __schedule+0x297/0x8b0
[ 484.046038] schedule+0x2c/0x80
[ 484.046040] schedule_preempt_disabled+0xe/0x10
[ 484.046043] __mutex_lock.isra.2+0x18c/0x4d0
[ 484.046045] ? wait_woken+0x80/0x80
[ 484.046048] ? fdatawait_one_bdev+0x20/0x20
[ 484.046050] __mutex_lock_slowpath+0x13/0x20
[ 484.046053] ? __mutex_lock_slowpath+0x13/0x20
[ 484.046055] mutex_lock+0x2f/0x40
[ 484.046057] iterate_bdevs+0xa0/0x160
[ 484.046059] sys_sync+0x70/0xb0
[ 484.046062] do_syscall_64+0x73/0x130
[ 484.046065] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 484.046066] RIP: 0033:0x7f6707b3f287
[ 484.046067] RSP: 002b:00007ffd0e393dc8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
[ 484.046069] RAX: ffffffffffffffda RBX: 00007ffd0e393ef8 RCX: 00007f6707b3f287
[ 484.046071] RDX: 00007f6707e16001 RSI: 0000000000000000 RDI: 00007f6707bdd4b0
[ 484.046072] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
[ 484.046073] R10: 0000564af80d2010 R11: 0000000000000246 R12: 0000000000000001
[ 484.046074] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 484.046077] INFO: task fdisk:2199 blocked for more than 120 seconds.
[ 484.046079] Tainted: G OE 4.15.0-15-generic #16-Ubuntu
[ 484.046081] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 484.046083] fdisk D 0 2199 2198 0x00000004
[ 484.046085] Call Trace:
[ 484.046088] __schedule+0x297/0x8b0
[ 484.046090] schedule+0x2c/0x80
[ 484.046092] schedule_preempt_disabled+0xe/0x10
[ 484.046095] __mutex_lock.isra.2+0x18c/0x4d0
[ 484.046098] __mutex_lock_slowpath+0x13/0x20
[ 484.046100] ? __mutex_lock_slowpath+0x13/0x20
[ 484.046102] mutex_lock+0x2f/0x40
[ 484.046104] __blkdev_get+0x71/0x4c0
[ 484.046107] blkdev_get+0x129/0x320
[ 484.046109] ? __fsnotify_parent+0x96/0x120
[ 484.046112] ? security_capable+0x4e/0x70
[ 484.046114] blkdev_open+0x95/0xf0
[ 484.046117] do_dentry_open+0x1c2/0x310
[ 484.046119] ? __inode_permission+0x5b/0x160
[ 484.046121] ? bd_acquire+0xd0/0xd0
[ 484.046124] vfs_open+0x4f/0x80
[ 484.046126] path_openat+0x66e/0x1770
[ 484.046129] do_filp_open+0x9b/0x110
[ 484.046132] ? __check_object_size+0xaf/0x1b0
[ 484.046135] ? __alloc_fd+0x46/0x170
[ 484.046138] do_sys_open+0x1bb/0x2c0
[ 484.046140] ? do_sys_open+0x1bb/0x2c0
[ 484.046143] SyS_openat+0x14/0x20
[ 484.046145] do_syscall_64+0x73/0x130
[ 484.046148] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 484.046150] RIP: 0033:0x7f7bf2007c8e
[ 484.046151] RSP: 002b:00007ffde2a82080 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
[ 484.046153] RAX: ffffffffffffffda RBX: 000055b725656400 RCX: 00007f7bf2007c8e
[ 484.046154] RDX: 0000000000080002 RSI: 00007ffde2a827c3 RDI: 00000000ffffff9c
[ 484.046155] RBP: 0000000000000000 R08: 000000000000000a R09: 6d6572206c6c6977
[ 484.046156] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7bf29bd444
[ 484.046157] R13: 00007ffde2a827c3 R14: 0000000000000000 R15: 0000000000000000
[ 604.909492] INFO: task fdisk:1798 blocked for more than 120 seconds.
[ 604.909499] Tainted: G OE 4.15.0-15-generic #16-Ubuntu
[ 604.909502] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 604.909505] fdisk D 0 1798 1728 0x00000000
[ 604.909509] Call Trace:
[ 604.909519] __schedule+0x297/0x8b0
[ 604.909523] ? fdatawait_one_bdev+0x20/0x20
[ 604.909526] schedule+0x2c/0x80
[ 604.909530] io_schedule+0x16/0x40
[ 604.909533] wait_on_page_bit_common+0xd8/0x160
[ 604.909536] ? page_cache_tree_insert+0xe0/0xe0
[ 604.909540] __filemap_fdatawait_range+0xfa/0x160
[ 604.909543] ? __filemap_fdatawrite_range+0xc1/0x100
[ 604.909546] ? __filemap_fdatawrite_range+0xcd/0x100
[ 604.909549] ? __sync_filesystem+0x60/0x60
[ 604.909552] filemap_fdatawait_keep_errors+0x1e/0x40
[ 604.909554] fdatawait_one_bdev+0x16/0x20
[ 604.909557] iterate_bdevs+0xb7/0x160
[ 604.909560] sys_sync+0x7e/0xb0
[ 604.909564] do_syscall_64+0x73/0x130
[ 604.909568] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 604.909571] RIP: 0033:0x7f2fcff17287
[ 604.909572] RSP: 002b:00007fffbbea61a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a2
[ 604.909575] RAX: ffffffffffffffda RBX: 000056096b767400 RCX: 00007f2fcff17287
[ 604.909576] RDX: 0000000000000000 RSI: 000056096b766018 RDI: 000056096b767400
[ 604.909578] RBP: 00007fffbbea82d8 R08: 000000000000000a R09: 7472617020656854
[ 604.909579] R10: 0000000000000008 R11: 0000000000000202 R12: 000056096a25b198
[ 604.909581] R13: 0000000000000000 R14: 000056096a25b198 R15: 0000000000000000
[ 604.909607] INFO: task sync:2149 blocked for more than 120 seconds.
[ 604.909610] Tainted: G OE 4.15.0-15-generic #16-Ubuntu
[ 604.909612] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 604.909614] sync D 0 2149 1821 0x00000004
[ 604.909617] Call Trace:
[ 604.909621] __schedule+0x297/0x8b0
[ 604.909624] schedule+0x2c/0x80
[ 604.909627] schedule_preempt_disabled+0xe/0x10
[ 604.909630] __mutex_lock.isra.2+0x18c/0x4d0
[ 604.909633] ? wait_woken+0x80/0x80
[ 604.909636] ? fdatawait_one_bdev+0x20/0x20
[ 604.909639] __mutex_lock_slowpath+0x13/0x20
[ 604.909642] ? __mutex_lock_slowpath+0x13/0x20
[ 604.909645] mutex_lock+0x2f/0x40
[ 604.909647] iterate_bdevs+0xa0/0x160
[ 604.909650] sys_sync+0x70/0xb0
[ 604.909653] do_syscall_64+0x73/0x130
[ 604.909657] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 604.909659] RIP: 0033:0x7f6707b3f287
[ 604.909660] RSP: 002b:00007ffd0e393dc8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
[ 604.909662] RAX: ffffffffffffffda RBX: 00007ffd0e393ef8 RCX: 00007f6707b3f287
[ 604.909664] RDX: 00007f6707e16001 RSI: 0000000000000000 RDI: 00007f6707bdd4b0
[ 604.909665] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
[ 604.909667] R10: 0000564af80d2010 R11: 0000000000000246 R12: 0000000000000001
[ 604.909668] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 604.909671] INFO: task fdisk:2199 blocked for more than 120 seconds.
[ 604.909674] Tainted: G OE 4.15.0-15-generic #16-Ubuntu
[ 604.909676] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 604.909678] fdisk D 0 2199 2198 0x00000004
[ 604.909681] Call Trace:
[ 604.909684] __schedule+0x297/0x8b0
[ 604.909688] schedule+0x2c/0x80
[ 604.909690] schedule_preempt_disabled+0xe/0x10
[ 604.909693] __mutex_lock.isra.2+0x18c/0x4d0
[ 604.909697] __mutex_lock_slowpath+0x13/0x20
[ 604.909700] ? __mutex_lock_slowpath+0x13/0x20
[ 604.909702] mutex_lock+0x2f/0x40
[ 604.909705] __blkdev_get+0x71/0x4c0
[ 604.909708] blkdev_get+0x129/0x320
[ 604.909710] ? __fsnotify_parent+0x96/0x120
[ 604.909714] ? security_capable+0x4e/0x70
[ 604.909717] blkdev_open+0x95/0xf0
[ 604.909721] do_dentry_open+0x1c2/0x310
[ 604.909723] ? __inode_permission+0x5b/0x160
[ 604.909726] ? bd_acquire+0xd0/0xd0
[ 604.909729] vfs_open+0x4f/0x80
[ 604.909732] path_openat+0x66e/0x1770
[ 604.909735] do_filp_open+0x9b/0x110
[ 604.909739] ? __check_object_size+0xaf/0x1b0
[ 604.909742] ? __alloc_fd+0x46/0x170
[ 604.909746] do_sys_open+0x1bb/0x2c0
[ 604.909748] ? do_sys_open+0x1bb/0x2c0
[ 604.909752] SyS_openat+0x14/0x20
[ 604.909755] do_syscall_64+0x73/0x130
[ 604.909759] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 604.909760] RIP: 0033:0x7f7bf2007c8e
[ 604.909762] RSP: 002b:00007ffde2a82080 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
[ 604.909764] RAX: ffffffffffffffda RBX: 000055b725656400 RCX: 00007f7bf2007c8e
[ 604.909766] RDX: 0000000000080002 RSI: 00007ffde2a827c3 RDI: 00000000ffffff9c
[ 604.909767] RBP: 0000000000000000 R08: 000000000000000a R09: 6d6572206c6c6977
[ 604.909768] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7bf29bd444
[ 604.909769] R13: 00007ffde2a827c3 R14: 0000000000000000 R15: 0000000000000000
[ 725.800041] INFO: task fdisk:1798 blocked for more than 120 seconds.
[ 725.800050] Tainted: G OE 4.15.0-15-generic #16-Ubuntu
[ 725.800052] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 725.800056] fdisk D 0 1798 1728 0x00000000
[ 725.800060] Call Trace:
[ 725.800071] __schedule+0x297/0x8b0
[ 725.800076] ? fdatawait_one_bdev+0x20/0x20
[ 725.800079] schedule+0x2c/0x80
[ 725.800083] io_schedule+0x16/0x40
[ 725.800088] wait_on_page_bit_common+0xd8/0x160
[ 725.800091] ? page_cache_tree_insert+0xe0/0xe0
[ 725.800095] __filemap_fdatawait_range+0xfa/0x160
[ 725.800099] ? __filemap_fdatawrite_range+0xc1/0x100
[ 725.800102] ? __filemap_fdatawrite_range+0xcd/0x100
[ 725.800106] ? __sync_filesystem+0x60/0x60
[ 725.800110] filemap_fdatawait_keep_errors+0x1e/0x40
[ 725.800113] fdatawait_one_bdev+0x16/0x20
[ 725.800117] iterate_bdevs+0xb7/0x160
[ 725.800120] sys_sync+0x7e/0xb0
[ 725.800124] do_syscall_64+0x73/0x130
[ 725.800128] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 725.800132] RIP: 0033:0x7f2fcff17287
[ 725.800134] RSP: 002b:00007fffbbea61a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a2
[ 725.800137] RAX: ffffffffffffffda RBX: 000056096b767400 RCX: 00007f2fcff17287
[ 725.800139] RDX: 0000000000000000 RSI: 000056096b766018 RDI: 000056096b767400
[ 725.800141] RBP: 00007fffbbea82d8 R08: 000000000000000a R09: 7472617020656854
[ 725.800143] R10: 0000000000000008 R11: 0000000000000202 R12: 000056096a25b198
[ 725.800145] R13: 0000000000000000 R14: 000056096a25b198 R15: 0000000000000000
[ 725.800172] INFO: task sync:2149 blocked for more than 120 seconds.
[ 725.800177] Tainted: G OE 4.15.0-15-generic #16-Ubuntu
[ 725.800179] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 725.800183] sync D 0 2149 1821 0x00000004
[ 725.800186] Call Trace:
[ 725.800190] __schedule+0x297/0x8b0
[ 725.800193] schedule+0x2c/0x80
[ 725.800196] schedule_preempt_disabled+0xe/0x10
[ 725.800199] __mutex_lock.isra.2+0x18c/0x4d0
[ 725.800203] ? wait_woken+0x80/0x80
[ 725.800206] ? fdatawait_one_bdev+0x20/0x20
[ 725.800209] __mutex_lock_slowpath+0x13/0x20
[ 725.800212] ? __mutex_lock_slowpath+0x13/0x20
[ 725.800214] mutex_lock+0x2f/0x40
[ 725.800217] iterate_bdevs+0xa0/0x160
[ 725.800220] sys_sync+0x70/0xb0
[ 725.800223] do_syscall_64+0x73/0x130
[ 725.800227] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 725.800229] RIP: 0033:0x7f6707b3f287
[ 725.800230] RSP: 002b:00007ffd0e393dc8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
[ 725.800233] RAX: ffffffffffffffda RBX: 00007ffd0e393ef8 RCX: 00007f6707b3f287
[ 725.800234] RDX: 00007f6707e16001 RSI: 0000000000000000 RDI: 00007f6707bdd4b0
[ 725.800235] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
[ 725.800237] R10: 0000564af80d2010 R11: 0000000000000246 R12: 0000000000000001
[ 725.800238] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 725.800241] INFO: task fdisk:2199 blocked for more than 120 seconds.
[ 725.800244] Tainted: G OE 4.15.0-15-generic #16-Ubuntu
[ 725.800246] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 725.800248] fdisk D 0 2199 2198 0x00000004
[ 725.800251] Call Trace:
[ 725.800254] __schedule+0x297/0x8b0
[ 725.800258] schedule+0x2c/0x80
[ 725.800260] schedule_preempt_disabled+0xe/0x10
[ 725.800263] __mutex_lock.isra.2+0x18c/0x4d0
[ 725.800267] __mutex_lock_slowpath+0x13/0x20
[ 725.800270] ? __mutex_lock_slowpath+0x13/0x20
[ 725.800273] mutex_lock+0x2f/0x40
[ 725.800275] __blkdev_get+0x71/0x4c0
[ 725.800278] blkdev_get+0x129/0x320
[ 725.800281] ? __fsnotify_parent+0x96/0x120
[ 725.800285] ? security_capable+0x4e/0x70
[ 725.800288] blkdev_open+0x95/0xf0
[ 725.800291] do_dentry_open+0x1c2/0x310
[ 725.800294] ? __inode_permission+0x5b/0x160
[ 725.800296] ? bd_acquire+0xd0/0xd0
[ 725.800299] vfs_open+0x4f/0x80
[ 725.800302] path_openat+0x66e/0x1770
[ 725.800306] do_filp_open+0x9b/0x110
[ 725.800309] ? __check_object_size+0xaf/0x1b0
[ 725.800313] ? __alloc_fd+0x46/0x170
[ 725.800316] do_sys_open+0x1bb/0x2c0
[ 725.800319] ? do_sys_open+0x1bb/0x2c0
[ 725.800322] SyS_openat+0x14/0x20
[ 725.800325] do_syscall_64+0x73/0x130
[ 725.800329] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[ 725.800331] RIP: 0033:0x7f7bf2007c8e
[ 725.800332] RSP: 002b:00007ffde2a82080 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
[ 725.800335] RAX: ffffffffffffffda RBX: 000055b725656400 RCX: 00007f7bf2007c8e
[ 725.800336] RDX: 0000000000080002 RSI: 00007ffde2a827c3 RDI: 00000000ffffff9c
[ 725.800338] RBP: 0000000000000000 R08: 000000000000000a R09: 6d6572206c6c6977
[ 725.800339] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7bf29bd444
[ 725.800340] R13: 00007ffde2a827c3 R14: 0000000000000000 R15: 0000000000000000

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-15-generic 4.15.0-15.16
ProcVersionSignature: Ubuntu 4.15.0-15.16-generic 4.15.15
Uname: Linux 4.15.0-15-generic x86_64
ApportVersion: 2.20.9-0ubuntu4
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: lgb 1463 F.... pulseaudio
 /dev/snd/controlC0: lgb 1463 F.... pulseaudio
 /dev/snd/controlC2: lgb 1463 F.... pulseaudio
CurrentDesktop: XFCE
Date: Mon Apr 9 17:11:31 2018
HibernationDevice: RESUME=UUID=c92777cb-b700-4a8e-b937-1ed4983fecb1
InstallationDate: Installed on 2015-07-10 (1003 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release i386 (20150422)
IwConfig:
 eth0 no wireless extensions.

 lo no wireless extensions.
MachineType: To Be Filled By O.E.M. To Be Filled By O.E.M.
ProcFB: 0 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-15-generic root=UUID=d203063e-78c0-425a-bee2-0e3ecb4ea74c ro quiet splash scsi_mod.use_blk_mq=1 vt.handoff=1
RelatedPackageVersions:
 linux-restricted-modules-4.15.0-15-generic N/A
 linux-backports-modules-4.15.0-15-generic N/A
 linux-firmware 1.173
RfKill:

SourcePackage: linux
UpgradeStatus: Upgraded to bionic on 2017-06-20 (293 days ago)
dmi.bios.date: 02/05/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P2.90
dmi.board.name: FM2A88M Extreme4+
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrP2.90:bd02/05/2016:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnFM2A88MExtreme4+:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.family: To Be Filled By O.E.M.
dmi.product.name: To Be Filled By O.E.M.
dmi.product.version: To Be Filled By O.E.M.
dmi.sys.vendor: To Be Filled By O.E.M.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Tetsuo Handa (9-launchpad-i-love-sakura-ne-jp)]

I can't answer what is happening here. But can you obtain more information using SysRq-t
and SysRq-m as described at https://akari.osdn.jp/capturing-kernel-messages.html#Tips5 ?

[LGB [Gábor Lénárt] (lgb)]

[22596.884250] sysrq: SysRq : This sysrq operation is disabled.

I got this, if I try to trigger those sysreq events by echoing t/m into that procfs file. I'm anyway curious how sysreq stuffs can be enabled/disabled, since I seldom use ALT-SYSREQ-.... combos as well, and many of them just reports the same as with this procfs trigger: operation is disabled.

One thing though:

If I attach the thumb drive, everything is fine, lsblk shows it, etc, I can remove it, lsblk does not show it, no problem. The problem seems to have after the first event when I try to write onto the device, then whatever I try even remove thumb drive physically, lsblk still shows it, all the "sync" commands (and anything which tries to write onto) stuck and cannot be killed. So even shutdown of system is problematic at this point. Now I've tried fdisk (btw, no partition on the thumb drive). Just displaying, everything is OK. However after the "w" command the problems begins. By checking the /proc entry for the PID of the fdisk, I see:

# cat /proc/11283/status
Name: fdisk
Umask: 0022
State: D (disk sleep)
[...]

# cat /proc/11283/stat
11283 (fdisk) D 11084 11283 10324 34827 11283 4194560 673 0 4 0 0 1 0 0 20 0 1 0 2254524 21024768 877 18446744073709551615 94293651558400 94293651671008 140732927217664 0 0 0 0 0 0 1 0 0 17 1 0 0 16 0 0 94293653771504 94293653778500 94293676326912 140732927223610 140732927223625 140732927223625 140732927225836 0

Full output of status file:

# cat /proc/11283/status
Name: fdisk
Umask: 0022
State: D (disk sleep)
Tgid: 11283
Ngid: 0
Pid: 11283
PPid: 11084
TracerPid: 0
Uid: 0 0 0 0
Gid: 0 0 0 0
FDSize: 256
Groups: 0
NStgid: 11283
NSpid: 11283
NSpgid: 11283
NSsid: 10324
VmPeak: 21568 kB
VmSize: 20532 kB
VmLck: 0 kB
VmPin: 0 kB
VmHWM: 4176 kB
VmRSS: 3508 kB
RssAnon: 372 kB
RssFile: 3136 kB
RssShmem: 0 kB
VmData: 284 kB
VmStk: 132 kB
VmExe: 112 kB
VmLib: 3144 kB
VmPTE: 80 kB
VmSwap: 0 kB
HugetlbPages: 0 kB
CoreDumping: 0
Threads: 1
SigQ: 0/13289
SigPnd: 0000000000000000
ShdPnd: 0000000000000000
SigBlk: 0000000000000000
SigIgn: 0000000000000000
SigCgt: 0000000000000000
CapInh: 0000000000000000
CapPrm: 0000003fffffffff
CapEff: 0000003fffffffff
CapBnd: 0000003fffffffff
CapAmb: 0000000000000000
NoNewPrivs: 0
Seccomp: 0
Cpus_allowed: f
Cpus_allowed_list: 0-3
Mems_allowed: 00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000001
Mems_allowed_list: 0
voluntary_ctxt_switches: 73
nonvoluntary_ctxt_switches: 0

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.16 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/v4.16

[LGB [Gábor Lénárt] (lgb)]

Ok, I will investigate as soon as I have time. By the way, I am wondering if using BFQ as I/O scheduler can be the problem, ie:

# cat /etc/udev/rules.d/60-schedulers.rules
## set noop scheduler for non-rotating disks
ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="0", ATTR{queue/scheduler}="noop"
## set bfq scheduler for rotating disks
ACTION=="add|change", KERNEL=="sd[a-z]", ATTR{queue/rotational}=="1", ATTR{queue/scheduler}="bfq"

# cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-4.15.0-15-generic root=UUID=d203063e-78c0-425a-bee2-0e3ecb4ea74c ro quiet splash scsi_mod.use_blk_mq=1 vt.handoff=1

I guess, I try to remove BFQ specific stuffs as well to see if this fixes the problem.

[LGB [Gábor Lénárt] (lgb)]

Removing the scsi_mod.use_blk_mq=1 from /etc/default/grub and the mentioned udev rule file, and regenerating initial ramdisk + reboot seems to do the trick, now everything works with default (cfq) I/O scheduler.

Before this comment, and the problem:

# cat /sys/block/sda/queue/scheduler
[bfq] none
# cat /sys/block/sdb/queue/scheduler
[none] bfq

After I removed the BFQ specific stuffs and everything worked again:

# cat /sys/block/sda/queue/scheduler
noop deadline [cfq]
# cat /sys/block/sdb/queue/scheduler
noop deadline [cfq]

So, sorry about the noise, maybe it was my fault ... Interestingly, this setup of mine with BFQ worked in 17.10 on other machines with that kernel parameter and udev rule I mentioned in the previous comment.

[Launchpad Janitor (janitor)]

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

[Launchpad Janitor (janitor)]

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