[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 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1762450 Title: [18.04] writing on thumb drives causes hang for write op, shutdown and 'sync' command To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1762450/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
