Activity log for bug #1495706

Date Who What changed Old value New value Message
2015-09-14 22:08:15 Mario Vietri bug added bug
2015-09-14 22:42:58 Mario Vietri description I am trying to run `strace` against kworker, but I cannot attach strace despite havingset ptrace_scope=0 and being root. Here is the proof: # echo 1 > /proc/sys/kernel/yama/ptrace_scope root@rasal:/home/me# whoami root root@rasal:/home/me# cat /proc/sys/kernel/yama/ptrace_scope 0 root@rasal:/home/me# ps ax | grep kworker 5 ? S< 0:00 [kworker/0:0H] 31 ? S< 0:00 [kworker/1:0H] 35 ? S 0:00 [kworker/2:0] 36 ? S< 0:00 [kworker/2:0H] 41 ? S< 0:00 [kworker/3:0H] 58 ? S 0:00 [kworker/1:1] 76 ? S 0:00 [kworker/3:1] 78 ? S 0:00 [kworker/1:2] 79 ? S 0:00 [kworker/2:1] 149 ? S 0:00 [kworker/0:1] 162 ? S 0:00 [kworker/u16:3] 163 ? S 0:00 [kworker/u16:4] 164 ? S 0:00 [kworker/u16:5] 448 ? S< 0:00 [kworker/3:1H] 449 ? S< 0:00 [kworker/1:1H] 451 ? S< 0:00 [kworker/2:1H] 452 ? S< 0:00 [kworker/0:1H] 560 ? S 0:00 [kworker/3:2] 604 ? S 0:00 [kworker/0:2] 1006 ? S< 0:00 [kworker/u17:0] 1017 ? S< 0:00 [kworker/u17:1] 4222 ? S 0:00 [kworker/3:0] 4249 pts/4 S+ 0:00 grep --color=auto kworker root@rasal:/home/me# strace -p 4222 strace: attach: ptrace(PTRACE_ATTACH, ...): Operation not permitted Could not attach to process. If your uid matches the uid of the target process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try again as the root user. For more details, see /etc/sysctl.d/10-ptrace.conf root@rasal:/home/me# uname -a Linux rasal 3.16.0-49-generic #65~14.04.1-Ubuntu SMP Wed Sep 9 10:03:23 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux Any info on this? ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-3.16.0-49-generic 3.16.0-49.65~14.04.1 ProcVersionSignature: Ubuntu 3.16.0-49.65~14.04.1-generic 3.16.7-ckt15 Uname: Linux 3.16.0-49-generic x86_64 ApportVersion: 2.14.1-0ubuntu3.13 Architecture: amd64 CurrentDesktop: KDE Date: Tue Sep 15 00:01:12 2015 InstallationDate: Installed on 2014-05-05 (497 days ago) InstallationMedia: Kubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.1) SourcePackage: linux-lts-utopic UpgradeStatus: Upgraded to trusty on 2014-11-21 (297 days ago) I am trying to run `strace` against kworker, but I cannot attach strace despite havingset ptrace_scope=0 and being root. Here is the proof: root@rasal:/home/me# whoami root root@rasal:/home/me# cat /proc/sys/kernel/yama/ptrace_scope 0 root@rasal:/home/me# ps ax | grep kworker     5 ? S< 0:00 [kworker/0:0H]    31 ? S< 0:00 [kworker/1:0H]    35 ? S 0:00 [kworker/2:0]    36 ? S< 0:00 [kworker/2:0H]    41 ? S< 0:00 [kworker/3:0H]    58 ? S 0:00 [kworker/1:1]    76 ? S 0:00 [kworker/3:1]    78 ? S 0:00 [kworker/1:2]    79 ? S 0:00 [kworker/2:1]   149 ? S 0:00 [kworker/0:1]   162 ? S 0:00 [kworker/u16:3]   163 ? S 0:00 [kworker/u16:4]   164 ? S 0:00 [kworker/u16:5]   448 ? S< 0:00 [kworker/3:1H]   449 ? S< 0:00 [kworker/1:1H]   451 ? S< 0:00 [kworker/2:1H]   452 ? S< 0:00 [kworker/0:1H]   560 ? S 0:00 [kworker/3:2]   604 ? S 0:00 [kworker/0:2]  1006 ? S< 0:00 [kworker/u17:0]  1017 ? S< 0:00 [kworker/u17:1]  4222 ? S 0:00 [kworker/3:0]  4249 pts/4 S+ 0:00 grep --color=auto kworker root@rasal:/home/me# strace -p 4222 strace: attach: ptrace(PTRACE_ATTACH, ...): Operation not permitted Could not attach to process. If your uid matches the uid of the target process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try again as the root user. For more details, see /etc/sysctl.d/10-ptrace.conf root@rasal:/home/me# uname -a Linux rasal 3.16.0-49-generic #65~14.04.1-Ubuntu SMP Wed Sep 9 10:03:23 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux Any info on this? ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: linux-image-3.16.0-49-generic 3.16.0-49.65~14.04.1 ProcVersionSignature: Ubuntu 3.16.0-49.65~14.04.1-generic 3.16.7-ckt15 Uname: Linux 3.16.0-49-generic x86_64 ApportVersion: 2.14.1-0ubuntu3.13 Architecture: amd64 CurrentDesktop: KDE Date: Tue Sep 15 00:01:12 2015 InstallationDate: Installed on 2014-05-05 (497 days ago) InstallationMedia: Kubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.1) SourcePackage: linux-lts-utopic UpgradeStatus: Upgraded to trusty on 2014-11-21 (297 days ago)