** Description changed: 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 + 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 + 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 + 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)
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-lts-utopic in Ubuntu. https://bugs.launchpad.net/bugs/1495706 Title: strace cannot attach to process despite being root and setting scope Status in linux-lts-utopic package in Ubuntu: New Bug 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: 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) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-utopic/+bug/1495706/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
