Public bug reported: [Impact]
While running seccomp_bpf, kill_after_ptrace() gets stuck if we run it via /usr/bin/timeout (that is the default), until the timeout expires. This is because /usr/bin/timeout is preventing to properly deliver signals to ptrace'd children (SIGSYS in this case). [Test case] This problem can be easily reproduced by running: $ sudo make TARGETS=seccomp kselftest ... # [ RUN ] TRACE_syscall.skip_a# not ok 1 selftests: seccomp: seccomp_bpf # TIMEOUT The test is hanging at this point until the timeout expires and then it reports the timeout error. [Fix] This problem can be prevented by passing --foreground to /usr/bin/timeout, allowing to properly deliver signals to children processes. [Regression potential] Not an upstream fix (patch has been sent to the lkml https://lkml.org/lkml/2020/4/10/153), but the fix is trivial and it's only affecting the selftests, not the kernel, so regression potential is minimal. ** Affects: linux (Ubuntu) Importance: Medium Assignee: Andrea Righi (arighi) Status: New ** Affects: linux (Ubuntu Eoan) Importance: Medium Assignee: Andrea Righi (arighi) Status: New ** Affects: linux (Ubuntu Focal) Importance: Medium Assignee: Andrea Righi (arighi) Status: New ** Changed in: linux (Ubuntu) Importance: Undecided => Medium ** Changed in: linux (Ubuntu) Assignee: (unassigned) => Andrea Righi (arighi) ** Also affects: linux (Ubuntu Focal) Importance: Medium Assignee: Andrea Righi (arighi) Status: New ** Also affects: linux (Ubuntu Eoan) Importance: Undecided Status: New ** Changed in: linux (Ubuntu Eoan) Importance: Undecided => Medium ** Changed in: linux (Ubuntu Eoan) Assignee: (unassigned) => Andrea Righi (arighi) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1872047 Title: kselftest: seccomp kill_after_ptrace() timeout To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1872047/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
