[Qemu-devel] [Bug 1061778] Re: signal mask not reset on exec

[Thomas Huth]

Triaging old bug tickets... can you still reproduce this issue with the
latest version of QEMU? Or could we close this ticket nowadays?

** Changed in: qemu
       Status: New => Incomplete

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https://bugs.launchpad.net/bugs/1061778

Title:
  signal mask not reset on exec

Status in QEMU:
  Incomplete

Bug description:
  Seen in qemu-1.0 under 12.04, but AFAICT from current git it hasn't
  changed.

  ./main-loop.c:qemu_signal_init blocks SIGALRM so it can be handled via
  signalfd.

  ./net/tap.c:launch_script does not reset the signal mask before the
  execv() call, and signal masks are inherited. So the script is run
  with SIGALRM blocked (as can be seen in /proc/$$/status, "SigBlk:
  0000000000002000"). One reasonable example of where this bites is an
  interface up script that calls ping with a timeout to give things a
  chance to settle down before continuing, but abort if this doesn't
  happen within a reasonable time). Since ping uses SIGALRM for the
  timeout, this now never terminates.

  qemu-0.14 didn't block SIGALRM, so such scripts worked fine there.

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