Red Hat Bugzilla – Bug 539506
[4.7] wait4 blocks on non-existing pid
Last modified: 2015-01-04 17:59:09 EST
2221 pts/3 S+ 0:00 | \_ ./strace -o trace -f /root/thread3 2222 pts/3 Dl+ 0:00 | \_ /root/thread3 2223 pts/3 Z+ 0:00 | \_ [thread3] <defunct> # strace -p 2221 Process 2221 attached - interrupt to quit wait4(2420, <unfinished ...> Process 2221 detached # ps 2420 PID TTY STAT TIME COMMAND
This issue is blocking the release of a 4.8.z kernel. What is the recommended course of action? Ron, using an imported RHTS from RHTS it was discovered that the 4.8.z kernel exhibits what appears to be a regression. I'm not certain though of what nvr it was re-introduced.
This bug blocks strace 4.8.z erratum RHBA-2009:9039. This bug is not a regression, it always used to be like this but: without this fix we won't reliably fix bug 532951 (RHBA-2009:9039).
Posted to RHKL today. I agree with Michal, this is not a regression.
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux maintenance release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Update release for currently deployed products. This request is not yet committed for inclusion in an Update release.
There are heavy discussion about Vitaly's patch on rkml, and since Vitaly is on pto 'til 1/13, Oleg has kind enough to take over the discussion and preparing a new patch for this issue. He was able to get help to test out his new patch, but given the complexity of the code paths, during testing, new issue was revealed. Therefore he is currently looking into the new issue. Therefore, move the bug back to ASSI state.
Committed in 89.19.EL . RPMS are available at http://people.redhat.com/vgoyal/rhel4/
Reproduced in 89.18.EL and verified in 89.19.EL.
Technical note added. If any revisions are required, please edit the "Technical Notes" field accordingly. All revisions will be proofread by the Engineering Content Services team. New Contents: If a process was using ptrace() to trace a multi-threaded process, and that multi-threaded process dumped its core, the process performing the trace could hang in wait4(). This issue could be triggered by running "strace -f" on a multi-threaded process that was dumping its core, resulting in the strace command hanging.
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on therefore solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2011-0263.html