Bug 151248
| Summary: | Process hangs and cannot be killed | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 3 | Reporter: | Bryce <root> |
| Component: | kernel | Assignee: | Don Howard <dhoward> |
| Status: | CLOSED NOTABUG | QA Contact: | Brian Brock <bbrock> |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 3.0 | CC: | petrides, riel |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2005-03-18 02:08:16 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
Hi Bryce (or is that Phil?) In each case above the process is being ptraced when the signal is sent. Processes that are being ptraced don't respond to signals as usual -- the debugger has to be notified of the event, among other things. The process is not unkillable, it's simply stopped and ptraced. If you send the process SIGCONT after the attached debuger has terminated, the process will start running again. As it's no longer being ptraced, it will respond to signals as usual again, and gdb won't block when attaching to it. I'm going to mark this ticket closed as not a bug. If you have more questions about this, feel free to re-open it and I'll try to address them. |
Description of problem: Process hangs and cannot be killed Version-Release number of selected component (if applicable): The following problem has been seen on RHEL 3.0 U4 but it can be seen even on RHEL 3.0 U2. How reproducible: [root@emerald ~]# cat foo.c main() { while(1); } [root@emerald ~]# gcc foo.c [root@emerald ~]# ./a.out & [1] 22433 [root@emerald ~]# gdb ./a.out 22433 & [2] 22434 [root@emerald ~]# GNU gdb Red Hat Linux (6.1post-1.20040607.43rh) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-redhat-linux-gnu"...(no debugging symbols found )...Using host libthread_db library "/lib/tls/libthread_db.so.1". Attaching to program: /root/a.out, process 22433 [2]+ Stopped gdb ./a.out 22433 Now get rid of gdb but leave the a.out process [root@emerald ~]# kill %2 [root@emerald ~]# [1]+ Stopped ./a.out [2] Terminated gdb ./a.out 22433 [root@emerald ~]# ps -elf |grep 22433 0 T root 22433 22396 16 85 0 - 593 ptrace 12:05 pts/0 00:00:07 ./a.o ut 0 S root 22439 22396 0 76 0 - 1149 pipe_w 12:06 pts/0 00:00:00 grep 22433 Lets reattach to the process [root@emerald ~]# gdb ./a.out 22433 GNU gdb Red Hat Linux (6.1post-1.20040607.43rh) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "i386-redhat-linux-gnu"...(no debugging symbols found )...Using host libthread_db library "/lib/tls/libthread_db.so.1". Attaching to program: /root/a.out, process 22433 <==== GDB IS NOW COMPLETELY HUNG ===============> <==== So from another window ===> [root@emerald ~]# ps -elf |grep 22433 4 S root 22442 22396 0 78 0 - 1698 wait 12:07 pts/0 00:00:00 gdb ./a.out 22433 0 T root 22433 22396 4 85 0 - 593 ptrace 12:05 pts/0 00:00:07 ./a.out 0 S root 22468 22450 0 76 0 - 1331 pipe_w 12:08 pts/10 00:00:00 grep 22433 [root@emerald ~]# kill -9 22433 [root@emerald ~]# ps -elf |grep 22433 4 S root 22442 22396 0 78 0 - 1698 wait 12:07 pts/0 00:00:00 gdb ./a.out 22433 0 T root 22433 22396 3 85 0 - 593 ptrace 12:05 pts/0 00:00:07 ./a.out 0 S root 22473 22450 0 78 0 - 1111 pipe_w 12:09 pts/10 00:00:00 grep 22433 As seen above, process still lives after it has been sent a kill -9. Essentially the kernel is not cleaning up correctly after a debugger process has been killed. The debuggee(?) should be freed up but it is not. Ideas? hints and yells of "don't do that then" Phil =--=