This is the mail archive of the mailing list for the systemtap project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[Bug runtime/3215] New: del_timer_sync causes softlockups

Need to investigate further.

rmmod a systemtap module on an SMP system. There is a good chance this will
cause a crash.

 ep 14 09:52:23 dragon kernel:  <c044a98a> softlockup_tick+0xad/0xc4  <c042d858>
Sep 14 09:52:23 dragon kernel:  <c0418af3> smp_apic_timer_interrupt+0x5a/0x63 
<c040490f> apic_timer_interrupt+0x1f/0x24
Sep 14 09:52:23 dragon kernel:  <c042d550> lock_timer_base+0x27/0x2f  <c042d569>
Sep 14 09:52:23 dragon kernel:  <c042d5ac> del_timer_sync+0xa/0x10  <f8e62ff7>
_stp_kill_time+0x21/0x41 [stap_2872]
Sep 14 09:52:23 dragon kernel:  <f8e63065> _stp_cleanup_and_exit+0x4e/0x62
[stap_2872]  <c04465b4> stop_machine_run+0x2e/0x34
Sep 14 09:52:23 dragon kernel:  <f8e63086> _stp_transport_close+0xd/0x5f
[stap_2872]  <c043eb8b> sys_delete_module+0x192/0x1bb
Sep 14 09:52:23 dragon kernel:  <c045be81> do_munmap+0x196/0x1af  <c0403e3f>

Culprit is in runtime/time.c (_stp_kill_time). I've been successfully running
this rewrite of that function, but it is an ugly hack.

	for_each_online_cpu(cpu) {
		stp_time_t *time = &per_cpu(stp_time, cpu);
		int retries = 0;
		while (!del_timer(&time->timer)) {
			if (retries > 1024) {
				printk("Exceeded retry count in _stp_kill_time\n");

Need to cleanup and understand this better.  See also possibly related bug

           Summary: del_timer_sync causes softlockups
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P1
         Component: runtime
        AssignedTo: systemtap at sources dot redhat dot com
        ReportedBy: hunt at redhat dot com

------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]