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[Bug runtime/3215] New: del_timer_sync causes softlockups
- From: "hunt at redhat dot com" <sourceware-bugzilla at sourceware dot org>
- To: systemtap at sources dot redhat dot com
- Date: 15 Sep 2006 16:43:53 -0000
- Subject: [Bug runtime/3215] New: del_timer_sync causes softlockups
- Reply-to: sourceware-bugzilla at sourceware dot org
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>
update_process_times+0x39/0x5c
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>
try_to_del_timer_sync+0x11/0x4a
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>
syscall_call+0x7/0xb
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)) {
retries++;
if (retries > 1024) {
printk("Exceeded retry count in _stp_kill_time\n");
break;
}
}
}
Need to cleanup and understand this better. See also possibly related bug
http://sources.redhat.com/bugzilla/show_bug.cgi?id=2989
--
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
http://sourceware.org/bugzilla/show_bug.cgi?id=3215
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