[Crash-utility] bt: cannot determine starting stack pointer
Dave Anderson
anderson at redhat.com
Tue Feb 14 19:07:23 UTC 2012
----- Original Message -----
> Hi,
>
> I need the stack traces of the tasks that are on-proc as well as the
> tasks that are not. "bt" fails for the on-proc tasks, even though there
> is a backup mechanism for finding the stack: the "stack" field of the
> task structure. Even if it is a bit out-of-date, it is better than an
> "I dunno" message. Perhaps augment the stack trace with a "this
> might be slightly out-of-date because the task was running when
> the kernel crashed" message.
>
> Example:
>
> crash> foreach bt
> [...]
> PID: 20311 TASK: ffff8803ff654140 CPU: 9 COMMAND: "xtnhc"
> bt: cannot determine starting stack pointer
> [...]
> crash> ps | egrep '^>'
> > 0 0 4 ffff880205f6b0c0 RU 0.0 0 0 [swapper]
> > 0 0 5 ffff880205f77870 RU 0.0 0 0 [swapper]
> > 0 0 7 ffff880205d557f0 RU 0.0 0 0 [swapper]
> > 0 0 10 ffff880205d5c080 RU 0.0 0 0 [swapper]
> > 2982 2 11 ffff8801fd3b07f0 RU 0.0 0 0 [ldlm_cb_00]
> > 2983 2 8 ffff880205548080 RU 0.0 0 0 [ldlm_cb_01]
> > 20250 20245 1 ffff880202deb0c0 RU 0.0 82388 2372 fcntl17
> > 20251 20245 2 ffff88020537b7b0 RU 0.0 82388 2396 fcntl17
> > 20252 20245 3 ffff8801fd3b4770 RU 0.0 82388 2376 fcntl17
> > 20264 20249 0 ffff8801fd444830 RU 0.0 0 0 fcntl17
> > 20290 1 6 ffff8803fe86f7b0 RU 0.0 14044 516 xtnhc
> > 20311 20305 9 ffff8803ff654140 RU 0.0 14044 516 xtnhc
> crash> set ffff8803ff654140
> PID: 20311
> COMMAND: "xtnhc"
> TASK: ffff8803ff654140 [THREAD_INFO: ffff8803fd85a000]
> CPU: 9
> STATE: TASK_RUNNING (ACTIVE)
> crash> p task->stack
> p: gdb request failed: p task->stack
> crash> task
> PID: 20311 TASK: ffff8803ff654140 CPU: 9 COMMAND: "xtnhc"
> struct task_struct {
> state = 0,
> stack = 0xffff8803fd85a000,
> [...]
> crash> bt -S 0xffff8803fd85a000
> PID: 20311 TASK: ffff8803ff654140 CPU: 9 COMMAND: "xtnhc"
> #0 [ffff8803fd85a000] schedule at ffffffff81297bc5
> #1 [ffff8803fd85b830] ldlm_resource_get at ffffffffa0269380 [ptlrpc]
> #2 [ffff8803fd85b900] ldlm_lock_match at ffffffffa0267359 [ptlrpc]
> #3 [ffff8803fd85ba10] mdc_revalidate_lock at ffffffffa0423a8e [mdc]
> #4 [ffff8803fd85bac0] mdc_intent_lock at ffffffffa042723f [mdc]
> #5 [ffff8803fd85bbc0] __ll_inode_revalidate_it at ffffffffa04a79c2 [lustre]
> #6 [ffff8803fd85bcf0] ll_inode_permission at ffffffffa04a8266 [lustre]
> #7 [ffff8803fd85bd90] inode_permission at ffffffff810f0a09
> #8 [ffff8803fd85bda0] may_open at ffffffff810f14d7
> #9 [ffff8803fd85bdd0] do_filp_open at ffffffff810f5294
> #10 [ffff8803fd85bf20] do_sys_open at ffffffff810e5850
> #11 [ffff8803fd85bf70] sys_open at ffffffff810e596b
> #12 [ffff8803fd85bf80] system_call_fastpath at ffffffff81002eab
> RIP: 00007ffff78f2f80 RSP: 00007fffffffd818 RFLAGS: 00010202
> RAX: 0000000000000002 RBX: ffffffff81002eab RCX: 00000000006130f0
> RDX: 00000000000001b6 RSI: 0000000000000000 RDI: 000000000060f960
> RBP: 0000000000000008 R8: 0000000000000008 R9: 0000000000000001
> R10: 000000000040a261 R11: 0000000000000246 R12: ffffffff810e596b
> R13: ffff8803fd85bf78 R14: 0000000000000000 R15: 0000000000000000
> ORIG_RAX: 0000000000000002 CS: 0033 SS: 002b
> crash>
You could also try "bt -t" or "bt -T".
But what kind of dumpfile was this anyway? I'm wondering why you aren't
getting any stack traces at all for the active tasks?
Dave
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