Hi,
I got a problem where it seemed crash got a bad backtrace.
The problem occurred under the following conditions:
On a qemu guest system loading a module that stuck at
the init function(say, call a function that did deadlooping),
then dumped the guest by `virsh dump vm dumpfile', and run
crash on the dumpfile.
The module is:
---
#include <linux/module.h>
int endless_loop(void)
{
printk("endless loop\n");
while (1);
return 0;
}
int __init endless_init(void)
{
endless_loop();
return 0;
}
module_init(endless_init);
MODULE_LICENSE("GPL");
---
crash bt command got:
crash> bt -a
PID: 0 TASK: ffffffff81648020 CPU: 0 COMMAND: "swapper"
#0 [ffffffff81601e08] schedule at ffffffff813e8a49
#1 [ffffffff81601e18] apic_timer_interrupt at ffffffff8100344e
#2 [ffffffff81601ea0] need_resched at ffffffff8100970c
#3 [ffffffff81601eb0] default_idle at ffffffff81009f6b
#4 [ffffffff81601ec0] cpu_idle at ffffffff81001bf5
PID: 1088 TASK: ffff88001dda2d60 CPU: 1 COMMAND: "insmod"
#0 [ffff88001e751dc8] schedule at ffffffff813e8a49
#1 [ffff88001e751dd0] schedule at ffffffff813e8aec
#2 [ffff88001e751e80] preempt_schedule_irq at ffffffff813e8c90
#3 [ffff88001e751e90] retint_kernel at ffffffff813eab86
#4 [ffff88001e751f20] do_one_initcall at ffffffff81000210
#5 [ffff88001e751f50] sys_init_module at ffffffff8106b7ca
#6 [ffff88001e751f80] system_call_fastpath at ffffffff81002a82
RIP: 00007f761bb58b7a RSP: 00007fff67a43120 RFLAGS: 00010206
RAX: 00000000000000af RBX: ffffffff81002a82 RCX: 0000000000020010
RDX: 0000000000b96010 RSI: 00000000000163da RDI: 0000000000b96030
RBP: 0000000000b96010 R8: 0000000000010011 R9: 0000000000080000
R10: 00007f761bb4b140 R11: 0000000000000202 R12: 00000000000163da
R13: 00007fff67a44985 R14: 00000000000163da R15: 0000000000b96010
ORIG_RAX: 00000000000000af CS: 0033 SS: 002b
Does it lose some function calls between do_one_initcall and retint_kernel?
(endless_loop <- endless_init)
--
Thanks,
Hu Tao
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