[ltt-dev] Kernel crashes when creating a trace

[Mathieu Desnoyers]

* Ashwin Tanugula (ashwin.tanugula at broadcom.com) wrote:
> Hi Mathieu,
> 
> >Yes, there is one thing: if you could put "return 1;" at the beginning of the mips trace clock functions, and ensure that the get_ put_ trace >clock (and the same for kernel/trace/trace-clock-32-to-64.c) also return without doing nothing, then we could see if it still hangs.
> 
> >Clearly the trace generated won't have any timestamps, so won't be useful, but at least it would allow us to pinpoint where the culprit is.
> 
> Here is what I see now, after putting "return 1;" in get_trace_clock and put_trace_clock functions in arch/mips/kernel/trace-clock.c and kernel/trace/trace-clock.c. kernel/trace/trace-clock-32-to-64.c does not have any get_trace_clock and put_trace_clock functions.
> 

Can you also try with a return 1; at the beginning of

trace_clock_async_tsc_read

?

Thanks,

Mathieu

> Call Trace:
> [<80018b8c>] dump_stack+0x8/0x34
> [<800410b4>] warn_slowpath_common+0x70/0x98
> [<8001be98>] trace_clock_async_tsc_read+0x2c/0x17c
> [<80233e1c>] ltt_trace_alloc+0x55c/0x56c
> [<80240310>] alloc_write+0x130/0x17c
> [<800c5540>] vfs_write+0xbc/0x180
> [<800c6048>] sys_write+0x60/0x130
> [<8000339c>] stack_done+0x20/0x3c
> 
> ---[ end trace 1d754008291a440c ]---
> ------------[ cut here ]------------
> WARNING: at arch/mips/kernel/trace-clock.c:77 trace_clock_async_tsc_read+0x2c/0x17c()
> Modules linked in:
> Call Trace:
> [<80018b8c>] dump_stack+0x8/0x34
> [<800410b4>] warn_slowpath_common+0x70/0x98
> [<8001be98>] trace_clock_async_tsc_read+0x2c/0x17c
> [<80089f3c>] trace_clock_read_synthetic_tsc+0x94/0xbc
> [<8001beec>] trace_clock_async_tsc_read+0x80/0x17c
> [<80233e1c>] ltt_trace_alloc+0x55c/0x56c
> [<80240310>] alloc_write+0x130/0x17c
> [<800c5540>] vfs_write+0xbc/0x180
> [<800c6048>] sys_write+0x60/0x130
> [<8000339c>] stack_done+0x20/0x3c
> 
> ---[ end trace 1d754008291a440d ]---
> 
> Here's the old call trace:
> 
> Controlling tModules linked in:race : trace1
> 
> 
> lttctl: CreatinCall Trace:
> g trace
> [<80018b84>] dump_stack+0x8/0x34
> [<8003e59c>] warn_slowpath_common+0x70/0x98 [<8001bfc0>] trace_clock_async_tsc_read+0x30/0x17c
> [<80086a18>] trace_clock_read_synthetic_tsc+0x94/0xbc
> [<80086d14>] get_synthetic_tsc+0xe0/0x1a0 [<8001c1b0>] get_trace_clock+0x34/0x17c [<8023019c>] ltt_trace_alloc+0x60/0x56c [<8023cb8c>] alloc_write+0x130/0x17c [<800c201c>] vfs_write+0xbc/0x180 [<800c2b24>] sys_write+0x60/0x130 [<8000339c>] stack_done+0x20/0x3c
> 
> ---[ end trace 8ffc6c83ddb229ea ]---
> ------------[ cut here ]------------
> WARNING: at arch/mips/kernel/trace-clock.c:77 trace_clock_async_tsc_read+0x30/0x17c()
> Modules linked in:
> Call Trace:
> [<80018b84>] dump_stack+0x8/0x34
> [<8003e59c>] warn_slowpath_common+0x70/0x98 [<8001bfc0>] trace_clock_async_tsc_read+0x30/0x17c
> [<80086a18>] trace_clock_read_synthetic_tsc+0x94/0xbc
> [<8001c014>] trace_clock_async_tsc_read+0x84/0x17c
> [<80086a18>] trace_clock_read_synthetic_tsc+0x94/0xbc
> [<80086d14>] get_synthetic_tsc+0xe0/0x1a0 [<8001c1b0>] get_trace_clock+0x34/0x17c [<8023019c>] ltt_trace_alloc+0x60/0x56c [<8023cb8c>] alloc_write+0x130/0x17c [<800c201c>] vfs_write+0xbc/0x180 [<800c2b24>] sys_write+0x60/0x130 [<8000339c>] stack_done+0x20/0x3c
> 
> ---[ end trace 8ffc6c83ddb229eb ]---
> 
> 
> Thanks,
> Ashwin
> 
> 

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68