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Re: Differences of stack traces between linux kernel and systap
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: "Peter Teoh" <htmldeveloper at gmail dot com>
- Cc: systemtap at sources dot redhat dot com
- Date: Fri, 02 May 2008 12:55:36 -0400
- Subject: Re: Differences of stack traces between linux kernel and systap
- References: <804dabb00805020935u643adf07s7225caeac93d9e92@mail.gmail.com>
"Peter Teoh" <htmldeveloper@gmail.com> writes:
> Notice the diference in the stack trace between systap:
>[...]
> And that of the linux kernel (latest patch):
> [<c042bad6>] warn_on_slowpath+0x46/0x56
> [<c0415a33>] ? apic_wait_icr_idle+0x16/0x1d
> [<c0415243>] ? __send_IPI_dest_field+0x50/0x54
>[...]
> The difference lies in the "?" in front of the function, which is to
> indicate that this function has just been executed and returned, so it
> is no longer on the stack.
I'm sorry, I don't know what that could possibly mean. A function
that has executed and returned should leave no traces on the stack.
Can you identify the "latest patch" that purports to implement this?
> Is it possible to modify the systap stacktrace dump to be inlined
> with that of the kernel? It this not more informative?
You mean integrated? Perhaps. In the mean time, a more pressing
thing to do is to get userspace backtraces working.
- FChE