Messages in this thread | | | Subject | Re: [ANNOUNCE][RFC][PATCH] Crash-utility, tracing: enable crash to analyze tracing from core-file (make tracing can act as a flight recorder) | From | Peter Zijlstra <> | Date | Tue, 04 Aug 2009 12:36:52 +0200 |
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On Tue, 2009-08-04 at 14:52 +0800, Lai Jiangshan wrote: > Peter Zijlstra wrote: > > On Mon, 2009-08-03 at 22:48 +0800, Lai Jiangshan wrote: > >> + /* SIGH, we cann't get "print fmt" from core-file */ > > > > doesn't crash have a vmlinux around to look at? > > > I don't known how to look at it: > > static int \ > ftrace_format_##call(struct trace_seq *s) \ > { \ > struct ftrace_raw_##call field __attribute__((unused)); \ > int ret = 0; \ > \ > tstruct; \ > \ > trace_seq_printf(s, "\nprint fmt: " print); \ > \ > return ret; \ > } > > We need the address of the const string <"\nprint fmt: " print>, > I don't know how to get it current from vmlinux. > > I have sent a patch which try to reduce the size of .txt in kernel > and reduce coupling. This patch has a little side-effect: > the "print fmt"'s address is saved in struct ftrace_event_call.
Aah, right, I thought the fmt string was easily obtainable from the _ftrace_events section, but now I see it is not, the patch you mention below does indeed make it so.
> [ > http://lkml.org/lkml/2009/7/30/30 > > This patch is really useful for kernel. We don't change the kernel > even a single line for the purpose of we can read the core-file easier.
Well, I see no harm in changing the kernel a little when it makes no difference to the kernel but makes post-mortem analysis a little bit easier.
> This patch is also helpful for crash more or less. So I mention it. > ]
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