Messages in this thread | | | Date | Mon, 22 Sep 2008 21:20:39 -0400 | From | Mathieu Desnoyers <> | Subject | Re: [PATCH] [RFC] tracehook: Hook in syscall tracing markers. |
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* KOSAKI Motohiro (kosaki.motohiro@jp.fujitsu.com) wrote: > Hi Paul, > > > At kernel summit, the idea that syscall tracing was generally desirable > > for tracing was mentioned several times, as was the argument that kernel > > developers aren't placing markers in meaningful locations. This is a > > simple patch to try and do that for the syscall case. > > > > Presently LTTng attempts to litter these trace markers all over the > > architecture code, primarily to get around the fact that there was no > > generic way to get at this information before. Now that platforms are > > starting to do their syscall entry/exit notifiers through tracehook and > > we have the asm/syscall.h interface, all of this information can be > > generically abstracted. > > > > Signed-off-by: Paul Mundt <lethal@linux-sh.org> > > > > I think marriage between tracehook and generic marker is very good idea. > at least, instruction pointer and return value are definitly useful. > > but... > Have you seen Mathieu's tracepoint patch? > I recommend to use tracepoint insted use marker directly. >
Yep, tracepoints would be better suited for this. They can be found in -tip or in -lttng trees.
Does tracehook have any infrastructure that would give us the system calls parameters (with correct typing ?) :-) Or could they evolve into this ?
Mathieu
> > > --- > > > > include/linux/tracehook.h | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h > > index 6186a78..481ff45 100644 > > --- a/include/linux/tracehook.h > > +++ b/include/linux/tracehook.h > > @@ -49,6 +49,9 @@ > > #include <linux/sched.h> > > #include <linux/ptrace.h> > > #include <linux/security.h> > > +#include <linux/marker.h> > > +#include <asm/syscall.h> > > + > > struct linux_binprm; > > > > /** > > @@ -112,6 +115,8 @@ static inline __must_check int tracehook_report_syscall_entry( > > struct pt_regs *regs) > > { > > ptrace_report_syscall(regs); > > + trace_mark(kernel_arch_syscall_entry, "syscall_id %ld ip #p%ld", > > + syscall_get_nr(NULL, regs), instruction_pointer(regs)); > > return 0; > > } > > > > @@ -135,6 +140,8 @@ static inline __must_check int tracehook_report_syscall_entry( > > static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step) > > { > > ptrace_report_syscall(regs); > > + trace_mark(kernel_arch_syscall_exit, "ret %ld", > > + syscall_get_return_value(NULL, regs)); > > } > >
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