On Wed, Oct 01, 2008 at 02:18:55PM +0200, Vladimir Kotal wrote:
>
> Hi all,
>
> I am trying to write a D script which would print ustack() for every
> program in the system receiving SIGSEGV. All the stacks printed in
> trap()/sigtoproc() context do not have meaningful symbols.
>
> The following solves the problem to some degree but I'd much rather have
> a self-contained D script.
>
> dtrace -w -n 'fbt:genunix:sigtoproc:entry/arg2 == 11/ {
> self->pid=((proc_t *)arg0)->p_pidp->pid_id; stop();
> system("/usr/bin/gcore %d", self->pid); system("/usr/bin/prun %d",
> self->pid); }'
This is stopping the signal sender, not the signal receiver.
#!/usr/sbin/dtrace -s
#pragma D option destructive
#pragma D option quiet
proc:::signal-send
/args[2] == SIGSEGV/
{
segv_sent[args[1]->pr_addr] = 1;
}
fbt::issig_forreal:entry
/segv_sent[(uintptr_t)curthread->t_procp]/
{
segv_sent[(uintptr_t)curthread->t_procp] = 0;
printf("%6d %s\n", pid, curpsinfo->pr_psargs);
ustack(20);
stop();
system("/usr/bin/prun %d", pid);
}
This should work regardless of the source of the segv. (the main trick is
calling stop() at the top of issig_forreal(); that will stop the process before
the SEGV is processed, letting dtrace get a stack trace from it.)
Cheers,
- jonathan
> Any ideas (or code) will be appreciated,
>
>
> v.
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