Re: signals logged / [RFC] log out-of-virtual-memory events

From: Folkert van Heusden
Date: Sun May 20 2007 - 12:12:17 EST


> > > >>>>I do not see such on i386, so why for x86_64?
> > > >>>So that you know that one of your programs crashed. That's a feature.
> > > >>This feature could be handy for i386 too.
> > > >Since 2.6.18.2 I use this patch. With 2.6.21.1 it still applies altough
> > > >with a small offsets. Works like a charm.
> > > >
> > > >Signed-off by: Folkert van Heusden <folkert@xxxxxxxxxxxxxx>
> > > >--- linux-2.6.18.2/kernel/signal.c 2006-11-04 02:33:58.000000000 +0100
> > > >+++ linux-2.6.18.2.new/kernel/signal.c 2006-11-17 15:59:13.000000000 +0100
> > ...
> > > >+ sig, t -> pid, t -> uid, t -> gid, t -> comm);
> > >
> > > Please check line 219 of Documentation/CodingStyle, Section 3.1: Spaces
> > > and no space around the '.' and "->" structure member operators.
> > New version without the spaces around '->' and a nice 'unlikely' added.
> > Signed-off by: Folkert van Heusden <folkert@xxxxxxxxxxxxxx>
> > --- linux-2.6.18.2/kernel/signal.c 2006-11-04 02:33:58.000000000 +0100
> > +++ linux-2.6.18.2.new/kernel/signal.c 2006-11-17 15:59:13.000000000 +0100
> > @@ -706,6 +706,15 @@
> > struct sigqueue * q = NULL;
> > int ret = 0;
> >
> > + if (unlikely(sig == SIGQUIT || sig == SIGILL || sig == SIGTRAP ||
> > + sig == SIGABRT || sig == SIGBUS || sig == SIGFPE ||
> > + sig == SIGSEGV || sig == SIGXCPU || sig == SIGXFSZ ||
> > + sig == SIGSYS || sig == SIGSTKFLT))
> > + {
> > + printk(KERN_WARNING "Sig %d send to %d owned by %d.%d (%s)\n",
> > + sig, t->pid, t->uid, t->gid, t->comm);
> > + }
> > +
> > /*
> > * fast-pathed signals for kernel-internal things like SIGSTOP
> > * or SIGKILL.
>
> Would turning that into a switch() generate better code.

Doubt it: in the worst case you still nee to check for each possibility.
Furthermore a.f.a.i.k. with switch you cannot do 'unlinkely()'.


Folkert van Heusden

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