Date: 06 Oct 2001 15:31:52 +0200 From: Dag-Erling Smorgrav <des@ofug.org> To: Bruce Evans <bde@zeta.org.au> Cc: Peter Wemm <peter@wemm.org>, <arch@FreeBSD.ORG> Subject: Re: Removing ptrace(2)'s dependency on procfs(5) Message-ID: <xzpvghsrj1z.fsf@flood.ping.uio.no> In-Reply-To: <20011006221156.X824-100000@delplex.bde.org> References: <20011006221156.X824-100000@delplex.bde.org>
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Bruce Evans <bde@zeta.org.au> writes:
> I noticed the following bugs:
> - PHOLD()/PRELE() is now missing from the register access functions of
> ptrace(). This makes the bogus EIO error in PROCFS_ACTION() much less
> unlikely.
Aieee, thanks for catching that before I committed!
BTW, I'm intrigued by the following bit of code in kern_sig.c:
do {
mtx_lock_spin(&sched_lock);
stop(p);
PROC_UNLOCK_NOSWITCH(p);
DROP_GIANT_NOSWITCH();
p->p_stats->p_ru.ru_nivcsw++;
mi_switch();
mtx_unlock_spin(&sched_lock);
PICKUP_GIANT();
PROC_LOCK(p);
} while (!trace_req(p)
&& p->p_flag & P_TRACED);
It's the only reference to trace_req() (defined in sys_process.c) in
the entire tree, and trace_req() has been a constant since revision
1.1 of sys_process.c, and true since revision 1.4 (1994/08/08), so
this loop will always execute exactly once. Is there a good reason
not to simply axe trace_req() and unroll the loop?
DES
--
Dag-Erling Smorgrav - des@ofug.org
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