Sergey Bugaev, le mar. 18 avril 2023 13:21:50 +0300, a ecrit:
> (Git managed to eat my email -- it both sent an empty one *and*
> truncated my local file (what?); so retyping and resending this.)
>
> On Tue, Apr 18, 2023 at 2:23 AM Samuel Thibault <samuel.thiba...@gnu.org>
> wrote:
> > That doesn't seem to be true, we get segfaults with this patch applied
> > in these tests:
> >
> > ./htl/tst-kill6.test-result:FAIL: htl/tst-kill6
> > ./htl/tst-pt-tls2.test-result:FAIL: htl/tst-pt-tls2
> >
> > #0 0x0105a7c2 in sigstate_is_global_rcv (ss=0x0) at hurdsig.c:183
> > 183 && (ss->actions[0].sa_handler == SIG_IGN);
> > (gdb) bt
> > #0 0x0105a7c2 in sigstate_is_global_rcv (ss=0x0) at hurdsig.c:183
> > #1 __GI__hurd_sigstate_lock (ss=0x0) at hurdsig.c:192
> > #2 0x0108bb17 in __sigreturn (scp=0x2104bec) at
> > ../sysdeps/mach/hurd/i386/sigreturn.c:94
> > #3 0x010602f6 in trampoline () from ./libc.so.0.3
>
> Interesting; so while the sigstate for the thread must have been
> initialized, it seems it has never been installed into the
> tcb->_hurd_sigstate slot, because the thread has never called
> _hurd_self_sigstate (). So we have to make the full call to
> _hurd_self_sigstate () the first time, to find the sigstate and
> install it into the slot.
>
> Please try this:
That one works fine, applied, thanks!
> Sergey
>
> ---- >8 ----
>
>
> From 94fc9499390b4de9fbe10c3014d473ac42878c6a Mon Sep 17 00:00:00 2001
> From: Sergey Bugaev <buga...@gmail.com>
> Date: Fri, 14 Apr 2023 16:32:45 +0300
> Subject: [PATCH] hurd: Microoptimize sigreturn
>
> Signed-off-by: Sergey Bugaev <buga...@gmail.com>
> ---
> sysdeps/mach/hurd/i386/sigreturn.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/sysdeps/mach/hurd/i386/sigreturn.c
> b/sysdeps/mach/hurd/i386/sigreturn.c
> index a0fc8891..1686734d 100644
> --- a/sysdeps/mach/hurd/i386/sigreturn.c
> +++ b/sysdeps/mach/hurd/i386/sigreturn.c
> @@ -29,7 +29,12 @@ static void
> __sigreturn2 (int *usp, struct sigcontext *scp)
> {
> mach_port_t reply_port;
> - struct hurd_sigstate *ss = _hurd_self_sigstate ();
> + struct hurd_sigstate *ss;
> +
> + /* We know the sigstate must be initialized by the call below, but the
> + compiler does not. Help it out a little bit by eliding the check that
> + _hurd_self_sigstate makes otherwise. */
> + ss = THREAD_GETMEM (THREAD_SELF, _hurd_sigstate);
> _hurd_sigstate_unlock (ss);
>
> /* Destroy the MiG reply port used by the signal handler, and restore the
> @@ -44,7 +49,7 @@ __sigreturn2 (int *usp, struct sigcontext *scp)
> do. */
> reply_port = THREAD_GETMEM (THREAD_SELF, reply_port);
> THREAD_SETMEM (THREAD_SELF, reply_port, MACH_PORT_DEAD);
> - if (MACH_PORT_VALID (reply_port))
> + if (__glibc_likely (MACH_PORT_VALID (reply_port)))
> (void) __mach_port_mod_refs (__mach_task_self (), reply_port,
> MACH_PORT_RIGHT_RECEIVE, -1);
> THREAD_SETMEM (THREAD_SELF, reply_port, scp->sc_reply_port);
> @@ -69,6 +74,7 @@ __sigreturn2 (int *usp, struct sigcontext *scp)
> /* Firewall. */
> A (hlt);
> #undef A
> + __builtin_unreachable ();
> }
>
> int
> @@ -77,7 +83,7 @@ __sigreturn (struct sigcontext *scp)
> struct hurd_sigstate *ss;
> struct hurd_userlink *link = (void *) &scp[1];
>
> - if (scp == NULL || (scp->sc_mask & _SIG_CANT_MASK))
> + if (__glibc_unlikely (scp == NULL || (scp->sc_mask & _SIG_CANT_MASK)))
> {
> errno = EINVAL;
> return -1;
> --
> 2.39.2
>
--
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.
