From: Samuel Thibault <samuel.thibault@gnu.org>
To: Sergey Bugaev <bugaevc@gmail.com>
Cc: libc-alpha@sourceware.org, bug-hurd@gnu.org
Subject: Re: [RFC PATCH glibc 25/34] hurd: Improve reply port handling when exiting signal handlers
Date: Tue, 11 Apr 2023 00:03:11 +0200 [thread overview]
Message-ID: <20230410220311.fecuaj4gicx3hh5l@begin> (raw)
In-Reply-To: <20230319151017.531737-26-bugaevc@gmail.com>
Applied, thanks!
Sergey Bugaev, le dim. 19 mars 2023 18:10:08 +0300, a ecrit:
> NOTE: I don't really understand why sigunwind wants to destroy both its
> current reply port and user's reply port. Prior to commit
> fb304035c41c7ee2afede51e5e8568974549ba5e, it was *restoring* the user's
> reply port, in which case it actually made sense to destroy the current
> reply port. Post-fb304035c41c7ee2afede51e5e8568974549ba5e, wouldn't it
> be better to just keep using the current reply port, destroying the
> user's one?
We could try that, yes.
I tend to be very cautious with reply port reuse since it can confuse
servers a lot when e.g. interrupted, so it's generally safer not to try
to reuse them.
> hurd/sigunwind.c | 24 +++++++++++-------------
> sysdeps/mach/hurd/i386/sigreturn.c | 21 +++++----------------
> 2 files changed, 16 insertions(+), 29 deletions(-)
>
> diff --git a/hurd/sigunwind.c b/hurd/sigunwind.c
> index edd40b14..399e6900 100644
> --- a/hurd/sigunwind.c
> +++ b/hurd/sigunwind.c
> @@ -18,7 +18,6 @@
>
> #include <hurd.h>
> #include <thread_state.h>
> -#include <hurd/threadvar.h>
> #include <jmpbuf-unwind.h>
> #include <assert.h>
> #include <stdint.h>
> @@ -39,19 +38,18 @@ _hurdsig_longjmp_from_handler (void *data, jmp_buf env, int val)
> {
> /* Destroy the MiG reply port used by the signal handler, and restore
> the reply port in use by the thread when interrupted. */
> - mach_port_t *reply_port = &__hurd_local_reply_port;
> - if (*reply_port)
> - {
> - mach_port_t port = *reply_port;
> - /* Assigning MACH_PORT_DEAD here tells libc's mig_get_reply_port
> - not to get another reply port, but avoids mig_dealloc_reply_port
> - trying to deallocate it after the receive fails (which it will,
> - because the reply port will be bogus, regardless). */
> - *reply_port = MACH_PORT_DEAD;
> - __mach_port_destroy (__mach_task_self (), port);
> - }
> + mach_port_t reply_port = THREAD_GETMEM (THREAD_SELF, reply_port);
> + /* Assigning MACH_PORT_DEAD here tells libc's mig_get_reply_port not to
> + get another reply port, but avoids mig_dealloc_reply_port trying to
> + deallocate it after the receive fails (which it will, because the
> + reply port will be bogus, regardless). */
> + THREAD_SETMEM (THREAD_SELF, reply_port, MACH_PORT_DEAD);
> + if (MACH_PORT_VALID (reply_port))
> + __mach_port_mod_refs (__mach_task_self (), reply_port,
> + MACH_PORT_RIGHT_RECEIVE, -1);
> if (scp->sc_reply_port)
> - __mach_port_destroy (__mach_task_self (), scp->sc_reply_port);
> + __mach_port_mod_refs (__mach_task_self (), scp->sc_reply_port,
> + MACH_PORT_RIGHT_RECEIVE, -1);
> }
>
> __spin_lock (&ss->lock);
> diff --git a/sysdeps/mach/hurd/i386/sigreturn.c b/sysdeps/mach/hurd/i386/sigreturn.c
> index db1a01f3..29c9629f 100644
> --- a/sysdeps/mach/hurd/i386/sigreturn.c
> +++ b/sysdeps/mach/hurd/i386/sigreturn.c
> @@ -19,7 +19,6 @@ register int *sp asm ("%esp");
>
> #include <hurd.h>
> #include <hurd/signal.h>
> -#include <hurd/threadvar.h>
> #include <hurd/msg.h>
> #include <stdlib.h>
> #include <string.h>
> @@ -59,7 +58,7 @@ __sigreturn (struct sigcontext *scp)
> {
> struct hurd_sigstate *ss;
> struct hurd_userlink *link = (void *) &scp[1];
> - mach_port_t *reply_port;
> + mach_port_t reply_port;
>
> if (scp == NULL || (scp->sc_mask & _SIG_CANT_MASK))
> {
> @@ -101,20 +100,10 @@ __sigreturn (struct sigcontext *scp)
>
> /* Destroy the MiG reply port used by the signal handler, and restore the
> reply port in use by the thread when interrupted. */
> - reply_port = &__hurd_local_reply_port;
> - if (*reply_port)
> - {
> - mach_port_t port = *reply_port;
> -
> - /* Assigning MACH_PORT_DEAD here tells libc's mig_get_reply_port not to
> - get another reply port, but avoids mig_dealloc_reply_port trying to
> - deallocate it after the receive fails (which it will, because the
> - reply port will be bogus, whether we do this or not). */
> - *reply_port = MACH_PORT_DEAD;
> -
> - __mach_port_destroy (__mach_task_self (), port);
> - }
> - *reply_port = scp->sc_reply_port;
> + reply_port = THREAD_GETMEM (THREAD_SELF, reply_port);
> + THREAD_SETMEM (THREAD_SELF, reply_port, scp->sc_reply_port);
> + __mach_port_mod_refs (__mach_task_self (), reply_port,
> + MACH_PORT_RIGHT_RECEIVE, -1);
>
> if (scp->sc_fpused)
> /* Restore the FPU state. Mach conveniently stores the state
> --
> 2.39.2
>
--
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.
next prev parent reply other threads:[~2023-04-10 22:03 UTC|newest]
Thread overview: 140+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-19 15:09 [RFC PATCH 00/34] The rest of the x86_64-gnu port Sergey Bugaev
2023-03-19 15:09 ` [RFC PATCH gnumach 01/34] Add i386_fsgs_base_state Sergey Bugaev
2023-04-02 22:43 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH gnumach 02/34] Remove bootstrap.defs Sergey Bugaev
2023-04-02 22:43 ` Samuel Thibault
2023-04-03 9:39 ` Sergey Bugaev
2023-03-19 15:09 ` [RFC PATCH gnumach 03/34] Make exception subcode a long Sergey Bugaev
2023-04-02 22:45 ` Samuel Thibault
2023-04-03 9:32 ` Sergey Bugaev
2023-04-06 2:11 ` Flávio Cruz
2023-04-10 23:52 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 04/34] hurd: " Sergey Bugaev
2023-04-02 22:52 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 05/34] hurd: Remove __hurd_threadvar_stack_{offset,mask} Sergey Bugaev
2023-04-02 22:53 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 06/34] hurd: Swap around two function calls Sergey Bugaev
2023-04-02 22:54 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 07/34] hurd: Fix file name in #error Sergey Bugaev
2023-04-02 22:55 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 08/34] hurd: Disable O_TRUNC and FS_RETRY_MAGICAL in rtld Sergey Bugaev
2023-04-02 22:57 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 09/34] hurd: Fix _hurd_setup_sighandler () signature Sergey Bugaev
2023-04-02 22:58 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 10/34] stdio-common: Fix building when !IS_IN (libc) Sergey Bugaev
2023-04-02 23:01 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 11/34] mach, hurd: Drop __libc_lock_self0 Sergey Bugaev
2023-04-02 23:02 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 12/34] hurd: More 64-bit integer casting fixes Sergey Bugaev
2023-04-02 23:03 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 13/34] x86-64: Disable prefer_map_32bit_exec tunable on non-Linux Sergey Bugaev
2023-04-02 23:09 ` Samuel Thibault
2023-04-03 10:10 ` Sergey Bugaev
2023-04-03 19:02 ` H.J. Lu
2023-04-03 20:11 ` Sergey Bugaev
2023-03-19 15:09 ` [RFC PATCH glibc 14/34] hurd: Move rtld-strncpy-c.c out of mach/hurd/ Sergey Bugaev
2023-04-02 23:10 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 15/34] hurd: Use uintptr_t for register values in trampoline.c Sergey Bugaev
2023-04-02 23:13 ` Samuel Thibault
2023-03-19 15:09 ` [RFC PATCH glibc 16/34] hurd: Add sys/ucontext.h and sigcontext.h for x86_64 Sergey Bugaev
2023-04-10 18:39 ` Samuel Thibault
2023-04-10 19:07 ` Sergey Bugaev
2023-04-10 19:21 ` Samuel Thibault
2023-04-10 18:58 ` Samuel Thibault
2023-04-10 19:13 ` Sergey Bugaev
2023-04-10 19:21 ` Samuel Thibault
2023-04-10 21:50 ` Sergey Bugaev
2023-04-10 22:23 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 17/34] hurd: Implement x86_64/intr-msg.h Sergey Bugaev
2023-04-10 18:41 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 18/34] hurd: Port trampoline.c to x86_64 Sergey Bugaev
2023-04-03 11:56 ` [PATCH v2 18.0/34] Alignment-respecting x86_64 trampoline.c Sergey Bugaev
2023-04-03 11:56 ` [PATCH v2 18.1/34] hurd: Do not declare local variables volatile Sergey Bugaev
2023-04-10 18:42 ` Samuel Thibault
2023-04-03 11:56 ` [PATCH v2 18.2/34] hurd: Port trampoline.c to x86_64 Sergey Bugaev
2023-04-10 19:04 ` Samuel Thibault
2023-04-10 21:33 ` Sergey Bugaev
2023-03-19 15:10 ` [RFC PATCH glibc 19/34] hurd: Move a couple of singal-related files to x86 Sergey Bugaev
2023-04-02 23:15 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 20/34] htl: Add tcb-offsets.sym for x86_64 Sergey Bugaev
2023-04-02 23:16 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 21/34] x86_64: Add rtld-stpncpy & rtld-strncpy Sergey Bugaev
2023-04-02 23:18 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 22/34] htl: Implement thread_set_pcsptp for x86_64 Sergey Bugaev
2023-04-02 23:19 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 23/34] elf: Stop including tls.h in ldsodefs.h Sergey Bugaev
2023-04-02 23:20 ` Samuel Thibault
2023-04-03 9:26 ` Sergey Bugaev
2023-04-10 21:26 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 24/34] hurd: Only check for TLS initialization inside rtld or in static builds Sergey Bugaev
2023-04-10 21:33 ` Samuel Thibault
2023-04-11 18:57 ` Samuel Thibault
2023-04-11 19:18 ` Samuel Thibault
2023-04-11 20:03 ` Samuel Thibault
2023-04-11 20:27 ` Sergey Bugaev
2023-04-11 21:23 ` Samuel Thibault
2023-04-12 8:36 ` Sergey Bugaev
2023-04-12 9:00 ` Samuel Thibault
2023-04-12 10:42 ` Sergey Bugaev
2023-04-12 10:45 ` Samuel Thibault
2023-04-12 17:18 ` Sergey Bugaev
2023-04-12 23:46 ` Samuel Thibault
2023-04-13 10:02 ` Sergey Bugaev
2023-04-13 10:10 ` Samuel Thibault
2023-04-13 12:17 ` Sergey Bugaev
2023-04-13 21:47 ` Samuel Thibault
2023-04-13 22:21 ` Samuel Thibault
2023-04-14 8:29 ` Sergey Bugaev
2023-04-14 8:36 ` Samuel Thibault
2023-04-14 8:53 ` Sergey Bugaev
2023-04-14 9:09 ` Samuel Thibault
2023-04-14 9:23 ` Sergey Bugaev
2023-04-14 9:31 ` Samuel Thibault
2023-04-17 7:16 ` Samuel Thibault
2023-04-14 17:34 ` Samuel Thibault
2023-04-14 19:52 ` Sergey Bugaev
2023-03-19 15:10 ` [RFC PATCH glibc 25/34] hurd: Improve reply port handling when exiting signal handlers Sergey Bugaev
2023-04-10 22:03 ` Samuel Thibault [this message]
2023-04-11 7:44 ` Sergey Bugaev
2023-04-11 20:15 ` Samuel Thibault
2023-04-11 20:35 ` Sergey Bugaev
2023-04-12 22:54 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 26/34] hurd: Remove __hurd_local_reply_port Sergey Bugaev
2023-04-10 22:07 ` Samuel Thibault
2023-04-10 22:35 ` Samuel Thibault
2023-04-11 8:00 ` Sergey Bugaev
2023-04-11 20:18 ` Samuel Thibault
2023-04-13 11:58 ` [RFC PATCH glibc v2 " Sergey Bugaev
2023-04-13 13:12 ` Samuel Thibault
2023-04-13 13:20 ` Sergey Bugaev
2023-04-13 21:28 ` Samuel Thibault
2023-04-14 17:33 ` Samuel Thibault
2023-04-14 20:29 ` Sergey Bugaev
2023-04-15 6:45 ` Samuel Thibault
2023-04-15 7:34 ` Sergey Bugaev
2023-04-15 7:42 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 27/34] hurd: Don't leak __hurd_reply_port0 Sergey Bugaev
2023-04-10 22:25 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 28/34] hurd: Implement _hurd_longjmp_thread_state for x86_64 Sergey Bugaev
2023-04-02 23:23 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 29/34] hurd: Add vm_param.h " Sergey Bugaev
2023-04-02 23:24 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 30/34] hurd: Implement longjmp " Sergey Bugaev
2023-03-19 15:10 ` [RFC PATCH glibc 31/34] hurd: Microoptimize _hurd_self_sigstate () Sergey Bugaev
2023-04-02 23:26 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 32/34] hurd: Implement sigreturn for x86_64 Sergey Bugaev
2023-04-03 11:47 ` [PATCH v2] " Sergey Bugaev
2023-03-19 15:10 ` [RFC PATCH glibc 33/34] hurd: Create abilist files for lib{mach,hurd}user Sergey Bugaev
2023-03-19 15:19 ` Samuel Thibault
2023-03-19 15:39 ` Sergey Bugaev
2023-03-19 15:43 ` Samuel Thibault
2023-03-19 15:10 ` [RFC PATCH glibc 34/34] hurd: Add expected abilist files for x86_64 Sergey Bugaev
2023-03-19 18:04 ` Florian Weimer
2023-03-19 20:14 ` [PATCH v2] " Sergey Bugaev
2023-03-20 6:30 ` Florian Weimer
2023-03-19 16:44 ` [RFC PATCH 00/34] The rest of the x86_64-gnu port Luca
2023-03-20 5:03 ` Flávio Cruz
2023-04-02 23:30 ` Samuel Thibault
2023-04-10 19:20 ` Samuel Thibault
2023-04-10 21:24 ` Sergey Bugaev
2023-04-10 21:27 ` Samuel Thibault
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230410220311.fecuaj4gicx3hh5l@begin \
--to=samuel.thibault@gnu.org \
--cc=bug-hurd@gnu.org \
--cc=bugaevc@gmail.com \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).