From: Samuel Thibault <samuel.thibault@gnu.org>
To: Sergey Bugaev <bugaevc@gmail.com>
Cc: libc-alpha@sourceware.org, bug-hurd@gnu.org, Luca <luca@orpolo.org>
Subject: Re: [PATCH 1/2] hurd: Don't migrate reply port into __init1_tcbhead
Date: Fri, 21 Apr 2023 03:02:33 +0200 [thread overview]
Message-ID: <20230421010233.fxweek6s74lakj7l@begin> (raw)
In-Reply-To: <20230420184220.300862-1-bugaevc@gmail.com>
Applied, thanks!
Sergey Bugaev, le jeu. 20 avril 2023 21:42:19 +0300, a ecrit:
> Properly differentiate between setting up the real TLS with
> TLS_INIT_TP, and setting up the early TLS (__init1_tcbhead) in static
> builds. In the latter case, don't yet migrate the reply port into the
> TCB, and don't yet set __libc_tls_initialized to 1.
>
> This also lets us move the __init1_desc assignment inside
> _hurd_tls_init ().
>
> Fixes cd019ddd892e182277fadd6aedccc57fa3923c8d
> "hurd: Don't leak __hurd_reply_port0"
>
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
> sysdeps/mach/hurd/i386/tls.h | 18 ++++++++++++------
> sysdeps/mach/hurd/x86/init-first.c | 7 +------
> sysdeps/mach/hurd/x86_64/tls.h | 11 ++++++-----
> 3 files changed, 19 insertions(+), 17 deletions(-)
>
> diff --git a/sysdeps/mach/hurd/i386/tls.h b/sysdeps/mach/hurd/i386/tls.h
> index 0ac8917a..e124fb10 100644
> --- a/sysdeps/mach/hurd/i386/tls.h
> +++ b/sysdeps/mach/hurd/i386/tls.h
> @@ -136,7 +136,7 @@ __LIBC_NO_TLS (void)
> special attention since 'errno' is not yet available and if the
> operation can cause a failure 'errno' must not be touched. */
> static inline bool __attribute__ ((unused))
> -_hurd_tls_init (tcbhead_t *tcb)
> +_hurd_tls_init (tcbhead_t *tcb, bool full)
> {
> HURD_TLS_DESC_DECL (desc, tcb);
> thread_t self = __mach_thread_self ();
> @@ -148,8 +148,9 @@ _hurd_tls_init (tcbhead_t *tcb)
> tcb->tcb = tcb;
> /* We always at least start the sigthread anyway. */
> tcb->multiple_threads = 1;
> - /* Take over the reply port we've been using. */
> - tcb->reply_port = __hurd_reply_port0;
> + if (full)
> + /* Take over the reply port we've been using. */
> + tcb->reply_port = __hurd_reply_port0;
>
> /* Get the first available selector. */
> int sel = -1;
> @@ -175,15 +176,20 @@ _hurd_tls_init (tcbhead_t *tcb)
>
> /* Now install the new selector. */
> asm volatile ("mov %w0, %%gs" :: "q" (sel));
> - /* This port is now owned by the TCB. */
> - __hurd_reply_port0 = MACH_PORT_NULL;
> + if (full)
> + /* This port is now owned by the TCB. */
> + __hurd_reply_port0 = MACH_PORT_NULL;
> +#ifndef SHARED
> + else
> + __init1_desc = sel;
> +#endif
>
> out:
> __mach_port_deallocate (__mach_task_self (), self);
> return success;
> }
>
> -# define TLS_INIT_TP(descr) _hurd_tls_init ((tcbhead_t *) (descr))
> +# define TLS_INIT_TP(descr) _hurd_tls_init ((tcbhead_t *) (descr), 1)
> #else /* defined (SHARED) && !IS_IN (rtld) */
> # define __LIBC_NO_TLS() 0
> #endif
> diff --git a/sysdeps/mach/hurd/x86/init-first.c b/sysdeps/mach/hurd/x86/init-first.c
> index 89a5f44c..d74a3c86 100644
> --- a/sysdeps/mach/hurd/x86/init-first.c
> +++ b/sysdeps/mach/hurd/x86/init-first.c
> @@ -156,12 +156,7 @@ first_init (void)
> #ifndef SHARED
> /* In the static case, we need to set up TLS early so that the stack
> protection guard can be read at gs:0x14 by the gcc-generated snippets. */
> - _hurd_tls_init (&__init1_tcbhead);
> -
> - /* Make sure __LIBC_NO_TLS () keeps evaluating to 1. */
> -# ifndef __x86_64__
> - asm ("movw %%gs,%w0" : "=m" (__init1_desc));
> -# endif
> + _hurd_tls_init (&__init1_tcbhead, 0);
> #endif
>
> RUN_RELHOOK (_hurd_preinit_hook, ());
> diff --git a/sysdeps/mach/hurd/x86_64/tls.h b/sysdeps/mach/hurd/x86_64/tls.h
> index 2b7135f6..1274723a 100644
> --- a/sysdeps/mach/hurd/x86_64/tls.h
> +++ b/sysdeps/mach/hurd/x86_64/tls.h
> @@ -173,7 +173,7 @@ extern unsigned char __libc_tls_initialized;
> # define __LIBC_NO_TLS() __builtin_expect (!__libc_tls_initialized, 0)
>
> static inline bool __attribute__ ((unused))
> -_hurd_tls_init (tcbhead_t *tcb)
> +_hurd_tls_init (tcbhead_t *tcb, bool full)
> {
> error_t err;
> thread_t self = __mach_thread_self ();
> @@ -181,11 +181,12 @@ _hurd_tls_init (tcbhead_t *tcb)
>
> /* We always at least start the sigthread anyway. */
> tcb->multiple_threads = 1;
> - /* Take over the reply port we've been using. */
> - tcb->reply_port = __hurd_reply_port0;
> + if (full)
> + /* Take over the reply port we've been using. */
> + tcb->reply_port = __hurd_reply_port0;
>
> err = _hurd_tls_new (self, tcb);
> - if (err == 0)
> + if (err == 0 && full)
> {
> __libc_tls_initialized = 1;
> /* This port is now owned by the TCB. */
> @@ -195,7 +196,7 @@ _hurd_tls_init (tcbhead_t *tcb)
> return err == 0;
> }
>
> -# define TLS_INIT_TP(descr) _hurd_tls_init ((tcbhead_t *) (descr))
> +# define TLS_INIT_TP(descr) _hurd_tls_init ((tcbhead_t *) (descr), 1)
> # else /* defined (SHARED) && !IS_IN (rtld) */
> # define __LIBC_NO_TLS() 0
> # endif
> --
> 2.40.0
>
--
Samuel
---
Pour une évaluation indépendante, transparente et rigoureuse !
Je soutiens la Commission d'Évaluation de l'Inria.
prev parent reply other threads:[~2023-04-21 1:02 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-20 18:42 Sergey Bugaev
2023-04-20 18:42 ` [VERY RFC PATCH 2/2] hurd: Make it possible to call memcpy very early Sergey Bugaev
2023-04-20 20:25 ` H.J. Lu
2023-04-20 20:38 ` Adhemerval Zanella Netto
2023-04-21 9:27 ` Sergey Bugaev
2023-04-21 11:50 ` Adhemerval Zanella Netto
2023-04-21 12:38 ` Sergey Bugaev
2023-04-21 12:58 ` Adhemerval Zanella Netto
2023-04-21 13:56 ` Sergey Bugaev
2023-04-21 14:28 ` Adhemerval Zanella Netto
2023-04-22 11:59 ` Samuel Thibault
2023-04-22 12:18 ` Sergey Bugaev
2023-04-22 16:20 ` Samuel Thibault
2023-04-22 17:04 ` Sergey Bugaev
2023-04-21 11:51 ` Sergey Bugaev
2023-04-21 1:02 ` Samuel Thibault [this message]
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