From: Martin Schwidefsky <schwidefsky@de.ibm.com>
To: Glibc hackers <libc-hacker@sources.redhat.com>
Subject: [PATCH] s390: tls pointer extraction in __libc_start_main
Date: Mon, 06 Oct 2008 18:17:00 -0000 [thread overview]
Message-ID: <1223316873.5245.2.camel@localhost> (raw)
Greetings,
a glibc compiled with the latest gcc crashes in __libc_start_main.
The cause is that the compiler has decided to extract the tls pointer
in __libc_start_main() from the access registers a0/a1 into a general
register before the tls pointer has been set up by the call to
__pthread_initialize_minimal().
The least invasive fix is to clobber the access registers before the
first use in THREAD_SET_STACK_GUARD(). This makes the compiler to
do the tls pointer extraction after __pthread_initialize_minimal().
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
--
2008-10-06 Martin Schwidefsky <schwidefsky@de.ibm.com>
* sysdeps/s390/tls.h (THREAD_SET_STACK_GUARD): Add empty inline
assembly with a clobber list for access registers a0 and a1.
diff -urpN libc/nptl/sysdeps/s390/tls.h libc-s390/nptl/sysdeps/s390/tls.h
--- libc/nptl/sysdeps/s390/tls.h 2007-08-07 13:09:01.000000000 +0200
+++ libc-s390/nptl/sysdeps/s390/tls.h 2008-10-06 19:55:46.000000000 +0200
@@ -161,7 +161,12 @@ typedef struct
/* Set the stack guard field in TCB head. */
#define THREAD_SET_STACK_GUARD(value) \
- THREAD_SETMEM (THREAD_SELF, header.stack_guard, value)
+ do \
+ { \
+ __asm __volatile ("" : : : "a0", "a1"); \
+ THREAD_SETMEM (THREAD_SELF, header.stack_guard, value); \
+ } \
+ while (0)
#define THREAD_COPY_STACK_GUARD(descr) \
((descr)->header.stack_guard \
= THREAD_GETMEM (THREAD_SELF, header.stack_guard))
next reply other threads:[~2008-10-06 18:17 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-06 18:17 Martin Schwidefsky [this message]
2008-10-22 21:45 ` Ulrich Drepper
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=1223316873.5245.2.camel@localhost \
--to=schwidefsky@de.ibm.com \
--cc=libc-hacker@sources.redhat.com \
/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).