Use ENTRY/END in sysdeps/x86_64/nptl/pthread_spin*.S
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Message ID CALoOobPfYEt0R4LJo3cGZEP-JA5YFAT11sSSzLqsFamkXcdYNg@mail.gmail.com
State New
Headers show

Commit Message

Paul Pluzhnikov Jan. 18, 2016, 9:11 p.m. UTC
Greetings,

Currently, x86_64 pthread_spin_{lock,unlock,trylock} lack unwind
descriptors, which causes tools like GDB and libunwind to guess how to
unwind from them. Libunwind happens to guess incorrectly, leading to
either bad stack trace, or a crash.

Attached patch fixes this. Tested on Linux/x86_64. Ok for trunk?

P.S. I'd like to excise other instances of functions that lack unwind
descriptors in a follow-up patch, if that's ok.

2016-01-18  Paul Pluzhnikov  <ppluzhnikov@google.com>

        * sysdeps/x86_64/nptl/pthread_spin_lock.S (pthread_spin_lock):
Use ENTRY/END
        * sysdeps/x86_64/nptl/pthread_spin_trylock.S
(pthread_spin_trylock): Likewise
        * sysdeps/x86_64/nptl/pthread_spin_unlock.S
(pthread_spin_unlock): Likewise

Comments

Carlos O'Donell Jan. 18, 2016, 10:18 p.m. UTC | #1
On 01/18/2016 04:11 PM, Paul Pluzhnikov wrote:
> Greetings,
> 
> Currently, x86_64 pthread_spin_{lock,unlock,trylock} lack unwind
> descriptors, which causes tools like GDB and libunwind to guess how to
> unwind from them. Libunwind happens to guess incorrectly, leading to
> either bad stack trace, or a crash.
> 
> Attached patch fixes this. Tested on Linux/x86_64. Ok for trunk?
> 
> P.S. I'd like to excise other instances of functions that lack unwind
> descriptors in a follow-up patch, if that's ok.
> 
> 2016-01-18  Paul Pluzhnikov  <ppluzhnikov@google.com>
> 
>         * sysdeps/x86_64/nptl/pthread_spin_lock.S (pthread_spin_lock):
> Use ENTRY/END
>         * sysdeps/x86_64/nptl/pthread_spin_trylock.S
> (pthread_spin_trylock): Likewise
>         * sysdeps/x86_64/nptl/pthread_spin_unlock.S
> (pthread_spin_unlock): Likewise
> 

Modulo your broken mail client wrapping the Changelog this looks good to me.

It needs a public bug though.

Cheers,
Carlos.
Paul Pluzhnikov Jan. 18, 2016, 11:22 p.m. UTC | #2
On Mon, Jan 18, 2016 at 2:18 PM, Carlos O'Donell <carlos@redhat.com> wrote:

> It needs a public bug though.

I opened https://sourceware.org/bugzilla/show_bug.cgi?id=19490

Thanks,

Patch
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diff --git a/sysdeps/x86_64/nptl/pthread_spin_lock.S b/sysdeps/x86_64/nptl/pthread_spin_lock.S
index c9b9424..b871241 100644
--- a/sysdeps/x86_64/nptl/pthread_spin_lock.S
+++ b/sysdeps/x86_64/nptl/pthread_spin_lock.S
@@ -16,11 +16,9 @@ 
    <http://www.gnu.org/licenses/>.  */
 
 #include <lowlevellock.h>
+#include <sysdep.h>
 
-	.globl	pthread_spin_lock
-	.type	pthread_spin_lock,@function
-	.align	16
-pthread_spin_lock:
+ENTRY(pthread_spin_lock)
 1:	LOCK
 	decl	0(%rdi)
 	jne	2f
@@ -33,4 +31,4 @@  pthread_spin_lock:
 	cmpl	$0, 0(%rdi)
 	jg	1b
 	jmp	2b
-	.size	pthread_spin_lock,.-pthread_spin_lock
+END(pthread_spin_lock)
diff --git a/sysdeps/x86_64/nptl/pthread_spin_trylock.S b/sysdeps/x86_64/nptl/pthread_spin_trylock.S
index fc74d77..c9c5317 100644
--- a/sysdeps/x86_64/nptl/pthread_spin_trylock.S
+++ b/sysdeps/x86_64/nptl/pthread_spin_trylock.S
@@ -17,6 +17,7 @@ 
    <http://www.gnu.org/licenses/>.  */
 
 #include <pthread-errnos.h>
+#include <sysdep.h>
 
 
 #ifdef UP
@@ -25,10 +26,7 @@ 
 # define LOCK lock
 #endif
 
-	.globl	pthread_spin_trylock
-	.type	pthread_spin_trylock,@function
-	.align	16
-pthread_spin_trylock:
+ENTRY(pthread_spin_trylock)
 	movl	$1, %eax
 	xorl	%ecx, %ecx
 	LOCK
@@ -36,4 +34,4 @@  pthread_spin_trylock:
 	movl	$EBUSY, %eax
 	cmovel	%ecx, %eax
 	retq
-	.size	pthread_spin_trylock,.-pthread_spin_trylock
+END(pthread_spin_trylock)
diff --git a/sysdeps/x86_64/nptl/pthread_spin_unlock.S b/sysdeps/x86_64/nptl/pthread_spin_unlock.S
index e341018..188de2e 100644
--- a/sysdeps/x86_64/nptl/pthread_spin_unlock.S
+++ b/sysdeps/x86_64/nptl/pthread_spin_unlock.S
@@ -16,14 +16,13 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-	.globl	pthread_spin_unlock
-	.type	pthread_spin_unlock,@function
-	.align	16
-pthread_spin_unlock:
+#include <sysdep.h>
+
+ENTRY(pthread_spin_unlock)
 	movl	$1, (%rdi)
 	xorl	%eax, %eax
 	retq
-	.size	pthread_spin_unlock,.-pthread_spin_unlock
+END(pthread_spin_unlock)
 
 	/* The implementation of pthread_spin_init is identical.  */
 	.globl	pthread_spin_init