On Tue, Jun 22, 2010 at 11:17 AM, Carlos O'Donell
<carlos@xxxxxxxxxxxxxxxx> wrote:
> Oh dear, yes I see. After the child returns from vfork, it calls exec,
> clobbering the vfork frame that the parent must still unwind from. Is
> that what you mean?
Is this a complete fix?
diff --git a/sysdeps/unix/sysv/linux/hppa/nptl/pt-vfork.S
b/sysdeps/unix/sysv/linux/hppa/nptl/pt-vfork.S
index 83a70b7..3c685cb 100644
--- a/sysdeps/unix/sysv/linux/hppa/nptl/pt-vfork.S
+++ b/sysdeps/unix/sysv/linux/hppa/nptl/pt-vfork.S
@@ -50,10 +50,9 @@
/* r26, r25, r24, r23 are free since vfork has no arguments */
ENTRY(__vfork)
- /* Prologue */
- stwm %r3, 64(%sp)
- stw %sp, -4(%sp)
- stw %r19, -32(%sp)
+ /* We must not create a frame, otherwise when the child unwinds
+ to call exec it will clobber the same frame that the parent
+ needs to unwind. */
/* Save the PIC register. */
#ifdef PIC
@@ -76,11 +75,16 @@ ENTRY(__vfork)
b,n .Lerror
/* Return, no need to restore the PIC register. */
- ldw -84(%sp), %rp
- bv %r0(%rp)
- ldwm -64(%sp), %r3
+ ldw -20(%sp), %rp
+ bv,n %r0(%rp)
.Lerror:
+ /* Now we need a stack to record the error. We are assured
+ that there is no child now, so it's safe to create
+ a frame. */
+ stwm %r3, 64(%sp)
+ stw %sp, -4(%sp)
+
sub %r0,%ret0,%r3
SYSCALL_ERROR_HANDLER
/* Restore the PIC register (in delay slot) on error */
I'm building/testing this and I will tell you how it goes.
Cheers,
Carlos.
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