http://sources.redhat.com/cgi-bin/cvsweb.cgi/libc/sysdeps/unix/sysv/linux/sh/socket.S.diff?r1=1.5&r2=1.6&cvsroot=glibc

Ankur Sheth said:
"The problem that I ran into was that multi-threaded apps would crash with a
seg fault when they invoked some of the socket calls (sendto() in my case.
This happened only on the sh4.  Turns out that a certain register (PR) was
not being saved and restored properly before and after invoking the system
call.  This patch fixes it.  It applies cleanly on glibc 2.3.2. 
[Thanks to Kaz for helping us find this.]"

===================================================================
RCS file: /cvs/glibc/libc/sysdeps/unix/sysv/linux/sh/socket.S,v
retrieving revision 1.5
retrieving revision 1.6
diff -u -r1.5 -r1.6
--- libc/sysdeps/unix/sysv/linux/sh/socket.S	2003/01/05 11:07:44	1.5
+++ libc/sysdeps/unix/sysv/linux/sh/socket.S	2003/07/12 01:25:53	1.6
@@ -94,7 +94,9 @@
 #if defined NEED_CANCELLATION && defined CENABLE
 .Lsocket_cancel:
 	/* Enable asynchronous cancellation.  */
+	sts.l pr,@-r15
 	CENABLE
+	lds.l @r15+,pr
 
 	/* Do the system call trap.  */
 	mov #+P(SOCKOP_,socket), r4
@@ -102,9 +104,11 @@
 	mov.l .L1,r3
 	trapa #0x12
 
+	sts.l pr,@-r15
 	mov.l r0,@-r15
 	CDISABLE
 	mov.l @r15+,r0
+	lds.l @r15+,pr
 
 	/* Pop args off the stack */
 	P(POPARGS_,NARGS)