Subject: kern/23524: Kernel segfaults with -Oxx and -march flags on p200mmx with gcc3x
To: None <>
From: None <pancake@panser.panser>
List: netbsd-bugs
Date: 11/21/2003 18:48:30
>Number:         23524
>Category:       kern
>Synopsis:       Kernel segfaults with -Oxx and -march flags on p200mmx with gcc3x
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Nov 21 17:39:00 UTC 2003
>Release:        NetBSD 1.6ZF
	no org =)
System: NetBSD panser 1.6ZF NetBSD 1.6ZF (PANCAKE-PANSER-SERVER) #20: Fri Nov 21 00:27:00 CET 2003 root@panser:/usr/src/sys/arch/i386/compile/PANCAKE_PANSER i386
Architecture: i386
Machine: i386
	In my p200mmx box I build the ZF kernel with gcc3.3.2 with -O3 and -march=
	i586 flags, then I reboot the box, and after load the kernel in ram,
	machine reboots O_O

	After that I rebuild a new kernel with -Os, with this kernel boots ok, but
	when take use of UVM code (compiling...) segfaults on UVM code and
	reboots. Finally I build the kernel with CFLAGS="" and all goes well.

	I know that using it doesn't happend, but I haven't got enought
	disk-space to download all of this.

	Another tip is that I also build kernels using gcc3.3 and -march -O flags
	on my p4 laptop, and all goes well. It seems that only fails on the p200
	Just rebuild:
	cd /usr/src/sys/arch/i386/compile/PANCAKE_PANSER/
	export CFLAGS="-O3 -march=i586 -funroll-loops"
	make clean ; make depend ; make
	Makefiles could take alert on that, or gcc doesn't have to optimize
	__asm__ code in kernel :? I don't know.