Re: [BUG] 2.6.25-rc2-mm1 - kernel oops while bootup on s390x

[Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>]

On Sun, Feb 17, 2008 at 10:06:16AM +0100, Heiko Carstens wrote:
> On Sun, Feb 17, 2008 at 09:10:46AM +0530, Kamalesh Babulal wrote:
> > To conform the patches causing the panic, I tested the 2.6.24.2 kernel with the futex-fix-init-order.patch and
> > futex-runtime-enable-pi-and-robust-functionality.patch applied and they seem to cause the kernel
> > panic.
> > 
> > Unable to handle kernel pointer dereference at virtual kernel address 0000000000
> > 000000
> > Oops: 0004 #1¨ SMP
> > Modules linked in:
> > CPU: 0 Not tainted 2.6.25-rc2-mm1-autotest #1
> > Process swapper (pid: 1, task: 000000003f830000, ksp: 000000003f83ba48)
> > Krnl PSW : 0704a00180000000 000000000024b2be (futex_atomic_cmpxchg_std+0x12/0x28
> > )
> >            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:2 CC:2 PM:0 EA:3
> > Krnl GPRS: 0000000000000074 00000000fffffff2 0000000000000000 0000000000000000
> >            0000000000000000 0000000000000001 0000000000000000 00000000004d0764
> >            0000000000000000 00000000004d8768 0000000000000000 000000003f83bdb0
> >            0000000000000040 0000000000343950 00000000000627e4 000000003f83bdb0
> > Krnl Code: 000000000024b2b2: b90400bf           lgr     %r11,%r15
> >            000000000024b2b6: a718fff2           lhi     %r1,-14
> >            000000000024b2ba: b2790100           sacf    256
> >           >000000000024b2be: ba342000           cs      %r3,%r4,0(%r2)
> >            000000000024b2c2: 1813               lr      %r1,%r3
> >            000000000024b2c4: b2790000           sacf    0
> >            000000000024b2c8: b9140021           lgfr    %r2,%r1
> >            000000000024b2cc: e3b0b0700004       lg      %r11,112(%r11)
> > Call Trace:
> > (<000000003f83bda8>¨ 0x3f83bda8)
> >  <00000000004bdeec>¨ init+0x30/0x104
> >  <00000000004b0c40>¨ kernel_init+0x1e0/0x370
> >  <000000000001a5c6>¨ kernel_thread_starter+0x6/0xc
> >  <000000000001a5c0>¨ kernel_thread_starter+0x0/0xc
> > 
> >  <4>--- end trace 561bb236c800851f ¨---
> > note: swapper1¨ exited with preempt_count 1
> > Kernel panic - not syncing: Attempted to kill init!
Hi Heiko,

Thanks for the patch, I have tested patch, it fixes the bootup panic.

Tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>

Index: linux-2.6/arch/s390/lib/uaccess_std.c
===================================================================
--- linux-2.6.orig/arch/s390/lib/uaccess_std.c
+++ linux-2.6/arch/s390/lib/uaccess_std.c
@@ -293,8 +293,8 @@ int futex_atomic_cmpxchg_std(int __user 

      asm volatile(
              "   sacf 256\n"
-             "   cs   %1,%4,0(%5)\n"
-             "0: lr   %0,%1\n"
+             "0: cs   %1,%4,0(%5)\n"
+             "   lr   %0,%1\n"
              "1: sacf 0\n"
              EX_TABLE(0b,1b)
              : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
--
-- 
Thanks & Regards,
Kamalesh Babulal,
Linux Technology Center,
IBM, ISTL.