Re: 2.6.19-rc2-mm1

[Michael Ellerman]

On Tue, 2006-10-17 at 13:22 -0700, Andrew Morton wrote:
> On Tue, 17 Oct 2006 12:37:48 -0700
> Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
> 
> > Andrew Morton wrote:
> > > -generic-implementatation-of-bug.patch
> > > -generic-implementatation-of-bug-fix.patch
> > > +generic-bug-implementation.patch
> > >  generic-bug-for-i386.patch
> > >  generic-bug-for-x86-64.patch
> > >  uml-add-generic-bug-support.patch
> > >  use-generic-bug-for-ppc.patch
> > >  bug-test-1.patch
> > >
> > >  Updated generic-BUG-handling patches
> > >   
> > I thought the powerpc patch had been given a clean bill of health?  Or 
> > was there still a problem with it?
> 
> No, last time I tested it the machine still froze after "returning from
> prom_init".  ie: before it had done any WARNs or BUGs.  It's rather
> mysterious.

Works for me:

Diego5:~# uname -a
Linux Diego5 2.6.19-rc2-mm1-git #9 SMP Wed Oct 18 19:30:38 EST 2006 ppc64 GNU/Linux
Diego5:~# echo 4 > /proc/sys/vm/drop_caches
Badness in drop_caches_sysctl_handler at /home/michael/src/auto/git/fs/drop_caches.c:67
Call Trace:
[C0000000431F7760] [C00000000000F8E4] .show_stack+0x6c/0x1a0 (unreliable)
[C0000000431F7800] [C000000000447B8C] .program_check_exception+0x19c/0x5cc
[C0000000431F78A0] [C00000000000446C] program_check_common+0xec/0x100
--- Exception: 700 at .drop_caches_sysctl_handler+0x5c/0x88
    LR = .drop_caches_sysctl_handler+0x20/0x88
[C0000000431F7C20] [C00000000005725C] .do_rw_proc+0x168/0x230
[C0000000431F7CF0] [C0000000000BC76C] .vfs_write+0xd0/0x1b4
[C0000000431F7D90] [C0000000000BD134] .sys_write+0x4c/0x8c
[C0000000431F7E30] [C00000000000861C] syscall_exit+0x0/0x40
Diego5:~# echo 8 > /proc/sys/vm/drop_caches
kernel BUG in drop_caches_sysctl_handler at /home/michael/src/auto/git/fs/drop_caches.c:69!
cpu 0xd: Vector: 700 (Program Check) at [c0000000431f7910]
    pc: c0000000000e3a5c: .drop_caches_sysctl_handler+0x68/0x88
    lr: c0000000000e3a14: .drop_caches_sysctl_handler+0x20/0x88
    sp: c0000000431f7b90
   msr: 8000000000029032
  current = 0xc00000000fc8c810
  paca    = 0xc000000000564e00
    pid   = 1465, comm = bash
kernel BUG in drop_caches_sysctl_handler at /home/michael/src/auto/git/fs/drop_caches.c:69!
enter ? for help
[c0000000431f7c20] c00000000005725c .do_rw_proc+0x168/0x230
[c0000000431f7cf0] c0000000000bc76c .vfs_write+0xd0/0x1b4
[c0000000431f7d90] c0000000000bd134 .sys_write+0x4c/0x8c
[c0000000431f7e30] c00000000000861c syscall_exit+0x0/0x40
--- Exception: c01 (System Call) at 000000000fec9aac
SP (ff8416f0) is in userspace
d:mon> 

There's some NUMA badness going around that you might be hitting.

cheers

-- 
Michael Ellerman
OzLabs, IBM Australia Development Lab

wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)

We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person

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