Re: mutex lock assertion panic in vm_page_free() on sparc64

Sorry for the top post, but bosko is out of country for the next week or
so.  Soemone else should look at this and commit this workaround if it'll
get us through the week.


On Tue, 22 Feb 2005, Ruslan Ermilov wrote:

> On Tue, Feb 22, 2005 at 01:03:18PM +0200, Ruslan Ermilov wrote:
> > Hi,
> >
> > I'm repeatedly getting the following panic (three-four times a day)
> > on sparc64 running a fresh -CURRENT, building world:
> >
> > db> show msgbuf
> > panic: mutex vm object not owned at /usr/src/sys/vm/vm_page.c:608
> > cpuid = 0
> > KDB: enter: panic
> > exclusive sleep mutex vm page queue mutex r = 0 (0xc04be700) locked _at_ /usr/src/sys/sparc64/sparc64/vm_machdep.c:483
> > exclusive sleep mutex UMA lock r = 0 (0xc04bdcc0) locked _at_ /usr/src/sys/vm/uma_core.c:1485
> > exclusive sleep mutex Giant r = 0 (0xc0422728) locked _at_ /usr/src/sys/vm/vm_pageout.c:666
> > db> where
> > Tracing pid 7 tid 100016 td 0xfffff80067c0c720
> > panic() at panic+0x16c
> > _mtx_assert() at _mtx_assert+0x6c
> > vm_page_remove() at vm_page_remove+0x34
> > vm_page_free_toq() at vm_page_free_toq+0xb8
> > vm_page_free() at vm_page_free+0x10
> > uma_small_free() at uma_small_free+0x54
> > zone_drain() at zone_drain+0x2e8
> > zone_foreach() at zone_foreach+0x3c
> > uma_reclaim() at uma_reclaim+0x10
> > vm_pageout_scan() at vm_pageout_scan+0x13c
> > vm_pageout() at vm_pageout+0x3e8
> > fork_exit() at fork_exit+0x9c
> > fork_trampoline() at fork_trampoline+0x8
> >
> I have no idea if this is the correct fix or not, but the necessary
> vm_object_t locking is certainly missing in uma_small_free() on all
> architectures implementing it (alpha, amd64, ia64, powerpc, and
> sparc64).
>
> %%%
> Index: vm_machdep.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/sparc64/sparc64/vm_machdep.c,v
> retrieving revision 1.71
> diff -u -r1.71 vm_machdep.c
> --- vm_machdep.c	19 Jan 2005 18:24:07 -0000	1.71
> +++ vm_machdep.c	22 Feb 2005 14:21:12 -0000
> _at__at_ -67,6 +67,7 _at__at_
>  #include <vm/pmap.h>
>  #include <vm/vm_kern.h>
>  #include <vm/vm_map.h>
> +#include <vm/vm_object.h>
>  #include <vm/vm_page.h>
>  #include <vm/vm_pageout.h>
>  #include <vm/vm_param.h>
> _at__at_ -477,10 +478,14 _at__at_
>  uma_small_free(void *mem, int size, u_int8_t flags)
>  {
>  	vm_page_t m;
> +	vm_object_t object;
>
>  	PMAP_STATS_INC(uma_nsmall_free);
>  	m = PHYS_TO_VM_PAGE(TLB_DIRECT_TO_PHYS((vm_offset_t)mem));
> +	object = m->object;
> +	VM_OBJECT_LOCK(object);
>  	vm_page_lock_queues();
>  	vm_page_free(m);
>  	vm_page_unlock_queues();
> +	VM_OBJECT_UNLOCK(object);
>  }
> %%%
>
>
> Cheers,
>

-- 
Doug White                    |  FreeBSD: The Power to Serve
dwhite_at_gumbysoft.com          |  www.FreeBSD.org