* Re: patch x86-xen-disable-highmem-pte-allocation-even-when-config_highpte-y.patch added to 2.6.33-stable tree [not found] <12683359492650@site> @ 2010-03-12 14:08 ` Stefan Lippers-Hollmann 2010-03-12 14:17 ` Ian Campbell 0 siblings, 1 reply; 3+ messages in thread From: Stefan Lippers-Hollmann @ 2010-03-12 14:08 UTC (permalink / raw) To: gregkh Cc: linux-kernel, ian.campbell, hpa, jeremy, mingo, pasik, xen-devel, stable Hi On Friday 12 March 2010, gregkh@suse.de wrote: > This is a note to let you know that we have just queued up the patch titled > > Subject: x86, xen: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y > > to the 2.6.33-stable tree. Its filename is > > x86-xen-disable-highmem-pte-allocation-even-when-config_highpte-y.patch > > A git repo of this tree can be found at > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > > From 817a824b75b1475f1b067c8cee318c7b4d66fcde Mon Sep 17 00:00:00 2001 > From: Ian Campbell <ian.campbell@citrix.com> > Date: Fri, 26 Feb 2010 17:16:00 +0000 > Subject: x86, xen: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y > MIME-Version: 1.0 > Content-Type: text/plain; charset=UTF-8 > Content-Transfer-Encoding: 8bit > > From: Ian Campbell <ian.campbell@citrix.com> > > commit 817a824b75b1475f1b067c8cee318c7b4d66fcde upstream. > > There's a path in the pagefault code where the kernel deliberately > breaks its own locking rules by kmapping a high pte page without > holding the pagetable lock (in at least page_check_address). This > breaks Xen's ability to track the pinned/unpinned state of the > page. There does not appear to be a viable workaround for this > behaviour so simply disable HIGHPTE for all Xen guests. This patch breaks compilation of the current 2.6.33 -stable queue and might also affect queue-2.6.32 (untested): CC arch/x86/xen/enlighten.o arch/x86/xen/enlighten.c: In function ‘xen_start_kernel’: arch/x86/xen/enlighten.c:1102: error: ‘__userpte_alloc_gfp’ undeclared (first use in this function) arch/x86/xen/enlighten.c:1102: error: (Each undeclared identifier is reported only once arch/x86/xen/enlighten.c:1102: error: for each function it appears in.) make[2]: *** [arch/x86/xen/enlighten.o] Error 1 make[1]: *** [arch/x86/xen] Error 2 as it seems to depend (tested) on: commit 14315592009c17035cac81f4954d5a1f4d71e489 Author: Ian Campbell <ian.campbell@citrix.com> Date: Wed Feb 17 10:38:10 2010 +0000 x86, mm: Allow highmem user page tables to be disabled at boot time Regards Stefan Lippers-Hollmann -- > Signed-off-by: Ian Campbell <ian.campbell@citrix.com> > LKML-Reference: <1267204562-11844-1-git-send-email-ian.campbell@citrix.com> > Cc: Jeremy Fitzhardinge <jeremy@goop.org> > Cc: Ingo Molnar <mingo@elte.hu> > Cc: Pasi Kärkkäinen <pasik@iki.fi> > Cc: <xen-devel@lists.xensource.com> > Signed-off-by: H. Peter Anvin <hpa@zytor.com> > Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> > > --- > arch/x86/xen/enlighten.c | 7 +++++++ > arch/x86/xen/mmu.c | 11 ++++++----- > 2 files changed, 13 insertions(+), 5 deletions(-) > > --- a/arch/x86/xen/enlighten.c > +++ b/arch/x86/xen/enlighten.c > @@ -50,6 +50,7 @@ > #include <asm/traps.h> > #include <asm/setup.h> > #include <asm/desc.h> > +#include <asm/pgalloc.h> > #include <asm/pgtable.h> > #include <asm/tlbflush.h> > #include <asm/reboot.h> > @@ -1094,6 +1095,12 @@ asmlinkage void __init xen_start_kernel( > > __supported_pte_mask |= _PAGE_IOMAP; > > + /* > + * Prevent page tables from being allocated in highmem, even > + * if CONFIG_HIGHPTE is enabled. > + */ > + __userpte_alloc_gfp &= ~__GFP_HIGHMEM; > + > /* Work out if we support NX */ > x86_configure_nx(); > > --- a/arch/x86/xen/mmu.c > +++ b/arch/x86/xen/mmu.c > @@ -1432,14 +1432,15 @@ static void *xen_kmap_atomic_pte(struct > { > pgprot_t prot = PAGE_KERNEL; > > + /* > + * We disable highmem allocations for page tables so we should never > + * see any calls to kmap_atomic_pte on a highmem page. > + */ > + BUG_ON(PageHighMem(page)); > + > if (PagePinned(page)) > prot = PAGE_KERNEL_RO; > > - if (0 && PageHighMem(page)) > - printk("mapping highpte %lx type %d prot %s\n", > - page_to_pfn(page), type, > - (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ"); > - > return kmap_atomic_prot(page, type, prot); > } > #endif ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: patch x86-xen-disable-highmem-pte-allocation-even-when-config_highpte-y.patch added to 2.6.33-stable tree 2010-03-12 14:08 ` patch x86-xen-disable-highmem-pte-allocation-even-when-config_highpte-y.patch added to 2.6.33-stable tree Stefan Lippers-Hollmann @ 2010-03-12 14:17 ` Ian Campbell 2010-03-12 16:35 ` Greg KH 0 siblings, 1 reply; 3+ messages in thread From: Ian Campbell @ 2010-03-12 14:17 UTC (permalink / raw) To: Stefan Lippers-Hollmann Cc: gregkh@suse.de, linux-kernel@vger.kernel.org, hpa@zytor.com, jeremy@goop.org, mingo@elte.hu, pasik@iki.fi, xen-devel@lists.xensource.com, stable@kernel.org On Fri, 2010-03-12 at 14:08 +0000, Stefan Lippers-Hollmann wrote: > Hi > > On Friday 12 March 2010, gregkh@suse.de wrote: > > This is a note to let you know that we have just queued up the patch titled > > > > Subject: x86, xen: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y > > > > to the 2.6.33-stable tree. Its filename is > > > > x86-xen-disable-highmem-pte-allocation-even-when-config_highpte-y.patch > > > > A git repo of this tree can be found at > > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > > > > > From 817a824b75b1475f1b067c8cee318c7b4d66fcde Mon Sep 17 00:00:00 2001 > > From: Ian Campbell <ian.campbell@citrix.com> > > Date: Fri, 26 Feb 2010 17:16:00 +0000 > > Subject: x86, xen: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y > > MIME-Version: 1.0 > > Content-Type: text/plain; charset=UTF-8 > > Content-Transfer-Encoding: 8bit > > > > From: Ian Campbell <ian.campbell@citrix.com> > > > > commit 817a824b75b1475f1b067c8cee318c7b4d66fcde upstream. > > > > There's a path in the pagefault code where the kernel deliberately > > breaks its own locking rules by kmapping a high pte page without > > holding the pagetable lock (in at least page_check_address). This > > breaks Xen's ability to track the pinned/unpinned state of the > > page. There does not appear to be a viable workaround for this > > behaviour so simply disable HIGHPTE for all Xen guests. > > This patch breaks compilation of the current 2.6.33 -stable queue and might > also affect queue-2.6.32 (untested): > > CC arch/x86/xen/enlighten.o > arch/x86/xen/enlighten.c: In function ‘xen_start_kernel’: > arch/x86/xen/enlighten.c:1102: error: ‘__userpte_alloc_gfp’ undeclared (first use in this function) > arch/x86/xen/enlighten.c:1102: error: (Each undeclared identifier is reported only once > arch/x86/xen/enlighten.c:1102: error: for each function it appears in.) > make[2]: *** [arch/x86/xen/enlighten.o] Error 1 > make[1]: *** [arch/x86/xen] Error 2 > > as it seems to depend (tested) on: > > commit 14315592009c17035cac81f4954d5a1f4d71e489 > Author: Ian Campbell <ian.campbell@citrix.com> > Date: Wed Feb 17 10:38:10 2010 +0000 > > x86, mm: Allow highmem user page tables to be disabled at boot time Thanks Stefan, this is indeed the correct fix. I pointed Greg to this patch in private mail this morning. Ian. ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: patch x86-xen-disable-highmem-pte-allocation-even-when-config_highpte-y.patch added to 2.6.33-stable tree 2010-03-12 14:17 ` Ian Campbell @ 2010-03-12 16:35 ` Greg KH 0 siblings, 0 replies; 3+ messages in thread From: Greg KH @ 2010-03-12 16:35 UTC (permalink / raw) To: Ian Campbell Cc: Stefan Lippers-Hollmann, linux-kernel@vger.kernel.org, hpa@zytor.com, jeremy@goop.org, mingo@elte.hu, pasik@iki.fi, xen-devel@lists.xensource.com, stable@kernel.org On Fri, Mar 12, 2010 at 02:17:33PM +0000, Ian Campbell wrote: > On Fri, 2010-03-12 at 14:08 +0000, Stefan Lippers-Hollmann wrote: > > Hi > > > > On Friday 12 March 2010, gregkh@suse.de wrote: > > > This is a note to let you know that we have just queued up the patch titled > > > > > > Subject: x86, xen: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y > > > > > > to the 2.6.33-stable tree. Its filename is > > > > > > x86-xen-disable-highmem-pte-allocation-even-when-config_highpte-y.patch > > > > > > A git repo of this tree can be found at > > > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > > > > > > > > From 817a824b75b1475f1b067c8cee318c7b4d66fcde Mon Sep 17 00:00:00 2001 > > > From: Ian Campbell <ian.campbell@citrix.com> > > > Date: Fri, 26 Feb 2010 17:16:00 +0000 > > > Subject: x86, xen: Disable highmem PTE allocation even when CONFIG_HIGHPTE=y > > > MIME-Version: 1.0 > > > Content-Type: text/plain; charset=UTF-8 > > > Content-Transfer-Encoding: 8bit > > > > > > From: Ian Campbell <ian.campbell@citrix.com> > > > > > > commit 817a824b75b1475f1b067c8cee318c7b4d66fcde upstream. > > > > > > There's a path in the pagefault code where the kernel deliberately > > > breaks its own locking rules by kmapping a high pte page without > > > holding the pagetable lock (in at least page_check_address). This > > > breaks Xen's ability to track the pinned/unpinned state of the > > > page. There does not appear to be a viable workaround for this > > > behaviour so simply disable HIGHPTE for all Xen guests. > > > > This patch breaks compilation of the current 2.6.33 -stable queue and might > > also affect queue-2.6.32 (untested): > > > > CC arch/x86/xen/enlighten.o > > arch/x86/xen/enlighten.c: In function ‘xen_start_kernel’: > > arch/x86/xen/enlighten.c:1102: error: ‘__userpte_alloc_gfp’ undeclared (first use in this function) > > arch/x86/xen/enlighten.c:1102: error: (Each undeclared identifier is reported only once > > arch/x86/xen/enlighten.c:1102: error: for each function it appears in.) > > make[2]: *** [arch/x86/xen/enlighten.o] Error 1 > > make[1]: *** [arch/x86/xen] Error 2 > > > > as it seems to depend (tested) on: > > > > commit 14315592009c17035cac81f4954d5a1f4d71e489 > > Author: Ian Campbell <ian.campbell@citrix.com> > > Date: Wed Feb 17 10:38:10 2010 +0000 > > > > x86, mm: Allow highmem user page tables to be disabled at boot time > > Thanks Stefan, this is indeed the correct fix. I pointed Greg to this > patch in private mail this morning. I've just added it. Odd that the kernel doesn't fail on my builds. Oh, I'm not enabling Xen, that's why, my fault... thanks, greg k-h ^ permalink raw reply [flat|nested] 3+ messages in thread
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2010-03-12 14:08 ` patch x86-xen-disable-highmem-pte-allocation-even-when-config_highpte-y.patch added to 2.6.33-stable tree Stefan Lippers-Hollmann
2010-03-12 14:17 ` Ian Campbell
2010-03-12 16:35 ` Greg KH
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