Messages in this thread | | | Date | Fri, 7 Sep 2018 11:36:01 -0700 | From | Nathan Chancellor <> | Subject | Re: Patch "arm64: mm: always enable CONFIG_HOLES_IN_ZONE" has been added to the 4.9-stable tree |
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On Fri, Sep 07, 2018 at 02:57:51PM +0200, gregkh@linuxfoundation.org wrote: > > This is a note to let you know that I've just added the patch titled > > arm64: mm: always enable CONFIG_HOLES_IN_ZONE > > to the 4.9-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > arm64-mm-always-enable-config_holes_in_zone.patch > and it can be found in the queue-4.9 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@vger.kernel.org> know about it. > > > From f52bb98f5aded4c43e52f5ce19fb83f7261e9e73 Mon Sep 17 00:00:00 2001 > From: James Morse <james.morse@arm.com> > Date: Thu, 30 Aug 2018 16:05:32 +0100 > Subject: arm64: mm: always enable CONFIG_HOLES_IN_ZONE > > From: James Morse <james.morse@arm.com> > > commit f52bb98f5aded4c43e52f5ce19fb83f7261e9e73 upstream. > > Commit 6d526ee26ccd ("arm64: mm: enable CONFIG_HOLES_IN_ZONE for NUMA") > only enabled HOLES_IN_ZONE for NUMA systems because the NUMA code was > choking on the missing zone for nomap pages. This problem doesn't just > apply to NUMA systems. > > If the architecture doesn't set HAVE_ARCH_PFN_VALID, pfn_valid() will > return true if the pfn is part of a valid sparsemem section. > > When working with multiple pages, the mm code uses pfn_valid_within() > to test each page it uses within the sparsemem section is valid. On > most systems memory comes in MAX_ORDER_NR_PAGES chunks which all > have valid/initialised struct pages. In this case pfn_valid_within() > is optimised out. > > Systems where this isn't true (e.g. due to nomap) should set > HOLES_IN_ZONE and provide HAVE_ARCH_PFN_VALID so that mm tests each > page as it works with it. > > Currently non-NUMA arm64 systems can't enable HOLES_IN_ZONE, leading to > a VM_BUG_ON(): > > | page:fffffdff802e1780 is uninitialized and poisoned > | raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff > | raw: ffffffffffffffff ffffffffffffffff ffffffffffffffff ffffffffffffffff > | page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) > | ------------[ cut here ]------------ > | kernel BUG at include/linux/mm.h:978! > | Internal error: Oops - BUG: 0 [#1] PREEMPT SMP > [...] > | CPU: 1 PID: 25236 Comm: dd Not tainted 4.18.0 #7 > | Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 > | pstate: 40000085 (nZcv daIf -PAN -UAO) > | pc : move_freepages_block+0x144/0x248 > | lr : move_freepages_block+0x144/0x248 > | sp : fffffe0071177680 > [...] > | Process dd (pid: 25236, stack limit = 0x0000000094cc07fb) > | Call trace: > | move_freepages_block+0x144/0x248 > | steal_suitable_fallback+0x100/0x16c > | get_page_from_freelist+0x440/0xb20 > | __alloc_pages_nodemask+0xe8/0x838 > | new_slab+0xd4/0x418 > | ___slab_alloc.constprop.27+0x380/0x4a8 > | __slab_alloc.isra.21.constprop.26+0x24/0x34 > | kmem_cache_alloc+0xa8/0x180 > | alloc_buffer_head+0x1c/0x90 > | alloc_page_buffers+0x68/0xb0 > | create_empty_buffers+0x20/0x1ec > | create_page_buffers+0xb0/0xf0 > | __block_write_begin_int+0xc4/0x564 > | __block_write_begin+0x10/0x18 > | block_write_begin+0x48/0xd0 > | blkdev_write_begin+0x28/0x30 > | generic_perform_write+0x98/0x16c > | __generic_file_write_iter+0x138/0x168 > | blkdev_write_iter+0x80/0xf0 > | __vfs_write+0xe4/0x10c > | vfs_write+0xb4/0x168 > | ksys_write+0x44/0x88 > | sys_write+0xc/0x14 > | el0_svc_naked+0x30/0x34 > | Code: aa1303e0 90001a01 91296421 94008902 (d4210000) > | ---[ end trace 1601ba47f6e883fe ]--- > > Remove the NUMA dependency. > > Link: https://www.spinics.net/lists/arm-kernel/msg671851.html > Cc: <stable@vger.kernel.org> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> > Reported-by: Mikulas Patocka <mpatocka@redhat.com> > Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com> > Tested-by: Mikulas Patocka <mpatocka@redhat.com> > Signed-off-by: James Morse <james.morse@arm.com> > Signed-off-by: Will Deacon <will.deacon@arm.com> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > --- > arch/arm64/Kconfig | 1 - > 1 file changed, 1 deletion(-) > > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -631,7 +631,6 @@ config HAVE_SETUP_PER_CPU_AREA > > config NEED_PER_CPU_EMBED_FIRST_CHUNK
Looks like git got confused here, this isn't HOLES_IN_ZONE.
Additionally, commit 6d526ee26ccd ("arm64: mm: enable CONFIG_HOLES_IN_ZONE for NUMA") that introduced it to this file didn't appear until 4.11 so this patch can be dropped from 4.9.
> def_bool y > - depends on NUMA > > source kernel/Kconfig.preempt > source kernel/Kconfig.hz > > > Patches currently in stable-queue which might be from james.morse@arm.com are > > queue-4.9/arm64-mm-always-enable-config_holes_in_zone.patch
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