The patch titled Subject: vmalloc: fix __GFP_HIGHMEM usage for vmalloc_32 on 32b systems has been added to the -mm tree. Its filename is vmalloc-fix-__gfp_highmem-usage-for-vmalloc_32-on-32b-systems.patch

This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/vmalloc-fix-__gfp_highmem-usage-for... and later at http://ozlabs.org/~akpm/mmotm/broken-out/vmalloc-fix-__gfp_highmem-usage-for...

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------------------------------------------------------ From: Michal Hocko mhocko@suse.com Subject: vmalloc: fix __GFP_HIGHMEM usage for vmalloc_32 on 32b systems

Kai Heng Feng has noticed that BUG_ON(PageHighMem(pg)) triggers in drivers/media/common/saa7146/saa7146_core.c since 19809c2da28a ("mm, vmalloc: use __GFP_HIGHMEM implicitly"). saa7146_vmalloc_build_pgtable uses vmalloc_32 and it is reasonable to expect that the resulting page is not in highmem. The above commit aimed to add __GFP_HIGHMEM only for those requests which do not specify any zone modifier gfp flag. vmalloc_32 relies on GFP_VMALLOC32 which should do the right thing. Except it has been missed that GFP_VMALLOC32 is an alias for GFP_KERNEL on 32b architectures. Thanks to Matthew to notice this.

Fix the problem by unconditionally setting GFP_DMA32 in GFP_VMALLOC32 for !64b arches (as a bailout). This should do the right thing and use ZONE_NORMAL which should be always below 4G on 32b systems.

Debugged by Matthew Wilcox.

Link: http://lkml.kernel.org/r/20180212095019.GX21609@dhcp22.suse.cz Fixes: 19809c2da28a ("mm, vmalloc: use __GFP_HIGHMEM implicitly”) Signed-off-by: Michal Hocko mhocko@suse.com Reported-by: Kai Heng Feng kai.heng.feng@canonical.com Cc: Matthew Wilcox willy@infradead.org Cc: Laura Abbott labbott@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/vmalloc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff -puN mm/vmalloc.c~vmalloc-fix-__gfp_highmem-usage-for-vmalloc_32-on-32b-systems mm/vmalloc.c --- a/mm/vmalloc.c~vmalloc-fix-__gfp_highmem-usage-for-vmalloc_32-on-32b-systems +++ a/mm/vmalloc.c @@ -1947,7 +1947,11 @@ void *vmalloc_exec(unsigned long size) #elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA) #define GFP_VMALLOC32 GFP_DMA | GFP_KERNEL #else -#define GFP_VMALLOC32 GFP_KERNEL +/* + * 64b systems should always have either DMA or DMA32 zones. For others + * GFP_DMA32 should do the right thing and use the normal zone. + */ +#define GFP_VMALLOC32 GFP_DMA32 | GFP_KERNEL #endif

/** _

Patches currently in -mm which might be from mhocko@suse.com are

vmalloc-fix-__gfp_highmem-usage-for-vmalloc_32-on-32b-systems.patch mm-oom-docs-describe-the-cgroup-aware-oom-killer-fix-2.patch mm-introduce-map_fixed_safe.patch fs-elf-drop-map_fixed-usage-from-elf_map.patch mm-numa-rework-do_pages_move.patch mm-migrate-remove-reason-argument-from-new_page_t.patch mm-unclutter-thp-migration.patch