Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 086/241] powerpc/mm/hugetlb: Filter out hugepage size not supported by page table layout | Date | Mon, 19 Mar 2018 19:05:51 +0100 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
[ Upstream commit a525108cf1cc14651602d678da38fa627a76a724 ]
Without this if firmware reports 1MB page size support we will crash trying to use 1MB as hugetlb page size.
echo 300 > /sys/kernel/mm/hugepages/hugepages-1024kB/nr_hugepages
kernel BUG at ./arch/powerpc/include/asm/hugetlb.h:19! ..... .... [c0000000e2c27b30] c00000000029dae8 .hugetlb_fault+0x638/0xda0 [c0000000e2c27c30] c00000000026fb64 .handle_mm_fault+0x844/0x1d70 [c0000000e2c27d70] c00000000004805c .do_page_fault+0x3dc/0x7c0 [c0000000e2c27e30] c00000000000ac98 handle_page_fault+0x10/0x30
With fix, we don't enable 1MB as hugepage size.
bash-4.2# cd /sys/kernel/mm/hugepages/ bash-4.2# ls hugepages-16384kB hugepages-16777216kB
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/powerpc/mm/hugetlbpage.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)
--- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -765,6 +765,24 @@ static int __init add_huge_page_size(uns if ((mmu_psize = shift_to_mmu_psize(shift)) < 0) return -EINVAL; +#ifdef CONFIG_PPC_BOOK3S_64 + /* + * We need to make sure that for different page sizes reported by + * firmware we only add hugetlb support for page sizes that can be + * supported by linux page table layout. + * For now we have + * Radix: 2M + * Hash: 16M and 16G + */ + if (radix_enabled()) { + if (mmu_psize != MMU_PAGE_2M) + return -EINVAL; + } else { + if (mmu_psize != MMU_PAGE_16M && mmu_psize != MMU_PAGE_16G) + return -EINVAL; + } +#endif + BUG_ON(mmu_psize_defs[mmu_psize].shift != shift); /* Return if huge page size has already been setup */
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