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author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2022-02-26 06:10:56 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-02-26 20:51:17 +0300 |
commit | db110a99d3367936058727ff4798e3a39c707969 (patch) | |
tree | fdd8d020d110f43a9e3258e8f065d2bce1c394f3 /lib/test_kasan.c | |
parent | bbcf7b0e2e4b8376ef4b401777f2852302c745e3 (diff) | |
download | linux-db110a99d3367936058727ff4798e3a39c707969.tar.xz |
mm/hugetlb: fix kernel crash with hugetlb mremap
This fixes the below crash:
kernel BUG at include/linux/mm.h:2373!
cpu 0x5d: Vector: 700 (Program Check) at [c00000003c6e76e0]
pc: c000000000581a54: pmd_to_page+0x54/0x80
lr: c00000000058d184: move_hugetlb_page_tables+0x4e4/0x5b0
sp: c00000003c6e7980
msr: 9000000000029033
current = 0xc00000003bd8d980
paca = 0xc000200fff610100 irqmask: 0x03 irq_happened: 0x01
pid = 9349, comm = hugepage-mremap
kernel BUG at include/linux/mm.h:2373!
move_hugetlb_page_tables+0x4e4/0x5b0 (link register)
move_hugetlb_page_tables+0x22c/0x5b0 (unreliable)
move_page_tables+0xdbc/0x1010
move_vma+0x254/0x5f0
sys_mremap+0x7c0/0x900
system_call_exception+0x160/0x2c0
the kernel can't use huge_pte_offset before it set the pte entry because
a page table lookup check for huge PTE bit in the page table to
differentiate between a huge pte entry and a pointer to pte page. A
huge_pte_alloc won't mark the page table entry huge and hence kernel
should not use huge_pte_offset after a huge_pte_alloc.
Link: https://lkml.kernel.org/r/20220211063221.99293-1-aneesh.kumar@linux.ibm.com
Fixes: 550a7d60bd5e ("mm, hugepages: add mremap() support for hugepage backed vma")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mina Almasry <almasrymina@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/test_kasan.c')
0 files changed, 0 insertions, 0 deletions