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powerpc/mm: Handle page table allocation failures
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This fixes kernel crash that arises due to not handling page table allocation
failures while allocating hugetlb page table.

Fixes: e2b3d20 ("powerpc: Switch 16GB and 16MB explicit hugepages to a different page table format")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Aneesh Kumar K.V authored and Michael Ellerman committed Jul 4, 2019
1 parent 57cadda commit 2230ebf
Showing 1 changed file with 8 additions and 0 deletions.
8 changes: 8 additions & 0 deletions arch/powerpc/mm/hugetlbpage.c
Original file line number Diff line number Diff line change
Expand Up @@ -130,6 +130,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
} else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
if (!pu)
return NULL;
if (pshift == PUD_SHIFT)
return (pte_t *)pu;
else if (pshift > PMD_SHIFT) {
Expand All @@ -138,6 +140,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
} else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
if (!pm)
return NULL;
if (pshift == PMD_SHIFT)
/* 16MB hugepage */
return (pte_t *)pm;
Expand All @@ -154,12 +158,16 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
} else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
if (!pu)
return NULL;
if (pshift >= PUD_SHIFT) {
ptl = pud_lockptr(mm, pu);
hpdp = (hugepd_t *)pu;
} else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
if (!pm)
return NULL;
ptl = pmd_lockptr(mm, pm);
hpdp = (hugepd_t *)pm;
}
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