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In pte_alloc_one(), pgtable_page_ctor() is passed an address that has not been converted by page_address() to the newly allocated PTE page. When the PTE is freed, __pte_free_tlb() calls pgtable_page_dtor() with an address to the PTE page that has been converted by page_address(). The mismatch in the PTE's page address causes pgtable_page_dtor() to access invalid memory, so resources for that PTE (such as the page lock) is not properly cleaned up. On PPC32, only SMP kernels are affected. On PPC64, only SMP kernels with 4K page size are affected. This bug was introduced by commitd614bb0412"powerpc: Move the pte free routines from common header". On a preempt-rt kernel, a spinlock is dynamically allocated for each PTE in pgtable_page_ctor(). When the PTE is freed, calling pgtable_page_dtor() with a mismatched page address causes a memory leak, as the pointer to the PTE's spinlock is bogus. On mainline, there isn't any immediately obvious symptoms, but the problem still exists here. Fixes:d614bb0412"powerpc: Move the pte free routes from common header" Cc: Paul Mackerras <paulus@samba.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: linux-stable <stable@vger.kernel.org> # v3.10+ Signed-off-by: Hong H. Pham <hong.pham@windriver.com> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
92 lines
2.6 KiB
C
92 lines
2.6 KiB
C
#ifndef _ASM_POWERPC_PGALLOC_32_H
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#define _ASM_POWERPC_PGALLOC_32_H
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#include <linux/threads.h>
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/* For 32-bit, all levels of page tables are just drawn from get_free_page() */
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#define MAX_PGTABLE_INDEX_SIZE 0
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extern void __bad_pte(pmd_t *pmd);
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extern pgd_t *pgd_alloc(struct mm_struct *mm);
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extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);
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/*
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* We don't have any real pmd's, and this code never triggers because
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* the pgd will always be present..
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*/
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/* #define pmd_alloc_one(mm,address) ({ BUG(); ((pmd_t *)2); }) */
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#define pmd_free(mm, x) do { } while (0)
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#define __pmd_free_tlb(tlb,x,a) do { } while (0)
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/* #define pgd_populate(mm, pmd, pte) BUG() */
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#ifndef CONFIG_BOOKE
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#define pmd_populate_kernel(mm, pmd, pte) \
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(pmd_val(*(pmd)) = __pa(pte) | _PMD_PRESENT)
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#define pmd_populate(mm, pmd, pte) \
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(pmd_val(*(pmd)) = (page_to_pfn(pte) << PAGE_SHIFT) | _PMD_PRESENT)
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#define pmd_pgtable(pmd) pmd_page(pmd)
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#else
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#define pmd_populate_kernel(mm, pmd, pte) \
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(pmd_val(*(pmd)) = (unsigned long)pte | _PMD_PRESENT)
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#define pmd_populate(mm, pmd, pte) \
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(pmd_val(*(pmd)) = (unsigned long)lowmem_page_address(pte) | _PMD_PRESENT)
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#define pmd_pgtable(pmd) pmd_page(pmd)
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#endif
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extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long addr);
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extern pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long addr);
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static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
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{
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free_page((unsigned long)pte);
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}
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static inline void pte_free(struct mm_struct *mm, pgtable_t ptepage)
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{
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pgtable_page_dtor(ptepage);
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__free_page(ptepage);
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}
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static inline void pgtable_free(void *table, unsigned index_size)
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{
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BUG_ON(index_size); /* 32-bit doesn't use this */
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free_page((unsigned long)table);
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}
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#define check_pgt_cache() do { } while (0)
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#ifdef CONFIG_SMP
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static inline void pgtable_free_tlb(struct mmu_gather *tlb,
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void *table, int shift)
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{
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unsigned long pgf = (unsigned long)table;
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BUG_ON(shift > MAX_PGTABLE_INDEX_SIZE);
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pgf |= shift;
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tlb_remove_table(tlb, (void *)pgf);
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}
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static inline void __tlb_remove_table(void *_table)
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{
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void *table = (void *)((unsigned long)_table & ~MAX_PGTABLE_INDEX_SIZE);
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unsigned shift = (unsigned long)_table & MAX_PGTABLE_INDEX_SIZE;
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pgtable_free(table, shift);
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}
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#else
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static inline void pgtable_free_tlb(struct mmu_gather *tlb,
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void *table, int shift)
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{
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pgtable_free(table, shift);
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}
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#endif
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static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
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unsigned long address)
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{
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tlb_flush_pgtable(tlb, address);
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pgtable_page_dtor(table);
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pgtable_free_tlb(tlb, page_address(table), 0);
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}
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#endif /* _ASM_POWERPC_PGALLOC_32_H */
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