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. This bug was introduced by commit d614bb041209fd7cb5e4b35e11a7b2f6ee8f62b8 "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: d614bb041209fd7c "powerpc: Move the pte free routes from common header" Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: linux-stable <stable@xxxxxxxxxxxxxxx> # v3.10+ Signed-off-by: Hong H. Pham <hong.pham@xxxxxxxxxxxxx> --- arch/powerpc/include/asm/pgalloc-32.h | 2 +- arch/powerpc/include/asm/pgalloc-64.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/pgalloc-32.h b/arch/powerpc/include/asm/pgalloc-32.h index 27b2386..7ff24f0 100644 --- a/arch/powerpc/include/asm/pgalloc-32.h +++ b/arch/powerpc/include/asm/pgalloc-32.h @@ -87,7 +87,7 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table, struct page *page = page_address(table); tlb_flush_pgtable(tlb, address); - pgtable_page_dtor(page); + pgtable_page_dtor(table); pgtable_free_tlb(tlb, page, 0); } #endif /* _ASM_POWERPC_PGALLOC_32_H */ diff --git a/arch/powerpc/include/asm/pgalloc-64.h b/arch/powerpc/include/asm/pgalloc-64.h index f65e27b..b187dc5 100644 --- a/arch/powerpc/include/asm/pgalloc-64.h +++ b/arch/powerpc/include/asm/pgalloc-64.h @@ -147,7 +147,7 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table, struct page *page = page_address(table); tlb_flush_pgtable(tlb, address); - pgtable_page_dtor(page); + pgtable_page_dtor(table); pgtable_free_tlb(tlb, page, 0); } -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
