From: Yaliang Wang Yaliang.Wang@windriver.com
[ Upstream commit 2bc5bab9a763d520937e4f3fe8df51c6a1eceb97 ]
pgd page is freed by generic implementation pgd_free() since commit f9cb654cb550 ("asm-generic: pgalloc: provide generic pgd_free()"), however, there are scenarios that the system uses more than one page as the pgd table, in such cases the generic implementation pgd_free() won't be applicable anymore. For example, when PAGE_SIZE_4KB is enabled and MIPS_VA_BITS_48 is not enabled in a 64bit system, the macro "PGD_ORDER" will be set as "1", which will cause allocating two pages as the pgd table. Well, at the same time, the generic implementation pgd_free() just free one pgd page, which will result in the memory leak.
The memory leak can be easily detected by executing shell command: "while true; do ls > /dev/null; grep MemFree /proc/meminfo; done"
Fixes: f9cb654cb550 ("asm-generic: pgalloc: provide generic pgd_free()") Signed-off-by: Yaliang Wang Yaliang.Wang@windriver.com Signed-off-by: Thomas Bogendoerfer tsbogend@alpha.franken.de Signed-off-by: Sasha Levin sashal@kernel.org --- arch/mips/include/asm/pgalloc.h | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/arch/mips/include/asm/pgalloc.h b/arch/mips/include/asm/pgalloc.h index c7925d0e9874..867e9c3db76e 100644 --- a/arch/mips/include/asm/pgalloc.h +++ b/arch/mips/include/asm/pgalloc.h @@ -15,6 +15,7 @@
#define __HAVE_ARCH_PMD_ALLOC_ONE #define __HAVE_ARCH_PUD_ALLOC_ONE +#define __HAVE_ARCH_PGD_FREE #include <asm-generic/pgalloc.h>
static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, @@ -48,6 +49,11 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) extern void pgd_init(unsigned long page); extern pgd_t *pgd_alloc(struct mm_struct *mm);
+static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd) +{ + free_pages((unsigned long)pgd, PGD_ORDER); +} + #define __pte_free_tlb(tlb,pte,address) \ do { \ pgtable_pte_page_dtor(pte); \