From: Stijn Tintel Date: Sun, 3 Apr 2022 02:14:06 +0000 (+0300) Subject: kernel: backport pgalloc memory leak fix X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=9283359bd53a889a270da4a7d5bbe3eaaa771e70;p=openwrt%2Fstaging%2Fthess.git kernel: backport pgalloc memory leak fix Backport a fix for the massive memory leak observed in Octeon after switching to kernel 5.10. Signed-off-by: Stijn Tintel --- diff --git a/target/linux/generic/backport-5.10/350-v5.18-MIPS-pgalloc-fix-memory-leak-caused-by-pgd_free.patch b/target/linux/generic/backport-5.10/350-v5.18-MIPS-pgalloc-fix-memory-leak-caused-by-pgd_free.patch new file mode 100644 index 0000000000..28ddbc2fbc --- /dev/null +++ b/target/linux/generic/backport-5.10/350-v5.18-MIPS-pgalloc-fix-memory-leak-caused-by-pgd_free.patch @@ -0,0 +1,48 @@ +From e852442da56f43795cb6255d90b9fd0c84b209bb Mon Sep 17 00:00:00 2001 +From: Yaliang Wang +Date: Thu, 10 Mar 2022 19:31:16 +0800 +Subject: [PATCH] MIPS: pgalloc: fix memory leak caused by pgd_free() + +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 +Signed-off-by: Thomas Bogendoerfer +(cherry picked from commit 2bc5bab9a763d520937e4f3fe8df51c6a1eceb97) +--- + arch/mips/include/asm/pgalloc.h | 6 ++++++ + 1 file changed, 6 insertions(+) + +--- 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 + + static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, +@@ -49,6 +50,11 @@ static inline void pud_populate(struct m + 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); \ diff --git a/target/linux/generic/backport-5.15/350-v5.18-MIPS-pgalloc-fix-memory-leak-caused-by-pgd_free.patch b/target/linux/generic/backport-5.15/350-v5.18-MIPS-pgalloc-fix-memory-leak-caused-by-pgd_free.patch new file mode 100644 index 0000000000..7ab9d0764b --- /dev/null +++ b/target/linux/generic/backport-5.15/350-v5.18-MIPS-pgalloc-fix-memory-leak-caused-by-pgd_free.patch @@ -0,0 +1,48 @@ +From 7f297c70bebd20f3e02c9b6046e4e5e71d38ffe9 Mon Sep 17 00:00:00 2001 +From: Yaliang Wang +Date: Thu, 10 Mar 2022 19:31:16 +0800 +Subject: [PATCH] MIPS: pgalloc: fix memory leak caused by pgd_free() + +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 +Signed-off-by: Thomas Bogendoerfer +(cherry picked from commit 2bc5bab9a763d520937e4f3fe8df51c6a1eceb97) +--- + arch/mips/include/asm/pgalloc.h | 6 ++++++ + 1 file changed, 6 insertions(+) + +--- 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 + + static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, +@@ -48,6 +49,11 @@ static inline void pud_populate(struct m + 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); \