linux/arch/mips/include/asm/pgalloc.h
Yaliang Wang 2bc5bab9a7 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 <Yaliang.Wang@windriver.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
2022-03-14 15:05:18 +01:00

112 lines
2.5 KiB
C

/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1994 - 2001, 2003 by Ralf Baechle
* Copyright (C) 1999, 2000, 2001 Silicon Graphics, Inc.
*/
#ifndef _ASM_PGALLOC_H
#define _ASM_PGALLOC_H
#include <linux/highmem.h>
#include <linux/mm.h>
#include <linux/sched.h>
#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,
pte_t *pte)
{
set_pmd(pmd, __pmd((unsigned long)pte));
}
static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
pgtable_t pte)
{
set_pmd(pmd, __pmd((unsigned long)page_address(pte)));
}
/*
* Initialize a new pmd table with invalid pointers.
*/
extern void pmd_init(unsigned long page, unsigned long pagetable);
#ifndef __PAGETABLE_PMD_FOLDED
static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
{
set_pud(pud, __pud((unsigned long)pmd));
}
#endif
/*
* Initialize a new pgd / pmd table with invalid pointers.
*/
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); \
tlb_remove_page((tlb), pte); \
} while (0)
#ifndef __PAGETABLE_PMD_FOLDED
static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)
{
pmd_t *pmd;
struct page *pg;
pg = alloc_pages(GFP_KERNEL_ACCOUNT, PMD_ORDER);
if (!pg)
return NULL;
if (!pgtable_pmd_page_ctor(pg)) {
__free_pages(pg, PMD_ORDER);
return NULL;
}
pmd = (pmd_t *)page_address(pg);
pmd_init((unsigned long)pmd, (unsigned long)invalid_pte_table);
return pmd;
}
#define __pmd_free_tlb(tlb, x, addr) pmd_free((tlb)->mm, x)
#endif
#ifndef __PAGETABLE_PUD_FOLDED
static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long address)
{
pud_t *pud;
pud = (pud_t *) __get_free_pages(GFP_KERNEL, PUD_ORDER);
if (pud)
pud_init((unsigned long)pud, (unsigned long)invalid_pmd_table);
return pud;
}
static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud)
{
set_p4d(p4d, __p4d((unsigned long)pud));
}
#define __pud_free_tlb(tlb, x, addr) pud_free((tlb)->mm, x)
#endif /* __PAGETABLE_PUD_FOLDED */
extern void pagetable_init(void);
#endif /* _ASM_PGALLOC_H */