lkml.org 
[lkml]   [2018]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v1 3/4] arm64: Fix the page leak in pud/pmd_set_huge
Date
While setting huge page, we need to take care of
previously existing next level mapping. Since,
we are going to overrite previous mapping, the
only reference to next level page table will get
lost and the next level page table will be zombie,
occupying space forever. So, free it before
overriding.

Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>
---
arch/arm64/mm/mmu.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 8c704f1..c0df264 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -32,7 +32,7 @@
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
-
+#include <linux/hugetlb.h>
#include <asm/barrier.h>
#include <asm/cputype.h>
#include <asm/fixmap.h>
@@ -45,6 +45,7 @@
#include <asm/memblock.h>
#include <asm/mmu_context.h>
#include <asm/ptdump.h>
+#include <asm/page.h>

#define NO_BLOCK_MAPPINGS BIT(0)
#define NO_CONT_MAPPINGS BIT(1)
@@ -939,6 +940,9 @@ int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
return 0;

BUG_ON(phys & ~PUD_MASK);
+ if (pud_val(*pud) && !pud_huge(*pud))
+ free_page((unsigned long)__va(pud_val(*pud)));
+
set_pud(pudp, pfn_pud(__phys_to_pfn(phys), sect_prot));
return 1;
}
@@ -953,6 +957,9 @@ int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
return 0;

BUG_ON(phys & ~PMD_MASK);
+ if (pmd_val(*pmd) && !pmd_huge(*pmd))
+ free_page((unsigned long)__va(pmd_val(*pmd)));
+
set_pmd(pmdp, pfn_pmd(__phys_to_pfn(phys), sect_prot));
return 1;
}
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation
Center, Inc., is a member of Code Aurora Forum, a Linux Foundation
Collaborative Project
\
 
 \ /
  Last update: 2018-03-14 09:49    [W:0.194 / U:4.976 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site