This is a note to let you know that I've just added the patch titled
ARC: mm: fix leakage of memory allocated for PTE
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arc-mm-fix-leakage-of-memory-allocated-for-pte.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4fd9df10cb7a9289fbd22d669f9f98164d95a1ce Mon Sep 17 00:00:00 2001
From: Pavel Kozlov <pavel.kozlov@xxxxxxxxxxxx>
Date: Mon, 17 Oct 2022 20:11:27 +0400
Subject: ARC: mm: fix leakage of memory allocated for PTE
From: Pavel Kozlov <pavel.kozlov@xxxxxxxxxxxx>
commit 4fd9df10cb7a9289fbd22d669f9f98164d95a1ce upstream.
Since commit d9820ff ("ARC: mm: switch pgtable_t back to struct page *")
a memory leakage problem occurs. Memory allocated for page table entries
not released during process termination. This issue can be reproduced by
a small program that allocates a large amount of memory. After several
runs, you'll see that the amount of free memory has reduced and will
continue to reduce after each run. All ARC CPUs are effected by this
issue. The issue was introduced since the kernel stable release v5.15-rc1.
As described in commit d9820ff after switch pgtable_t back to struct
page *, a pointer to "struct page" and appropriate functions are used to
allocate and free a memory page for PTEs, but the pmd_pgtable macro hasn't
changed and returns the direct virtual address from the PMD (PGD) entry.
Than this address used as a parameter in the __pte_free() and as a result
this function couldn't release memory page allocated for PTEs.
Fix this issue by changing the pmd_pgtable macro and returning pointer to
struct page.
Fixes: d9820ff76f95 ("ARC: mm: switch pgtable_t back to struct page *")
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 5.15.x
Signed-off-by: Pavel Kozlov <pavel.kozlov@xxxxxxxxxxxx>
Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arc/include/asm/pgtable-levels.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/arc/include/asm/pgtable-levels.h
+++ b/arch/arc/include/asm/pgtable-levels.h
@@ -163,7 +163,7 @@
#define pmd_page_vaddr(pmd) (pmd_val(pmd) & PAGE_MASK)
#define pmd_page(pmd) virt_to_page(pmd_page_vaddr(pmd))
#define set_pmd(pmdp, pmd) (*(pmdp) = pmd)
-#define pmd_pgtable(pmd) ((pgtable_t) pmd_page_vaddr(pmd))
+#define pmd_pgtable(pmd) ((pgtable_t) pmd_page(pmd))
/*
* 4th level paging: pte
Patches currently in stable-queue which might be from pavel.kozlov@xxxxxxxxxxxx are
queue-5.15/arc-mm-fix-leakage-of-memory-allocated-for-pte.patch
