This is a note to let you know that I've just added the patch titled
powerpc: Fix PTE page address mismatch in pgtable ctor/dtor
to the 3.12-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:
powerpc-fix-pte-page-address-mismatch-in-pgtable-ctor-dtor.patch
and it can be found in the queue-3.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From cf77ee54362a245f9a01f240adce03a06c05eb68 Mon Sep 17 00:00:00 2001
From: "Hong H. Pham" <hong.pham@xxxxxxxxxxxxx>
Date: Sat, 7 Dec 2013 09:06:33 -0500
Subject: powerpc: Fix PTE page address mismatch in pgtable ctor/dtor
From: "Hong H. Pham" <hong.pham@xxxxxxxxxxxxx>
commit cf77ee54362a245f9a01f240adce03a06c05eb68 upstream.
In pte_alloc_one(), pgtable_page_ctor() is passed an address that has
not been converted by page_address() to the newly allocated PTE page.
When the PTE is freed, __pte_free_tlb() calls pgtable_page_dtor()
with an address to the PTE page that has been converted by page_address().
The mismatch in the PTE's page address causes pgtable_page_dtor() to access
invalid memory, so resources for that PTE (such as the page lock) is not
properly cleaned up.
On PPC32, only SMP kernels are affected.
On PPC64, only SMP kernels with 4K page size are affected.
This bug was introduced by commit d614bb041209fd7cb5e4b35e11a7b2f6ee8f62b8
"powerpc: Move the pte free routines from common header".
On a preempt-rt kernel, a spinlock is dynamically allocated for each
PTE in pgtable_page_ctor(). When the PTE is freed, calling
pgtable_page_dtor() with a mismatched page address causes a memory leak,
as the pointer to the PTE's spinlock is bogus.
On mainline, there isn't any immediately obvious symptoms, but the
problem still exists here.
Fixes: d614bb041209fd7c "powerpc: Move the pte free routes from common header"
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Hong H. Pham <hong.pham@xxxxxxxxxxxxx>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/pgalloc-32.h | 6 ++----
arch/powerpc/include/asm/pgalloc-64.h | 6 ++----
2 files changed, 4 insertions(+), 8 deletions(-)
--- a/arch/powerpc/include/asm/pgalloc-32.h
+++ b/arch/powerpc/include/asm/pgalloc-32.h
@@ -84,10 +84,8 @@ static inline void pgtable_free_tlb(stru
static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
unsigned long address)
{
- struct page *page = page_address(table);
-
tlb_flush_pgtable(tlb, address);
- pgtable_page_dtor(page);
- pgtable_free_tlb(tlb, page, 0);
+ pgtable_page_dtor(table);
+ pgtable_free_tlb(tlb, page_address(table), 0);
}
#endif /* _ASM_POWERPC_PGALLOC_32_H */
--- a/arch/powerpc/include/asm/pgalloc-64.h
+++ b/arch/powerpc/include/asm/pgalloc-64.h
@@ -144,11 +144,9 @@ static inline void pgtable_free_tlb(stru
static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
unsigned long address)
{
- struct page *page = page_address(table);
-
tlb_flush_pgtable(tlb, address);
- pgtable_page_dtor(page);
- pgtable_free_tlb(tlb, page, 0);
+ pgtable_page_dtor(table);
+ pgtable_free_tlb(tlb, page_address(table), 0);
}
#else /* if CONFIG_PPC_64K_PAGES */
Patches currently in stable-queue which might be from hong.pham@xxxxxxxxxxxxx are
queue-3.12/powerpc-fix-pte-page-address-mismatch-in-pgtable-ctor-dtor.patch
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