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authorAndrey Vagin <avagin@openvz.org>2014-01-30 15:46:10 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-30 16:56:56 -0800
commit24f91eba18bbfdb27e71a1aae5b3a61b67fcd091 (patch)
tree0d2f8a9cf99676eca52508f35de928138c929030 /arch
parenta03208652dad18232e9ec3432df69f9c19c856ec (diff)
downloadlinux-linaro-stable-24f91eba18bbfdb27e71a1aae5b3a61b67fcd091.tar.gz
mm: don't lose the SOFT_DIRTY flag on mprotect
The SOFT_DIRTY bit shows that the content of memory was changed after a defined point in the past. mprotect() doesn't change the content of memory, so it must not change the SOFT_DIRTY bit. This bug causes a malfunction: on the first iteration all pages are dumped. On other iterations only pages with the SOFT_DIRTY bit are dumped. So if the SOFT_DIRTY bit is cleared from a page by mistake, the page is not dumped and its content will be restored incorrectly. This patch does nothing with _PAGE_SWP_SOFT_DIRTY, becase pte_modify() is called only for present pages. Fixes commit 0f8975ec4db2 ("mm: soft-dirty bits for user memory changes tracking"). Signed-off-by: Andrey Vagin <avagin@openvz.org> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: Borislav Petkov <bp@suse.de> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/include/asm/pgtable_types.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index a83aa44bb1fb..1aa9ccd43223 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -121,7 +121,8 @@
/* Set of bits not changed in pte_modify */
#define _PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \
- _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY)
+ _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY | \
+ _PAGE_SOFT_DIRTY)
#define _HPAGE_CHG_MASK (_PAGE_CHG_MASK | _PAGE_PSE)
#define _PAGE_CACHE_MASK (_PAGE_PCD | _PAGE_PWT)