+ kasan-use-is_aligned-in-memory_is_poisoned_8.patch added to -mm tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The patch titled
     Subject: kasan: use IS_ALIGNED in memory_is_poisoned_8()
has been added to the -mm tree.  Its filename is
     kasan-use-is_aligned-in-memory_is_poisoned_8.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/kasan-use-is_aligned-in-memory_is_poisoned_8.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/kasan-use-is_aligned-in-memory_is_poisoned_8.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/SubmitChecklist when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Subject: kasan: use IS_ALIGNED in memory_is_poisoned_8()

Use IS_ALIGNED() to determine whether the shadow span two bytes.  It
generates less code and more readable.  Also add some comments in shadow
check functions.

Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Andrey Konovalov <adech.fo@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/kasan/kasan.c |   24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff -puN mm/kasan/kasan.c~kasan-use-is_aligned-in-memory_is_poisoned_8 mm/kasan/kasan.c
--- a/mm/kasan/kasan.c~kasan-use-is_aligned-in-memory_is_poisoned_8
+++ a/mm/kasan/kasan.c
@@ -86,6 +86,11 @@ static __always_inline bool memory_is_po
 		if (memory_is_poisoned_1(addr + 1))
 			return true;
 
+		/*
+		 * If single shadow byte covers 2-byte access, we don't
+		 * need to do anything more. Otherwise, test the first
+		 * shadow byte.
+		 */
 		if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0))
 			return false;
 
@@ -103,6 +108,11 @@ static __always_inline bool memory_is_po
 		if (memory_is_poisoned_1(addr + 3))
 			return true;
 
+		/*
+		 * If single shadow byte covers 4-byte access, we don't
+		 * need to do anything more. Otherwise, test the first
+		 * shadow byte.
+		 */
 		if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3))
 			return false;
 
@@ -120,7 +130,12 @@ static __always_inline bool memory_is_po
 		if (memory_is_poisoned_1(addr + 7))
 			return true;
 
-		if (likely(((addr + 7) & KASAN_SHADOW_MASK) >= 7))
+		/*
+		 * If single shadow byte covers 8-byte access, we don't
+		 * need to do anything more. Otherwise, test the first
+		 * shadow byte.
+		 */
+		if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
 			return false;
 
 		return unlikely(*(u8 *)shadow_addr);
@@ -139,7 +154,12 @@ static __always_inline bool memory_is_po
 		if (unlikely(shadow_first_bytes))
 			return true;
 
-		if (likely(IS_ALIGNED(addr, 8)))
+		/*
+		 * If two shadow bytes covers 16-byte access, we don't
+		 * need to do anything more. Otherwise, test the last
+		 * shadow byte.
+		 */
+		if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
 			return false;
 
 		return memory_is_poisoned_1(addr + 15);
_

Patches currently in -mm which might be from qiuxishi@xxxxxxxxxx are

kasan-fix-last-shadow-judgement-in-memory_is_poisoned_16.patch
kasan-use-is_aligned-in-memory_is_poisoned_8.patch

--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Kernel Newbies FAQ]     [Kernel Archive]     [IETF Annouce]     [DCCP]     [Netdev]     [Networking]     [Security]     [Bugtraq]     [Photo]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux SCSI]

  Powered by Linux