Patch "bitops: Fix shift overflow in GENMASK macros" has been added to the 3.14-stable tree

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

 



This is a note to let you know that I've just added the patch titled

    bitops: Fix shift overflow in GENMASK macros

to the 3.14-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:
     bitops-fix-shift-overflow-in-genmask-macros.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 00b4d9a14125f1e51874def2b9de6092e007412d Mon Sep 17 00:00:00 2001
From: Maxime COQUELIN <maxime.coquelin@xxxxxx>
Date: Thu, 6 Nov 2014 10:54:19 +0100
Subject: bitops: Fix shift overflow in GENMASK macros

From: Maxime COQUELIN <maxime.coquelin@xxxxxx>

commit 00b4d9a14125f1e51874def2b9de6092e007412d upstream.

On some 32 bits architectures, including x86, GENMASK(31, 0) returns 0
instead of the expected ~0UL.

This is the same on some 64 bits architectures with GENMASK_ULL(63, 0).

This is due to an overflow in the shift operand, 1 << 32 for GENMASK,
1 << 64 for GENMASK_ULL.

Reported-by: Eric Paire <eric.paire@xxxxxx>
Suggested-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Maxime Coquelin <maxime.coquelin@xxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: linux@xxxxxxxxxxxxxxxxxx
Cc: gong.chen@xxxxxxxxxxxxxxx
Cc: John Sullivan <jsrhbz@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Fixes: 10ef6b0dffe4 ("bitops: Introduce a more generic BITMASK macro")
Link: http://lkml.kernel.org/r/1415267659-10563-1-git-send-email-maxime.coquelin@xxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index be5fd38bd5a0..5d858e02997f 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -18,8 +18,11 @@
  * position @h. For example
  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  */
-#define GENMASK(h, l)		(((U32_C(1) << ((h) - (l) + 1)) - 1) << (l))
-#define GENMASK_ULL(h, l)	(((U64_C(1) << ((h) - (l) + 1)) - 1) << (l))
+#define GENMASK(h, l) \
+	(((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
+
+#define GENMASK_ULL(h, l) \
+	(((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
 
 extern unsigned int __sw_hweight8(unsigned int w);
 extern unsigned int __sw_hweight16(unsigned int w);


Patches currently in stable-queue which might be from maxime.coquelin@xxxxxx are

queue-3.14/bitops-fix-shift-overflow-in-genmask-macros.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]