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Patch "zram: fix operator precedence to get offset" has been added to the 4.9-stable tree

PATCH [email protected] 2 participants 2 messages Apr 18, 2017 – Apr 19, 2017

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

zram: fix operator precedence to get offset

to the 4.9-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:
zram-fix-operator-precedence-to-get-offset.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 4ca82dabc9fbf7bc5322aa54d802cb3cb7b125c5 Mon Sep 17 00:00:00 2001

From: Minchan Kim <[email protected]>
Date: Thu, 13 Apr 2017 14:56:35 -0700
Subject: zram: fix operator precedence to get offset

From: Minchan Kim <[email protected]>

commit 4ca82dabc9fbf7bc5322aa54d802cb3cb7b125c5 upstream.

In zram_rw_page, the logic to get offset is wrong by operator precedence (i.e., "<<" is higher than "&"). With wrong offset, zram can corrupt the user's data. This patch fixes it.

Fixes 8c7f01025 ("zram: implement rw_page operation of zram")
Link http://lkml.kernel.org/r/[email protected] open here
Signed-off-by Minchan Kim <[email protected]>
Cc Sergey Senozhatsky <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
Signed-off-by Linus Torvalds <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 drivers/block/zram/zram_drv.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/block/zram/zram_drv.c +1 -1
@@ -998,7 +998,7 @@ static int zram_rw_page(struct block_dev
 	}
 
 	index = sector >> SECTORS_PER_PAGE_SHIFT;
-	offset = sector & (SECTORS_PER_PAGE - 1) << SECTOR_SHIFT;
+	offset = (sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
 
 	bv.bv_page = page;
 	bv.bv_len = PAGE_SIZE;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/zram-do-not-use-copy_page-with-non-page-aligned-address.patch queue-4.9/zram-fix-operator-precedence-to-get-offset.patch queue-4.9/thp-fix-madv_dontneed-vs.-madv_free-race.patch queue-4.9/zsmalloc-expand-class-bit.patch

maintainer
#1 lore raw
Quoted 29 lines · On Tue, Apr 18, 2017 at 02:50:42PM +0200, [email protected] wrote:

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

zram: fix operator precedence to get offset

to the 4.9-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:
zram-fix-operator-precedence-to-get-offset.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From 4ca82dabc9fbf7bc5322aa54d802cb3cb7b125c5 Mon Sep 17 00:00:00 2001
From: Minchan Kim <[email protected]>
Date: Thu, 13 Apr 2017 14:56:35 -0700
Subject: zram: fix operator precedence to get offset

From: Minchan Kim <[email protected]>

commit 4ca82dabc9fbf7bc5322aa54d802cb3cb7b125c5 upstream.

In zram_rw_page, the logic to get offset is wrong by operator precedence (i.e., "<<" is higher than "&"). With wrong offset, zram can corrupt the user's data. This patch fixes it.

Quoted 7 lines
Fixes 8c7f01025 ("zram: implement rw_page operation of zram")
Link http://lkml.kernel.org/r/[email protected] open here
Signed-off-by Minchan Kim <[email protected]>
Cc Sergey Senozhatsky <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
Signed-off-by Linus Torvalds <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>

After Linus merging this patch, I got realized that patch itself is correct but no need to apply this patch to the stable by review from Sergey.

Please drop this patch.
Sorry for the noise caused by zram.