This is a note to let you know that I've just added the patch titled
zram: protect sysfs handler from invalid memory access
to the 3.4-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-protect-sysfs-handler-from-invalid-memory-access.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5863e10b441e7ea4b492f930f1be180a97d026f3 Mon Sep 17 00:00:00 2001
From: Jiang Liu <liuj97@xxxxxxxxx>
Date: Fri, 7 Jun 2013 00:07:27 +0800
Subject: zram: protect sysfs handler from invalid memory access
From: Jiang Liu <liuj97@xxxxxxxxx>
commit 5863e10b441e7ea4b492f930f1be180a97d026f3 upstream.
Use zram->init_lock to protect access to zram->meta, otherwise it
may cause invalid memory access if zram->meta has been freed by
zram_reset_device().
This issue may be triggered by:
Thread 1:
while true; do cat mem_used_total; done
Thread 2:
while true; do echo 8M > disksize; echo 1 > reset; done
Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
[wyj: Backported to 3.4: adjust context]
Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/zram/zram_sysfs.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/staging/zram/zram_sysfs.c
+++ b/drivers/staging/zram/zram_sysfs.c
@@ -188,10 +188,12 @@ static ssize_t mem_used_total_show(struc
u64 val = 0;
struct zram *zram = dev_to_zram(dev);
+ down_read(&zram->init_lock);
if (zram->init_done) {
val = zs_get_total_size_bytes(zram->mem_pool) +
((u64)(zram->stats.pages_expand) << PAGE_SHIFT);
}
+ up_read(&zram->init_lock);
return sprintf(buf, "%llu\n", val);
}
Patches currently in stable-queue which might be from liuj97@xxxxxxxxx are
queue-3.4/zram-protect-sysfs-handler-from-invalid-memory-access.patch
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