3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jiang Liu <liu...@gmail.com>
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....@huawei.com>
Acked-by: Minchan Kim <minc...@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
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
@@ -188,8 +188,10 @@ static ssize_t mem_used_total_show(struc
struct zram *zram = dev_to_zram(dev);
struct zram_meta *meta = zram->meta;
+ down_read(&zram->init_lock);
if (zram->init_done)
val = zs_get_total_size_bytes(meta->mem_pool);
+ up_read(&zram->init_lock);
return sprintf(buf, "%llu\n", val);
}
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