| From | Greg Kroah-Hartman <> | Subject | [ 065/102] zram: protect sysfs handler from invalid memory access | Date | Thu, 8 Aug 2013 18:57:41 -0700 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Jiang Liu <liuj97@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.liu@huawei.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@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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