From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20130911042916.484871625@goodmis.org> Date: Wed, 11 Sep 2013 00:29:32 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jiang Liu , Greg Kroah-Hartman Subject: [145/251] zram: avoid invalid memory access in zram_exit() References: <20130911042707.738353451@goodmis.org> Content-Disposition: inline; filename=0145-zram-avoid-invalid-memory-access-in-zram_exit.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.6.11.9-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiang Liu [ Upstream commit 6030ea9b35971a4200062f010341ab832e878ac9 ] Memory for zram->disk object may have already been freed after returning from destroy_device(zram), then it's unsafe for zram_reset_device(zram) to access zram->disk again. We can't solve this bug by flipping the order of destroy_device(zram) and zram_reset_device(zram), that will cause deadlock issues to the zram sysfs handler. So fix it by holding an extra reference to zram->disk before calling destroy_device(zram). Signed-off-by: Jiang Liu Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Steven Rostedt --- drivers/staging/zram/zram_drv.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 6edefde..38a1b44 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -771,9 +771,11 @@ static void __exit zram_exit(void) for (i = 0; i < num_devices; i++) { zram = &zram_devices[i]; + get_disk(zram->disk); destroy_device(zram); if (zram->init_done) zram_reset_device(zram); + put_disk(zram->disk); } unregister_blkdev(zram_major, "zram"); -- 1.7.10.4