From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754124AbaBLT3B (ORCPT ); Wed, 12 Feb 2014 14:29:01 -0500 Received: from mga09.intel.com ([134.134.136.24]:51317 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754004AbaBLT27 (ORCPT ); Wed, 12 Feb 2014 14:28:59 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.95,833,1384329600"; d="scan'208";a="454399646" From: Tomas Winkler To: gregkh@linuxfoundation.org Cc: arnd@arndb.de, linux-kernel@vger.kernel.org, "Chao Bi" , stable , Tomas Winkler Subject: [char-misc V2] mei: set client's read_cb to NULL when flow control fails Date: Wed, 12 Feb 2014 21:27:25 +0200 Message-Id: <1392233245-4680-1-git-send-email-tomas.winkler@intel.com> X-Mailer: git-send-email 1.8.5.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Chao Bi" In mei_cl_read_start(), if it fails to send flow control request, it will release "cl->read_cb" but forget to set pointer to NULL, leaving "cl->read_cb" still pointing to random memory, next time this client is operated like mei_release(), it has chance to refer to this wrong pointer. Fixes: PANIC at kfree in mei_release() [228781.826904] Call Trace: [228781.829737] [] ? mei_cl_unlink+0x48/0xa0 [228781.835283] [] mei_io_cb_free+0x17/0x30 [228781.840733] [] mei_release+0xa8/0x180 [228781.845989] [] ? __fsnotify_parent+0xa0/0xf0 [228781.851925] [] __fput+0xd9/0x200 [228781.856696] [] ____fput+0xd/0x10 [228781.861467] [] task_work_run+0x81/0xb0 [228781.866821] [] do_exit+0x283/0xa00 [228781.871786] [] ? kprobe_flush_task+0x66/0xc0 [228781.877722] [] ? __dequeue_signal+0x18/0x1a0 [228781.883657] [] ? dequeue_signal+0x32/0x190 [228781.889397] [] do_group_exit+0x34/0xa0 [228781.894750] [] get_signal_to_deliver+0x206/0x610 [228781.901075] [] do_signal+0x38/0x100 [228781.906136] [] ? mei_read+0x42c/0x4e0 [228781.911393] [] ? wake_up_bit+0x30/0x30 [228781.916745] [] ? mei_poll+0x120/0x120 [228781.922001] [] ? vfs_read+0x89/0x160 [228781.927158] [] ? mei_poll+0x120/0x120 [228781.932414] [] ? fget_light+0x44/0xe0 [228781.937670] [] ? SyS_read+0x68/0x80 [228781.942730] [] do_notify_resume+0x55/0x70 [228781.948376] [] work_notifysig+0x29/0x30 [228781.953827] [] ? bad_area+0x5/0x3e Cc: stable # 3.9+ Signed-off-by: Chao Bi Signed-off-by: Tomas Winkler --- V2: fix the signed-off drivers/misc/mei/client.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c index 9b809cf..89a5579 100644 --- a/drivers/misc/mei/client.c +++ b/drivers/misc/mei/client.c @@ -666,7 +666,6 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length) goto err; cb->fop_type = MEI_FOP_READ; - cl->read_cb = cb; if (dev->hbuf_is_ready) { dev->hbuf_is_ready = false; if (mei_hbm_cl_flow_control_req(dev, cl)) { @@ -678,6 +677,9 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length) } else { list_add_tail(&cb->list, &dev->ctrl_wr_list.list); } + + cl->read_cb = cb; + return rets; err: mei_io_cb_free(cb); -- 1.8.5.3