From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chao Bi , Tomas Winkler Subject: [PATCH 3.10 72/97] mei: set clients read_cb to NULL when flow control fails Date: Tue, 4 Mar 2014 12:04:25 -0800 Message-Id: <20140304200348.365551158@linuxfoundation.org> In-Reply-To: <20140304200345.895517495@linuxfoundation.org> References: <20140304200345.895517495@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chao Bi commit accb884b32e82f943340688c9cd30290531e73e0 upstream. 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 Signed-off-by: Chao Bi Signed-off-by: Tomas Winkler Signed-off-by: Greg Kroah-Hartman --- drivers/misc/mei/client.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/misc/mei/client.c +++ b/drivers/misc/mei/client.c @@ -664,7 +664,6 @@ int mei_cl_read_start(struct mei_cl *cl, 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)) { @@ -675,6 +674,9 @@ int mei_cl_read_start(struct mei_cl *cl, } else { list_add_tail(&cb->list, &dev->ctrl_wr_list.list); } + + cl->read_cb = cb; + return rets; err: mei_io_cb_free(cb);