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ChaoBigregkh
ChaoBi
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gregkh
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mei: set client's read_cb to NULL when flow control fails
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] [<c16249b8>] ? mei_cl_unlink+0x48/0xa0 [228781.835283] [<c1624487>] mei_io_cb_free+0x17/0x30 [228781.840733] [<c16265d8>] mei_release+0xa8/0x180 [228781.845989] [<c135c610>] ? __fsnotify_parent+0xa0/0xf0 [228781.851925] [<c1325a69>] __fput+0xd9/0x200 [228781.856696] [<c1325b9d>] ____fput+0xd/0x10 [228781.861467] [<c125cae1>] task_work_run+0x81/0xb0 [228781.866821] [<c1242e53>] do_exit+0x283/0xa00 [228781.871786] [<c1a82b36>] ? kprobe_flush_task+0x66/0xc0 [228781.877722] [<c124eeb8>] ? __dequeue_signal+0x18/0x1a0 [228781.883657] [<c124f072>] ? dequeue_signal+0x32/0x190 [228781.889397] [<c1243744>] do_group_exit+0x34/0xa0 [228781.894750] [<c12517b6>] get_signal_to_deliver+0x206/0x610 [228781.901075] [<c12018d8>] do_signal+0x38/0x100 [228781.906136] [<c1626d1c>] ? mei_read+0x42c/0x4e0 [228781.911393] [<c12600a0>] ? wake_up_bit+0x30/0x30 [228781.916745] [<c16268f0>] ? mei_poll+0x120/0x120 [228781.922001] [<c1324be9>] ? vfs_read+0x89/0x160 [228781.927158] [<c16268f0>] ? mei_poll+0x120/0x120 [228781.932414] [<c133ca34>] ? fget_light+0x44/0xe0 [228781.937670] [<c1324e58>] ? SyS_read+0x68/0x80 [228781.942730] [<c12019f5>] do_notify_resume+0x55/0x70 [228781.948376] [<c1a7de5d>] work_notifysig+0x29/0x30 [228781.953827] [<c1a70000>] ? bad_area+0x5/0x3e Cc: stable <stable@vger.kernel.org> # 3.9+ Signed-off-by: Chao Bi <chao.bi@intel.com> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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‎drivers/misc/mei/client.c

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -666,7 +666,6 @@ int mei_cl_read_start(struct mei_cl *cl, size_t length)
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goto err;
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cb->fop_type = MEI_FOP_READ;
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cl->read_cb = cb;
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if (dev->hbuf_is_ready) {
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dev->hbuf_is_ready = false;
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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)
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} else {
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list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
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}
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cl->read_cb = cb;
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return rets;
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err:
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mei_io_cb_free(cb);

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