From: Chao Bi <chao.bi@xxxxxxxxx>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
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] [<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
Signed-off-by: Chao Bi <chao.bi@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
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 8c33f943abbf..b66cec93ebb3 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -660,7 +660,6 @@ 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)) {
@@ -671,6 +670,9 @@ 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);
--
1.9.0
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