[PATCH 3.12 48/82] mei: dont unset read cb ptr on reset

Greg Kroah-Hartman
2014-02-21T00:33:42Z

From: Alexander Usyskin <alexander.usyskin@intel.com>

commit 5cb906c7035f03a3a44fecece9d3ff8fcc75d6e0 upstream.

Don't set read callback to NULL during reset as
this leads to memory leak of both cb and its buffer.
The memory is correctly freed during mei_release.

The memory leak is detectable by kmemleak if
application has open read call while system is going through
suspend/resume.

unreferenced object 0xecead780 (size 64):
comm "AsyncTask #1", pid 1018, jiffies 4294949621 (age 152.440s)
hex dump (first 32 bytes):
00 01 10 00 00 02 20 00 00 bf 30 f1 00 00 00 00 ...... ...0.....
00 00 00 00 00 00 00 00 36 01 00 00 00 70 da e2 ........6....p..
backtrace:
[<c1a60aec>] kmemleak_alloc+0x3c/0xa0
[<c131ed56>] kmem_cache_alloc_trace+0xc6/0x190
[<c16243c9>] mei_io_cb_init+0x29/0x50
[<c1625722>] mei_cl_read_start+0x102/0x360
[<c16268f3>] mei_read+0x103/0x4e0
[<c1324b09>] vfs_read+0x89/0x160
[<c1324d5f>] SyS_read+0x4f/0x80
[<c1a7b318>] syscall_call+0x7/0xb
[<ffffffff>] 0xffffffff
unreferenced object 0xe2da7000 (size 512):
comm "AsyncTask #1", pid 1018, jiffies 4294949621 (age 152.440s)
hex dump (first 32 bytes):
00 6c da e2 7c 00 00 00 00 00 00 00 c0 eb 0c 59 .l..|..........Y
1b 00 00 00 01 00 00 00 02 10 00 00 01 00 00 00 ................
backtrace:
[<c1a60aec>] kmemleak_alloc+0x3c/0xa0
[<c131f127>] __kmalloc+0xe7/0x1d0
[<c162447e>] mei_io_cb_alloc_resp_buf+0x2e/0x60
[<c162574c>] mei_cl_read_start+0x12c/0x360
[<c16268f3>] mei_read+0x103/0x4e0
[<c1324b09>] vfs_read+0x89/0x160
[<c1324d5f>] SyS_read+0x4f/0x80
[<c1a7b318>] syscall_call+0x7/0xb
[<ffffffff>] 0xffffffff

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/misc/mei/client.c | 1 -
1 file changed, 1 deletion(-)

--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -882,7 +882,6 @@ void mei_cl_all_disconnect(struct mei_de
list_for_each_entry_safe(cl, next, &dev->file_list, link) {
cl->state = MEI_FILE_DISCONNECTED;
cl->mei_flow_ctrl_creds = 0;
- cl->read_cb = NULL;
cl->timer_count = 0;
}
}