coresight: access conn->child_name only if it's initialised
If the addition of the coresight devices get deferred, then there's a
window before child_name is populated by of_get_coresight_platform_data
from the respective component driver's probe and the attempted to access
the same from coresight_orphan_match resulting in kernel NULL pointer
dereference as below:
Unable to handle kernel NULL pointer dereference at virtual address 0x0
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 1038 Comm: kworker/0:1 Not tainted 4.7.0-rc3 #124
Hardware name: ARM Juno development board (r2) (DT)
Workqueue: events amba_deferred_retry_func
PC is at strcmp+0x1c/0x160
LR is at coresight_orphan_match+0x7c/0xd0
Call trace:
strcmp+0x1c/0x160
bus_for_each_dev+0x60/0xa0
coresight_register+0x264/0x2e0
tmc_probe+0x130/0x310
amba_probe+0xd4/0x1c8
driver_probe_device+0x22c/0x418
__device_attach_driver+0xbc/0x158
bus_for_each_drv+0x58/0x98
__device_attach+0xc4/0x160
device_initial_probe+0x10/0x18
bus_probe_device+0x94/0xa0
device_add+0x344/0x580
amba_device_try_add+0x194/0x238
amba_deferred_retry_func+0x48/0xd0
process_one_work+0x118/0x378
worker_thread+0x48/0x498
kthread+0xd0/0xe8
ret_from_fork+0x10/0x40
This patch adds a check for non-NULL conn->child_name before accessing
the same.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed