[PATCH] PM / devfreq: try_then_request_governor should not return NULL
From: Rob Clark
Date: Thu May 23 2019 - 18:01:58 EST
From: Rob Clark <robdclark@xxxxxxxxxxxx>
The two spots it is called expect either an IS_ERR() or a valid pointer,
but not NULL.
Fixes this crash that I came across:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030
Mem abort info:
ESR = 0x96000005
Exception class = DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000005
CM = 0, WnR = 0
[0000000000000030] user address but active_mm is swapper
Internal error: Oops: 96000005 [#1] PREEMPT SMP
Modules linked in:
Process kworker/2:1 (pid: 212, stack limit = 0x(____ptrval____))
CPU: 2 PID: 212 Comm: kworker/2:1 Not tainted 5.1.0-43338-g460e6984675c-dirty #54
Hardware name: Google Cheza (rev3+) (DT)
Workqueue: events deferred_probe_work_func
pstate: 00c00009 (nzcv daif +PAN +UAO)
pc : devfreq_add_device+0x2e4/0x410
lr : devfreq_add_device+0x2d4/0x410
sp : ffffff8013d93740
x29: ffffff8013d93790 x28: ffffffc0f54f8670
x27: 0000000000000001 x26: 0000000000000007
x25: ffffff80124abfd8 x24: 0000000000000000
x23: ffffffc0fabc4048 x22: ffffffc0fabc4388
x21: ffffffc0fabc4010 x20: ffffffc0fa243010
x19: ffffffc0fabc4000 x18: 0000000091c3d373
x17: 0000000000000400 x16: 000000000000001a
x15: 000000019e06d400 x14: 0000000000000001
x13: 0000000000000000 x12: 00000000000006b6
x11: 0000000000000000 x10: 0000000000000000
x9 : ffffffc0fa18ba00 x8 : 0000000000000000
x7 : 0000000000000000 x6 : ffffff80127a3d9a
x5 : ffffff8013d93550 x4 : 0000000000000000
x3 : 0000000000000000 x2 : 0000000000000000
x1 : 00000000000000fe x0 : 0000000000000000
Call trace:
devfreq_add_device+0x2e4/0x410
devm_devfreq_add_device+0x64/0xac
msm_gpu_init+0x320/0x5c0
adreno_gpu_init+0x21c/0x274
a6xx_gpu_init+0x68/0xf4
adreno_bind+0x158/0x284
component_bind_all+0x110/0x204
msm_drm_bind+0x118/0x5b8
try_to_bring_up_master+0x15c/0x19c
component_master_add_with_match+0xb4/0xec
msm_pdev_probe+0x1f0/0x27c
platform_drv_probe+0x90/0xb0
really_probe+0x120/0x298
driver_probe_device+0x64/0xfc
__device_attach_driver+0x8c/0xa4
bus_for_each_drv+0x88/0xd0
__device_attach+0xac/0x134
device_initial_probe+0x20/0x2c
bus_probe_device+0x34/0x90
deferred_probe_work_func+0x74/0xac
process_one_work+0x210/0x428
worker_thread+0x278/0x3e4
kthread+0x120/0x130
ret_from_fork+0x10/0x18
Code: aa0003f8 b13ffc1f 54000762 f901c278 (f9401b08)
---[ end trace a6ecc18ce5894375 ]---
Kernel panic - not syncing: Fatal exception
Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
---
drivers/devfreq/devfreq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 0ae3de76833b..d29f66f0e52a 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -254,7 +254,7 @@ static struct devfreq_governor *try_then_request_governor(const char *name)
/* Restore previous state before return */
mutex_lock(&devfreq_list_lock);
if (err)
- return NULL;
+ return ERR_PTR(err);
governor = find_devfreq_governor(name);
}
--
2.20.1