On 13/08/2024 22:03, Vladimir Zapolskiy wrote:
There is a chance to meet runtime issues during configuration of CAMSS
power domains, because on the error path dev_pm_domain_detach() is
unexpectedly called with NULL or error pointer.
One of the simplest ways to reproduce the problem is to probe CAMSS
driver before registration of CAMSS power domains, for instance if
a platform CAMCC driver is simply not built.
Warning backtrace example:
Unable to handle kernel NULL pointer dereference at virtual address 00000000000001a2
<snip>
pc : dev_pm_domain_detach+0x8/0x48
lr : camss_probe+0x374/0x9c0
<snip>
Call trace:
dev_pm_domain_detach+0x8/0x48
platform_probe+0x70/0xf0
really_probe+0xc4/0x2a8
__driver_probe_device+0x80/0x140
driver_probe_device+0x48/0x170
__device_attach_driver+0xc0/0x148
bus_for_each_drv+0x88/0xf0
__device_attach+0xb0/0x1c0
device_initial_probe+0x1c/0x30
bus_probe_device+0xb4/0xc0
deferred_probe_work_func+0x90/0xd0
process_one_work+0x164/0x3e0
worker_thread+0x310/0x420
kthread+0x120/0x130
ret_from_fork+0x10/0x20
Fixes: 23aa4f0cd327 ("media: qcom: camss: Move VFE power-domain specifics into vfe.c")
Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@xxxxxxxxxx>
---
The first version of the patch and discussion is found over here:
https://lore.kernel.org/all/20240806221204.1560258-1-vladimir.zapolskiy@xxxxxxxxxx/
Changes from v1 to v2:
* added an encountered runtime warning to the commit message per ask from Bryan.
I tested this fix in both cases of set and unset "power-domain-names"
property in camss device tree node, and I didn't find any negative side
effects of the fix.
drivers/media/platform/qcom/camss/camss.c | 19 ++++++++-----------
1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
index 51b1d3550421..aa894be1461d 100644
--- a/drivers/media/platform/qcom/camss/camss.c
+++ b/drivers/media/platform/qcom/camss/camss.c
+ stable@xxxxxxxxxxxxxxx
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
