Hi Mathieu,

url:    https://github.com/0day-ci/linux/commits/Mathieu-Poirier/rpmsg-Make-RPMSG-name-service-modular/20200922-081745
base:    b10b8ad862118bf42c28a98b0f067619aadcfb23
config: i386-randconfig-m021-20200923 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/rpmsg/rpmsg_core.c:33 rpmsg16_to_cpu() warn: signedness bug returning '(-22)'
drivers/rpmsg/rpmsg_core.c:44 cpu_to_rpmsg16() warn: signedness bug returning '(-22)'

# https://github.com/0day-ci/linux/commit/547ad00c50065bf914ac4090882d0ac692f5452d
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Mathieu-Poirier/rpmsg-Make-RPMSG-name-service-modular/20200922-081745
git checkout 547ad00c50065bf914ac4090882d0ac692f5452d
vim +33 drivers/rpmsg/rpmsg_core.c

547ad00c50065bf Mathieu Poirier 2020-09-21  30  u16 rpmsg16_to_cpu(struct rpmsg_device *rpdev, u16 val)
                                                ^^^

547ad00c50065bf Mathieu Poirier 2020-09-21  31  {
547ad00c50065bf Mathieu Poirier 2020-09-21  32  	if (WARN_ON(!rpdev))
547ad00c50065bf Mathieu Poirier 2020-09-21 @33  		return -EINVAL;
                                                                ^^^^^^^^^^^^^^
All the negative returns get truncated to a high u16 value.

547ad00c50065bf Mathieu Poirier 2020-09-21  34  	if (!rpdev->ops || !rpdev->ops->transport16_to_cpu)
547ad00c50065bf Mathieu Poirier 2020-09-21  35  		return -EPERM;
                                                                ^^^^^^^^^^^^^^
547ad00c50065bf Mathieu Poirier 2020-09-21  36  
547ad00c50065bf Mathieu Poirier 2020-09-21  37  	return rpdev->ops->transport16_to_cpu(rpdev, val);
547ad00c50065bf Mathieu Poirier 2020-09-21  38  }
547ad00c50065bf Mathieu Poirier 2020-09-21  39  EXPORT_SYMBOL(rpmsg16_to_cpu);
547ad00c50065bf Mathieu Poirier 2020-09-21  40  
547ad00c50065bf Mathieu Poirier 2020-09-21  41  u16 cpu_to_rpmsg16(struct rpmsg_device *rpdev, u16 val)
547ad00c50065bf Mathieu Poirier 2020-09-21  42  {
547ad00c50065bf Mathieu Poirier 2020-09-21  43  	if (WARN_ON(!rpdev))
547ad00c50065bf Mathieu Poirier 2020-09-21 @44  		return -EINVAL;
                                                                ^^^^^^^^^^^^^^
547ad00c50065bf Mathieu Poirier 2020-09-21  45  	if (!rpdev->ops || !rpdev->ops->cpu_to_transport16)
547ad00c50065bf Mathieu Poirier 2020-09-21  46  		return -EPERM;
                                                                ^^^^^^^^^^^^^
547ad00c50065bf Mathieu Poirier 2020-09-21  47  
547ad00c50065bf Mathieu Poirier 2020-09-21  48  	return rpdev->ops->cpu_to_transport16(rpdev, val);
547ad00c50065bf Mathieu Poirier 2020-09-21  49  }

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org