Re: [PATCH] netdevsim: Fix task hung by releasing bus lock before device ops

Hi Jiakai,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v7.1-rc2 next-20260508]
[cannot apply to horms-ipvs/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Jiakai-Xu/netdevsim-Fix-task-hung-by-releasing-bus-lock-before-device-ops/20260510-070550
base:   linus/master
patch link:    https://lore.kernel.org/r/20260509092837.3432281-1-xujiakai24%40mails.ucas.ac.cn
patch subject: [PATCH] netdevsim: Fix task hung by releasing bus lock before device ops
config: m68k-allmodconfig (https://download.01.org/0day-ci/archive/20260510/202605101038.mxF4QH95-lkp@intel.com/config)
compiler: m68k-linux-gcc (GCC) 15.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260510/202605101038.mxF4QH95-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot [off-list ref]
| Closes: https://lore.kernel.org/oe-kbuild-all/202605101038.mxF4QH95-lkp@intel.com/ (local)

All error/warnings (new ones prefixed by >>):

   drivers/net/netdevsim/bus.c: In function 'new_device_store':

quoted

drivers/net/netdevsim/bus.c:192:17: error: implicit declaration of function 'nsim_bus_dev_del'; did you mean 'nsim_bus_dev_new'? [-Wimplicit-function-declaration]

     192 |                 nsim_bus_dev_del(nsim_bus_dev);
         |                 ^~~~~~~~~~~~~~~~
         |                 nsim_bus_dev_new
   drivers/net/netdevsim/bus.c: At top level:

quoted

drivers/net/netdevsim/bus.c:206:13: warning: conflicting types for 'nsim_bus_dev_del'; have 'void(struct nsim_bus_dev *)'

     206 | static void nsim_bus_dev_del(struct nsim_bus_dev *nsim_bus_dev);
         |             ^~~~~~~~~~~~~~~~

quoted

drivers/net/netdevsim/bus.c:206:13: error: static declaration of 'nsim_bus_dev_del' follows non-static declaration

   drivers/net/netdevsim/bus.c:192:17: note: previous implicit declaration of 'nsim_bus_dev_del' with type 'void(struct nsim_bus_dev *)'
     192 |                 nsim_bus_dev_del(nsim_bus_dev);
         |                 ^~~~~~~~~~~~~~~~


vim +192 drivers/net/netdevsim/bus.c

   157	
   158	static ssize_t
   159	new_device_store(const struct bus_type *bus, const char *buf, size_t count)
   160	{
   161		unsigned int id, port_count, num_queues;
   162		struct nsim_bus_dev *nsim_bus_dev;
   163		int err;
   164	
   165		err = sscanf(buf, "%u %u %u", &id, &port_count, &num_queues);
   166		switch (err) {
   167		case 1:
   168			port_count = 1;
   169			fallthrough;
   170		case 2:
   171			num_queues = 1;
   172			fallthrough;
   173		case 3:
   174			if (id > INT_MAX) {
   175				pr_err("Value of \"id\" is too big.\n");
   176				return -EINVAL;
   177			}
   178			break;
   179		default:
   180			pr_err("Format for adding new device is \"id port_count num_queues\" (uint uint uint).\n");
   181			return -EINVAL;
   182		}
   183	
   184		nsim_bus_dev = nsim_bus_dev_new(id, port_count, num_queues);
   185		if (IS_ERR(nsim_bus_dev))
   186			return PTR_ERR(nsim_bus_dev);
   187	
   188		mutex_lock(&nsim_bus_dev_list_lock);
   189		/* Prevent to use resource before initialization. */
   190		if (!smp_load_acquire(&nsim_bus_enable)) {
   191			mutex_unlock(&nsim_bus_dev_list_lock);
 > 192			nsim_bus_dev_del(nsim_bus_dev);
   193			return -EBUSY;
   194		}
   195	
   196		/* Allow using nsim_bus_dev */
   197		smp_store_release(&nsim_bus_dev->init, true);
   198	
   199		list_add_tail(&nsim_bus_dev->list, &nsim_bus_dev_list);
   200		mutex_unlock(&nsim_bus_dev_list_lock);
   201	
   202		return count;
   203	}
   204	static BUS_ATTR_WO(new_device);
   205	
 > 206	static void nsim_bus_dev_del(struct nsim_bus_dev *nsim_bus_dev);
   207	

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