Re: [PATCH 1/3] kthread: allow caller to pass in user_struct

[kernel test robot]

Hi Mike,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on vhost/linux-next]
[also build test WARNING on linux/master linus/master v5.13-rc7]
[cannot apply to next-20210623]
[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]

url:    https://github.com/0day-ci/linux/commits/Mike-Christie/kthread-pass-in-user-and-check-RLIMIT_NPROC/20210624-110925
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
config: um-x86_64_defconfig (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/9b4a744e588ed25e06eed415174977e7533b24dc
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Mike-Christie/kthread-pass-in-user-and-check-RLIMIT_NPROC/20210624-110925
        git checkout 9b4a744e588ed25e06eed415174977e7533b24dc
        # save the attached .config to linux build tree
        make W=1 ARCH=um SUBARCH=x86_64

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

   cc1: warning: arch/um/include/uapi: No such file or directory [-Wmissing-include-dirs]
   kernel/kthread.c: In function 'kthread_create_for_user':
>> kernel/kthread.c:466:6: warning: function 'kthread_create_for_user' might be a candidate for 'gnu_printf' format attribute [-Wsuggest-attribute=format]
     466 |      namefmt, args);
         |      ^~~~~~~


vim +466 kernel/kthread.c

   443	
   444	/**
   445	 * kthread_create_for_user - create a kthread and check @user's RLIMIT_NPROC
   446	 * @threadfn: the function to run until signal_pending(current).
   447	 * @data: data ptr for @threadfn.
   448	 * @user: user_struct that will have its RLIMIT_NPROC checked
   449	 * @namefmt: printf-style name for the thread.
   450	 *
   451	 * This will create a kthread on the current node, leaving it in the stopped
   452	 * state.  This is just a helper for kthread_create_on_node() that will check
   453	 * @user's process count against its RLIMIT_NPROC.  See the
   454	 * kthread_create_on_node() documentation for more details.
   455	 */
   456	struct task_struct *kthread_create_for_user(int (*threadfn)(void *data),
   457						    void *data,
   458						    struct user_struct *user,
   459						    const char namefmt[], ...)
   460	{
   461		struct task_struct *task;
   462		va_list args;
   463	
   464		va_start(args, namefmt);
   465		task = __kthread_create_on_node(threadfn, data, NUMA_NO_NODE, user,
 > 466						namefmt, args);
   467		va_end(args);
   468	
   469		return task;
   470	}
   471	EXPORT_SYMBOL(kthread_create_for_user);
   472	

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

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