Re: [PATCH v1 2/2] signal: add procfd_signal() syscall

kbuild test robot
2018-11-19T23:38:34Z

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Hi Christian,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.20-rc3]
[cannot apply to next-20181119]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Christian-Brauner/proc-allow-signaling-processes-via-file-descriptors/20181120-063836
config: riscv-tinyconfig (attached as .config)
compiler: riscv64-linux-gcc (GCC) 8.1.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=8.1.0 make.cross ARCH=riscv

All errors (new ones prefixed by >>):

kernel/signal.c: In function '__do_sys_procfd_signal':
>> kernel/signal.c:3341:7: error: implicit declaration of function 'proc_is_procfd'; did you mean 'clockid_to_fd'? [-Werror=implicit-function-declaration]
if (!proc_is_procfd(f.file))
^~~~~~~~~~~~~~
clockid_to_fd
cc1: some warnings being treated as errors

vim +3341 kernel/signal.c

3314
3315 /**
3316 * sys_procfd_signal - send a signal to a process through a process file
3317 * descriptor
3318 * @fd: the file descriptor of the process
3319 * @sig: signal to be sent
3320 * @info: the signal info
3321 * @flags: future flags to be passed
3322 */
3323 SYSCALL_DEFINE4(procfd_signal, int, fd, int, sig, siginfo_t __user *, info,
3324 int, flags)
3325 {
3326 int ret;
3327 struct pid *pid;
3328 kernel_siginfo_t kinfo;
3329 struct fd f;
3330
3331 /* Enforce flags be set to 0 until we add an extension. */
3332 if (flags)
3333 return -EINVAL;
3334
3335 f = fdget_raw(fd);
3336 if (!f.file)
3337 return -EBADF;
3338
3339 ret = -EINVAL;
3340 /* Is this a process file descriptor? */
> 3341 if (!proc_is_procfd(f.file))
3342 goto err;
3343
3344 pid = f.file->private_data;
3345 if (!pid)
3346 goto err;
3347
3348 if (info) {
3349 ret = __copy_siginfo_from_user(sig, &kinfo, info);
3350 if (unlikely(ret))
3351 goto err;
3352 /*
3353 * Not even root can pretend to send signals from the kernel.
3354 * Nor can they impersonate a kill()/tgkill(), which adds
3355 * source info.
3356 */
3357 ret = -EPERM;
3358 if ((kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL) &&
3359 (task_pid(current) != pid))
3360 goto err;
3361 } else {
3362 prepare_kill_siginfo(sig, &kinfo);
3363 }
3364
3365 ret = kill_pid_info(sig, &kinfo, pid);
3366
3367 err:
3368 fdput(f);
3369 return ret;
3370 }
3371

---
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