linux-kernel - Re: [PATCH bpf-next v3 1/2] bpf: implement bpf_send_signal

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Message-ID: <202410080907.DFxFxfor-lkp@intel.com>
Date: Tue, 8 Oct 2024 09:41:36 +0800
From: kernel test robot <lkp@...el.com>
To: Puranjay Mohan <puranjay@...nel.org>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Eduard Zingerman <eddyz87@...il.com>, Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	John Fastabend <john.fastabend@...il.com>,
	KP Singh <kpsingh@...nel.org>, bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org, puranjay12@...il.com
Cc: oe-kbuild-all@...ts.linux.dev
Subject: Re: [PATCH bpf-next v3 1/2] bpf: implement bpf_send_signal_task()
 kfunc

Hi Puranjay,

kernel test robot noticed the following build warnings:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Puranjay-Mohan/bpf-implement-bpf_send_signal_task-kfunc/20241007-183648
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20241007103426.128923-2-puranjay%40kernel.org
patch subject: [PATCH bpf-next v3 1/2] bpf: implement bpf_send_signal_task() kfunc
config: i386-randconfig-141-20241008 (https://download.01.org/0day-ci/archive/20241008/202410080907.DFxFxfor-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241008/202410080907.DFxFxfor-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 <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410080907.DFxFxfor-lkp@intel.com/

All warnings (new ones prefixed by >>):

   kernel/trace/bpf_trace.c: In function 'bpf_send_signal_common':
>> kernel/trace/bpf_trace.c:839:43: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
     839 |                 info.si_value.sival_ptr = (void *)value;
         |                                           ^


vim +839 kernel/trace/bpf_trace.c

   822	
   823	static int bpf_send_signal_common(u32 sig, enum pid_type type, struct task_struct *tsk, u64 value)
   824	{
   825		struct send_signal_irq_work *work = NULL;
   826		kernel_siginfo_t info;
   827		bool has_siginfo = false;
   828	
   829		if (!tsk) {
   830			tsk = current;
   831		} else {
   832			has_siginfo = true;
   833			clear_siginfo(&info);
   834			info.si_signo = sig;
   835			info.si_errno = 0;
   836			info.si_code = SI_KERNEL;
   837			info.si_pid = 0;
   838			info.si_uid = 0;
 > 839			info.si_value.sival_ptr = (void *)value;
   840		}
   841	
   842		/* Similar to bpf_probe_write_user, task needs to be
   843		 * in a sound condition and kernel memory access be
   844		 * permitted in order to send signal to the current
   845		 * task.
   846		 */
   847		if (unlikely(tsk->flags & (PF_KTHREAD | PF_EXITING)))
   848			return -EPERM;
   849		if (unlikely(!nmi_uaccess_okay()))
   850			return -EPERM;
   851		/* Task should not be pid=1 to avoid kernel panic. */
   852		if (unlikely(is_global_init(tsk)))
   853			return -EPERM;
   854	
   855		if (irqs_disabled()) {
   856			/* Do an early check on signal validity. Otherwise,
   857			 * the error is lost in deferred irq_work.
   858			 */
   859			if (unlikely(!valid_signal(sig)))
   860				return -EINVAL;
   861	
   862			work = this_cpu_ptr(&send_signal_work);
   863			if (irq_work_is_busy(&work->irq_work))
   864				return -EBUSY;
   865	
   866			/* Add the current task, which is the target of sending signal,
   867			 * to the irq_work. The current task may change when queued
   868			 * irq works get executed.
   869			 */
   870			work->task = get_task_struct(tsk);
   871			work->has_siginfo = has_siginfo;
   872			work->info = info;
   873			work->sig = sig;
   874			work->type = type;
   875			irq_work_queue(&work->irq_work);
   876			return 0;
   877		}
   878	
   879		if (has_siginfo)
   880			return group_send_sig_info(sig, &info, tsk, type);
   881	
   882		return group_send_sig_info(sig, SEND_SIG_PRIV, tsk, type);
   883	}
   884	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki