Re: [PATCH v2] signal: Avoid undefined behaviour in kill_something_info

[Michal Hocko]

On Mon 05-06-17 20:53:27, zhongjiang wrote:
> diff --git a/kernel/signal.c b/kernel/signal.c
> index ca92bcf..63148f7 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -1395,6 +1395,12 @@ static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
>  
>  	read_lock(&tasklist_lock);
>  	if (pid != -1) {
> +		/*
> +	 	 * -INT_MIN is undefined, it need to exclude following case to 
> + 		 * avoid the UBSAN detection.
> +		 */
> +		if (pid == INT_MIN)
> +			return -ESRCH;

this will obviously keep the tasklist_lock held...

>  		ret = __kill_pgrp_info(sig, info,
>  				pid ? find_vpid(-pid) : task_pgrp(current));
>  	} else {
> -- 
> 1.7.12.4

-- 
Michal Hocko
SUSE Labs