Re: [PATCH] Linux-2.5 fix/improve get_pid()

[Paul Larson <plars@austin.ibm.com>]

I suspect that it would actually require more than just this.  I tried
this with the same test I've been using and had several failed attepmts
at low numbers by getting wierd unexpected signals (like 28), and then
one that ran for a much longer time and produced an oops with random
garbage to the console (trying to extract this now).

-Paul Larson

On Thu, 2002-08-08 at 17:02, Linus Torvalds wrote:
> ----
> --- 1.2/include/linux/threads.h	Tue Feb  5 07:23:04 2002
> +++ edited/include/linux/threads.h	Thu Aug  8 14:58:28 2002
> @@ -19,6 +19,7 @@
>  /*
>   * This controls the maximum pid allocated to a process
>   */
> -#define PID_MAX 0x8000
> +#define PID_MASK 0x3fffffff
> +#define PID_MAX (PID_MASK+1)
>  
>  #endif
> ===== kernel/fork.c 1.57 vs edited =====
> --- 1.57/kernel/fork.c	Tue Jul 30 15:49:20 2002
> +++ edited/kernel/fork.c	Thu Aug  8 15:00:16 2002
> @@ -142,7 +142,7 @@
>  		return 0;
>  
>  	spin_lock(&lastpid_lock);
> -	if((++last_pid) & 0xffff8000) {
> +	if((++last_pid) & ~PID_MASK) {
>  		last_pid = 300;		/* Skip daemons etc. */
>  		goto inside;
>  	}
> @@ -157,7 +157,7 @@
>  			   p->tgid == last_pid	||
>  			   p->session == last_pid) {
>  				if(++last_pid >= next_safe) {
> -					if(last_pid & 0xffff8000)
> +					if(last_pid & ~PID_MASK)
>  						last_pid = 300;
>  					next_safe = PID_MAX;
>  				}
> 
>