Re: possible kernel bug in signal transit.

[Andrew Morton <akpm@osdl.org>]

Alex Lyashkov <shadow@psoft.net> wrote:
>
> Hello All
> 
> I analyze kernel vanila 2.6.4 and found one possible bug in
> __kill_pg_info function.
> 
>         for_each_task_pid(pgrp, PIDTYPE_PGID, p, l, pid) {
>                 err = group_send_sig_info(sig, info, p);
>                 if (retval)
>                         retval = err;
>         }
> but I think if (retval) is incorrect check. possible this cycle must be
>         for_each_task_pid(pgrp, PIDTYPE_PGID, p, l, pid) {
>                 err = group_send_sig_info(sig, info, p);
>                 if (ret) {
>                         retval = err;
> 			break;
> 		}
>         }
> because in original variant me assign to retval only first value from
> ret and other be ignored if this value be 0.
> 

No, the code's OK, albeit undesirably obscure.  It will return -ESRCH if
none of the tasks had a matching pgrp and will return the result of the
final non-zero-returning group_send_sig_info() if one or more of the
group_send_sig_info() calls failed, and will return zero if all of the
group_send_sig_info() calls returned zero.

Thanks for checking though..