linux-kernel - Re: [PATCH 04/16] ptrace: kill tracehook_notify

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20101220145956.GC11583@redhat.com>
Date:	Mon, 20 Dec 2010 15:59:56 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	roland@...hat.com, linux-kernel@...r.kernel.org,
	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	rjw@...k.pl, jan.kratochvil@...hat.com
Subject: Re: [PATCH 04/16] ptrace: kill tracehook_notify_jctl()

On 12/06, Tejun Heo wrote:
>
> tracehook_notify_jctl() aids in determining whether and what to report
> to the parent when a task is stopped or continued.  The function also
> adds an extra requirement that siglock may be released across it,
> which is currently unused and quite difficult to satisfy in
> well-defined manner.

OK. I agree, tracehook_notify_jctl() looks very unobvious, especially
because it is not really used currently.

The patch looks correct, except

> @@ -1853,21 +1850,19 @@ relock:
>  	if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
>  		int why;
>
> -		if (signal->flags & SIGNAL_CLD_CONTINUED)
> +		if (task_ptrace(current) ||
> +		    (signal->flags & SIGNAL_CLD_CONTINUED))
>  			why = CLD_CONTINUED;
>  		else
>  			why = CLD_STOPPED;

Hmm, I can't understand this.

task_ptrace() should not turn CLD_STOPPED in CLD_CONTINUED?

Looking ahead, it _seems_ that the next patches keep this logic,
could you explain?

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/