linux-kernel - Re: do_wait: Add missing tasklist unlocking in error paths.

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] [day] [month] [year] [list]

Message-ID: <20130920170322.GA762@redhat.com>
Date:	Fri, 20 Sep 2013 13:03:22 -0400
From:	Dave Jones <davej@...hat.com>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	Linux Kernel <linux-kernel@...r.kernel.org>, roland@...k.frob.com,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: do_wait: Add missing tasklist unlocking in error paths.

On Fri, Sep 20, 2013 at 06:41:44PM +0200, Oleg Nesterov wrote:
 > On 09/20, Dave Jones wrote:
 > >
 > > It looks like both 64a16caf5, and 98abed020 both introduced error paths to do_wait
 > > where we miss unlocking the tasklist.
 > >
 > > Spotted with coverity.
 > 
 > Not really, afaics.
 > 
 > > --- a/kernel/exit.c
 > > +++ b/kernel/exit.c
 > > @@ -1526,13 +1526,15 @@ repeat:
 > >  	tsk = current;
 > >  	do {
 > >  		retval = do_wait_thread(wo, tsk);
 > > -		if (retval)
 > > +		if (retval) {
 > > +			read_unlock(&tasklist_lock);
 > 
 > note that do_wait_thread() paths should drop tasklist if it returns non-zero.

Ah, I missed the unlock in wait_task_continued. 

I'm not sure why the checker didn't infer that. Perhaps it thinks it's possible we
can get take one of the early returns in that function before we do the tasklist unlock.

thanks,

	Dave


--
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/