linux-kernel - Re: futex question

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-next>] [day] [month] [year] [list]

Date:	Sun, 04 Oct 2009 09:37:06 -0700
From:	Anirban Sinha <ani@...rban.org>
To:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	linux-kernel@...r.kernel.org, Darren Hart <dvhltc@...ibm.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Kaz Kylheku <kaz@...gmasystems.com>,
	Anirban Sinha <asinha@...gmasystems.com>
Subject: Re: futex question

>> 1) What caused you to instrument this path in the first place?  Were you
>> seeing some unexpected behavior?
>>
>> 2) I wonder why we would need to clear the robust list, but I don't see other
>> things like pi_blocked_on, etc. in execve being cleared.  I'm looking into
>> this now (perhaps we don't do the same cleanup, need to check).... have to get
>> on the plane...
> 
> Hmm, just setting the robust list pointer to NULL fixes the problem at
> hand, but I wonder whether we need to call exit_robust_list() as
> well. 

hmm. That is an interesting thought. But I wonder if acquiring a lock and then exec()ing in the critical section is a legal thing to do. It does not feel right. Currently, with or without my change, such a thing would indefinitely block other waiters on the same futex.  

Ani
--
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/