linux-kernel - Re: [PATCH] Fix x86_64 TIF_SYSCALL

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: <20071028212150.GA20321@one.firstfloor.org>
Date:	Sun, 28 Oct 2007 22:21:50 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	Mathieu Desnoyers <compudj@...stal.dyndns.org>
Cc:	Andi Kleen <andi@...stfloor.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Fix x86_64 TIF_SYSCALL_TRACE race in entry.S

> Setting the thread flag being an atomic operation, I would expect
> setting/clearing it asynchronously from another thread to be a valid

It could be a very short stop. Also do you start kernel tracing that often?

> Here is a modified version where I add my test only in the path where we
> know that we have work to do, therefore removing the supplementary test
> from the performance critical path. Would it be more acceptable ?

It's better, but stopping would be even better. I wouldn't
be surprised if there are other problems with async thread flags changing.
 
Also I object to you calling this a bug. It's a new feature.

-Andi
-
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/