linux-kernel - Re: [PATCH 0 of 4] Generic AIO by scheduling stacks

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]

Date:	Wed, 31 Jan 2007 13:04:04 +1100
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Zach Brown <zach.brown@...cle.com>
Cc:	linux-kernel@...r.kernel.org, linux-aio@...ck.org,
	Suparna Bhattacharya <suparna@...ibm.com>,
	Benjamin LaHaise <bcrl@...ck.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 0 of 4] Generic AIO by scheduling stacks

> - We would now have some measure of task_struct concurrency.  Read that twice,
> it's scary.  As two fibrils execute and block in turn they'll each be
> referencing current->.  It means that we need to audit task_struct to make sure
> that paths can handle racing as its scheduled away.  The current implementation
> *does not* let preemption trigger a fibril switch.  So one only has to worry
> about racing with voluntary scheduling of the fibril paths.  This can mean
> moving some task_struct members under an accessor that hides them in a struct
> in task_struct so they're switched along with the fibril.  I think this is a
> manageable burden.

That's the one scaring me in fact ... Maybe it will end up being an easy
one but I don't feel too comfortable... we didn't create fibril-like
things for threads, instead, we share PIDs between tasks. I wonder if
the sane approach would be to actually create task structs (or have a
pool of them pre-created sitting there for performances) and add a way
to share the necessary bits so that syscalls can be run on those
spin-offs.

Ben.


-
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/