linux-kernel - RE: Bad Reference Semantics in PIDs Controller.

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, 23 Aug 2015 22:24:18 +1000
From:	Aleksa Sarai <cyphar@...har.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	linux-kernel@...r.kernel.org, cgroups@...r.kernel.org
Subject: RE: Bad Reference Semantics in PIDs Controller.

It turns out that, actually, the can_attach(), cancel_attach() and
attach() code is broken -- we're incrementing a ref on the old_css of
a task in can_attach(). Then we decrement the ref on a *different* css
(because the task has been migrated). This is clearly a bad thing.
Should we make cgroup_migrate() deal with the accounting for us (by
getting it to grab a ref before can_attach() and dropping it after the
attach succeeds or fails?).

-- 
Aleksa Sarai (cyphar)
www.cyphar.com
--
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/