From: Oleg Nesterov <oleg@redhat.com>
To: Will Drewry <wad@chromium.org>
Cc: linux-kernel@vger.kernel.org, nschichan@freebox.fr,
keescook@chromium.org, james.l.morris@oracle.com,
akpm@linux-foundation.org, holt@sgi.com, viro@zeniv.linux.org.uk
Subject: Re: [PATCH 2/2] sys, seccomp: add PR_SECCOMP_EXT and SECCOMP_EXT_ACT_TSYNC
Date: Tue, 14 Jan 2014 21:02:40 +0100 [thread overview]
Message-ID: <20140114200240.GA801@redhat.com> (raw)
In-Reply-To: <20140114192118.GA31411@redhat.com>
On 01/14, Oleg Nesterov wrote:
>
> > + get_seccomp_filter(caller);
> > + /*
> > + * Drop the task reference to the shared ancestor since
> > + * current's path will hold a reference. (This also
> > + * allows a put before the assignment.)
> > + */
> > + put_seccomp_filter(thread);
> > + thread->seccomp.filter = caller->seccomp.filter;
>
> As I said, I do not understand this patch yet, but this looks suspicious.
>
> Why we can't race with this thread doing clone(CLONE_THREAD) ? We do
> not the the new thread yet, but its ->seccomp can be already copied
> by copy_process(), no?
And it seems that this can obviously race with seccomp_attach_filter()
called by this "thread".
Oleg.
next prev parent reply other threads:[~2014-01-14 20:02 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-13 20:30 [PATCH 1/2] seccomp: protect seccomp.filter pointer (w) with the task_lock Will Drewry
2014-01-13 20:30 ` [PATCH 2/2] sys, seccomp: add PR_SECCOMP_EXT and SECCOMP_EXT_ACT_TSYNC Will Drewry
2014-01-13 22:42 ` [PATCH 3/3] Documentation/prctl/seccomp_filter.txt: document extensions Will Drewry
2014-01-13 23:36 ` [PATCH 2/2] sys, seccomp: add PR_SECCOMP_EXT and SECCOMP_EXT_ACT_TSYNC Andy Lutomirski
2014-01-14 18:59 ` Will Drewry
2014-01-14 20:24 ` Andy Lutomirski
2014-01-14 20:59 ` Will Drewry
2014-01-14 21:09 ` Andy Lutomirski
2014-01-14 21:19 ` Will Drewry
2014-01-14 19:07 ` Oleg Nesterov
2014-01-14 19:21 ` Oleg Nesterov
2014-01-14 20:02 ` Oleg Nesterov [this message]
2014-01-14 20:13 ` Oleg Nesterov
2014-01-14 20:53 ` Will Drewry
2014-01-14 21:06 ` Will Drewry
2014-01-15 19:04 ` Oleg Nesterov
2014-01-15 19:28 ` Oleg Nesterov
2014-01-15 19:33 ` Will Drewry
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