From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Kees Cook <keescook@chromium.org>,
Troy Kensinger <tkensinger@google.com>,
"security@kernel.org" <security@kernel.org>,
Paul McKenney <paulmck@linux.vnet.ibm.com>,
Josh Triplett <josh@joshtriplett.org>,
linux-kernel@vger.kernel.org,
"Eric W. Biederman" <ebiederm@xmission.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] pids: make task_tgid_nr_ns() safe
Date: Mon, 21 Aug 2017 22:05:20 +0200 [thread overview]
Message-ID: <20170821200520.GB32112@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20170821153502.GA652@redhat.com>
On Mon, Aug 21, 2017 at 05:35:02PM +0200, Oleg Nesterov wrote:
> This was reported many times, and this was even mentioned in commit
> 52ee2dfdd4f5 "pids: refactor vnr/nr_ns helpers to make them safe" but
> somehow nobody bothered to fix the obvious problem: task_tgid_nr_ns()
> is not safe because task->group_leader points to nowhere after the
> exiting task passes exit_notify(), rcu_read_lock() can not help.
>
> We really need to change __unhash_process() to nullify group_leader,
> parent, and real_parent, but this needs some cleanups. Until then we
> can turn task_tgid_nr_ns() into another user of __task_pid_nr_ns() and
> fix the problem.
>
> Reported-by: Troy Kensinger <tkensinger@google.com>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
prev parent reply other threads:[~2017-08-21 20:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAMKL9z2A8VSmLc9gz4Vtd1N5nGwR5d9Mxi1Nc8VjTQKsURoMkA@mail.gmail.com>
[not found] ` <CA+55aFyfaBZmDVSpx3F7cQZcck8u_vg53wL1ykRE-ccgrtg14w@mail.gmail.com>
[not found] ` <CAGXu5jKLDAnKoRg_v8Nc7s6AtQ6_QfaMtJorjFkbaX64MDHy2g@mail.gmail.com>
[not found] ` <CA+55aFy+0cQUcPjWmnD8qFL2gHVYHYTxJmHVy6L=Bz03KaP2Rw@mail.gmail.com>
[not found] ` <20170820142953.GA3767@redhat.com>
[not found] ` <CA+55aFzA+0jzTdknmf0OUB7WSPgAa56nqckqdz=iDmbR2P9eRw@mail.gmail.com>
2017-08-21 15:35 ` [PATCH] pids: make task_tgid_nr_ns() safe Oleg Nesterov
2017-08-21 15:36 ` perf_event_pid() (Was: [PATCH] pids: make task_tgid_nr_ns() safe) Oleg Nesterov
2017-08-21 19:18 ` Peter Zijlstra
2017-08-21 19:49 ` [PATCH] pids: make task_tgid_nr_ns() safe Linus Torvalds
2017-08-22 12:20 ` Oleg Nesterov
2017-08-22 16:57 ` Linus Torvalds
2017-08-22 17:51 ` Greg KH
2017-08-21 20:05 ` Peter Zijlstra [this message]
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