From: Peter Zijlstra <peterz@infradead.org>
To: Kees Cook <keescook@chromium.org>
Cc: Greg KH <gregkh@linuxfoundation.org>,
Will Deacon <will.deacon@arm.com>,
"Reshetova, Elena" <elena.reshetova@intel.com>,
Arnd Bergmann <arnd@arndb.de>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
David Windsor <dave@progbits.org>,
LKML <linux-kernel@vger.kernel.org>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Daniel Borkmann <daniel@iogearbox.net>
Subject: Re: [RFC][PATCH 2/7] kref: Add kref_read()
Date: Wed, 16 Nov 2016 11:09:25 +0100 [thread overview]
Message-ID: <20161116100925.GM3142@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CAGXu5jLNduviFkM1A4ozub_n2uB2nAHrhE41BsPFJZq+uhn4Mg@mail.gmail.com>
On Tue, Nov 15, 2016 at 12:53:35PM -0800, Kees Cook wrote:
>
> What should we do about things like this (bpf_prog_put() and callbacks
> from kernel/bpf/syscall.c):
>
>
> static void bpf_prog_uncharge_memlock(struct bpf_prog *prog)
> {
> struct user_struct *user = prog->aux->user;
>
> atomic_long_sub(prog->pages, &user->locked_vm);
> free_uid(user);
> }
>
> static void __bpf_prog_put_rcu(struct rcu_head *rcu)
> {
> struct bpf_prog_aux *aux = container_of(rcu, struct bpf_prog_aux, rcu);
>
> free_used_maps(aux);
> bpf_prog_uncharge_memlock(aux->prog);
> bpf_prog_free(aux->prog);
> }
>
> void bpf_prog_put(struct bpf_prog *prog)
> {
> if (atomic_dec_and_test(&prog->aux->refcnt))
> call_rcu(&prog->aux->rcu, __bpf_prog_put_rcu);
> }
>
>
> Not only do we want to protect prog->aux->refcnt, but I think we want
> to protect user->locked_vm too ... I don't think it's sane for
> user->locked_vm to be a stats_t ?
Why would you want to mess with locked_vm? You seem of the opinion that
everything atomic_t is broken, this isn't the case.
next prev parent reply other threads:[~2016-11-16 10:09 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-14 17:39 [RFC][PATCH 0/7] kref improvements Peter Zijlstra
2016-11-14 17:39 ` [RFC][PATCH 1/7] kref: Add KREF_INIT() Peter Zijlstra
2016-11-14 17:39 ` [RFC][PATCH 2/7] kref: Add kref_read() Peter Zijlstra
2016-11-14 18:16 ` Christoph Hellwig
2016-11-15 7:28 ` Greg KH
2016-11-15 7:47 ` Peter Zijlstra
2016-11-15 8:37 ` [PATCH] printk, locking/atomics, kref: Introduce new %pAr and %pAk format string options for atomic_t and 'struct kref' Ingo Molnar
2016-11-15 8:43 ` [PATCH v2] " Ingo Molnar
2016-11-15 9:21 ` Peter Zijlstra
2016-11-15 9:41 ` [PATCH v3] printk, locking/atomics, kref: Introduce new %pAa " Ingo Molnar
2016-11-15 10:10 ` [PATCH v2] printk, locking/atomics, kref: Introduce new %pAr " kbuild test robot
2016-11-15 16:42 ` [PATCH] " Linus Torvalds
2016-11-16 8:13 ` Ingo Molnar
2016-11-15 7:33 ` [RFC][PATCH 2/7] kref: Add kref_read() Greg KH
2016-11-15 8:03 ` Peter Zijlstra
2016-11-15 20:53 ` Kees Cook
2016-11-16 8:21 ` Greg KH
2016-11-16 10:10 ` Peter Zijlstra
2016-11-16 10:18 ` Greg KH
2016-11-16 10:11 ` Daniel Borkmann
2016-11-16 10:19 ` Greg KH
2016-11-16 10:09 ` Peter Zijlstra [this message]
2016-11-16 18:58 ` Kees Cook
2016-11-17 8:34 ` Peter Zijlstra
2016-11-17 12:30 ` David Windsor
2016-11-17 12:43 ` Peter Zijlstra
2016-11-17 13:01 ` Reshetova, Elena
2016-11-17 13:22 ` Peter Zijlstra
2016-11-17 15:42 ` Reshetova, Elena
2016-11-17 18:02 ` Reshetova, Elena
2016-11-17 19:10 ` Peter Zijlstra
2016-11-17 19:29 ` Peter Zijlstra
2016-11-17 19:34 ` Kees Cook
2016-11-14 17:39 ` [RFC][PATCH 3/7] kref: Kill kref_sub() Peter Zijlstra
2016-11-14 17:39 ` [RFC][PATCH 4/7] kref: Use kref_get_unless_zero() more Peter Zijlstra
2016-11-14 17:39 ` [RFC][PATCH 5/7] kref: Implement kref_put_lock() Peter Zijlstra
2016-11-14 20:35 ` Kees Cook
2016-11-15 7:50 ` Peter Zijlstra
2016-11-14 17:39 ` [RFC][PATCH 6/7] kref: Avoid more abuse Peter Zijlstra
2016-11-14 17:39 ` [RFC][PATCH 7/7] kref: Implement using refcount_t Peter Zijlstra
2016-11-15 8:40 ` Ingo Molnar
2016-11-15 9:47 ` Peter Zijlstra
2016-11-15 10:03 ` Ingo Molnar
2016-11-15 10:46 ` Peter Zijlstra
2016-11-15 13:03 ` Ingo Molnar
2016-11-15 18:06 ` Kees Cook
2016-11-15 19:16 ` Peter Zijlstra
2016-11-15 19:23 ` Kees Cook
2016-11-16 8:31 ` Ingo Molnar
2016-11-16 8:51 ` Greg KH
2016-11-16 9:07 ` Ingo Molnar
2016-11-16 9:24 ` Greg KH
2016-11-16 10:15 ` Peter Zijlstra
2016-11-16 18:55 ` Kees Cook
2016-11-17 8:33 ` Peter Zijlstra
2016-11-17 19:50 ` Kees Cook
2016-11-16 18:41 ` Kees Cook
2016-11-15 12:33 ` Boqun Feng
2016-11-15 13:01 ` Peter Zijlstra
2016-11-15 14:19 ` Boqun Feng
2016-11-17 9:28 ` Peter Zijlstra
2016-11-17 9:48 ` Boqun Feng
2016-11-17 10:29 ` Peter Zijlstra
2016-11-17 10:39 ` Peter Zijlstra
2016-11-17 11:03 ` Greg KH
2016-11-17 12:48 ` Peter Zijlstra
[not found] ` <CAL0jBu-GnREUPSX4kUDp-Cc8ZGp6+Cb2q0HVandswcLzPRnChQ@mail.gmail.com>
2016-11-17 12:08 ` Peter Zijlstra
2016-11-17 12:08 ` Will Deacon
2016-11-17 16:11 ` Peter Zijlstra
2016-11-17 16:36 ` Will Deacon
2016-11-18 8:26 ` Boqun Feng
2016-11-18 10:16 ` Will Deacon
2016-11-18 10:07 ` Reshetova, Elena
2016-11-18 11:37 ` Peter Zijlstra
2016-11-18 17:06 ` Will Deacon
2016-11-18 18:57 ` Peter Zijlstra
2016-11-21 4:06 ` Boqun Feng
2016-11-21 7:48 ` Ingo Molnar
2016-11-21 8:38 ` Boqun Feng
2016-11-21 8:44 ` Boqun Feng
2016-11-21 9:02 ` Peter Zijlstra
2016-11-21 9:37 ` Boqun Feng
2016-11-18 10:47 ` Reshetova, Elena
2016-11-18 10:52 ` Peter Zijlstra
2016-11-18 16:58 ` Reshetova, Elena
2016-11-18 18:53 ` Peter Zijlstra
2016-11-19 7:14 ` Reshetova, Elena
2016-11-19 11:45 ` Peter Zijlstra
2017-01-26 23:14 ` Kees Cook
2017-01-27 9:58 ` Peter Zijlstra
2017-01-27 21:07 ` Kees Cook
2017-01-30 13:40 ` Peter Zijlstra
2016-11-15 7:27 ` [RFC][PATCH 0/7] kref improvements Greg KH
2016-11-15 7:42 ` Ingo Molnar
2016-11-15 15:05 ` Greg KH
2016-11-15 7:48 ` Peter Zijlstra
2016-11-16 20:08 [RFC][PATCH 2/7] kref: Add kref_read() Alexei Starovoitov
2016-11-17 8:53 ` Peter Zijlstra
2016-11-17 16:19 ` Alexei Starovoitov
2016-11-17 16:34 ` Thomas Gleixner
2016-11-18 17:33 ` Reshetova, Elena
2016-11-19 3:47 ` Alexei Starovoitov
2016-11-21 8:18 ` Reshetova, Elena
2016-11-21 12:47 ` David Windsor
2016-11-21 15:39 ` Reshetova, Elena
2016-11-21 15:49 ` Peter Zijlstra
2016-11-21 16:00 ` Peter Zijlstra
2016-11-21 19:27 ` Reshetova, Elena
2016-11-21 20:12 ` David Windsor
2016-11-22 10:37 ` Peter Zijlstra
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