From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755023AbbCBTji (ORCPT ); Mon, 2 Mar 2015 14:39:38 -0500 Received: from e34.co.us.ibm.com ([32.97.110.152]:45549 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754638AbbCBTjh (ORCPT ); Mon, 2 Mar 2015 14:39:37 -0500 Date: Mon, 2 Mar 2015 11:39:33 -0800 From: "Paul E. McKenney" To: Peter Zijlstra Cc: mingo@kernel.org, rusty@rustcorp.com.au, mathieu.desnoyers@efficios.com, oleg@redhat.com, linux-kernel@vger.kernel.org, andi@firstfloor.org, rostedt@goodmis.org, tglx@linutronix.de, Jason Baron Subject: Re: [RFC][PATCH 4/9] module, jump_label: Fix module locking Message-ID: <20150302193933.GU15405@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20150228212447.381543289@infradead.org> <20150228213110.069189155@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150228213110.069189155@infradead.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15030219-0017-0000-0000-000009286DC8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 28, 2015 at 10:24:51PM +0100, Peter Zijlstra wrote: > As per the module core lockdep annotations: > > [ 18.034047] ---[ end trace 9294429076a9c673 ]--- > [ 18.047760] Hardware name: Intel Corporation S2600GZ/S2600GZ, BIOS SE5C600.86B.02.02.0002.122320131210 12/23/2013 > [ 18.059228] ffffffff817d8676 ffff880036683c38 ffffffff8157e98b 0000000000000001 > [ 18.067541] 0000000000000000 ffff880036683c78 ffffffff8105fbc7 ffff880036683c68 > [ 18.075851] ffffffffa0046b08 0000000000000000 ffffffffa0046d00 ffffffffa0046cc8 > [ 18.084173] Call Trace: > [ 18.086906] [] dump_stack+0x4f/0x7b > [ 18.092649] [] warn_slowpath_common+0x97/0xe0 > [ 18.099361] [] warn_slowpath_null+0x1a/0x20 > [ 18.105880] [] __module_address+0x1d2/0x1e0 > [ 18.112400] [] jump_label_module_notify+0x143/0x1e0 > [ 18.119710] [] notifier_call_chain+0x4f/0x70 > [ 18.126326] [] __blocking_notifier_call_chain+0x5e/0x90 > [ 18.134009] [] blocking_notifier_call_chain+0x16/0x20 > [ 18.141490] [] load_module+0x1b50/0x2660 > [ 18.147720] [] SyS_init_module+0xce/0x100 > [ 18.154045] [] system_call_fastpath+0x12/0x17 > [ 18.160748] ---[ end trace 9294429076a9c674 ]--- > > Jump labels is not doing it right; fix this. > > Cc: Rusty Russell > Cc: Jason Baron > Signed-off-by: Peter Zijlstra (Intel) Acked-by: Paul E. McKenney > --- > kernel/jump_label.c | 21 +++++++++++++++++---- > 1 file changed, 17 insertions(+), 4 deletions(-) > > --- a/kernel/jump_label.c > +++ b/kernel/jump_label.c > @@ -280,6 +280,17 @@ void jump_label_apply_nops(struct module > } > } > > +static inline bool address_in_module(unsigned long addr, struct module *mod) > +{ > + bool ret; > + > + preempt_disable(); > + ret = __module_address(addr) == mod; > + preempt_enable(); > + > + return ret; > +} > + > static int jump_label_add_module(struct module *mod) > { > struct jump_entry *iter_start = mod->jump_entries; > @@ -302,7 +313,7 @@ static int jump_label_add_module(struct > continue; > > key = iterk; > - if (__module_address(iter->key) == mod) { > + if (address_in_module(iter->key, mod)) { > /* > * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH. > */ > @@ -339,7 +350,7 @@ static void jump_label_del_module(struct > > key = (struct static_key *)(unsigned long)iter->key; > > - if (__module_address(iter->key) == mod) > + if (address_in_module(iter->key, mod)) > continue; > > prev = &key->next; > @@ -443,14 +454,16 @@ static void jump_label_update(struct sta > { > struct jump_entry *stop = __stop___jump_table; > struct jump_entry *entry = jump_label_get_entries(key); > - > #ifdef CONFIG_MODULES > - struct module *mod = __module_address((unsigned long)key); > + struct module *mod; > > __jump_label_mod_update(key, enable); > > + preempt_disable(); > + mod = __module_address((unsigned long)key); > if (mod) > stop = mod->jump_entries + mod->num_jump_entries; > + preempt_enable(); > #endif > /* if there are no users, entry can be NULL */ > if (entry) > >