From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751251AbbCTE15 (ORCPT ); Fri, 20 Mar 2015 00:27:57 -0400 Received: from ozlabs.org ([103.22.144.67]:52403 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750871AbbCTE1y (ORCPT ); Fri, 20 Mar 2015 00:27:54 -0400 From: Rusty Russell To: Peter Zijlstra , mingo@kernel.org, mathieu.desnoyers@efficios.com, oleg@redhat.com, paulmck@linux.vnet.ibm.com, torvalds@linux-foundation.org Cc: linux-kernel@vger.kernel.org, andi@firstfloor.org, rostedt@goodmis.org, tglx@linutronix.de, peterz@infradead.org, Jason Baron Subject: Re: [PATCH 3/8] module, jump_label: Fix module locking In-Reply-To: <20150318134631.743042205@infradead.org> References: <20150318133626.526984618@infradead.org> <20150318134631.743042205@infradead.org> User-Agent: Notmuch/0.17 (http://notmuchmail.org) Emacs/24.3.1 (x86_64-pc-linux-gnu) Date: Fri, 20 Mar 2015 14:56:25 +1030 Message-ID: <87egokjnv2.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra writes: > 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 > Acked-by: Paul E. McKenney > Signed-off-by: Peter Zijlstra (Intel) > --- > 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; Using __module_address() for this was just plain weird in the first place. How about: if (within_module(iter->key, mod)) Cheers, Rusty.