From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757157AbbCMP0k (ORCPT ); Fri, 13 Mar 2015 11:26:40 -0400 Received: from smtprelay0246.hostedemail.com ([216.40.44.246]:33546 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932145AbbCMPPW (ORCPT ); Fri, 13 Mar 2015 11:15:22 -0400 X-Session-Marker: 6E657665747340676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,,::::::::::::::::::::,RULES_HIT:355:379:871:988:989:1183:1260:1277:1312:1313:1314:1345:1516:1518:1519:1522:1534:1593:1594:1595:1596:1692:1730:1747:1777:1792:2392:2393:2559:2562:2828:3138:3139:3140:3141:3142:3876:3877:5007:6114:6261:6642:6748:7281:7901:10004:10848:11604:11914:12517:12519:13895:14394:21080:21088,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0 X-HE-Tag: teeth81_68b16dacdb162 X-Filterd-Recvd-Size: 3521 Message-Id: <20150313151518.828107573@goodmis.org> User-Agent: quilt/0.61-1 Date: Fri, 13 Mar 2015 11:15:17 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Paul Gortmaker , , Nikita Yushchenko , Mike Galbraith Subject: [PATCH RT 23/31] scheduling while atomic in cgroup code References: <20150313151454.809081378@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0023-scheduling-while-atomic-in-cgroup-code.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10.70-rt75-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Galbraith mm, memcg: make refill_stock() use get_cpu_light() Nikita reported the following memcg scheduling while atomic bug: Call Trace: [e22d5a90] [c0007ea8] show_stack+0x4c/0x168 (unreliable) [e22d5ad0] [c0618c04] __schedule_bug+0x94/0xb0 [e22d5ae0] [c060b9ec] __schedule+0x530/0x550 [e22d5bf0] [c060bacc] schedule+0x30/0xbc [e22d5c00] [c060ca24] rt_spin_lock_slowlock+0x180/0x27c [e22d5c70] [c00b39dc] res_counter_uncharge_until+0x40/0xc4 [e22d5ca0] [c013ca88] drain_stock.isra.20+0x54/0x98 [e22d5cc0] [c01402ac] __mem_cgroup_try_charge+0x2e8/0xbac [e22d5d70] [c01410d4] mem_cgroup_charge_common+0x3c/0x70 [e22d5d90] [c0117284] __do_fault+0x38c/0x510 [e22d5df0] [c011a5f4] handle_pte_fault+0x98/0x858 [e22d5e50] [c060ed08] do_page_fault+0x42c/0x6fc [e22d5f40] [c000f5b4] handle_page_fault+0xc/0x80 What happens: refill_stock() get_cpu_var() drain_stock() res_counter_uncharge() res_counter_uncharge_until() spin_lock() <== boom Fix it by replacing get/put_cpu_var() with get/put_cpu_light(). Cc: stable-rt@vger.kernel.org Reported-by: Nikita Yushchenko Signed-off-by: Mike Galbraith Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Steven Rostedt --- mm/memcontrol.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 33d8392f33eb..89540bca5c5b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2463,14 +2463,17 @@ static void __init memcg_stock_init(void) */ static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) { - struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); + struct memcg_stock_pcp *stock; + int cpu = get_cpu_light(); + + stock = &per_cpu(memcg_stock, cpu); if (stock->cached != memcg) { /* reset if necessary */ drain_stock(stock); stock->cached = memcg; } stock->nr_pages += nr_pages; - put_cpu_var(memcg_stock); + put_cpu_light(); } /* -- 2.1.4