From patchwork Thu Aug 20 09:21:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 11725989 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6B1A6722 for ; Thu, 20 Aug 2020 10:01:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 383E720724 for ; Thu, 20 Aug 2020 10:01:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="if+H3TZE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 383E720724 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 472F88D0003; Thu, 20 Aug 2020 06:01:18 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 424B68D0001; Thu, 20 Aug 2020 06:01:18 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3115C8D0003; Thu, 20 Aug 2020 06:01:18 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0145.hostedemail.com [216.40.44.145]) by kanga.kvack.org (Postfix) with ESMTP id 18DBC8D0001 for ; Thu, 20 Aug 2020 06:01:18 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id CF79B5DFE for ; Thu, 20 Aug 2020 10:01:17 +0000 (UTC) X-FDA: 77170504194.09.tent07_3d12dcf2702f Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin09.hostedemail.com (Postfix) with ESMTP id A17DD180AD817 for ; Thu, 20 Aug 2020 10:01:17 +0000 (UTC) X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,gregkh@linuxfoundation.org,,RULES_HIT:30012:30029:30045:30054:30056:30075,0,RBL:198.145.29.99:@linuxfoundation.org:.lbl8.mailshell.net-64.10.201.10 62.18.0.100;04yganruxbe1zm4nnrph6fwmrr7dbyp18wy5tgwtwrixop9wx9s5meyqumqr9cm.osqarcq8thwebahehuhmweza5q4k7ckmwqpastqnfc6chadftkw5kekiwk4axwt.a-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:linux-foundation.org-sh.dbl.urbl.hostedemail.com-127.0.0.175,Custom_rules:0:0:0,LFtime:23,LUA_SUMMARY:none X-HE-Tag: tent07_3d12dcf2702f X-Filterd-Recvd-Size: 4778 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Thu, 20 Aug 2020 10:01:17 +0000 (UTC) Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A744622BEA; Thu, 20 Aug 2020 10:01:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597917676; bh=1gBw/nizSjzEAkxJYCzqvO1twynNchzj+53LZt4J2us=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=if+H3TZEAEoSfE6hNm0Ss4/80ofvNfsaOtOeYmWMjL0O4W7nRWb3EwGr60Kjedkis pezsm98/kzfTNA4611hhZuJzt7hjNORZzSNTVzrMqj4FbU2+ppvy2H8X+vf7nt/Ir9 viF+BfVlKdcQZHHZUO9md+8/WJFdmYPDmZpK5jJM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrew Morton , linux-mm@kvack.org, Shakeel Butt , "Joel Fernandes (Google)" , "Paul E. McKenney" , Sasha Levin Subject: [PATCH 4.9 099/212] mm/mmap.c: Add cond_resched() for exit_mmap() CPU stalls Date: Thu, 20 Aug 2020 11:21:12 +0200 Message-Id: <20200820091607.345136281@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200820091602.251285210@linuxfoundation.org> References: <20200820091602.251285210@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 X-Rspamd-Queue-Id: A17DD180AD817 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Paul E. McKenney [ Upstream commit 0a3b3c253a1eb2c7fe7f34086d46660c909abeb3 ] A large process running on a heavily loaded system can encounter the following RCU CPU stall warning: rcu: INFO: rcu_sched self-detected stall on CPU rcu: 3-....: (20998 ticks this GP) idle=4ea/1/0x4000000000000002 softirq=556558/556558 fqs=5190 (t=21013 jiffies g=1005461 q=132576) NMI backtrace for cpu 3 CPU: 3 PID: 501900 Comm: aio-free-ring-w Kdump: loaded Not tainted 5.2.9-108_fbk12_rc3_3858_gb83b75af7909 #1 Hardware name: Wiwynn HoneyBadger/PantherPlus, BIOS HBM6.71 02/03/2016 Call Trace: dump_stack+0x46/0x60 nmi_cpu_backtrace.cold.3+0x13/0x50 ? lapic_can_unplug_cpu.cold.27+0x34/0x34 nmi_trigger_cpumask_backtrace+0xba/0xca rcu_dump_cpu_stacks+0x99/0xc7 rcu_sched_clock_irq.cold.87+0x1aa/0x397 ? tick_sched_do_timer+0x60/0x60 update_process_times+0x28/0x60 tick_sched_timer+0x37/0x70 __hrtimer_run_queues+0xfe/0x270 hrtimer_interrupt+0xf4/0x210 smp_apic_timer_interrupt+0x5e/0x120 apic_timer_interrupt+0xf/0x20 RIP: 0010:kmem_cache_free+0x223/0x300 Code: 88 00 00 00 0f 85 ca 00 00 00 41 8b 55 18 31 f6 f7 da 41 f6 45 0a 02 40 0f 94 c6 83 c6 05 9c 41 5e fa e8 a0 a7 01 00 41 56 9d <49> 8b 47 08 a8 03 0f 85 87 00 00 00 65 48 ff 08 e9 3d fe ff ff 65 RSP: 0018:ffffc9000e8e3da8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 RAX: 0000000000020000 RBX: ffff88861b9de960 RCX: 0000000000000030 RDX: fffffffffffe41e8 RSI: 000060777fe3a100 RDI: 000000000001be18 RBP: ffffea00186e7780 R08: ffffffffffffffff R09: ffffffffffffffff R10: ffff88861b9dea28 R11: ffff88887ffde000 R12: ffffffff81230a1f R13: ffff888854684dc0 R14: 0000000000000206 R15: ffff8888547dbc00 ? remove_vma+0x4f/0x60 remove_vma+0x4f/0x60 exit_mmap+0xd6/0x160 mmput+0x4a/0x110 do_exit+0x278/0xae0 ? syscall_trace_enter+0x1d3/0x2b0 ? handle_mm_fault+0xaa/0x1c0 do_group_exit+0x3a/0xa0 __x64_sys_exit_group+0x14/0x20 do_syscall_64+0x42/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 And on a PREEMPT=n kernel, the "while (vma)" loop in exit_mmap() can run for a very long time given a large process. This commit therefore adds a cond_resched() to this loop, providing RCU any needed quiescent states. Cc: Andrew Morton Cc: Reviewed-by: Shakeel Butt Reviewed-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney Signed-off-by: Sasha Levin --- mm/mmap.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/mmap.c b/mm/mmap.c index d221266d100f4..7109f886e739e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -3018,6 +3018,7 @@ void exit_mmap(struct mm_struct *mm) if (vma->vm_flags & VM_ACCOUNT) nr_accounted += vma_pages(vma); vma = remove_vma(vma); + cond_resched(); } vm_unacct_memory(nr_accounted); }