From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B210AC433FE for ; Sat, 12 Feb 2022 13:28:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235678AbiBLN2E (ORCPT ); Sat, 12 Feb 2022 08:28:04 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:47390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231276AbiBLN2B (ORCPT ); Sat, 12 Feb 2022 08:28:01 -0500 Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57034245AF for ; Sat, 12 Feb 2022 05:27:56 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=guanghuifeng@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0V4DccNi_1644672462; Received: from VM20190228-102.tbsite.net(mailfrom:guanghuifeng@linux.alibaba.com fp:SMTPD_---0V4DccNi_1644672462) by smtp.aliyun-inc.com(127.0.0.1); Sat, 12 Feb 2022 21:27:52 +0800 From: Guanghui Feng To: pmladek@suse.com, senozhatsky@chromium.org, rostedt@goodmis.org, john.ogness@linutronix.de, keescook@chromium.org, anton@enomsg.org, ccross@android.com, tony.luck@intel.com, linux-kernel@vger.kernel.org Cc: baolin.wang@linux.alibaba.com, yaohongbo@linux.alibaba.com, zhangliguang@linux.alibaba.com, zhuo.song@linux.alibaba.com Subject: [PATCH] printk: fix softlockup/rcu stall warning without setting CONFIG_PREEMPTION Date: Sat, 12 Feb 2022 21:27:42 +0800 Message-Id: <1644672462-20793-1-git-send-email-guanghuifeng@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If without setting CONFIG_PREEMPTION, and there are too many messages only in one cpu which will set console_may_schedule to 0 without cond_resched, we will find softlockup/rcu stall warning. Although the timer interrupt can be raised in the routine of console_unlock, the irq interrupt return to user/kernel will't schedule other tasks(without setting CONFIG_PREEMPTION). So I add need_resched() for cond_schedule to avoid it. Call trace: console_unlock+0x220/0x420 vprintk_emit+0x17c/0x1ac vprintk_default+0x3c/0x44 vprintk+0x38/0x70 printk+0x64/0x88 dump_task.part.0+0xc4/0xe0 dump_task+0x70/0x74 dump_tasks+0x78/0x90 dump_global_header+0xcc/0xe8 oom_kill_process+0x258/0x274 out_of_memory.part.0+0xb0/0x33c out_of_memory+0x4c/0xa0 __alloc_pages_may_oom+0x11c/0x1a0 __alloc_pages_slowpath.constprop.0+0x4c0/0x75c __alloc_pages_nodemask+0x2b4/0x310 alloc_pages_current+0x8c/0x140 get_zeroed_page+0x20/0x50 __pud_alloc+0x40/0x190 copy_pud_range+0x264/0x280 copy_page_range+0xe8/0x204 dup_mmap+0x334/0x434 dup_mm+0x64/0x11c copy_process+0x5e0/0x11a0 kernel_clone+0x94/0x364 __do_sys_clone+0x54/0x80 __arm64_sys_clone+0x24/0x30 el0_svc_common.constprop.0+0x7c/0x210 do_el0_svc+0x74/0x90 el0_svc+0x24/0x60 el0_sync_handler+0xa8/0xb0 el0_sync+0x140/0x180 Signed-off-by: Guanghui Feng --- kernel/printk/printk.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 82abfaf..54b6cf2 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2716,7 +2716,11 @@ void console_unlock(void) if (handover) return; +#ifndef CONFIG_PREEMPTION + if (do_cond_resched || need_resched()) +#else if (do_cond_resched) +#endif cond_resched(); } -- 1.8.3.1