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 E2B6DC00140 for ; Tue, 2 Aug 2022 10:43:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236136AbiHBKnf (ORCPT ); Tue, 2 Aug 2022 06:43:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232695AbiHBKnc (ORCPT ); Tue, 2 Aug 2022 06:43:32 -0400 Received: from mail-il1-f199.google.com (mail-il1-f199.google.com [209.85.166.199]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 369EF22539 for ; Tue, 2 Aug 2022 03:43:32 -0700 (PDT) Received: by mail-il1-f199.google.com with SMTP id h7-20020a92c267000000b002dd80cf0989so8274583ild.5 for ; Tue, 02 Aug 2022 03:43:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc; bh=yVlgNZB/I47whXL8t7L3xLdkxatXwDbux5hHs6L8d7A=; b=Ef5g5QJr8wF6haeA6fmE3rjQUkHq14FrykR3tYJgCZ4QWSZSaZkD+kdYs3BtEZ/RSz V+ofdOjSqOrltoPTqy+QMBPgpBxuWbamyMOS1rijhLzmSU3/ICH5vyfv2zvJi8gSX18N uu4B81f80o6OIBOEO1Hx6sbvyxPgQI5P4YwBCIA16tlCaAegbecCkgwlNk+eC1L+4Tve 1Vz8kpZGNksSqpJdIWis/Hpjf5bDjSo4LdZd5RgEsnAQo4JFi8viSuMGiGGuqAdB3GLJ vLT6EW/pwxz+ON6SzpxzkrRWlulaWfew0X4QJ5GbAGulbvpnuXs4MgVKNqDD+T71B8f5 Y3GQ== X-Gm-Message-State: ACgBeo1w3us4AyhpPeIOBybliPDGE8gp6xm/e6UqLSM46o0BnWmp5fHm FrMIyQySnMyj5UbHB4OZzP7oVrq+bfO2iXYxu17MiQc1k5Lw X-Google-Smtp-Source: AA6agR49guNSo2nSzDN/SGEJ81vI0fTNZY4iWEpP4R1Zms6eo/YxNQADqWTM2B7dX5hoHOxaDK9bGhD8lSMbxtm77CMwsyuoP2zp MIME-Version: 1.0 X-Received: by 2002:a92:d2d2:0:b0:2de:a91b:3ac6 with SMTP id w18-20020a92d2d2000000b002dea91b3ac6mr3525545ilg.194.1659437011617; Tue, 02 Aug 2022 03:43:31 -0700 (PDT) Date: Tue, 02 Aug 2022 03:43:31 -0700 In-Reply-To: <20220802104319.1450-1-hdanton@sina.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000009ad11905e53fc99f@google.com> Subject: Re: [syzbot] INFO: rcu detected stall in gc_worker (2) From: syzbot To: Hillf Danton Cc: hdanton@sina.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Thu, 09 Dec 2021 00:56:26 -0800 >> syzbot found the following issue on: >> >> HEAD commit: 2a987e65025e Merge tag 'perf-tools-fixes-for-v5.16-2021-12.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=114fe575b00000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=7d5e878e3399b6cc >> dashboard link: https://syzkaller.appspot.com/bug?extid=70c4a3a8fe7f7e1af947 >> compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2 >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=128048b9b00000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10ceddadb00000 > > Print the hrtimer hog. > > #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master This bug is already marked as invalid. No point in testing. > > diff -pur a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c > --- a/kernel/time/hrtimer.c 2022-08-02 18:24:33.200242000 +0800 > +++ b/kernel/time/hrtimer.c 2022-08-02 18:40:52.895892600 +0800 > @@ -1647,6 +1647,7 @@ static void __run_hrtimer(struct hrtimer > enum hrtimer_restart (*fn)(struct hrtimer *); > bool expires_in_hardirq; > int restart; > + unsigned long ts; > > lockdep_assert_held(&cpu_base->lock); > > @@ -1682,8 +1683,13 @@ static void __run_hrtimer(struct hrtimer > trace_hrtimer_expire_entry(timer, now); > expires_in_hardirq = lockdep_hrtimer_enter(timer); > > + ts = jiffies + 500; > + > restart = fn(timer); > > + WARN_ONCE(time_after(jiffies, ts), > + "CPU%u hrtimer %ps took more than 500 ticks\n", cpu_base->cpu, fn); > + > lockdep_hrtimer_exit(expires_in_hardirq); > trace_hrtimer_expire_exit(timer); > raw_spin_lock_irq(&cpu_base->lock); > --