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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78B35C433ED for ; Mon, 19 Apr 2021 11:31:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 53C2261006 for ; Mon, 19 Apr 2021 11:31:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238551AbhDSLcB (ORCPT ); Mon, 19 Apr 2021 07:32:01 -0400 Received: from foss.arm.com ([217.140.110.172]:40990 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230272AbhDSLb4 (ORCPT ); Mon, 19 Apr 2021 07:31:56 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E5B4931B; Mon, 19 Apr 2021 04:31:25 -0700 (PDT) Received: from e113632-lin (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 93C053F792; Mon, 19 Apr 2021 04:31:24 -0700 (PDT) From: Valentin Schneider To: syzbot , bp@alien8.de, dwmw@amazon.co.uk, hpa@zytor.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, x86@kernel.org Subject: Re: [syzbot] WARNING in kthread_is_per_cpu In-Reply-To: <000000000000a61f7705c050e601@google.com> References: <000000000000a61f7705c050e601@google.com> Date: Mon, 19 Apr 2021 12:31:22 +0100 Message-ID: <87im4ilddh.mognet@arm.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/04/21 03:36, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 1216f02e Add linux-next specific files for 20210415 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=1032ba29d00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=3491b04113499f81 > dashboard link: https://syzkaller.appspot.com/bug?extid=9362b31a2e0cad8b749d > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+9362b31a2e0cad8b749d@syzkaller.appspotmail.com > > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 23550 at kernel/kthread.c:83 to_kthread kernel/kthread.c:83 [inline] > WARNING: CPU: 1 PID: 23550 at kernel/kthread.c:83 kthread_is_per_cpu+0xc4/0xf0 kernel/kthread.c:519 > Modules linked in: > CPU: 1 PID: 23550 Comm: syz-executor.3 Not tainted 5.12.0-rc7-next-20210415-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:to_kthread kernel/kthread.c:83 [inline] > RIP: 0010:kthread_is_per_cpu+0xc4/0xf0 kernel/kthread.c:519 > Code: 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 75 2e 4c 8b 23 41 83 e4 01 e8 89 d3 27 00 44 89 e0 5b 5d 41 5c c3 e8 7c d3 27 00 <0f> 0b eb 88 e8 33 90 6c 00 e9 68 ff ff ff e8 39 90 6c 00 eb 9a 48 > RSP: 0018:ffffc90000dc0c08 EFLAGS: 00010046 > RAX: 0000000000000000 RBX: ffff88802533d580 RCX: 0000000000000100 > RDX: ffff8880549bb900 RSI: ffffffff814ca4c4 RDI: 0000000000000003 > RBP: 0000000000000000 R08: 0000000000000000 R09: ffff88802533d580 > R10: ffffffff814ca44c R11: 00000000018a3b90 R12: 0000000000000001 > R13: ffffc90000dc0d90 R14: 0000000000000001 R15: ffff88802533d580 > FS: 00007f4be57d3700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000001b2cd24000 CR3: 0000000024626000 CR4: 00000000001506e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > can_migrate_task+0x124/0x1630 kernel/sched/fair.c:7610 > detach_tasks kernel/sched/fair.c:7774 [inline] > load_balance+0xc72/0x2730 kernel/sched/fair.c:9696 > rebalance_domains+0x668/0xda0 kernel/sched/fair.c:10075 > __do_softirq+0x29b/0x9fe kernel/softirq.c:559 > invoke_softirq kernel/softirq.c:433 [inline] > __irq_exit_rcu+0x136/0x200 kernel/softirq.c:637 > irq_exit_rcu+0x5/0x20 kernel/softirq.c:649 > sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100 > > asm_sysvec_apic_timer_interrupt+0x12/0x20 > arch/x86/include/asm/idtentry.h:632 if ((p->flags & PF_KTHREAD) && kthread_is_per_cpu(p)) `\ to_kthread(p); `\ WARN_ON(!(p->flags & PF_KTHREAD)); ... Huh?