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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ACB1FC433FE for ; Sun, 31 Oct 2021 17:40:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FD2461077 for ; Sun, 31 Oct 2021 17:40:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230209AbhJaRnC (ORCPT ); Sun, 31 Oct 2021 13:43:02 -0400 Received: from mail-il1-f198.google.com ([209.85.166.198]:43638 "EHLO mail-il1-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229732AbhJaRnA (ORCPT ); Sun, 31 Oct 2021 13:43:00 -0400 Received: by mail-il1-f198.google.com with SMTP id s8-20020a92cbc8000000b002582a281a7bso8679158ilq.10 for ; Sun, 31 Oct 2021 10:40:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=g3iEMigpYmU/b8rBRslVB998+5hcxkuudEXmxIOgDVQ=; b=pSKzSkm1U7bgmEcak6np5DMxdnunBd8aGr4qTELIQkg4rtrKnTAVdr3nLMZkk4lMU1 uJMQx8x/19e6NZbY2nPYlxjMHIloAuo47Hnt/mPbNcM0dJI4Rkkm78R44dKNeEN93g8c Z1So+py3GKx1tG6JyMtJ8suo+RH51e2xz3S0DN52n8MXFDmM4Ztam3PfGb6RiMcZa46a 0IsQDWv3hnz0uwUq/aJO8RrC0EjsiJAxVRNLdoW+WuoRvt/QnL45Ds7ktzV7z2+fayhT pg9RIs6rByhhDdtJTJLUbUTPfi1xqA+g2Bh7OReVXagOvTV3tTv2uoVolcUaZA/IqekK JZlA== X-Gm-Message-State: AOAM530KDNLUk7Lbf1cROnXfEj03RzgggrG3m0hvHgzB82enH2B+1Rtn KIyR5hSZiQSNvdOoovoLMfysObqBxJML0Q9BFXW0ZIShpiKe X-Google-Smtp-Source: ABdhPJwBy9L/zia1sGaKa7r0CDGian0MZa65jmQvaLCVyYYMcrPKoF1hmQ8WdIuU7QlF+YHj7MkGmsV8xIwpnC8zcqejrBU6p50v MIME-Version: 1.0 X-Received: by 2002:a05:6e02:17c8:: with SMTP id z8mr17163125ilu.247.1635702025534; Sun, 31 Oct 2021 10:40:25 -0700 (PDT) Date: Sun, 31 Oct 2021 10:40:25 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <00000000000030c35005cfa98ed5@google.com> Subject: [syzbot] INFO: rcu detected stall in tctx_task_work From: syzbot To: asml.silence@gmail.com, axboe@kernel.dk, fweisbec@gmail.com, io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, mingo@kernel.org, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, xiaoguang.wang@linux.alibaba.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Hello, syzbot found the following issue on: HEAD commit: bdcc9f6a5682 Add linux-next specific files for 20211029 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=10be38f4b00000 kernel config: https://syzkaller.appspot.com/x/.config?x=4b504bcb4c507265 dashboard link: https://syzkaller.appspot.com/bug?extid=e4f5deeeccdd5a4873fe compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10b915d4b00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1395f3e2b00000 The issue was bisected to: commit 34ced75ca1f63fac6148497971212583aa0f7a87 Author: Xiaoguang Wang Date: Mon Oct 25 05:38:48 2021 +0000 io_uring: reduce frequent add_wait_queue() overhead for multi-shot poll request bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13f4a9d4b00000 final oops: https://syzkaller.appspot.com/x/report.txt?x=100ca9d4b00000 console output: https://syzkaller.appspot.com/x/log.txt?x=17f4a9d4b00000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+e4f5deeeccdd5a4873fe@syzkaller.appspotmail.com Fixes: 34ced75ca1f6 ("io_uring: reduce frequent add_wait_queue() overhead for multi-shot poll request") rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10499 ticks this GP) idle=91d/1/0x4000000000000000 softirq=9714/9714 fqs=3884 (t=10500 jiffies g=11093 q=47) NMI backtrace for cpu 0 CPU: 0 PID: 6487 Comm: syz-executor141 Not tainted 5.15.0-rc7-next-20211029-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:604 [inline] check_cpu_stall kernel/rcu/tree_stall.h:688 [inline] rcu_pending kernel/rcu/tree.c:3922 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2620 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:104 [inline] RIP: 0010:do_raw_spin_unlock+0x101/0x230 kernel/locking/spinlock_debug.c:140 Code: 8e fc 00 00 00 65 8b 05 e5 c5 a4 7e 39 45 08 0f 85 b5 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 <0f> 85 f5 00 00 00 4c 89 e2 48 c7 45 10 ff ff ff ff 48 b8 00 00 00 RSP: 0018:ffffc90002a8fcc8 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff88801a315950 RCX: ffffffff815d4f10 RDX: 1ffff1100449ce7a RSI: 0000000000000004 RDI: ffff8880224e73c0 RBP: ffff8880224e73c0 R08: 0000000000000000 R09: ffff8880224e73c3 R10: ffffed100449ce78 R11: 0000000000000000 R12: ffff8880224e73c8 R13: ffff8880224e73d0 R14: ffff88801a315918 R15: ffff88801a3158c0 __raw_spin_unlock include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock+0x1a/0x40 kernel/locking/spinlock.c:186 tctx_task_work+0x1b3/0x630 fs/io_uring.c:2207 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 exit_task_work include/linux/task_work.h:32 [inline] do_exit+0xc14/0x2b40 kernel/exit.c:832 do_group_exit+0x125/0x310 kernel/exit.c:929 __do_sys_exit_group kernel/exit.c:940 [inline] __se_sys_exit_group kernel/exit.c:938 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:938 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fe6950481a9 Code: Unable to access opcode bytes at RIP 0x7fe69504817f. RSP: 002b:00007ffc42a91cb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007fe6950bc330 RCX: 00007fe6950481a9 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 0000000000000000 R08: ffffffffffffffc0 R09: 00000000f5ffffff R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe6950bc330 R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001 ---------------- Code disassembly (best guess): 0: 8e fc mov %esp,%? 2: 00 00 add %al,(%rax) 4: 00 65 8b add %ah,-0x75(%rbp) 7: 05 e5 c5 a4 7e add $0x7ea4c5e5,%eax c: 39 45 08 cmp %eax,0x8(%rbp) f: 0f 85 b5 00 00 00 jne 0xca 15: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1c: fc ff df 1f: 4c 89 ea mov %r13,%rdx 22: 48 c1 ea 03 shr $0x3,%rdx 26: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) * 2a: 0f 85 f5 00 00 00 jne 0x125 <-- trapping instruction 30: 4c 89 e2 mov %r12,%rdx 33: 48 c7 45 10 ff ff ff movq $0xffffffffffffffff,0x10(%rbp) 3a: ff 3b: 48 rex.W 3c: b8 .byte 0xb8 3d: 00 00 add %al,(%rax) --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches