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=-5.7 required=3.0 tests=FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_PASS,URIBL_BLOCKED autolearn=ham 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 31690C43387 for ; Mon, 31 Dec 2018 15:02:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF9F821019 for ; Mon, 31 Dec 2018 15:02:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727287AbeLaPCG (ORCPT ); Mon, 31 Dec 2018 10:02:06 -0500 Received: from mail-io1-f72.google.com ([209.85.166.72]:51822 "EHLO mail-io1-f72.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725899AbeLaPCF (ORCPT ); Mon, 31 Dec 2018 10:02:05 -0500 Received: by mail-io1-f72.google.com with SMTP id q207so29470387iod.18 for ; Mon, 31 Dec 2018 07:02:04 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:in-reply-to:message-id:subject :from:to; bh=lKrWsMQnR9/JFmQJJSFRO4EcWAZz5/k9b3LxItMmKZ4=; b=NcLhPAabPs+4lvwAfrmyAqDNii0q/X5u93i3qY9RzTQGtEt8i2q6L1QKl6iF8/G1b5 l7JlfjhSbf+gfuHnXHPuNUcQqMAfP6/VtFMWAqohzYUHRc5fIkVuzADyjQ4xaqKuT8nQ 4d//4wa4Ka0Nyo3hs30TzvCuKzg9j84y6+2Q4WPk2/46tvN9KjLP+z6xtphxdP2VFESb nMEEQVPpq+PoODF89MmiR8T1W7MXKbyPzxOJyQnVbk7KpF0NB1Ri4dzOEEl0Oijdyh8W 2Dc/IzEuO6zpc8iflbaeNVAwmQxpVKaCs15DsniSfbuhMSlxuQww7vxXN3iZBYIySrom vCsw== X-Gm-Message-State: AA+aEWbjP7ShoITnr7p5ysrGB9X6FPYakqDF4qhtmGUlXhfKZcVL/+2b qOaA+2uylZdvc/W46ojPxCYAcGjg66MtckM2a07bws7C5mjv X-Google-Smtp-Source: ALg8bN5+HqaevJmDdV+6cSTGbY/pg+cWhKbrBaeGAyWvs5X6vf/4JpGlcdROZPDbiRZGhEIcWAs9AqqCmH1M9zmp0QuRRxUlQNdD MIME-Version: 1.0 X-Received: by 2002:a05:660c:4e:: with SMTP id p14mr27570744itk.31.1546268524364; Mon, 31 Dec 2018 07:02:04 -0800 (PST) Date: Mon, 31 Dec 2018 07:02:04 -0800 In-Reply-To: <000000000000b5e346057af4da06@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000001f4fee057e52b284@google.com> Subject: Re: WARNING in enqueue_task_dl From: syzbot To: bp@alien8.de, bristot@redhat.com, hpa@zytor.com, juri.lelli@redhat.com, linux-kernel@vger.kernel.org, luca.abeni@santannapisa.it, luto@kernel.org, mingo@redhat.com, peterz@infradead.org, syzkaller-bugs@googlegroups.com, tglx@linutronix.de, x86@kernel.org Content-Type: text/plain; charset="UTF-8"; format=flowed; delsp=yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org syzbot has found a reproducer for the following crash on: HEAD commit: 195303136f19 Merge tag 'kconfig-v4.21-2' of git://git.kern.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=118af84b400000 kernel config: https://syzkaller.appspot.com/x/.config?x=76d28549be7c27cf dashboard link: https://syzkaller.appspot.com/bug?extid=119ba87189432ead09b4 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10eb7ebf400000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14156d77400000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+119ba87189432ead09b4@syzkaller.appspotmail.com WARNING: CPU: 0 PID: 9019 at kernel/sched/deadline.c:628 setup_new_dl_entity kernel/sched/deadline.c:629 [inline] WARNING: CPU: 0 PID: 9019 at kernel/sched/deadline.c:628 enqueue_dl_entity kernel/sched/deadline.c:1429 [inline] WARNING: CPU: 0 PID: 9019 at kernel/sched/deadline.c:628 enqueue_task_dl+0x2355/0x3dc0 kernel/sched/deadline.c:1500 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 9019 Comm: syz-executor280 Not tainted 4.20.0+ #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 panic+0x2cb/0x589 kernel/panic.c:189 __warn.cold+0x20/0x4b kernel/panic.c:544 report_bug+0x263/0x2b0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 RIP: 0010:setup_new_dl_entity kernel/sched/deadline.c:628 [inline] RIP: 0010:enqueue_dl_entity kernel/sched/deadline.c:1429 [inline] RIP: 0010:enqueue_task_dl+0x2355/0x3dc0 kernel/sched/deadline.c:1500 Code: 3c 02 00 0f 85 ba 05 00 00 49 8b b5 50 0a 00 00 e9 53 fa ff ff e8 fb f2 64 00 48 8d 4d d8 e9 48 dd ff ff 0f 0b e9 92 f1 ff ff <0f> 0b e9 18 f1 ff ff 4c 89 ef 4c 89 95 28 ff ff ff 4c 89 85 30 ff RSP: 0018:ffff88809eebfaf8 EFLAGS: 00010002 RAX: 0000000000000002 RBX: 1ffff11013dd7f6a RCX: dffffc0000000000 RDX: 000000333cf09f75 RSI: 0000000000000004 RDI: ffff8880ae62d850 RBP: ffff88809eebfbf8 R08: ffff88807fb0a538 R09: ffff88807fb0a2fc R10: ffff88807fb0a580 R11: ffff8880ae62dc7b R12: ffff88807fb0a2c0 R13: ffff8880ae62ce00 R14: ffff8880ae62ce00 R15: ffff88807fb0a58c enqueue_task+0xb9/0x380 kernel/sched/core.c:730 __sched_setscheduler+0xe32/0x1fe0 kernel/sched/core.c:4336 sched_setattr kernel/sched/core.c:4394 [inline] __do_sys_sched_setattr kernel/sched/core.c:4570 [inline] __se_sys_sched_setattr kernel/sched/core.c:4549 [inline] __x64_sys_sched_setattr+0x1af/0x2f0 kernel/sched/core.c:4549 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x44c829 Code: e8 8c d8 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb c9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f28685e8ce8 EFLAGS: 00000246 ORIG_RAX: 000000000000013a RAX: ffffffffffffffda RBX: 00000000006e49f8 RCX: 000000000044c829 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000000 RBP: 00000000006e49f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e49fc R13: 00007ffd1981c8af R14: 00007f28685e99c0 R15: 0000000000000001 ====================================================== WARNING: possible circular locking dependency detected 4.20.0+ #1 Not tainted ------------------------------------------------------ syz-executor280/9019 is trying to acquire lock: 000000001aef527c ((console_sem).lock){-.-.}, at: down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 but task is already holding lock: 000000000ba17b09 (&rq->lock){-.-.}, at: task_rq_lock+0xc8/0x290 kernel/sched/core.c:99 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&rq->lock){-.-.}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:144 rq_lock kernel/sched/sched.h:1149 [inline] task_fork_fair+0xb5/0x7a0 kernel/sched/fair.c:10083 sched_fork+0x437/0xb90 kernel/sched/core.c:2359 copy_process+0x1ff6/0x8730 kernel/fork.c:1893 _do_fork+0x1a9/0x1170 kernel/fork.c:2222 kernel_thread+0x34/0x40 kernel/fork.c:2281 rest_init+0x28/0x37b init/main.c:409 arch_call_rest_init+0xe/0x1b start_kernel+0x882/0x8bd init/main.c:741 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:451 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243 -> #1 (&p->pi_lock){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 try_to_wake_up+0xb9/0x1480 kernel/sched/core.c:1965 wake_up_process+0x10/0x20 kernel/sched/core.c:2129 __up.isra.0+0x1c0/0x2a0 kernel/locking/semaphore.c:262 up+0x13e/0x1c0 kernel/locking/semaphore.c:187 __up_console_sem+0xb7/0x1c0 kernel/printk/printk.c:236 console_unlock+0x778/0x11e0 kernel/printk/printk.c:2426 con_flush_chars drivers/tty/vt/vt.c:3197 [inline] con_flush_chars drivers/tty/vt/vt.c:3185 [inline] con_write+0xa2/0xb0 drivers/tty/vt/vt.c:3117 process_output_block drivers/tty/n_tty.c:593 [inline] n_tty_write+0x497/0x1220 drivers/tty/n_tty.c:2331 do_tty_write drivers/tty/tty_io.c:959 [inline] tty_write+0x45b/0x7a0 drivers/tty/tty_io.c:1043 __vfs_write+0x116/0xb40 fs/read_write.c:485 vfs_write+0x20c/0x580 fs/read_write.c:549 ksys_write+0x105/0x260 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:607 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 ((console_sem).lock){-.-.}: lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 __down_trylock_console_sem+0xa8/0x210 kernel/printk/printk.c:219 console_trylock+0x15/0xa0 kernel/printk/printk.c:2242 console_trylock_spinning kernel/printk/printk.c:1662 [inline] vprintk_emit+0x351/0x960 kernel/printk/printk.c:1930 vprintk_default+0x28/0x30 kernel/printk/printk.c:1958 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:1991 __warn+0x9e/0x1d0 kernel/panic.c:526 report_bug+0x263/0x2b0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 setup_new_dl_entity kernel/sched/deadline.c:629 [inline] enqueue_dl_entity kernel/sched/deadline.c:1429 [inline] enqueue_task_dl+0x2355/0x3dc0 kernel/sched/deadline.c:1500 enqueue_task+0xb9/0x380 kernel/sched/core.c:730 __sched_setscheduler+0xe32/0x1fe0 kernel/sched/core.c:4336 sched_setattr kernel/sched/core.c:4394 [inline] __do_sys_sched_setattr kernel/sched/core.c:4570 [inline] __se_sys_sched_setattr kernel/sched/core.c:4549 [inline] __x64_sys_sched_setattr+0x1af/0x2f0 kernel/sched/core.c:4549 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Chain exists of: (console_sem).lock --> &p->pi_lock --> &rq->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rq->lock); lock(&p->pi_lock); lock(&rq->lock); lock((console_sem).lock); *** DEADLOCK *** 3 locks held by syz-executor280/9019: #0: 0000000014b8e16d (rcu_read_lock){....}, at: __do_sys_sched_setattr kernel/sched/core.c:4563 [inline] #0: 0000000014b8e16d (rcu_read_lock){....}, at: __se_sys_sched_setattr kernel/sched/core.c:4549 [inline] #0: 0000000014b8e16d (rcu_read_lock){....}, at: __x64_sys_sched_setattr+0x144/0x2f0 kernel/sched/core.c:4549 #1: 00000000b31ff59d (&p->pi_lock){-.-.}, at: task_rq_lock+0x6a/0x290 kernel/sched/core.c:97 #2: 000000000ba17b09 (&rq->lock){-.-.}, at: task_rq_lock+0xc8/0x290 kernel/sched/core.c:99 stack backtrace: CPU: 0 PID: 9019 Comm: syz-executor280 Not tainted 4.20.0+ #1 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1db/0x2d0 lib/dump_stack.c:113 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1224 check_prev_add kernel/locking/lockdep.c:1866 [inline] check_prevs_add kernel/locking/lockdep.c:1979 [inline] validate_chain kernel/locking/lockdep.c:2350 [inline] __lock_acquire+0x3014/0x4a30 kernel/locking/lockdep.c:3338 lock_acquire+0x1db/0x570 kernel/locking/lockdep.c:3841 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 down_trylock+0x13/0x70 kernel/locking/semaphore.c:136 __down_trylock_console_sem+0xa8/0x210 kernel/printk/printk.c:219 console_trylock+0x15/0xa0 kernel/printk/printk.c:2242 console_trylock_spinning kernel/printk/printk.c:1662 [inline] vprintk_emit+0x351/0x960 kernel/printk/printk.c:1930 vprintk_default+0x28/0x30 kernel/printk/printk.c:1958 vprintk_func+0x7e/0x189 kernel/printk/printk_safe.c:398 printk+0xba/0xed kernel/printk/printk.c:1991 __warn+0x9e/0x1d0 kernel/panic.c:526 report_bug+0x263/0x2b0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] fixup_bug arch/x86/kernel/traps.c:173 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:290 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973 RIP: 0010:setup_new_dl_entity kernel/sched/deadline.c:628 [inline] RIP: 0010:enqueue_dl_entity kernel/sched/deadline.c:1429 [inline] RIP: 0010:enqueue_task_dl+0x2355/0x3dc0 kernel/sched/deadline.c:1500 Code: 3c 02 00 0f 85 ba 05 00 00 49 8b b5 50 0a 00 00 e9 53 fa ff ff e8 fb f2 64 00 48 8d 4d d8 e9 48 dd ff ff 0f 0b e9 92 f1 ff ff <0f> 0b e9 18 f1 ff ff 4c 89 ef 4c 89 95 28 ff ff ff 4c 89 85 30 ff RSP: 0018:ffff88809eebfaf8 EFLAGS: 00010002 RAX: 0000000000000002 RBX: 1ffff11013dd7f6a RCX: dffffc0000000000 RDX: 000000333cf09f75 RSI: 0000000000000004 RDI: ffff8880ae62d850 RBP: ffff88809eebfbf8 R08: ffff88807fb0a538 R09: ffff88807fb0a2fc R10: ffff88807fb0a580 R11: ffff8880ae62dc7b R12: ffff88807fb0a2c0 R13: ffff8880ae62ce00 R14: ffff8880ae62ce00 R15: ffff88807fb0a58c enqueue_task+0xb9/0x380 kernel/sched/core.c:730 __sched_setscheduler+0xe32/0x1fe0 kernel/sched/core.c:4336 sched_setattr kernel/sched/core.c:4394 [inline] __do_sys_sched_setattr kernel/sched/core.c:4570 [inline] __se_sys_sched_setattr kernel/sched/core.c:4549 [inline] __x64_sys_sched_setattr+0x1af/0x2f0 kernel/sched/core.c:4549 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x44c829 Code: e8 8c d8 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb c9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f28685e8ce8 EFLAGS: 00000246 ORIG_RAX: 000000000000013a RAX: ffffffffffffffda RBX: 00000000006e49f8 RCX: 000000000044c829 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000000 RBP: 00000000006e49f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e49fc R13: 00007ffd1981c8af R14: 00007f28685e99c0 R15: 0000000000000001 Shutting down cpus with NMI Kernel Offset: disabled Rebooting in 86400 seconds..