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Mon, 06 Jul 2020 08:42:24 -0700 (PDT) Date: Mon, 06 Jul 2020 08:42:24 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000009caba805a9c7b840@google.com> Subject: INFO: rcu detected stall in __se_sys_mount From: syzbot To: fweisbec@gmail.com, linux-kernel@vger.kernel.org, mingo@kernel.org, syzkaller-bugs@googlegroups.com, tglx@linutronix.de Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following crash on: HEAD commit: 7cc2a8ea Merge tag 'block-5.8-2020-07-01' of git://git.ker.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15ea5e6b100000 kernel config: https://syzkaller.appspot.com/x/.config?x=183dd243398ba7ec dashboard link: https://syzkaller.appspot.com/bug?extid=3f2db34df769d77edf8c compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13901c1f100000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+3f2db34df769d77edf8c@syzkaller.appspotmail.com rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (1 GPs behind) idle=53a/1/0x4000000000000000 softirq=11025/11028 fqs=5230 (t=10500 jiffies g=9573 q=1291) NMI backtrace for cpu 0 CPU: 0 PID: 8924 Comm: syz-executor.3 Not tainted 5.8.0-rc3-syzkaller #0 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+0x1f0/0x31e lib/dump_stack.c:118 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x199/0x2a0 kernel/rcu/tree_stall.h:320 print_cpu_stall kernel/rcu/tree_stall.h:553 [inline] check_cpu_stall kernel/rcu/tree_stall.h:627 [inline] rcu_pending kernel/rcu/tree.c:3489 [inline] rcu_sched_clock_irq+0x1928/0x1eb0 kernel/rcu/tree.c:2504 update_process_times+0x12c/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:176 [inline] tick_sched_timer+0x254/0x410 kernel/time/tick-sched.c:1320 __run_hrtimer kernel/time/hrtimer.c:1520 [inline] __hrtimer_run_queues+0x42d/0x930 kernel/time/hrtimer.c:1584 hrtimer_interrupt+0x373/0xd60 kernel/time/hrtimer.c:1646 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline] __sysvec_apic_timer_interrupt+0xf0/0x260 arch/x86/kernel/apic/apic.c:1097 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline] sysvec_apic_timer_interrupt+0xb9/0x130 arch/x86/kernel/apic/apic.c:1091 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:596 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 [inline] RIP: 0010:slab_alloc mm/slab.c:3313 [inline] RIP: 0010:kmem_cache_alloc+0x1a8/0x2d0 mm/slab.c:3484 Code: 8b 3c 24 57 9d 0f 1f 44 00 00 e8 c3 30 c7 ff eb 1e e8 ac 2b c7 ff 48 83 3d a4 d6 78 07 00 0f 84 26 01 00 00 48 8b 3c 24 57 9d <0f> 1f 44 00 00 41 0f 18 0e e9 21 00 00 00 89 e8 c1 e8 08 83 e0 01 RSP: 0018:ffffc90001587d88 EFLAGS: 00000282 RAX: 0000000007e4a93f RBX: 0000000000000cc0 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000282 RBP: 0000000000000cc0 R08: ffffffff817a1d20 R09: ffffed10154bbe01 R10: ffffed10154bbe01 R11: 0000000000000000 R12: ffff88821bc4e700 R13: ffff88821bc4e700 R14: ffff888079f3a840 R15: ffffffff81bf92c8 getname_flags+0xb8/0x610 fs/namei.c:138 user_path_at_empty+0x28/0x50 fs/namei.c:2646 user_path_at include/linux/namei.h:59 [inline] do_mount+0xd1/0x2900 fs/namespace.c:3137 __do_sys_mount fs/namespace.c:3409 [inline] __se_sys_mount+0xd3/0x100 fs/namespace.c:3386 do_syscall_64+0x73/0xe0 arch/x86/entry/common.c:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45f57a Code: Bad RIP value. RSP: 002b:00007ffe24a11b48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 000000000050a560 RCX: 000000000045f57a RDX: 00007ffe24a11bc0 RSI: 0000000000000000 RDI: 00007ffe24a11be0 RBP: 000000000078bf00 R08: 00007ffe24a11c20 R09: 00007ffe24a11bc0 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000c3b R14: 00000000004ce8d8 R15: 0000000001b1c914 --- This bug 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 bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. syzbot can test patches for this bug, for details see: https://goo.gl/tpsmEJ#testing-patches