Messages in this thread | | | From | Dmitry Vyukov <> | Date | Tue, 3 Dec 2019 09:34:30 +0100 | Subject | Re: INFO: rcu detected stall in pipe_read |
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On Tue, Dec 3, 2019 at 9:28 AM syzbot <syzbot+7047406d4ba783c8eb7b@syzkaller.appspotmail.com> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: 596cf45c Merge branch 'akpm' (patches from Andrew) > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=17b1af36e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=9bbcda576154a4b4 > dashboard link: https://syzkaller.appspot.com/bug?extid=7047406d4ba783c8eb7b > compiler: clang version 9.0.0 (/home/glider/llvm/clang > 80fee25776c2fb61e74c1ecb1a523375c2500b69) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+7047406d4ba783c8eb7b@syzkaller.appspotmail.com
Something seriously broke in smack+kasan+vmap stacks, we now have 60 rcu stalls all over the place and counting. This is one of the samples. Let's dup all of them to a single one and continue the discussion there:
#syz dup: INFO: rcu detected stall in sys_kill
> rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: > (detected by 0, t=10502 jiffies, g=5977, q=61) > rcu: All QSes seen, last rcu_preempt kthread activity 10503 > (4294953644-4294943141), jiffies_till_next_fqs=1, root ->qsmask 0x0 > syz-executor.0 R running task 24296 8125 8124 0x0000400a > Call Trace: > <IRQ> > sched_show_task+0x40f/0x560 kernel/sched/core.c:5954 > print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline] > check_cpu_stall kernel/rcu/tree_stall.h:538 [inline] > rcu_pending kernel/rcu/tree.c:2827 [inline] > rcu_sched_clock_irq+0x1861/0x1ad0 kernel/rcu/tree.c:2271 > update_process_times+0x12d/0x180 kernel/time/timer.c:1726 > tick_sched_handle kernel/time/tick-sched.c:167 [inline] > tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 > __run_hrtimer kernel/time/hrtimer.c:1514 [inline] > __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 > hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 > local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] > smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 > apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 > </IRQ> > RIP: 0010:mod_memcg_page_state+0x2b/0x190 include/linux/memcontrol.h:653 > Code: 48 89 e5 41 57 41 56 41 54 53 41 89 f6 48 89 fb e8 da 28 2e 00 48 83 > c3 38 48 89 d8 48 c1 e8 03 49 bc 00 00 00 00 00 fc ff df <42> 80 3c 20 00 > 74 08 48 89 df e8 b6 9f 69 00 48 8b 1b 48 85 db 0f > RSP: 0018:ffffc90001f27998 EFLAGS: 00000a02 ORIG_RAX: ffffffffffffff13 > RAX: 1ffffd40005452bf RBX: ffffea0002a295f8 RCX: ffff88808f094580 > RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea0002a295c0 > RBP: ffffc90001f279b8 R08: dffffc0000000000 R09: fffffbfff1287025 > R10: fffffbfff1287025 R11: 0000000000000000 R12: dffffc0000000000 > R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff8880a8a6f4a8 > free_thread_stack+0x168/0x590 kernel/fork.c:280 > release_task_stack kernel/fork.c:440 [inline] > put_task_stack+0xa3/0x130 kernel/fork.c:451 > finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 > context_switch kernel/sched/core.c:3388 [inline] > __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 > preempt_schedule_common kernel/sched/core.c:4236 [inline] > preempt_schedule+0xdb/0x120 kernel/sched/core.c:4261 > ___preempt_schedule+0x16/0x18 arch/x86/entry/thunk_64.S:50 > __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] > _raw_spin_unlock_irqrestore+0xcc/0xe0 kernel/locking/spinlock.c:191 > spin_unlock_irqrestore include/linux/spinlock.h:393 [inline] > __wake_up_common_lock kernel/sched/wait.c:125 [inline] > __wake_up+0xe1/0x150 kernel/sched/wait.c:142 > pipe_read+0x8e1/0x9e0 fs/pipe.c:374 > call_read_iter include/linux/fs.h:1896 [inline] > new_sync_read fs/read_write.c:414 [inline] > __vfs_read+0x59e/0x730 fs/read_write.c:427 > vfs_read+0x1dd/0x420 fs/read_write.c:461 > ksys_read+0x117/0x220 fs/read_write.c:587 > __do_sys_read fs/read_write.c:597 [inline] > __se_sys_read fs/read_write.c:595 [inline] > __x64_sys_read+0x7b/0x90 fs/read_write.c:595 > do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x414190 > Code: 01 f0 ff ff 0f 83 90 1b 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f > 44 00 00 83 3d dd 42 66 00 00 75 14 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff > ff 0f 83 64 1b 00 00 c3 48 83 ec 08 e8 6a fc ff ff > RSP: 002b:00007fff84902588 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000414190 > RDX: 0000000000000038 RSI: 0000000000758040 RDI: 00000000000000f9 > RBP: 0000000000000002 R08: 00000000000003b8 R09: 0000000000004000 > R10: 0000000000717660 R11: 0000000000000246 R12: 0000000000000000 > R13: 00007fff849025c0 R14: 000000000000e9c4 R15: 00007fff849025d0 > rcu: rcu_preempt kthread starved for 10534 jiffies! g5977 f0x2 > RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 > rcu: RCU grace-period kthread stack dump: > rcu_preempt R running task 29104 10 2 0x80004000 > Call Trace: > context_switch kernel/sched/core.c:3385 [inline] > __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 > schedule+0x181/0x210 kernel/sched/core.c:4155 > schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 > rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] > rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 > kthread+0x332/0x350 kernel/kthread.c:255 > ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 > > > --- > 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. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/000000000000d2a8cc0598c8798f%40google.com.
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