My fuzz tester keeps hitting this. Every instance shows the non-irq stack came in from mlockall. I'm only seeing this on one box, but that has more ram (8gb) than my other machines, which might explain it. Dave INFO: rcu_preempt self-detected stall on CPU { 3} (t=6500 jiffies g=470344 c=470343 q=0) sending NMI to all CPUs: NMI backtrace for cpu 3 CPU: 3 PID: 29664 Comm: trinity-child2 Not tainted 3.11.0-rc1+ #32 task: ffff88023e743fc0 ti: ffff88022f6f2000 task.ti: ffff88022f6f2000 RIP: 0010:[<ffffffff810bf7d1>] [<ffffffff810bf7d1>] trace_hardirqs_off_caller+0x21/0xb0 RSP: 0018:ffff880244e03c30 EFLAGS: 00000046 RAX: ffff88023e743fc0 RBX: 0000000000000001 RCX: 000000000000003c RDX: 000000000000000f RSI: 0000000000000004 RDI: ffffffff81033cab RBP: ffff880244e03c38 R08: ffff880243288a80 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: ffff880243288a80 R13: ffff8802437eda40 R14: 0000000000080000 R15: 000000000000d010 FS: 00007f50ae33b740(0000) GS:ffff880244e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000097f000 CR3: 0000000240fa0000 CR4: 00000000001407e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Stack: ffffffff810bf86d ffff880244e03c98 ffffffff81033cab 0000000000000096 000000000000d008 0000000300000002 0000000000000004 0000000000000003 0000000000002710 ffffffff81c50d00 ffffffff81c50d00 ffff880244fcde00 Call Trace: <IRQ> [<ffffffff810bf86d>] ? trace_hardirqs_off+0xd/0x10 [<ffffffff81033cab>] __x2apic_send_IPI_mask+0x1ab/0x1c0 [<ffffffff81033cdc>] x2apic_send_IPI_all+0x1c/0x20 [<ffffffff81030115>] arch_trigger_all_cpu_backtrace+0x65/0xa0 [<ffffffff811144b1>] rcu_check_callbacks+0x331/0x8e0 [<ffffffff8108bfa0>] ? hrtimer_run_queues+0x20/0x180 [<ffffffff8109e905>] ? sched_clock_cpu+0xb5/0x100 [<ffffffff81069557>] update_process_times+0x47/0x80 [<ffffffff810bd115>] tick_sched_handle.isra.16+0x25/0x60 [<ffffffff810bd231>] tick_sched_timer+0x41/0x60 [<ffffffff8108ace1>] __run_hrtimer+0x81/0x4e0 [<ffffffff810bd1f0>] ? tick_sched_do_timer+0x60/0x60 [<ffffffff8108b93f>] hrtimer_interrupt+0xff/0x240 [<ffffffff8102de84>] local_apic_timer_interrupt+0x34/0x60 [<ffffffff81718c5f>] smp_apic_timer_interrupt+0x3f/0x60 [<ffffffff817178ef>] apic_timer_interrupt+0x6f/0x80 [<ffffffff8170e8e0>] ? retint_restore_args+0xe/0xe [<ffffffff8105f101>] ? __do_softirq+0xb1/0x440 [<ffffffff8105f64d>] irq_exit+0xcd/0xe0 [<ffffffff81718c65>] smp_apic_timer_interrupt+0x45/0x60 [<ffffffff817178ef>] apic_timer_interrupt+0x6f/0x80 <EOI> [<ffffffff8170e8e0>] ? retint_restore_args+0xe/0xe [<ffffffff8170b830>] ? wait_for_completion_killable+0x170/0x170 [<ffffffff8170c853>] ? preempt_schedule_irq+0x53/0x90 [<ffffffff8170e9f6>] retint_kernel+0x26/0x30 [<ffffffff8107a523>] ? queue_work_on+0x43/0x90 [<ffffffff8107c369>] schedule_on_each_cpu+0xc9/0x1a0 [<ffffffff81167770>] ? lru_add_drain+0x50/0x50 [<ffffffff811677c5>] lru_add_drain_all+0x15/0x20 [<ffffffff81186965>] SyS_mlockall+0xa5/0x1a0 [<ffffffff81716e94>] tracesys+0xdd/0xe2 Code: 5d c3 0f 1f 84 00 00 00 00 00 44 8b 1d 29 73 bd 00 65 48 8b 04 25 00 ba 00 00 45 85 db 74 69 44 8b 90 a4 06 00 00 45 85 d2 75 5d <44> 8b 0d a0 47 00 01 45 85 c9 74 33 44 8b 80 70 06 00 00 45 85 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>