Hi, Commit 1c3c5ea "sched/core: Enable might_sleep() and smp_processor_id() checks early" seem to have uncovered an issue with amd-iommu/x2apic.
Starting with that commit the following warning started to show up on AMD systems during boot: [ 0.140480] smpboot: Max logical packages: 6 [ 0.160000] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:747 [ 0.160000] in_atomic(): 0, irqs_disabled(): 1, pid: 1, name: swapper/0 [ 0.160000] no locks held by swapper/0/1. [ 0.160000] irq event stamp: 304 [ 0.160000] hardirqs last enabled at (303): [<ffffffff818a87b6>] _raw_spin_unlock_irqrestore+0x36/0x60 [ 0.160000] hardirqs last disabled at (304): [<ffffffff8235d440>] enable_IR_x2apic+0x79/0x196 [ 0.160000] softirqs last enabled at (36): [<ffffffff818ae75f>] __do_softirq+0x35f/0x4ec [ 0.160000] softirqs last disabled at (31): [<ffffffff810c1955>] irq_exit+0x105/0x120 [ 0.160000] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.13.0-rc2.1.el7a.test.x86_64.debug #1 [ 0.160000] Hardware name: PowerEdge C6145 /040N24, BIOS 3.5.0 10/28/2014 [ 0.160000] Call Trace: [ 0.160000] dump_stack+0x85/0xca [ 0.160000] ___might_sleep+0x22a/0x260 [ 0.160000] __might_sleep+0x4a/0x80 [ 0.160000] __mutex_lock+0x58/0x960 [ 0.160000] ? iommu_completion_wait.part.17+0xb5/0x160 [ 0.160000] ? register_syscore_ops+0x1d/0x70 [ 0.160000] ? iommu_flush_all_caches+0x120/0x150 [ 0.160000] mutex_lock_nested+0x1b/0x20 [ 0.160000] register_syscore_ops+0x1d/0x70 [ 0.160000] state_next+0x119/0x910 [ 0.160000] iommu_go_to_state+0x29/0x30 [ 0.160000] amd_iommu_enable+0x13/0x23 [ 0.160000] irq_remapping_enable+0x1b/0x39 [ 0.160000] enable_IR_x2apic+0x91/0x196 [ 0.160000] default_setup_apic_routing+0x16/0x6e [ 0.160000] native_smp_prepare_cpus+0x257/0x2d5 [ 0.160000] kernel_init_freeable+0x131/0x2a7 [ 0.160000] ? kernel_init+0xe/0x104 [ 0.160000] ? _raw_spin_unlock_irq+0x2c/0x40 [ 0.160000] ? rest_init+0xe0/0xe0 [ 0.160000] kernel_init+0xe/0x104 [ 0.160000] ret_from_fork+0x2a/0x40 [ 0.160010] Switched APIC routing to physical flat. -- Regards, Artem