Fix splat below. Lock is short hold, make it raw. [15528.614216] BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:995 [15528.614218] in_atomic(): 0, irqs_disabled(): 1, pid: 19619, name: qemu-system-x86 [15528.614218] no locks held by qemu-system-x86/19619. [15528.614219] irq event stamp: 321840 [15528.614224] hardirqs last enabled at (321839): [<ffffffff816a8467>] entry_SYSCALL_64_fastpath+0x5/0xc2 [15528.614244] hardirqs last disabled at (321840): [<ffffffffa08578f4>] kvm_arch_vm_ioctl+0x234/0xda0 [kvm] [15528.614246] softirqs last enabled at (0): [<ffffffff81077e8a>] copy_process.part.36+0x5ba/0x20b0 [15528.614247] softirqs last disabled at (0): [< (null)>] (null) [15528.614250] CPU: 7 PID: 19619 Comm: qemu-system-x86 Tainted: G E 4.9.0-rt1-virgin #1 [15528.614250] Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.20C 09/23/2013 [15528.614253] ffffc9000b98bc30 ffffffff8136874d 0000000000000000 ffff8803e76db200 [15528.614255] ffffc9000b98bc68 ffffffff810abe9d ffff8800353472d0 ffff8800353472d0 [15528.614257] 00007ffc53dbc2b0 000000000000000b 00007ffc53dbc2b0 ffffc9000b98bc88 [15528.614257] Call Trace: [15528.614262] [<ffffffff8136874d>] dump_stack+0x85/0xc8 [15528.614266] [<ffffffff810abe9d>] ___might_sleep+0x15d/0x260 [15528.614268] [<ffffffff816a7ca4>] rt_spin_lock+0x24/0x80 [15528.614283] [<ffffffffa084b212>] __get_kvmclock_ns+0x22/0xf0 [kvm] [15528.614297] [<ffffffffa08578fc>] kvm_arch_vm_ioctl+0x23c/0xda0 [kvm] [15528.614300] [<ffffffff810dc5d5>] ? __lock_acquire+0x305/0x16a0 [15528.614301] [<ffffffff8107d916>] ? unpin_current_cpu+0x16/0x70 [15528.614314] [<ffffffffa08409dd>] kvm_vm_ioctl+0x9d/0x920 [kvm] [15528.614316] [<ffffffff8127b547>] ? __fget+0x107/0x220 [15528.614318] [<ffffffff810da5f9>] ? __lock_is_held+0x49/0x70 [15528.614320] [<ffffffff8126e9b6>] do_vfs_ioctl+0x96/0x6c0 [15528.614321] [<ffffffff8127b564>] ? __fget+0x124/0x220 [15528.614322] [<ffffffff8127b445>] ? __fget+0x5/0x220 [15528.614324] [<ffffffff8126f021>] SyS_ioctl+0x41/0x70 [15528.614326] [<ffffffff816a8481>] entry_SYSCALL_64_fastpath+0x1f/0xc2 Signed-off-by: Mike Galbraith <efault@gmx.de> --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/x86.c | 20 ++++++++++---------- 2 files changed, 11 insertions(+), 11 deletions(-) Index: linux-4.9.20-rt16/arch/x86/include/asm/kvm_host.h =================================================================== @ linux-4.9.20-rt16/arch/x86/include/asm/kvm_host.h:758 @ struct kvm_arch { u64 cur_tsc_generation; int nr_vcpus_matched_tsc; - spinlock_t pvclock_gtod_sync_lock; + raw_spinlock_t pvclock_gtod_sync_lock; bool use_master_clock; u64 master_kernel_ns; cycle_t master_cycle_now; Index: linux-4.9.20-rt16/arch/x86/kvm/x86.c =================================================================== --- linux-4.9.20-rt16.orig/arch/x86/kvm/x86.c +++ linux-4.9.20-rt16/arch/x86/kvm/x86.c @ linux-4.9.20-rt16/arch/x86/include/asm/kvm_host.h:1543 @ void kvm_write_tsc(struct kvm_vcpu *vcpu kvm_vcpu_write_tsc_offset(vcpu, offset); raw_spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags); - spin_lock(&kvm->arch.pvclock_gtod_sync_lock); + raw_spin_lock(&kvm->arch.pvclock_gtod_sync_lock); if (!matched) { kvm->arch.nr_vcpus_matched_tsc = 0; } else if (!already_matched) { @ linux-4.9.20-rt16/arch/x86/include/asm/kvm_host.h:1551 @ void kvm_write_tsc(struct kvm_vcpu *vcpu } kvm_track_tsc_matching(vcpu); - spin_unlock(&kvm->arch.pvclock_gtod_sync_lock); + raw_spin_unlock(&kvm->arch.pvclock_gtod_sync_lock); } EXPORT_SYMBOL_GPL(kvm_write_tsc); @ linux-4.9.20-rt16/arch/x86/include/asm/kvm_host.h:1718 @ static void kvm_gen_update_masterclock(s struct kvm_vcpu *vcpu; struct kvm_arch *ka = &kvm->arch; - spin_lock(&ka->pvclock_gtod_sync_lock); + raw_spin_lock(&ka->pvclock_gtod_sync_lock); kvm_make_mclock_inprogress_request(kvm); /* no guest entries from this point */ pvclock_update_vm_gtod_copy(kvm); @ linux-4.9.20-rt16/arch/x86/include/asm/kvm_host.h:1730 @ static void kvm_gen_update_masterclock(s kvm_for_each_vcpu(i, vcpu, kvm) clear_bit(KVM_REQ_MCLOCK_INPROGRESS, &vcpu->requests); - spin_unlock(&ka->pvclock_gtod_sync_lock); + raw_spin_unlock(&ka->pvclock_gtod_sync_lock); #endif } @ linux-4.9.20-rt16/arch/x86/include/asm/kvm_host.h:1740 @ static u64 __get_kvmclock_ns(struct kvm struct pvclock_vcpu_time_info hv_clock; u64 ret; - spin_lock(&ka->pvclock_gtod_sync_lock); + raw_spin_lock(&ka->pvclock_gtod_sync_lock); if (!ka->use_master_clock) { - spin_unlock(&ka->pvclock_gtod_sync_lock); + raw_spin_unlock(&ka->pvclock_gtod_sync_lock); return ktime_get_boot_ns() + ka->kvmclock_offset; } hv_clock.tsc_timestamp = ka->master_cycle_now; hv_clock.system_time = ka->master_kernel_ns + ka->kvmclock_offset; - spin_unlock(&ka->pvclock_gtod_sync_lock); + raw_spin_unlock(&ka->pvclock_gtod_sync_lock); /* both __this_cpu_read() and rdtsc() should be on the same cpu */ get_cpu(); @ linux-4.9.20-rt16/arch/x86/include/asm/kvm_host.h:1846 @ static int kvm_guest_time_update(struct * If the host uses TSC clock, then passthrough TSC as stable * to the guest. */ - spin_lock(&ka->pvclock_gtod_sync_lock); + raw_spin_lock(&ka->pvclock_gtod_sync_lock); use_master_clock = ka->use_master_clock; if (use_master_clock) { host_tsc = ka->master_cycle_now; kernel_ns = ka->master_kernel_ns; } - spin_unlock(&ka->pvclock_gtod_sync_lock); + raw_spin_unlock(&ka->pvclock_gtod_sync_lock); /* Keep irq disabled to prevent changes to the clock */ local_irq_save(flags); @ linux-4.9.20-rt16/arch/x86/include/asm/kvm_host.h:7886 @ int kvm_arch_init_vm(struct kvm *kvm, un raw_spin_lock_init(&kvm->arch.tsc_write_lock); mutex_init(&kvm->arch.apic_map_lock); - spin_lock_init(&kvm->arch.pvclock_gtod_sync_lock); + raw_spin_lock_init(&kvm->arch.pvclock_gtod_sync_lock); kvm->arch.kvmclock_offset = -ktime_get_boot_ns(); pvclock_update_vm_gtod_copy(kvm);