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Date: Mon, 26 Dec 2016 07:54:08 +0100
From: Mike Galbraith <efault@....de>
To: Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Thomas Gleixner <tglx@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>,
linux-rt-users <linux-rt-users@...r.kernel.org>,
Steven Rostedt <rostedt@...dmis.org>
Subject: [patch-rt] kvm: Convert pvclock_gtod_sync_lock to raw_spinlock_t
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@....de>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/x86.c | 20 ++++++++++----------
2 files changed, 11 insertions(+), 11 deletions(-)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -755,7 +755,7 @@ 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;
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1540,7 +1540,7 @@ 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) {
@@ -1548,7 +1548,7 @@ 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);
@@ -1715,7 +1715,7 @@ 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);
@@ -1727,7 +1727,7 @@ 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
}
@@ -1736,15 +1736,15 @@ static u64 __get_kvmclock_ns(struct kvm
struct kvm_arch *ka = &kvm->arch;
struct pvclock_vcpu_time_info hv_clock;
- 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);
kvm_get_time_scale(NSEC_PER_SEC, __this_cpu_read(cpu_tsc_khz) * 1000LL,
&hv_clock.tsc_shift,
@@ -1835,13 +1835,13 @@ 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);
@@ -7831,7 +7831,7 @@ 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);
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