KVM: PPC: Book3S HV: Fix lockdep warning when entering the guest
The trace_hardirqs_on() sets current->hardirqs_enabled and from here
the lockdep assumes interrupts are enabled although they are remain
disabled until the context switches to the guest. Consequent
srcu_read_lock() checks the flags in rcu_lock_acquire(), observes
disabled interrupts and prints a warning (see below).
This moves trace_hardirqs_on/off closer to __kvmppc_vcore_entry to
prevent lockdep from being confused.
DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)
WARNING: CPU: 16 PID: 8038 at kernel/locking/lockdep.c:4128 check_flags.part.25+0x224/0x280
[...]
NIP [
c000000000185b84] check_flags.part.25+0x224/0x280
LR [
c000000000185b80] check_flags.part.25+0x220/0x280
Call Trace:
[
c000003fec253710] [
c000000000185b80] check_flags.part.25+0x220/0x280 (unreliable)
[
c000003fec253780] [
c000000000187ea4] lock_acquire+0x94/0x260
[
c000003fec253840] [
c00800001a1e9768] kvmppc_run_core+0xa60/0x1ab0 [kvm_hv]
[
c000003fec253a10] [
c00800001a1ed944] kvmppc_vcpu_run_hv+0x73c/0xec0 [kvm_hv]
[
c000003fec253ae0] [
c00800001a1095dc] kvmppc_vcpu_run+0x34/0x48 [kvm]
[
c000003fec253b00] [
c00800001a1056bc] kvm_arch_vcpu_ioctl_run+0x2f4/0x400 [kvm]
[
c000003fec253b90] [
c00800001a0f3618] kvm_vcpu_ioctl+0x460/0x850 [kvm]
[
c000003fec253d00] [
c00000000041c4f4] do_vfs_ioctl+0xe4/0x930
[
c000003fec253db0] [
c00000000041ce04] ksys_ioctl+0xc4/0x110
[
c000003fec253e00] [
c00000000041ce78] sys_ioctl+0x28/0x80
[
c000003fec253e20] [
c00000000000b5a4] system_call+0x5c/0x70
Instruction dump:
419e0034 3d220004 39291730 81290000 2f890000 409e0020 3c82ffc6 3c62ffc5
3884be70 386329c0 4bf6ea71 60000000 <
0fe00000>
3c62ffc6 3863be90 4801273d
irq event stamp: 1025
hardirqs last enabled at (1025): [<
c00800001a1e9728>] kvmppc_run_core+0xa20/0x1ab0 [kvm_hv]
hardirqs last disabled at (1024): [<
c00800001a1e9358>] kvmppc_run_core+0x650/0x1ab0 [kvm_hv]
softirqs last enabled at (0): [<
c0000000000f1210>] copy_process.isra.4.part.5+0x5f0/0x1d00
softirqs last disabled at (0): [<
0000000000000000>] (null)
---[ end trace
31180adcc848993e ]---
possible reason: unannotated irqs-off.
irq event stamp: 1025
hardirqs last enabled at (1025): [<
c00800001a1e9728>] kvmppc_run_core+0xa20/0x1ab0 [kvm_hv]
hardirqs last disabled at (1024): [<
c00800001a1e9358>] kvmppc_run_core+0x650/0x1ab0 [kvm_hv]
softirqs last enabled at (0): [<
c0000000000f1210>] copy_process.isra.4.part.5+0x5f0/0x1d00
softirqs last disabled at (0): [<
0000000000000000>] (null)
Fixes:
8b24e69fc47e ("KVM: PPC: Book3S HV: Close race with testing for signals on guest entry", 2017-06-26)
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>