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| author | Will Deacon <will.deacon@arm.com> | 2015-11-05 18:33:00 +0000 |
|---|---|---|
| committer | Will Deacon <will.deacon@arm.com> | 2015-11-05 18:35:13 +0000 |
| commit | 2aa76b2616bcace1d668a879d834679dfa00dc8c (patch) | |
| tree | 7a7829f06ee5830de2e8c202381438433b80d4d8 /include | |
| parent | 3ce000c5f3a8341fe190883f43dd9bd6cf15a2e7 (diff) | |
| download | kvmtool-2aa76b2616bcace1d668a879d834679dfa00dc8c.tar.gz | |
kvmtool: fix VM exit race attempting to pthread_kill an exited thread
lkvm currently suffers from a Segmentation Fault when exiting, which can
also lead to the console not being cleaned up correctly after a VM exits.
The issue is that (the misnamed) kvm_cpu__reboot function sends a
SIGKVMEXIT to each vcpu thread, which causes those vcpu threads to exit
once their main loops (kvm_cpu__start) detect that cpu->is_running is
now false. The lack of synchronisation in this exit path means that a
concurrent pause event (due to the br_write_lock in ioport__unregister)
ends up sending SIGKVMPAUSE to an exited thread, resulting in a SEGV.
This patch fixes the issue by moving kvm_cpu__reboot into kvm.c
(renaming it in the process) where it can hold the pause_lock mutex
across the reboot operation. This in turn makes it safe for the pause
code to check the is_running field of each CPU before attempting to
send a SIGKVMPAUSE signal.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/kvm/kvm-cpu.h | 1 | ||||
| -rw-r--r-- | include/kvm/kvm.h | 1 |
2 files changed, 1 insertions, 1 deletions
diff --git a/include/kvm/kvm-cpu.h b/include/kvm/kvm-cpu.h index aa0cb543..c4c9cca4 100644 --- a/include/kvm/kvm-cpu.h +++ b/include/kvm/kvm-cpu.h @@ -12,7 +12,6 @@ void kvm_cpu__reset_vcpu(struct kvm_cpu *vcpu); void kvm_cpu__setup_cpuid(struct kvm_cpu *vcpu); void kvm_cpu__enable_singlestep(struct kvm_cpu *vcpu); void kvm_cpu__run(struct kvm_cpu *vcpu); -void kvm_cpu__reboot(struct kvm *kvm); int kvm_cpu__start(struct kvm_cpu *cpu); bool kvm_cpu__handle_exit(struct kvm_cpu *vcpu); int kvm_cpu__get_endianness(struct kvm_cpu *vcpu); diff --git a/include/kvm/kvm.h b/include/kvm/kvm.h index 37155dbc..a474dae6 100644 --- a/include/kvm/kvm.h +++ b/include/kvm/kvm.h @@ -93,6 +93,7 @@ int kvm__register_mmio(struct kvm *kvm, u64 phys_addr, u64 phys_addr_len, bool c void (*mmio_fn)(struct kvm_cpu *vcpu, u64 addr, u8 *data, u32 len, u8 is_write, void *ptr), void *ptr); bool kvm__deregister_mmio(struct kvm *kvm, u64 phys_addr); +void kvm__reboot(struct kvm *kvm); void kvm__pause(struct kvm *kvm); void kvm__continue(struct kvm *kvm); void kvm__notify_paused(void); |