From fe6bda58e083ec8ffa5c5166e3b1055501b6318a Mon Sep 17 00:00:00 2001 From: Gavin Shan Date: Mon, 31 Jul 2023 22:59:46 +1000 Subject: kvm: Fix crash due to access uninitialized kvm_state MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Runs into core dump on arm64 and the backtrace extracted from the core dump is shown as below. It's caused by accessing uninitialized @kvm_state in kvm_flush_coalesced_mmio_buffer() due to commit 176d073029 ("hw/arm/virt: Use machine_memory_devices_init()"), where the machine's memory region is added earlier than before. main qemu_init configure_accelerators qemu_opts_foreach do_configure_accelerator accel_init_machine kvm_init virt_kvm_type virt_set_memmap machine_memory_devices_init memory_region_add_subregion memory_region_add_subregion_common memory_region_update_container_subregions memory_region_transaction_begin qemu_flush_coalesced_mmio_buffer kvm_flush_coalesced_mmio_buffer Fix it by bailing early in kvm_flush_coalesced_mmio_buffer() on the uninitialized @kvm_state. With this applied, no crash is observed on arm64. Fixes: 176d073029 ("hw/arm/virt: Use machine_memory_devices_init()") Signed-off-by: Gavin Shan Reviewed-by: David Hildenbrand Reviewed-by: Philippe Mathieu-Daudé Message-id: 20230731125946.2038742-1-gshan@redhat.com Signed-off-by: Peter Maydell --- accel/kvm/kvm-all.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'accel') diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 373d876c05..7b3da8dc3a 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -2812,7 +2812,7 @@ void kvm_flush_coalesced_mmio_buffer(void) { KVMState *s = kvm_state; - if (s->coalesced_flush_in_progress) { + if (!s || s->coalesced_flush_in_progress) { return; } -- cgit v1.2.3