[PATCH] qemu: segmentation fault in virtqemud executing qemuDomainUndefineFlags

[Jim Fehlig]

On 3/1/22 10:47, Boris Fiuczynski wrote:
> Commit 5adfb3472342741c443ac91dee0abb18b5a3d038 causes a segmentation fault.
> 
> Stack trace of thread 664419:
>   #0  0x000003ff62ec553c in qemuDomainUndefineFlags (dom=0x3ff6c002810, flags=<optimized out>) at ../src/qemu/qemu_driver.c:6618
>   #1  0x000003ff876a7e5c in virDomainUndefineFlags (domain=domain at entry=0x3ff6c002810, flags=<optimized out>) at ../src/libvirt-domain.c:6519
>   #2  0x000002aa2b64a808 in remoteDispatchDomainUndefineFlags (server=0x2aa2c3d7880, msg=0x2aa2c3d2770, args=<optimized out>, rerr=0x3ff8287b950, client=<optimized out>)
>          at src/remote/remote_daemon_dispatch_stubs.h:13080
>   #3  remoteDispatchDomainUndefineFlagsHelper (server=0x2aa2c3d7880, client=<optimized out>, msg=0x2aa2c3d2770, rerr=0x3ff8287b950, args=<optimized out>, ret=0x0)
>          at src/remote/remote_daemon_dispatch_stubs.h:13059
>   #4  0x000003ff8758bbf4 in virNetServerProgramDispatchCall (msg=0x2aa2c3d2770, client=0x2aa2c3e3050, server=0x2aa2c3d7880, prog=0x2aa2c3d8010)
>          at ../src/rpc/virnetserverprogram.c:428
>   #5  virNetServerProgramDispatch (prog=0x2aa2c3d8010, server=server at entry=0x2aa2c3d7880, client=0x2aa2c3e3050, msg=0x2aa2c3d2770) at ../src/rpc/virnetserverprogram.c:302
>   #6  0x000003ff8758c260 in virNetServerProcessMsg (msg=<optimized out>, prog=<optimized out>, client=<optimized out>, srv=0x2aa2c3d7880) at ../src/rpc/virnetserver.c:140
>   #7  virNetServerHandleJob (jobOpaque=0x2aa2c3e2d30, opaque=0x2aa2c3d7880) at ../src/rpc/virnetserver.c:160
>   #8  0x000003ff874c49aa in virThreadPoolWorker (opaque=<optimized out>) at ../src/util/virthreadpool.c:164
>   #9  0x000003ff874c3f62 in virThreadHelper (data=<optimized out>) at ../src/util/virthread.c:256
>   #10 0x000003ff86c1cf8c in start_thread () from /lib64/libc.so.6
>   #11 0x000003ff86c9650e in thread_start () from /lib64/libc.so.6

libvirt-tck encountered the same segfault in my test environment.

> Signed-off-by: Boris Fiuczynski <fiuczy at linux.ibm.com>
> ---
>   src/qemu/qemu_driver.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Jim Fehlig <jfehlig at suse.com>

Regards,
Jim

> 
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index b74b0375a7..18f1156862 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -6615,7 +6615,7 @@ qemuDomainUndefineFlags(virDomainPtr dom,
>           }
>       }
>   
> -    if (vm->def->os.loader->nvram) {
> +    if (vm->def->os.loader && vm->def->os.loader->nvram) {
>           nvram_path = g_strdup(vm->def->os.loader->nvram);
>       } else if (vm->def->os.firmware == VIR_DOMAIN_OS_DEF_FIRMWARE_EFI) {
>           qemuDomainNVRAMPathFormat(cfg, vm->def, &nvram_path);