Re: [Qemu-devel] [PATCH for-4.0 v9 16/16] qemu_thread_join: fix segmentation fault

[Markus Armbruster]

Fei Li <address@hidden> writes:

> To avoid the segmentation fault in qemu_thread_join(), just directly
> return when the QemuThread *thread failed to be created in either
> qemu-thread-posix.c or qemu-thread-win32.c.
>
> Cc: Stefan Weil <address@hidden>
> Signed-off-by: Fei Li <address@hidden>
> Reviewed-by: Fam Zheng <address@hidden>
> ---
>  util/qemu-thread-posix.c | 3 +++
>  util/qemu-thread-win32.c | 2 +-
>  2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c
> index 39834b0551..3548935dac 100644
> --- a/util/qemu-thread-posix.c
> +++ b/util/qemu-thread-posix.c
> @@ -571,6 +571,9 @@ void *qemu_thread_join(QemuThread *thread)
>      int err;
>      void *ret;
>  
> +    if (!thread->thread) {
> +        return NULL;
> +    }

How can this happen?

>      err = pthread_join(thread->thread, &ret);
>      if (err) {
>          error_exit(err, __func__);
> diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c
> index 57b1143e97..ca4d5329e3 100644
> --- a/util/qemu-thread-win32.c
> +++ b/util/qemu-thread-win32.c
> @@ -367,7 +367,7 @@ void *qemu_thread_join(QemuThread *thread)
>      HANDLE handle;
>  
>      data = thread->data;
> -    if (data->mode == QEMU_THREAD_DETACHED) {
> +    if (data == NULL || data->mode == QEMU_THREAD_DETACHED) {
>          return NULL;
>      }