On Wed, Jan 22, 2025 at 2:59 PM Vitalii Mordan <mor...@ispras.ru> wrote:
>
> This patch addresses a potential data race involving the global variable
> goflag in the rcutorture test. The issue is resolved by adding the atomic
> qualifier to ensure proper synchronization.
Hello!
QEMU does not use _Atomic; in general, the C11 committee decision to
default to sequentially consistent atomics is a bad idea and we prefer
to annotate _accesses_ rather than _variables_ (yes, I'm aware that
volatile has the same issue!).
Can you redo the patch to access goflag with qatomic_read and qatomic_set?
Paolo
> Fixes: 8fda74a52b ("rcu: add rcutorture")
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2750
> Signed-off-by: Vitalii Mordan <mor...@ispras.ru>
> ---
> tests/unit/rcutorture.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tests/unit/rcutorture.c b/tests/unit/rcutorture.c
> index 7662081683..c4971632f8 100644
> --- a/tests/unit/rcutorture.c
> +++ b/tests/unit/rcutorture.c
> @@ -70,7 +70,7 @@ int nthreadsrunning;
> #define GOFLAG_RUN 1
> #define GOFLAG_STOP 2
>
> -static volatile int goflag = GOFLAG_INIT;
> +static _Atomic int goflag = GOFLAG_INIT;
>
> #define RCU_READ_RUN 1000
>
> --
> 2.34.1
>
