Re: [Qemu-devel] [PATCH] linux-user: fix fork()

[Peter Maydell]

On 16 February 2017 at 17:37, Laurent Vivier <address@hidden> wrote:
> Since commit 5ea2fc8 ("linux-user: Sanity check clone flags"),
> trying to run fork() fails with old distro on some architectures.
>
> This is the case with HP-PA and Debian 5 (Lenny).
>
> It fails on:
>
>          if ((flags & CSIGNAL) != TARGET_SIGCHLD) {
>              return -TARGET_EINVAL;
>          }
>
> because flags is 17, whereas on HP-PA, SIGCHLD is 18.
> 17 is the SIGCHLD value of my host (x86_64).
>
> It appears that for TARGET_NR_fork and TARGET_NR_vfork, QEMU calls
> do_fork() with SIGCHLD instead of TARGET_SIGCHLD.
>
> Signed-off-by: Laurent Vivier <address@hidden>
> ---
>  linux-user/syscall.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index f569f82..4d85355 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -7680,7 +7680,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long 
> arg1,
>          break;
>  #ifdef TARGET_NR_fork
>      case TARGET_NR_fork:
> -        ret = get_errno(do_fork(cpu_env, SIGCHLD, 0, 0, 0, 0));
> +        ret = get_errno(do_fork(cpu_env, TARGET_SIGCHLD, 0, 0, 0, 0));
>          break;
>  #endif
>  #ifdef TARGET_NR_waitpid
> @@ -10490,7 +10490,8 @@ abi_long do_syscall(void *cpu_env, int num, abi_long 
> arg1,
>  #endif
>  #ifdef TARGET_NR_vfork
>      case TARGET_NR_vfork:
> -        ret = get_errno(do_fork(cpu_env, CLONE_VFORK | CLONE_VM | SIGCHLD,
> +        ret = get_errno(do_fork(cpu_env,
> +                        CLONE_VFORK | CLONE_VM | TARGET_SIGCHLD,
>                          0, 0, 0, 0));
>          break;
>  #endif

Reviewed-by: Peter Maydell <address@hidden>

thanks
-- PMM