Re: [PATCH 0/2] wait/ptrace: always assume __WALL if the child is traced

From: Oleg Nesterov
Date: Sun Oct 25 2015 - 10:46:42 EST


On 10/22, Pedro Alves wrote:
>
> In any case, to make sure existing gdb binaries would still work
> with your kernel change, I ran GDB's testsuite with this:
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> diff --git a/gdb/nat/linux-waitpid.c b/gdb/nat/linux-waitpid.c
> index cbcdd95..864ba2e 100644
> --- a/gdb/nat/linux-waitpid.c
> +++ b/gdb/nat/linux-waitpid.c
> @@ -149,3 +149,17 @@ my_waitpid (int pid, int *status, int flags)
> errno = out_errno;
> return ret;
> }
> +
> +#include <dlfcn.h>
> +
> +pid_t
> +waitpid (pid_t pid, int *status, int options)
> +{
> + static pid_t (*waitpid2) (pid_t pid, int *status, int options) = NULL;
> +
> + if (waitpid2 == NULL)
> + waitpid2 = dlsym (RTLD_NEXT, "waitpid");
> +
> + options |= __WALL;
> + return waitpid2 (pid, status, options);
> +}
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Thanks a lot Pedro!

So gdb should be fine, strace too. Perhaps we should change the kernel
this way and forget about /sbin/init fixes.

Oleg.

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