[PATCH v2 10/12] ptrace: Only return signr from ptrace_stop if it was provided

[Sebastian Andrzej Siewior]

On 2022-04-29 16:48:35 [-0500], Eric W. Biederman wrote:
> In ptrace_stop a ptrace_unlink or SIGKILL can occur either after
> siglock is dropped or after tasklist_lock is dropped.  At either point
> the result can be that ptrace will continue and not stop at schedule.
> 
> This means that there are cases where the current logic fails to handle
> the fact that ptrace_stop did not actually stop, and can potentially
> cause ptrace_report_syscall to attempt to deliver a signal.
> 
> Instead of attempting to detect in ptrace_stop when it fails to
> stop update ptrace_resume and ptrace_detach to set a flag to indicate
      ,
> that the signal to continue with has be set.   Use that
                                       been
> new flag to decided how to set return signal.
> 
> Signed-off-by: "Eric W. Biederman" <ebiederm at xmission.com>

Sebastian