[PATCH v2] arm64: ptrace: don't warn on missing siginfo in a group-stop

[Oleg Nesterov]

On 11/02, Zhao Gongyi wrote:
>
> Hi Jinjie,
>
>
> On 11/2/26 3:54 PM, Jinjie Ruan wrote:
> >
> > I think maybe we can refer to ptrace_get_syscall_info_op()?
> >
>
> Thanks for the suggestion.
>
> I checked ptrace_get_syscall_info_op(). It is currently static to
> kernel/ptrace.c and identifies a syscall stop only when
> last_siginfo->si_code is SIGTRAP | 0x80.
>
> The arm64 path here also needs to handle a syscall-exit-stop when the
> tracer has not enabled PTRACE_O_TRACESYSGOOD. In that case, the tested

Yes, PTRACE_GET_SYSCALL_INFO/etc depends on PTRACE_O_TRACESYSGOOD
by design, this is even documented in man 2 ptrace.

> For this patch, I think
> the local check of last_siginfo, with bit 0x80 masked and ptrace_message
> checked for PTRACE_EVENTMSG_SYSCALL_EXIT, is the smaller and safer change.

Agreed.

Oleg.