Re: [cip-dev] [PATCH RESEND 4.19.y-cip] signal/m68k: Use force_sigsegv(SIGSEGV) in fpsp040_die

[Ulrich Hecht <uli@fpond.eu>]

> On 05/16/2025 11:28 AM CEST Finn Thain <fthain@linux-m68k.org> wrote:
> 
>  
> From: "Eric W. Biederman" <ebiederm@xmission.com>
> 
> [ Upstream commit a3616a3c02722d1edb95acc7fceade242f6553ba ]
> 
> In the fpsp040 code when copyin or copyout fails call
> force_sigsegv(SIGSEGV) instead of do_exit(SIGSEGV).
> 
> This solves a couple of problems.  Because do_exit embeds the ptrace
> stop PTRACE_EVENT_EXIT a complete stack frame needs to be present for
> that to work correctly.  There is always the information needed for a
> ptrace stop where get_signal is called.  So exiting with a signal
> solves the ptrace issue.
> 
> Further exiting with a signal ensures that all of the threads in a
> process are killed not just the thread that malfunctioned.  Which
> avoids confusing userspace.
> 
> To make force_sigsegv(SIGSEGV) work in fpsp040_die modify the code to
> save all of the registers and jump to ret_from_exception (which
> ultimately calls get_signal) after fpsp040_die returns.
> 
> v2: Updated the branches to use gas's pseudo ops that automatically
>     calculate the best branch instruction to use for the purpose.
> 
> v1: https://lkml.kernel.org/r/87a6m8kgtx.fsf_-_@disp2133
> Link: https://lkml.kernel.org/r/87tukghjfs.fsf_-_@disp2133
> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
> [ Pass 'current' to force_sigsegv() as was done prior to v5.3 ]
> Signed-off-by: Finn Thain <fthain@linux-m68k.org>

Thanks, applied for the next 4.19.
Please CC me for 4.4 and 4.19 patches in the future.

CU
Uli