ARM: Call syscall_trace_exit even when system call skipped

On Mon, Oct 08, 2018 at 11:08:16AM -0700, Kees Cook wrote:

On Mon, Oct 8, 2018 at 4:00 AM, Eugene Syromyatnikov [off-list ref] wrote:

quoted

From: Timothy E Baldwin <redacted>

On at least x86 and ARM64, and as documented in the ptrace man page
a skipped system call will still cause a syscall exit ptrace stop.

Previous to this commit 32-bit ARM did not, resulting in strace
being confused when seccomp skips system calls.

This change also impacts programs that use ptrace to skip system calls.

Fixes: ad75b51459ae ("ARM: 7579/1: arch/allow a scno of -1 to not cause a SIGILL")
Signed-off-by: Timothy E Baldwin <redacted>
Signed-off-by: Eugene Syromyatnikov <redacted>
Reviewed-by: Kees Cook <redacted>
Tested-by: Kees Cook <redacted>
Tested-by: Eugene Syromyatnikov <redacted>
---
KernelVersion: 4.19-rc7

Did this actually make it into the patch tracker? I don't see it in Incoming...

No, rejected at SMTP time (so bounced) due to it being sent from a
gmail.com address but _not_ going through gmail servers (so no DKIM
signature.)  Hence, looks like all the other fake gmail crud and gets
rejected outright.

I guess if Eugene didn't get the bounce notification, then gmail
decided to discard that as fake too!

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