Kernel: Make Process::start_tracing_from API OOM safe

Modify the API so it's possible to propagate error on OOM failure.
NonnullOwnPtr<T> is not appropriate for the ThreadTracer::create() API,
so switch to OwnPtr<T>, use adopt_own_if_nonnull() to handle creation.

1 files changed, 3 insertions, 1 deletions

diff --git a/Kernel/Syscalls/ptrace.cpp b/Kernel/Syscalls/ptrace.cpp
index f380921834..1b9695f410 100644
--- a/Kernel/Syscalls/ptrace.cpp
+++ b/Kernel/Syscalls/ptrace.cpp
@@ -51,7 +51,9 @@ static KResultOr<u32> handle_ptrace(const Kernel::Syscall::SC_ptrace_params& par
         if (peer_process.tracer()) {
             return EBUSY;
         }
-        peer_process.start_tracing_from(caller.pid());
+        auto result = peer_process.start_tracing_from(caller.pid());
+        if (result.is_error())
+            return result.error();
         ScopedSpinLock lock(peer->get_lock());
         if (peer->state() != Thread::State::Stopped) {
             peer->send_signal(SIGSTOP, &caller);