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R. Silva" , linux-kernel@vger.kernel.org (open list:TRACING), linux-hardening@vger.kernel.org (open list:KERNEL HARDENING (not covered by other areas):Keyword:\b__counted_by(_le|_be|_ptr)?\b) Subject: [PATCH] tracing: Use flexible array for entry fetch code Date: Wed, 20 May 2026 14:58:17 -0700 Message-ID: <20260520215817.16560-1-rosenp@gmail.com> X-Mailer: git-send-email 2.54.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Store probe entry fetch instructions in the probe_entry_arg allocation instead of allocating a separate instruction array. This keeps the entry fetch code tied to the entry argument lifetime while leaving regular probe_arg instruction arrays separately allocated and freed. Assisted-by: Codex:GPT-5.5 Signed-off-by: Rosen Penev --- kernel/trace/trace_probe.c | 8 +------- kernel/trace/trace_probe.h | 2 +- 2 files changed, 2 insertions(+), 8 deletions(-) diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index e0d3a0da26af..39f040c863e8 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -838,15 +838,10 @@ static int __store_entry_arg(struct trace_probe *tp, = int argnum) int i, offset, last_offset =3D 0; =20 if (!earg) { - earg =3D kzalloc_obj(*tp->entry_arg); + earg =3D kzalloc_flex(*earg, code, 2 * tp->nr_args + 1); if (!earg) return -ENOMEM; earg->size =3D 2 * tp->nr_args + 1; - earg->code =3D kzalloc_objs(struct fetch_insn, earg->size); - if (!earg->code) { - kfree(earg); - return -ENOMEM; - } /* Fill the code buffer with 'end' to simplify it */ for (i =3D 0; i < earg->size; i++) earg->code[i].op =3D FETCH_OP_END; @@ -2051,7 +2046,6 @@ void trace_probe_cleanup(struct trace_probe *tp) traceprobe_free_probe_arg(&tp->args[i]); =20 if (tp->entry_arg) { - kfree(tp->entry_arg->code); kfree(tp->entry_arg); tp->entry_arg =3D NULL; } diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 262d8707a3df..1076f1df347b 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -238,8 +238,8 @@ struct probe_arg { }; =20 struct probe_entry_arg { - struct fetch_insn *code; unsigned int size; /* The entry data size */ + struct fetch_insn code[] __counted_by(size); }; =20 struct trace_uprobe_filter { --=20 2.54.0