tracing: Use flexible array for entry fetch code

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 Link: https://lore.kernel.org/all/20260520215817.16560-1-rosenp@gmail.com/

Rosen Penev committed 5 months ago

Commit cf24cbb1 parent 4304c812 files · +2 −8Browse files

Showing the changes to kernel/trace (2 of 2 files). Show all

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2 files

kernel/trace/trace_probe.c +1 −7
kernel/trace/trace_probe.h +1 −1

kernel/trace/trace_probe.c+1−7

 	int i, offset, last_offset = 0;
 	if (!earg) {
-		earg = kzalloc_obj(*tp->entry_arg);
+		earg = kzalloc_flex(*earg, code, 2 * tp->nr_args + 1);
 		if (!earg)
 			return -ENOMEM;
 		earg->size = 2 * tp->nr_args + 1;
-		earg->code = 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 = 0; i < earg->size; i++)
 			earg->code[i].op = FETCH_OP_END;
 		traceprobe_free_probe_arg(&tp->args[i]);
 	if (tp->entry_arg) {
-		kfree(tp->entry_arg->code);
 		kfree(tp->entry_arg);
 		tp->entry_arg = NULL;
 	}

kernel/trace/trace_probe.h+1−1

@@ -238,8 +238,8 @@ struct probe_arg { · 237 unmodified lines
238	};	238	};
239		239
240	struct probe_entry_arg {	240	struct probe_entry_arg {
241	struct fetch_insn *code;
242	unsigned int size; /* The entry data size */	241	unsigned int size; /* The entry data size */
		242	struct fetch_insn code[] __counted_by(size);
243	};	243	};
244		244
245	struct trace_uprobe_filter {	245	struct trace_uprobe_filter {