117 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			117 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0
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#include <vmlinux.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_helpers.h>
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struct map_value {
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	struct prog_test_ref_kfunc __kptr_ref *ptr;
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};
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struct {
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	__uint(type, BPF_MAP_TYPE_ARRAY);
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	__type(key, int);
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	__type(value, struct map_value);
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	__uint(max_entries, 16);
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} array_map SEC(".maps");
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extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
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extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
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static __noinline int cb1(void *map, void *key, void *value, void *ctx)
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{
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	void *p = *(void **)ctx;
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	bpf_kfunc_call_test_release(p);
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	/* Without the fix this would cause underflow */
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	return 0;
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}
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SEC("?tc")
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int underflow_prog(void *ctx)
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{
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	struct prog_test_ref_kfunc *p;
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	unsigned long sl = 0;
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	p = bpf_kfunc_call_test_acquire(&sl);
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	if (!p)
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		return 0;
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	bpf_for_each_map_elem(&array_map, cb1, &p, 0);
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	return 0;
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}
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static __always_inline int cb2(void *map, void *key, void *value, void *ctx)
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{
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	unsigned long sl = 0;
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	*(void **)ctx = bpf_kfunc_call_test_acquire(&sl);
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	/* Without the fix this would leak memory */
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	return 0;
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}
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SEC("?tc")
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int leak_prog(void *ctx)
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{
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	struct prog_test_ref_kfunc *p;
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	struct map_value *v;
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	unsigned long sl;
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	v = bpf_map_lookup_elem(&array_map, &(int){0});
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	if (!v)
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		return 0;
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	p = NULL;
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	bpf_for_each_map_elem(&array_map, cb2, &p, 0);
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	p = bpf_kptr_xchg(&v->ptr, p);
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	if (p)
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		bpf_kfunc_call_test_release(p);
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	return 0;
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}
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static __always_inline int cb(void *map, void *key, void *value, void *ctx)
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{
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	return 0;
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}
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static __always_inline int cb3(void *map, void *key, void *value, void *ctx)
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{
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	unsigned long sl = 0;
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	void *p;
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	bpf_kfunc_call_test_acquire(&sl);
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	bpf_for_each_map_elem(&array_map, cb, &p, 0);
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	/* It should only complain here, not in cb. This is why we need
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	 * callback_ref to be set to frameno.
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	 */
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	return 0;
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}
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SEC("?tc")
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int nested_cb(void *ctx)
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{
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	struct prog_test_ref_kfunc *p;
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	unsigned long sl = 0;
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	int sp = 0;
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	p = bpf_kfunc_call_test_acquire(&sl);
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	if (!p)
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		return 0;
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	bpf_for_each_map_elem(&array_map, cb3, &sp, 0);
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	bpf_kfunc_call_test_release(p);
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	return 0;
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}
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SEC("?tc")
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int non_cb_transfer_ref(void *ctx)
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{
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	struct prog_test_ref_kfunc *p;
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	unsigned long sl = 0;
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	p = bpf_kfunc_call_test_acquire(&sl);
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	if (!p)
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		return 0;
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	cb1(NULL, NULL, NULL, &p);
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	bpf_kfunc_call_test_acquire(&sl);
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	return 0;
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}
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char _license[] SEC("license") = "GPL";
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