Commit 91c96842 authored by Dave Marchevsky's avatar Dave Marchevsky Committed by Alexei Starovoitov
Browse files

selftests/bpf: Test bpf_kptr_xchg stashing into local kptr 



Test stashing both referenced kptr and local kptr into local kptrs. Then,
test unstashing them.

Acked-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Acked-by: default avatarHou Tao <houtao1@huawei.com>
Signed-off-by: default avatarDave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: default avatarAmery Hung <amery.hung@bytedance.com>
Link: https://lore.kernel.org/r/20240813212424.2871455-6-amery.hung@bytedance.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent b0966c72

tools/testing/selftests/bpf/progs/local_kptr_stash.c

+28 −2
Original line number Diff line number Diff line
@@ -8,9 +8,12 @@ 
#include "../bpf_experimental.h"

#include "../bpf_testmod/bpf_testmod_kfunc.h"



struct plain_local;



struct node_data {

	long key;

	long data;

	struct plain_local __kptr * stashed_in_local_kptr;

	struct bpf_rb_node node;

};
@@ -85,6 +88,7 @@ static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b) 


static int create_and_stash(int idx, int val)

{

	struct plain_local *inner_local_kptr;

	struct map_value *mapval;

	struct node_data *res;
@@ -92,11 +96,25 @@ static int create_and_stash(int idx, int val) 
	if (!mapval)

		return 1;



	inner_local_kptr = bpf_obj_new(typeof(*inner_local_kptr));

	if (!inner_local_kptr)

		return 2;



	res = bpf_obj_new(typeof(*res));

	if (!res)

		return 1;

	if (!res) {

		bpf_obj_drop(inner_local_kptr);

		return 3;

	}

	res->key = val;



	inner_local_kptr = bpf_kptr_xchg(&res->stashed_in_local_kptr, inner_local_kptr);

	if (inner_local_kptr) {

		/* Should never happen, we just obj_new'd res */

		bpf_obj_drop(inner_local_kptr);

		bpf_obj_drop(res);

		return 4;

	}



	res = bpf_kptr_xchg(&mapval->node, res);

	if (res)

		bpf_obj_drop(res);
@@ -169,6 +187,7 @@ long stash_local_with_root(void *ctx) 
SEC("tc")

long unstash_rb_node(void *ctx)

{

	struct plain_local *inner_local_kptr = NULL;

	struct map_value *mapval;

	struct node_data *res;

	long retval;
@@ -180,6 +199,13 @@ long unstash_rb_node(void *ctx) 


	res = bpf_kptr_xchg(&mapval->node, NULL);

	if (res) {

		inner_local_kptr = bpf_kptr_xchg(&res->stashed_in_local_kptr, inner_local_kptr);

		if (!inner_local_kptr) {

			bpf_obj_drop(res);

			return 1;

		}

		bpf_obj_drop(inner_local_kptr);



		retval = res->key;

		bpf_obj_drop(res);

		return retval;

tools/testing/selftests/bpf/progs/task_kfunc_success.c

+25 −1
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include <bpf/bpf_tracing.h>

#include <bpf/bpf_helpers.h>



#include "../bpf_experimental.h"

#include "task_kfunc_common.h"



char _license[] SEC("license") = "GPL";
@@ -143,7 +144,7 @@ SEC("tp_btf/task_newtask") 
int BPF_PROG(test_task_xchg_release, struct task_struct *task, u64 clone_flags)

{

	struct task_struct *kptr;

	struct __tasks_kfunc_map_value *v;

	struct __tasks_kfunc_map_value *v, *local;

	long status;



	if (!is_test_kfunc_task())
@@ -167,6 +168,29 @@ int BPF_PROG(test_task_xchg_release, struct task_struct *task, u64 clone_flags) 
		return 0;

	}



	local = bpf_obj_new(typeof(*local));

	if (!local) {

		err = 4;

		bpf_task_release(kptr);

		return 0;

	}



	kptr = bpf_kptr_xchg(&local->task, kptr);

	if (kptr) {

		err = 5;

		bpf_obj_drop(local);

		bpf_task_release(kptr);

		return 0;

	}



	kptr = bpf_kptr_xchg(&local->task, NULL);

	if (!kptr) {

		err = 6;

		bpf_obj_drop(local);

		return 0;

	}



	bpf_obj_drop(local);

	bpf_task_release(kptr);



	return 0;