Commit c93c1246 authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'bpf-cpumap-improve-error-propagation-in-cpu_map_update_elem' 

Kohei Enju says:

====================
bpf: cpumap: improve error propagation in cpu_map_update_elem()

This series improves error propagation in cpumap and adds selftests that
cover the failure cases.

Currently, failures returned from __cpu_map_entry_alloc() are ignored
and always converted to -ENOMEM by cpu_map_update_elem(). This series
ensures the correct error propagation and adds selftests.

Changes:
  v2:
    - send to bpf-next, not to bpf
    - drop Fixes: tag
  v1: https://lore.kernel.org/bpf/20251128160504.57844-1-enjuk@amazon.com/
====================

Link: https://patch.msgid.link/20251208131449.73036-1-enjuk@amazon.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 5d9fb42f 18352f8f

kernel/bpf/cpumap.c

+13 −8
Original line number Diff line number Diff line
@@ -430,7 +430,7 @@ static struct bpf_cpu_map_entry * 
__cpu_map_entry_alloc(struct bpf_map *map, struct bpf_cpumap_val *value,

		      u32 cpu)

{

	int numa, err, i, fd = value->bpf_prog.fd;

	int numa, err = -ENOMEM, i, fd = value->bpf_prog.fd;

	gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;

	struct bpf_cpu_map_entry *rcpu;

	struct xdp_bulk_queue *bq;
@@ -440,7 +440,7 @@ __cpu_map_entry_alloc(struct bpf_map *map, struct bpf_cpumap_val *value, 


	rcpu = bpf_map_kmalloc_node(map, sizeof(*rcpu), gfp | __GFP_ZERO, numa);

	if (!rcpu)

		return NULL;

		return ERR_PTR(err);



	/* Alloc percpu bulkq */

	rcpu->bulkq = bpf_map_alloc_percpu(map, sizeof(*rcpu->bulkq),
@@ -468,16 +468,21 @@ __cpu_map_entry_alloc(struct bpf_map *map, struct bpf_cpumap_val *value, 
	rcpu->value.qsize  = value->qsize;

	gro_init(&rcpu->gro);



	if (fd > 0 && __cpu_map_load_bpf_program(rcpu, map, fd))

	if (fd > 0) {

		err = __cpu_map_load_bpf_program(rcpu, map, fd);

		if (err)

			goto free_ptr_ring;

	}



	/* Setup kthread */

	init_completion(&rcpu->kthread_running);

	rcpu->kthread = kthread_create_on_node(cpu_map_kthread_run, rcpu, numa,

					       "cpumap/%d/map:%d", cpu,

					       map->id);

	if (IS_ERR(rcpu->kthread))

	if (IS_ERR(rcpu->kthread)) {

		err = PTR_ERR(rcpu->kthread);

		goto free_prog;

	}



	/* Make sure kthread runs on a single CPU */

	kthread_bind(rcpu->kthread, cpu);
@@ -503,7 +508,7 @@ __cpu_map_entry_alloc(struct bpf_map *map, struct bpf_cpumap_val *value, 
	free_percpu(rcpu->bulkq);

free_rcu:

	kfree(rcpu);

	return NULL;

	return ERR_PTR(err);

}



static void __cpu_map_entry_free(struct work_struct *work)
@@ -596,8 +601,8 @@ static long cpu_map_update_elem(struct bpf_map *map, void *key, void *value, 
	} else {

		/* Updating qsize cause re-allocation of bpf_cpu_map_entry */

		rcpu = __cpu_map_entry_alloc(map, &cpumap_value, key_cpu);

		if (!rcpu)

			return -ENOMEM;

		if (IS_ERR(rcpu))

			return PTR_ERR(rcpu);

	}

	rcu_read_lock();

	__cpu_map_entry_replace(cmap, key_cpu, rcpu);

tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c

+17 −2
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ static void test_xdp_with_cpumap_helpers(void) 
	struct bpf_cpumap_val val = {

		.qsize = 192,

	};

	int err, prog_fd, prog_redir_fd, map_fd;

	int err, prog_fd, prog_redir_fd, map_fd, bad_fd;

	struct nstoken *nstoken = NULL;

	__u32 idx = 0;
@@ -79,7 +79,22 @@ static void test_xdp_with_cpumap_helpers(void) 
	val.qsize = 192;

	val.bpf_prog.fd = bpf_program__fd(skel->progs.xdp_dummy_prog);

	err = bpf_map_update_elem(map_fd, &idx, &val, 0);

	ASSERT_NEQ(err, 0, "Add non-BPF_XDP_CPUMAP program to cpumap entry");

	ASSERT_EQ(err, -EINVAL, "Add non-BPF_XDP_CPUMAP program to cpumap entry");



	/* Try to attach non-BPF file descriptor */

	bad_fd = open("/dev/null", O_RDONLY);

	ASSERT_GE(bad_fd, 0, "Open /dev/null for non-BPF fd");



	val.bpf_prog.fd = bad_fd;

	err = bpf_map_update_elem(map_fd, &idx, &val, 0);

	ASSERT_EQ(err, -EINVAL, "Add non-BPF fd to cpumap entry");



	/* Try to attach nonexistent file descriptor */

	err = close(bad_fd);

	ASSERT_EQ(err, 0, "Close non-BPF fd for nonexistent fd");



	err = bpf_map_update_elem(map_fd, &idx, &val, 0);

	ASSERT_EQ(err, -EBADF, "Add nonexistent fd to cpumap entry");



	/* Try to attach BPF_XDP program with frags to cpumap when we have

	 * already loaded a BPF_XDP program on the map