[PATCH bpf-next v1 0/6] Fix ring buffer callback consumption

[PATCH bpf-next v1 0/6] Fix ring buffer callback consumption

[Kumar Kartikeya Dwivedi]

Commandeering some patches from Tamir for libbpf ringbuf callback
consumption fixes. See commit logs for details.

Tamir Duberstein (6):
  libbpf: Honor zero consume bounds
  libbpf: Prevent NULL callback crash
  libbpf: Reject overwrite callback use
  selftests/bpf: Test ring buffer consumption with a zero bound
  selftests/bpf: Test the ring buffer consumer with a NULL sample
    callback
  selftests/bpf: Test that callbacks reject an overwritable ring buffer

 tools/lib/bpf/libbpf.h                        |  12 +-
 tools/lib/bpf/ringbuf.c                       |  50 +++++-
 .../selftests/bpf/prog_tests/ringbuf.c        | 145 ++++++++++++++++++
 3 files changed, 196 insertions(+), 11 deletions(-)


base-commit: bd75869299f1d4ff6e9f45117cce28f8badee1cd
-- 
2.53.0

[PATCH bpf-next v1 1/6] libbpf: Honor zero consume bounds

[Kumar Kartikeya Dwivedi]

From: Tamir Duberstein <tamird@kernel.org>

ringbuf_process_ring() checks the record bound only after advancing the
consumer position and invoking the callback. A zero bound therefore
consumes the first available record.

Return before reading the ring positions when the bound is zero so
ring_buffer__consume_n() and ring__consume_n() leave all records queued.

Fixes: 4d22ea94ea33 ("libbpf: Add ring__consume_n / ring_buffer__consume_n")
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
 tools/lib/bpf/ringbuf.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index c8fe57401a8b..6e88ac209298 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -240,6 +240,9 @@ static int64_t ringbuf_process_ring(struct ring *r, size_t n)
 	bool got_new_data;
 	void *sample;
 
+	if (n == 0)
+		return 0;
+
 	cons_pos = smp_load_acquire(r->consumer_pos);
 	do {
 		got_new_data = false;
-- 
2.53.0

[PATCH bpf-next v1 2/6] libbpf: Prevent NULL callback crash

[Kumar Kartikeya Dwivedi]

From: Tamir Duberstein <tamird@kernel.org>

ring_buffer__new() and ring_buffer__add() allow a NULL sample
callback. When callback-based consumption reaches such a ring, it calls
through the NULL function pointer and crashes.

Check every ring before manager polling or consumption so a missing
callback returns -EINVAL before the manager waits or consumes another
ring. Check the selected ring before direct per-ring consumption. Perform
both checks before honoring a zero record bound so invalid callback use
always reports the error.

Fixes: bf99c936f947 ("libbpf: Add BPF ring buffer support")
Signed-off-by: Tamir Duberstein <tamird@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
 tools/lib/bpf/libbpf.h  | 11 +++++------
 tools/lib/bpf/ringbuf.c | 43 ++++++++++++++++++++++++++++++++++++-----
 2 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index a8a23c135c17..1c45648fa578 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -1628,18 +1628,17 @@ LIBBPF_API int ring__map_fd(const struct ring *r);
  *
  * @param r A ringbuffer object.
  * @return The number of records consumed (or INT_MAX, whichever is less), or
- * a negative number if any of the callbacks return an error.
+ * a negative error code on failure.
  */
 LIBBPF_API int ring__consume(struct ring *r);
 
 /**
- * @brief **ring__consume_n()** consumes up to a requested amount of items from
- * a ringbuffer without event polling.
+ * @brief **ring__consume_n()** consumes up to a requested number of records
+ * from a ringbuffer without event polling.
  *
  * @param r A ringbuffer object.
- * @param n Maximum amount of items to consume.
- * @return The number of items consumed, or a negative number if any of the
- * callbacks return an error.
+ * @param n Maximum number of records to consume.
+ * @return The number of records consumed, or a negative error code on failure.
  */
 LIBBPF_API int ring__consume_n(struct ring *r, size_t n);
 
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index 6e88ac209298..b7fde7d0a0fd 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -231,6 +231,26 @@ static inline int roundup_len(__u32 len)
 	return (len + 7) / 8 * 8;
 }
 
+static int ringbuf_validate(const struct ring *r)
+{
+	if (unlikely(!r->sample_cb))
+		return -EINVAL;
+	return 0;
+}
+
+static int ringbuf_validate_callbacks(const struct ring_buffer *rb)
+{
+	int i, err;
+
+	for (i = 0; i < rb->ring_cnt; i++) {
+		err = ringbuf_validate(rb->rings[i]);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
 static int64_t ringbuf_process_ring(struct ring *r, size_t n)
 {
 	int *len_ptr, len, err;
@@ -240,6 +260,9 @@ static int64_t ringbuf_process_ring(struct ring *r, size_t n)
 	bool got_new_data;
 	void *sample;
 
+	err = ringbuf_validate(r);
+	if (err)
+		return err;
 	if (n == 0)
 		return 0;
 
@@ -284,14 +307,17 @@ static int64_t ringbuf_process_ring(struct ring *r, size_t n)
  * records.
  *
  * Returns number of records consumed across all registered ring buffers (or
- * n, whichever is less), or negative number if any of the callbacks return
- * error.
+ * n, whichever is less), or a negative error code on failure.
  */
 int ring_buffer__consume_n(struct ring_buffer *rb, size_t n)
 {
 	int64_t err, res = 0;
 	int i;
 
+	err = ringbuf_validate_callbacks(rb);
+	if (err)
+		return libbpf_err(err);
+
 	for (i = 0; i < rb->ring_cnt; i++) {
 		struct ring *ring = rb->rings[i];
 
@@ -309,14 +335,17 @@ int ring_buffer__consume_n(struct ring_buffer *rb, size_t n)
 
 /* Consume available ring buffer(s) data without event polling.
  * Returns number of records consumed across all registered ring buffers (or
- * INT_MAX, whichever is less), or negative number if any of the callbacks
- * return error.
+ * INT_MAX, whichever is less), or a negative error code on failure.
  */
 int ring_buffer__consume(struct ring_buffer *rb)
 {
 	int64_t err, res = 0;
 	int i;
 
+	err = ringbuf_validate_callbacks(rb);
+	if (err)
+		return libbpf_err(err);
+
 	for (i = 0; i < rb->ring_cnt; i++) {
 		struct ring *ring = rb->rings[i];
 
@@ -334,13 +363,17 @@ int ring_buffer__consume(struct ring_buffer *rb)
 
 /* Poll for available data and consume records, if any are available.
  * Returns number of records consumed (or INT_MAX, whichever is less), or
- * negative number, if any of the registered callbacks returned error.
+ * a negative error code on failure.
  */
 int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms)
 {
 	int i, cnt;
 	int64_t err, res = 0;
 
+	err = ringbuf_validate_callbacks(rb);
+	if (err)
+		return libbpf_err(err);
+
 	cnt = epoll_wait(rb->epoll_fd, rb->events, rb->ring_cnt, timeout_ms);
 	if (cnt < 0)
 		return libbpf_err(-errno);
-- 
2.53.0

[PATCH bpf-next v1 3/6] libbpf: Reject overwrite callback use

[Kumar Kartikeya Dwivedi]

From: Tamir Duberstein <tamird@kernel.org>

BPF_F_RB_OVERWRITE can advance overwrite_pos past consumer_pos.
Callback traversal does not read overwrite_pos, so after the producer
laps the consumer it can treat overwritten data as a record header.

An earlier proposal [0] copied the readable window before invoking
callbacks. Review concluded that callbacks are a poor fit because
copying penalizes zero-copy users and the API cannot report skipped
records.

Record the map flag and reject callback consumption with -EOPNOTSUPP.

Link: https://lore.kernel.org/bpf/CAEf4Bzaq5drHWChXoRBnrmkb6reAsSVj8r=uByFSup31FMA7hw@mail.gmail.com
Fixes: feeaf1346f80 ("bpf: Add overwrite mode for BPF ring buffer")
Signed-off-by: Tamir Duberstein <tamird@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
 tools/lib/bpf/libbpf.h  | 1 +
 tools/lib/bpf/ringbuf.c | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 1c45648fa578..49f1120f4021 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -1541,6 +1541,7 @@ struct ring_buffer;
 struct ring;
 struct user_ring_buffer;
 
+/* Callback-based consumption is unsupported for BPF_F_RB_OVERWRITE maps. */
 typedef int (*ring_buffer_sample_fn)(void *ctx, void *data, size_t size);
 
 struct ring_buffer_opts {
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index b7fde7d0a0fd..78fcb3df243f 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -30,6 +30,7 @@ struct ring {
 	unsigned long *producer_pos;
 	unsigned long mask;
 	int map_fd;
+	bool overwrite;
 };
 
 struct ring_buffer {
@@ -118,6 +119,7 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd,
 	r->sample_cb = sample_cb;
 	r->ctx = ctx;
 	r->mask = info.max_entries - 1;
+	r->overwrite = info.map_flags & BPF_F_RB_OVERWRITE;
 
 	/* Map writable consumer page */
 	tmp = mmap(NULL, rb->page_size, PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, 0);
@@ -233,6 +235,8 @@ static inline int roundup_len(__u32 len)
 
 static int ringbuf_validate(const struct ring *r)
 {
+	if (unlikely(r->overwrite))
+		return -EOPNOTSUPP;
 	if (unlikely(!r->sample_cb))
 		return -EINVAL;
 	return 0;
-- 
2.53.0

[PATCH bpf-next v1 4/6] selftests/bpf: Test ring buffer consumption with a zero bound

[Kumar Kartikeya Dwivedi]

From: Tamir Duberstein <tamird@kernel.org>

Extend the ringbuf_n subtest. With all samples queued,
ring_buffer__consume_n() and ring__consume_n() with a zero bound must
return 0, and the batched consumption that follows must still find
N_SAMPLES records in every batch, so neither call may consume a record.

[kkd: split out of "libbpf: Honor zero consume bounds" (Eduard)]
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Tamir Duberstein <tamird@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
 tools/testing/selftests/bpf/prog_tests/ringbuf.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
index 64520684d2cb..4f0558f14847 100644
--- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
@@ -404,6 +404,7 @@ static int process_n_sample(void *ctx, void *data, size_t len)
 static void ringbuf_n_subtest(void)
 {
 	struct test_ringbuf_n_lskel *skel_n;
+	struct ring *ring;
 	int err, i;
 
 	skel_n = test_ringbuf_n_lskel__open();
@@ -431,6 +432,18 @@ static void ringbuf_n_subtest(void)
 	for (i = 0; i < N_TOT_SAMPLES; i++)
 		syscall(__NR_getpgid);
 
+	ring = ring_buffer__ring(ringbuf, 0);
+	if (!ASSERT_OK_PTR(ring, "ring_buffer__ring"))
+		goto cleanup_ringbuf;
+
+	err = ring_buffer__consume_n(ringbuf, 0);
+	if (!ASSERT_EQ(err, 0, "ringbuf_consume_zero"))
+		goto cleanup_ringbuf;
+
+	err = ring__consume_n(ring, 0);
+	if (!ASSERT_EQ(err, 0, "ring_consume_zero"))
+		goto cleanup_ringbuf;
+
 	/* Consume all samples from the ring buffer in batches of N_SAMPLES */
 	for (i = 0; i < N_TOT_SAMPLES; i += err) {
 		err = ring_buffer__consume_n(ringbuf, N_SAMPLES);
-- 
2.53.0

[PATCH bpf-next v1 5/6] selftests/bpf: Test the ring buffer consumer with a NULL sample callback

[Kumar Kartikeya Dwivedi]

From: Tamir Duberstein <tamird@kernel.org>

Add the ringbuf_null_cb subtest. A manager holding a ring with a sample
callback and one added without must return -EINVAL from
ring_buffer__consume_n(), ring_buffer__consume() and ring_buffer__poll()
and leave the consumer position of the valid ring alone, since the checks
run before any ring is consumed. A manager created with a NULL callback
must return -EINVAL from the same entry points and from ring__consume_n()
and ring__consume() on its ring, instead of calling through the NULL
pointer.

[kkd: split out of "libbpf: Prevent NULL callback crash" (Eduard)]
Signed-off-by: Tamir Duberstein <tamird@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
 .../selftests/bpf/prog_tests/ringbuf.c        | 93 +++++++++++++++++++
 1 file changed, 93 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
index 4f0558f14847..9ce996bcea8c 100644
--- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
@@ -401,6 +401,97 @@ static int process_n_sample(void *ctx, void *data, size_t len)
 	return 0;
 }
 
+static int process_noop_sample(void *ctx, void *data, size_t len)
+{
+	return 0;
+}
+
+static void ringbuf_null_cb_subtest(void)
+{
+	struct test_ringbuf_n_lskel *skel_n;
+	struct ring_buffer *ringbuf = NULL;
+	struct ring *ring;
+	unsigned long consumer_pos;
+	int no_cb_map_fd = -1;
+	int err;
+
+	skel_n = test_ringbuf_n_lskel__open();
+	if (!ASSERT_OK_PTR(skel_n, "test_ringbuf_n_lskel__open"))
+		return;
+
+	skel_n->maps.ringbuf.max_entries = getpagesize();
+	skel_n->bss->pid = getpid();
+	skel_n->bss->value = SAMPLE_VALUE;
+
+	err = test_ringbuf_n_lskel__load(skel_n);
+	if (!ASSERT_OK(err, "test_ringbuf_n_lskel__load"))
+		goto cleanup;
+
+	err = test_ringbuf_n_lskel__attach(skel_n);
+	if (!ASSERT_OK(err, "test_ringbuf_n_lskel__attach"))
+		goto cleanup;
+
+	syscall(__NR_getpgid);
+
+	no_cb_map_fd = bpf_map_create(BPF_MAP_TYPE_RINGBUF, NULL, 0, 0,
+				      getpagesize(), NULL);
+	if (!ASSERT_OK_FD(no_cb_map_fd, "bpf_map_create"))
+		goto cleanup;
+
+	/* Manager APIs must validate all rings before consuming any of them. */
+	ringbuf = ring_buffer__new(skel_n->maps.ringbuf.map_fd,
+				   process_noop_sample, NULL, NULL);
+	if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new"))
+		goto cleanup_fd;
+
+	ring = ring_buffer__ring(ringbuf, 0);
+	if (!ASSERT_OK_PTR(ring, "ring_buffer__ring"))
+		goto cleanup_ringbuf;
+
+	err = ring_buffer__add(ringbuf, no_cb_map_fd, NULL, NULL);
+	if (!ASSERT_OK(err, "ring_buffer__add_no_cb"))
+		goto cleanup_ringbuf;
+
+	consumer_pos = ring__consumer_pos(ring);
+	ASSERT_GT(ring__producer_pos(ring), consumer_pos,
+		  "producer_pos_mixed_cb");
+
+	err = ring_buffer__consume_n(ringbuf, 0);
+	ASSERT_EQ(err, -EINVAL, "ringbuf_consume_zero_mixed_cb");
+	err = ring_buffer__consume(ringbuf);
+	ASSERT_EQ(err, -EINVAL, "ringbuf_consume_mixed_cb");
+	err = ring_buffer__poll(ringbuf, 0);
+	ASSERT_EQ(err, -EINVAL, "ringbuf_poll_mixed_cb");
+	ASSERT_EQ(ring__consumer_pos(ring), consumer_pos,
+		  "consumer_pos_mixed_cb");
+
+	ring_buffer__free(ringbuf);
+	ringbuf =
+		ring_buffer__new(skel_n->maps.ringbuf.map_fd, NULL, NULL, NULL);
+	if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new_no_cb"))
+		goto cleanup_fd;
+
+	ring = ring_buffer__ring(ringbuf, 0);
+	if (!ASSERT_OK_PTR(ring, "ring_buffer__ring_no_cb"))
+		goto cleanup_ringbuf;
+	consumer_pos = ring__consumer_pos(ring);
+
+	err = ring_buffer__consume_n(ringbuf, 0);
+	ASSERT_EQ(err, -EINVAL, "ringbuf_consume_zero_no_cb");
+	err = ring__consume_n(ring, 0);
+	ASSERT_EQ(err, -EINVAL, "ring_consume_zero_no_cb");
+	err = ring__consume(ring);
+	ASSERT_EQ(err, -EINVAL, "ring_consume_no_cb");
+	ASSERT_EQ(ring__consumer_pos(ring), consumer_pos, "consumer_pos_no_cb");
+
+cleanup_ringbuf:
+	ring_buffer__free(ringbuf);
+cleanup_fd:
+	close(no_cb_map_fd);
+cleanup:
+	test_ringbuf_n_lskel__destroy(skel_n);
+}
+
 static void ringbuf_n_subtest(void)
 {
 	struct test_ringbuf_n_lskel *skel_n;
@@ -579,6 +670,8 @@ void test_ringbuf(void)
 		ringbuf_subtest();
 	if (test__start_subtest("ringbuf_n"))
 		ringbuf_n_subtest();
+	if (test__start_subtest("ringbuf_null_cb"))
+		ringbuf_null_cb_subtest();
 	if (test__start_subtest("ringbuf_map_key"))
 		ringbuf_map_key_subtest();
 	if (test__start_subtest("ringbuf_write"))
-- 
2.53.0

[PATCH bpf-next v1 6/6] selftests/bpf: Test that callbacks reject an overwritable ring buffer

[Kumar Kartikeya Dwivedi]

From: Tamir Duberstein <tamird@kernel.org>

Add the ringbuf_overwrite_callback subtest: on a BPF_F_RB_OVERWRITE map,
creating the manager succeeds, and ring_buffer__consume_n(),
ring_buffer__consume(), ring_buffer__poll(), ring__consume_n() and
ring__consume() all return -EOPNOTSUPP.

[kkd: split out of "libbpf: Reject overwrite callback use" (Eduard)]
Signed-off-by: Tamir Duberstein <tamird@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
 .../selftests/bpf/prog_tests/ringbuf.c        | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
index 9ce996bcea8c..29be2476c478 100644
--- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
@@ -602,6 +602,43 @@ static void ringbuf_map_key_subtest(void)
 	test_ringbuf_map_key_lskel__destroy(skel_map_key);
 }
 
+static void ringbuf_overwrite_callback_subtest(void)
+{
+	LIBBPF_OPTS(bpf_map_create_opts, opts, .map_flags = BPF_F_RB_OVERWRITE);
+	struct ring_buffer *ringbuf;
+	struct ring *ring;
+	int map_fd, err;
+
+	map_fd = bpf_map_create(BPF_MAP_TYPE_RINGBUF, NULL, 0, 0, getpagesize(),
+				&opts);
+	if (!ASSERT_OK_FD(map_fd, "bpf_map_create"))
+		return;
+
+	ringbuf = ring_buffer__new(map_fd, process_noop_sample, NULL, NULL);
+	if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new"))
+		goto cleanup_fd;
+
+	ring = ring_buffer__ring(ringbuf, 0);
+	if (!ASSERT_OK_PTR(ring, "ring_buffer__ring"))
+		goto cleanup_ringbuf;
+
+	err = ring_buffer__consume_n(ringbuf, 0);
+	ASSERT_EQ(err, -EOPNOTSUPP, "ringbuf_consume_zero");
+	err = ring_buffer__consume(ringbuf);
+	ASSERT_EQ(err, -EOPNOTSUPP, "ringbuf_consume");
+	err = ring_buffer__poll(ringbuf, 0);
+	ASSERT_EQ(err, -EOPNOTSUPP, "ringbuf_poll");
+	err = ring__consume_n(ring, 0);
+	ASSERT_EQ(err, -EOPNOTSUPP, "ring_consume_zero");
+	err = ring__consume(ring);
+	ASSERT_EQ(err, -EOPNOTSUPP, "ring_consume");
+
+cleanup_ringbuf:
+	ring_buffer__free(ringbuf);
+cleanup_fd:
+	close(map_fd);
+}
+
 static void ringbuf_overwrite_mode_subtest(void)
 {
 	unsigned long size, len1, len2, len3, len4, len5;
@@ -676,6 +713,8 @@ void test_ringbuf(void)
 		ringbuf_map_key_subtest();
 	if (test__start_subtest("ringbuf_write"))
 		ringbuf_write_subtest();
+	if (test__start_subtest("ringbuf_overwrite_callback"))
+		ringbuf_overwrite_callback_subtest();
 	if (test__start_subtest("ringbuf_overwrite_mode"))
 		ringbuf_overwrite_mode_subtest();
 }
-- 
2.53.0

Re: [PATCH bpf-next v1 0/6] Fix ring buffer callback consumption

[patchwork-bot+netdevbpf]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Kumar Kartikeya Dwivedi <memxor@gmail.com>:

On Mon,  9 Nov 2026 20:47:26 +0100 you wrote:
> Commandeering some patches from Tamir for libbpf ringbuf callback
> consumption fixes. See commit logs for details.
> 
> Tamir Duberstein (6):
>   libbpf: Honor zero consume bounds
>   libbpf: Prevent NULL callback crash
>   libbpf: Reject overwrite callback use
>   selftests/bpf: Test ring buffer consumption with a zero bound
>   selftests/bpf: Test the ring buffer consumer with a NULL sample
>     callback
>   selftests/bpf: Test that callbacks reject an overwritable ring buffer
> 
> [...]

Here is the summary with links:
  - [bpf-next,v1,1/6] libbpf: Honor zero consume bounds
    https://git.kernel.org/bpf/bpf-next/c/40edacd47993
  - [bpf-next,v1,2/6] libbpf: Prevent NULL callback crash
    https://git.kernel.org/bpf/bpf-next/c/c0628a0659b6
  - [bpf-next,v1,3/6] libbpf: Reject overwrite callback use
    https://git.kernel.org/bpf/bpf-next/c/f756eedb24d4
  - [bpf-next,v1,4/6] selftests/bpf: Test ring buffer consumption with a zero bound
    https://git.kernel.org/bpf/bpf-next/c/c82153312a0a
  - [bpf-next,v1,5/6] selftests/bpf: Test the ring buffer consumer with a NULL sample callback
    https://git.kernel.org/bpf/bpf-next/c/21f96738feb7
  - [bpf-next,v1,6/6] selftests/bpf: Test that callbacks reject an overwritable ring buffer
    https://git.kernel.org/bpf/bpf-next/c/249c9bb9f3ac

You are awesome, thank you!
-- 
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