Merge branch 'selftests-bpf-fix-a-few-dynptr-test-failures-with-64k-page-size'

Yonghong Song says:

====================
selftests/bpf: Fix a few dynptr test failures with 64K page size

There are a few dynptr test failures with arm64 64K page size.
They are fixed in this patch set and please see individual patches
for details.
====================

Link: https://patch.msgid.link/20250725043425.208128-1-yonghong.song@linux.dev
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Author: Martin KaFai Lau

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

@@ -51,6 +51,8 @@ static struct {
 	{"test_copy_from_user_task_str_dynptr", SETUP_SYSCALL_SLEEP},
 };
 
+#define PAGE_SIZE_64K 65536
+
 static void verify_success(const char *prog_name, enum test_setup_type setup_type)
 {
 	char user_data[384] = {[0 ... 382] = 'a', '\0'};
@@ -146,14 +148,18 @@ static void verify_success(const char *prog_name, enum test_setup_type setup_typ
 	}
 	case SETUP_XDP_PROG:
 	{
-		char data[5000];
+		char data[90000];
 		int err, prog_fd;
 		LIBBPF_OPTS(bpf_test_run_opts, opts,
 			    .data_in = &data,
-			    .data_size_in = sizeof(data),
 			    .repeat = 1,
 		);
 
+		if (getpagesize() == PAGE_SIZE_64K)
+			opts.data_size_in = sizeof(data);
+		else
+			opts.data_size_in = 5000;
+
 		prog_fd = bpf_program__fd(prog);
 		err = bpf_prog_test_run_opts(prog_fd, &opts);
 

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

@@ -9,6 +9,8 @@
 #include "bpf_misc.h"
 #include "errno.h"
 
+#define PAGE_SIZE_64K 65536
+
 char _license[] SEC("license") = "GPL";
 
 int pid, err, val;
@@ -611,11 +613,12 @@ int test_dynptr_copy_xdp(struct xdp_md *xdp)
 	struct bpf_dynptr ptr_buf, ptr_xdp;
 	char data[] = "qwertyuiopasdfghjkl";
 	char buf[32] = {'\0'};
-	__u32 len = sizeof(data);
+	__u32 len = sizeof(data), xdp_data_size;
 	int i, chunks = 200;
 
 	/* ptr_xdp is backed by non-contiguous memory */
 	bpf_dynptr_from_xdp(xdp, 0, &ptr_xdp);
+	xdp_data_size = bpf_dynptr_size(&ptr_xdp);
 	bpf_ringbuf_reserve_dynptr(&ringbuf, len * chunks, 0, &ptr_buf);
 
 	/* Destination dynptr is backed by non-contiguous memory */
@@ -673,7 +676,7 @@ int test_dynptr_copy_xdp(struct xdp_md *xdp)
 			goto out;
 	}
 
-	if (bpf_dynptr_copy(&ptr_xdp, 2000, &ptr_xdp, 0, len * chunks) != -E2BIG)
+	if (bpf_dynptr_copy(&ptr_xdp, xdp_data_size - 3000, &ptr_xdp, 0, len * chunks) != -E2BIG)
 		err = 1;
 
 out:
@@ -820,8 +823,17 @@ int test_dynptr_memset_xdp_chunks(struct xdp_md *xdp)
 	data_sz = bpf_dynptr_size(&ptr_xdp);
 
 	err = bpf_dynptr_memset(&ptr_xdp, 0, data_sz, DYNPTR_MEMSET_VAL);
-	if (err)
+	if (err) {
+		/* bpf_dynptr_memset() eventually called bpf_xdp_pointer()
+		 * where if data_sz is greater than 0xffff, -EFAULT will be
+		 * returned. For 64K page size, data_sz is greater than
+		 * 64K, so error is expected and let us zero out error and
+		 * return success.
+		 */
+		if (data_sz >= PAGE_SIZE_64K)
+			err = 0;
 		goto out;
+	}
 
 	bpf_for(i, 0, max_chunks) {
 		offset = i * sizeof(buf);