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* [PATCH bpf-next 1/2] selftests/bpf: Fix task_local_data failure with 64K page
@ 2026-01-20 21:09 Yonghong Song
  2026-01-20 21:09 ` [PATCH bpf-next 2/2] selftests/bpf: Fix xdp_pull_data " Yonghong Song
  2026-01-22  8:00 ` [PATCH bpf-next 1/2] selftests/bpf: Fix task_local_data " Alan Maguire
  0 siblings, 2 replies; 5+ messages in thread
From: Yonghong Song @ 2026-01-20 21:09 UTC (permalink / raw)
  To: bpf
  Cc: Alexei Starovoitov, Andrii Nakryiko, Daniel Borkmann, kernel-team,
	Martin KaFai Lau, Amery Hung

On arm64 systems with 64K pages, the selftest task_local_data has the following
failures:
  ...
  test_task_local_data_basic:PASS:tld_create_key 0 nsec
  test_task_local_data_basic:FAIL:tld_create_key unexpected tld_create_key: actual 0 != expected -28
  ...
  test_task_local_data_basic_thread:PASS:run task_main 0 nsec
  test_task_local_data_basic_thread:FAIL:task_main retval unexpected error: 2 (errno 0)
  test_task_local_data_basic_thread:FAIL:tld_get_data value0 unexpected tld_get_data value0: actual 0 != expected 6268
  ...
  #447/1   task_local_data/task_local_data_basic:FAIL
  ...
  #447/2   task_local_data/task_local_data_race:FAIL
  #447     task_local_data:FAIL

When TLD_DYN_DATA_SIZE is 64K page size, for
  struct tld_meta_u {
       _Atomic __u8 cnt;
       __u16 size;
        struct tld_metadata metadata[];
  };
fields 'cnt' and 'size' would overflow. For example,
for 4K page, 'cnt' will be 4096/64 = 64. But for 64K page,
'cnt' will be 65536/64 = 1024 and 'cnt' is not enough for 1024.
For field 'size', it is okay for value 4K, but it is not enough
for 64K as maximum 'size' value is '64K - 1'.

To accommodate 64K page, '_Atomic __u8 cnt' becomes '_Atomic __u16 cnt'
and '__u16 size' becomes '__u32 size'. A few other places are adjusted
accordingly.

Cc: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
 tools/testing/selftests/bpf/prog_tests/task_local_data.h    | 6 +++---
 .../testing/selftests/bpf/prog_tests/test_task_local_data.c | 2 +-
 tools/testing/selftests/bpf/progs/task_local_data.bpf.h     | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/task_local_data.h b/tools/testing/selftests/bpf/prog_tests/task_local_data.h
index 2de38776a2d4..4c38f9a7bc90 100644
--- a/tools/testing/selftests/bpf/prog_tests/task_local_data.h
+++ b/tools/testing/selftests/bpf/prog_tests/task_local_data.h
@@ -94,8 +94,8 @@ struct tld_metadata {
 };
 
 struct tld_meta_u {
-	_Atomic __u8 cnt;
-	__u16 size;
+	_Atomic __u16 cnt;
+	__u32 size;
 	struct tld_metadata metadata[];
 };
 
@@ -217,7 +217,7 @@ static int __tld_init_data_p(int map_fd)
 static tld_key_t __tld_create_key(const char *name, size_t size, bool dyn_data)
 {
 	int err, i, sz, off = 0;
-	__u8 cnt;
+	__u16 cnt;
 
 	if (!TLD_READ_ONCE(tld_meta_p)) {
 		err = __tld_init_meta_p();
diff --git a/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c b/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c
index 9fd6306b455c..cc4d49222d9d 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_task_local_data.c
@@ -4,7 +4,7 @@
 #include <test_progs.h>
 
 #define TLD_FREE_DATA_ON_THREAD_EXIT
-#define TLD_DYN_DATA_SIZE 4096
+#define TLD_DYN_DATA_SIZE getpagesize()
 #include "task_local_data.h"
 
 struct test_tld_struct {
diff --git a/tools/testing/selftests/bpf/progs/task_local_data.bpf.h b/tools/testing/selftests/bpf/progs/task_local_data.bpf.h
index 432fff2af844..e13f239b46b0 100644
--- a/tools/testing/selftests/bpf/progs/task_local_data.bpf.h
+++ b/tools/testing/selftests/bpf/progs/task_local_data.bpf.h
@@ -80,8 +80,8 @@ struct tld_metadata {
 };
 
 struct tld_meta_u {
-	__u8 cnt;
-	__u16 size;
+	__u16 cnt;
+	__u32 size;
 	struct tld_metadata metadata[TLD_MAX_DATA_CNT];
 };
 
-- 
2.47.3


^ permalink raw reply related	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2026-01-22 15:32 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2026-01-20 21:09 [PATCH bpf-next 1/2] selftests/bpf: Fix task_local_data failure with 64K page Yonghong Song
2026-01-20 21:09 ` [PATCH bpf-next 2/2] selftests/bpf: Fix xdp_pull_data " Yonghong Song
2026-01-22 11:02   ` Alan Maguire
2026-01-22 15:31     ` Yonghong Song
2026-01-22  8:00 ` [PATCH bpf-next 1/2] selftests/bpf: Fix task_local_data " Alan Maguire

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