* [PATCH bpf-next 0/3] selftests/bpf: Fix a few dynptr test failures with 64K page size
@ 2025-07-25 4:34 Yonghong Song
2025-07-25 4:34 ` [PATCH bpf-next 1/3] selftests/bpf: Increase xdp data size for arm64 " Yonghong Song
` (3 more replies)
0 siblings, 4 replies; 10+ messages in thread
From: Yonghong Song @ 2025-07-25 4:34 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Andrii Nakryiko, Daniel Borkmann, kernel-team,
Martin KaFai Lau
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.
Yonghong Song (3):
selftests/bpf: Increase xdp data size for arm64 64K page size
selftests/bpf: Fix test dynptr/test_dynptr_copy_xdp failure
selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure
.../testing/selftests/bpf/prog_tests/dynptr.c | 10 ++++++++--
.../selftests/bpf/progs/dynptr_success.c | 18 +++++++++++++++---
2 files changed, 23 insertions(+), 5 deletions(-)
--
2.47.3
^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH bpf-next 1/3] selftests/bpf: Increase xdp data size for arm64 64K page size
2025-07-25 4:34 [PATCH bpf-next 0/3] selftests/bpf: Fix a few dynptr test failures with 64K page size Yonghong Song
@ 2025-07-25 4:34 ` Yonghong Song
2025-07-25 11:53 ` Mykyta Yatsenko
2025-07-25 4:34 ` [PATCH bpf-next 2/3] selftests/bpf: Fix test dynptr/test_dynptr_copy_xdp failure Yonghong Song
` (2 subsequent siblings)
3 siblings, 1 reply; 10+ messages in thread
From: Yonghong Song @ 2025-07-25 4:34 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Andrii Nakryiko, Daniel Borkmann, kernel-team,
Martin KaFai Lau
With arm64 64K page size, the following 4 subtests failed:
#97/25 dynptr/test_probe_read_user_dynptr:FAIL
#97/26 dynptr/test_probe_read_kernel_dynptr:FAIL
#97/27 dynptr/test_probe_read_user_str_dynptr:FAIL
#97/28 dynptr/test_probe_read_kernel_str_dynptr:FAIL
These failures are due to function bpf_dynptr_check_off_len() in
include/linux/bpf.h where there is a test
if (len > size || offset > size - len)
return -E2BIG;
With 64K page size, the 'offset' is greater than 'size - len',
which caused the test failure.
For 64KB page size, this patch increased the xdp buffer size from 5000 to
90000. The above 4 test failures are fixed as 'size' value is increased.
But it introduced two new failures:
#97/4 dynptr/test_dynptr_copy_xdp:FAIL
#97/12 dynptr/test_dynptr_memset_xdp_chunks:FAIL
These two failures will be addressed in subsequent patches.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
tools/testing/selftests/bpf/prog_tests/dynptr.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/dynptr.c b/tools/testing/selftests/bpf/prog_tests/dynptr.c
index f2b65398afce..9b2d9ceda210 100644
--- a/tools/testing/selftests/bpf/prog_tests/dynptr.c
+++ b/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);
--
2.47.3
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH bpf-next 2/3] selftests/bpf: Fix test dynptr/test_dynptr_copy_xdp failure
2025-07-25 4:34 [PATCH bpf-next 0/3] selftests/bpf: Fix a few dynptr test failures with 64K page size Yonghong Song
2025-07-25 4:34 ` [PATCH bpf-next 1/3] selftests/bpf: Increase xdp data size for arm64 " Yonghong Song
@ 2025-07-25 4:34 ` Yonghong Song
2025-07-25 11:53 ` Mykyta Yatsenko
2025-07-25 4:34 ` [PATCH bpf-next 3/3] selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure Yonghong Song
2025-07-26 1:40 ` [PATCH bpf-next 0/3] selftests/bpf: Fix a few dynptr test failures with 64K page size patchwork-bot+netdevbpf
3 siblings, 1 reply; 10+ messages in thread
From: Yonghong Song @ 2025-07-25 4:34 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Andrii Nakryiko, Daniel Borkmann, kernel-team,
Martin KaFai Lau
For arm64 64K page size, the bpf_dynptr_copy() in test dynptr/test_dynptr_copy_xdp
will succeed, but the test will failure with 4K page size. This patch made a change
so the test will fail expectedly for both 4K and 64K page sizes.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
tools/testing/selftests/bpf/progs/dynptr_success.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c
index 7d7081d05d47..3094a1e4ee91 100644
--- a/tools/testing/selftests/bpf/progs/dynptr_success.c
+++ b/tools/testing/selftests/bpf/progs/dynptr_success.c
@@ -611,11 +611,12 @@ 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 +674,7 @@ 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:
--
2.47.3
^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH bpf-next 3/3] selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure
2025-07-25 4:34 [PATCH bpf-next 0/3] selftests/bpf: Fix a few dynptr test failures with 64K page size Yonghong Song
2025-07-25 4:34 ` [PATCH bpf-next 1/3] selftests/bpf: Increase xdp data size for arm64 " Yonghong Song
2025-07-25 4:34 ` [PATCH bpf-next 2/3] selftests/bpf: Fix test dynptr/test_dynptr_copy_xdp failure Yonghong Song
@ 2025-07-25 4:34 ` Yonghong Song
2025-07-25 23:29 ` Martin KaFai Lau
2025-07-26 1:40 ` [PATCH bpf-next 0/3] selftests/bpf: Fix a few dynptr test failures with 64K page size patchwork-bot+netdevbpf
3 siblings, 1 reply; 10+ messages in thread
From: Yonghong Song @ 2025-07-25 4:34 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Andrii Nakryiko, Daniel Borkmann, kernel-team,
Martin KaFai Lau
For arm64 64K page size, the xdp data size was set to be more than 64K
in one of previous patches. This will cause failure for bpf_dynptr_memset().
Since the failure of bpf_dynptr_memset() is expected with 64K page size,
return success.
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
tools/testing/selftests/bpf/progs/dynptr_success.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c
index 3094a1e4ee91..8315273cb900 100644
--- a/tools/testing/selftests/bpf/progs/dynptr_success.c
+++ b/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;
@@ -821,8 +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);
--
2.47.3
^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH bpf-next 1/3] selftests/bpf: Increase xdp data size for arm64 64K page size
2025-07-25 4:34 ` [PATCH bpf-next 1/3] selftests/bpf: Increase xdp data size for arm64 " Yonghong Song
@ 2025-07-25 11:53 ` Mykyta Yatsenko
0 siblings, 0 replies; 10+ messages in thread
From: Mykyta Yatsenko @ 2025-07-25 11:53 UTC (permalink / raw)
To: Yonghong Song, bpf
Cc: Alexei Starovoitov, Andrii Nakryiko, Daniel Borkmann, kernel-team,
Martin KaFai Lau
On 7/25/25 05:34, Yonghong Song wrote:
> With arm64 64K page size, the following 4 subtests failed:
> #97/25 dynptr/test_probe_read_user_dynptr:FAIL
> #97/26 dynptr/test_probe_read_kernel_dynptr:FAIL
> #97/27 dynptr/test_probe_read_user_str_dynptr:FAIL
> #97/28 dynptr/test_probe_read_kernel_str_dynptr:FAIL
>
> These failures are due to function bpf_dynptr_check_off_len() in
> include/linux/bpf.h where there is a test
> if (len > size || offset > size - len)
> return -E2BIG;
> With 64K page size, the 'offset' is greater than 'size - len',
> which caused the test failure.
>
> For 64KB page size, this patch increased the xdp buffer size from 5000 to
> 90000. The above 4 test failures are fixed as 'size' value is increased.
> But it introduced two new failures:
> #97/4 dynptr/test_dynptr_copy_xdp:FAIL
> #97/12 dynptr/test_dynptr_memset_xdp_chunks:FAIL
>
> These two failures will be addressed in subsequent patches.
>
> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
> ---
> tools/testing/selftests/bpf/prog_tests/dynptr.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/dynptr.c b/tools/testing/selftests/bpf/prog_tests/dynptr.c
> index f2b65398afce..9b2d9ceda210 100644
> --- a/tools/testing/selftests/bpf/prog_tests/dynptr.c
> +++ b/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);
>
Thanks for fixing these tests for 64K page size.
Acked-by: Mykyta Yatsenko <yatsenko@meta.com>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf-next 2/3] selftests/bpf: Fix test dynptr/test_dynptr_copy_xdp failure
2025-07-25 4:34 ` [PATCH bpf-next 2/3] selftests/bpf: Fix test dynptr/test_dynptr_copy_xdp failure Yonghong Song
@ 2025-07-25 11:53 ` Mykyta Yatsenko
0 siblings, 0 replies; 10+ messages in thread
From: Mykyta Yatsenko @ 2025-07-25 11:53 UTC (permalink / raw)
To: Yonghong Song, bpf
Cc: Alexei Starovoitov, Andrii Nakryiko, Daniel Borkmann, kernel-team,
Martin KaFai Lau
On 7/25/25 05:34, Yonghong Song wrote:
> For arm64 64K page size, the bpf_dynptr_copy() in test dynptr/test_dynptr_copy_xdp
> will succeed, but the test will failure with 4K page size. This patch made a change
> so the test will fail expectedly for both 4K and 64K page sizes.
>
> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
> ---
> tools/testing/selftests/bpf/progs/dynptr_success.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c
> index 7d7081d05d47..3094a1e4ee91 100644
> --- a/tools/testing/selftests/bpf/progs/dynptr_success.c
> +++ b/tools/testing/selftests/bpf/progs/dynptr_success.c
> @@ -611,11 +611,12 @@ 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 +674,7 @@ 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:
Acked-by: Mykyta Yatsenko <yatsenko@meta.com>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf-next 3/3] selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure
2025-07-25 4:34 ` [PATCH bpf-next 3/3] selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure Yonghong Song
@ 2025-07-25 23:29 ` Martin KaFai Lau
2025-07-26 0:59 ` Yonghong Song
0 siblings, 1 reply; 10+ messages in thread
From: Martin KaFai Lau @ 2025-07-25 23:29 UTC (permalink / raw)
To: Yonghong Song
Cc: Alexei Starovoitov, Andrii Nakryiko, Daniel Borkmann, kernel-team,
Martin KaFai Lau, bpf
On 7/24/25 9:34 PM, Yonghong Song wrote:
> For arm64 64K page size, the xdp data size was set to be more than 64K
> in one of previous patches. This will cause failure for bpf_dynptr_memset().
> Since the failure of bpf_dynptr_memset() is expected with 64K page size,
> return success.
>
> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
> ---
> tools/testing/selftests/bpf/progs/dynptr_success.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/testing/selftests/bpf/progs/dynptr_success.c
> index 3094a1e4ee91..8315273cb900 100644
> --- a/tools/testing/selftests/bpf/progs/dynptr_success.c
> +++ b/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;
> @@ -821,8 +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()
I don't think I understand why the test fixed in patch 1 (e.g.
test_probe_read_user_dynptr) can pass the bpf_xdp_pointer test on 0xffff. I
thought the bpf_probe_read_user_str_dynptr will eventually call the
__bpf_xdp_store_bytes which also does a 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);
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf-next 3/3] selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure
2025-07-25 23:29 ` Martin KaFai Lau
@ 2025-07-26 0:59 ` Yonghong Song
2025-07-26 1:41 ` Martin KaFai Lau
0 siblings, 1 reply; 10+ messages in thread
From: Yonghong Song @ 2025-07-26 0:59 UTC (permalink / raw)
To: Martin KaFai Lau
Cc: Alexei Starovoitov, Andrii Nakryiko, Daniel Borkmann, kernel-team,
Martin KaFai Lau, bpf
On 7/25/25 4:29 PM, Martin KaFai Lau wrote:
> On 7/24/25 9:34 PM, Yonghong Song wrote:
>> For arm64 64K page size, the xdp data size was set to be more than 64K
>> in one of previous patches. This will cause failure for
>> bpf_dynptr_memset().
>> Since the failure of bpf_dynptr_memset() is expected with 64K page size,
>> return success.
>>
>> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
>> ---
>> tools/testing/selftests/bpf/progs/dynptr_success.c | 13 ++++++++++++-
>> 1 file changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c
>> b/tools/testing/selftests/bpf/progs/dynptr_success.c
>> index 3094a1e4ee91..8315273cb900 100644
>> --- a/tools/testing/selftests/bpf/progs/dynptr_success.c
>> +++ b/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;
>> @@ -821,8 +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()
>
> I don't think I understand why the test fixed in patch 1 (e.g.
> test_probe_read_user_dynptr) can pass the bpf_xdp_pointer test on
> 0xffff. I thought the bpf_probe_read_user_str_dynptr will eventually
> call the __bpf_xdp_store_bytes which also does a bpf_xdp_pointer?
For example, for test_probe_read_user_dynptr, for function test_dynptr_probe_xdp(),
for this one:
off = xdp_near_frag_end_offset();
the off = 64928. Note that xdp_near_frag_end_offset() return value depends page size.
__u32 xdp_near_frag_end_offset(void)
{
const __u32 headroom = 256;
const __u32 max_frag_size = __PAGE_SIZE - headroom - sizeof(struct skb_shared_info);
/* 32 bytes before the approximate end of the fragment */
return max_frag_size - 32;
}
The 'len' depends on 'test_len[i]' and test_len is
__u32 test_len[7] = {0/* placeholder */, 0, 1, 2, 255, 256, 257};
In bpf_xdp_pointer, we have the following test
if (unlikely(offset > 0xffff || len > 0xffff))
return ERR_PTR(-EFAULT);
In this particular case, offset = 64928, len = {0, 1, 2, 255, 256, 257}, so
it won't return -EFAULT.
For this patch 3, test_dynptr_memset_xdp_chunks, eventually we reached here:
for (write_off = 0; write_off < size; write_off += chunk_sz) {
chunk_sz = min_t(u32, sizeof(buf), size - write_off);
err = __bpf_dynptr_write(ptr, offset + write_off, buf, chunk_sz, 0);
if (err)
return err;
}
So the 'size' is 90000, chunk_sz is 256.
So 'offset + write_off' will be 0, 256, 512, ..., 65536
Once it reached 65536, 'offset > 0xffff' will become true since 0xffff = 65535.
and the -EFAULT will be returned.
>
>> + * 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);
>
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf-next 0/3] selftests/bpf: Fix a few dynptr test failures with 64K page size
2025-07-25 4:34 [PATCH bpf-next 0/3] selftests/bpf: Fix a few dynptr test failures with 64K page size Yonghong Song
` (2 preceding siblings ...)
2025-07-25 4:34 ` [PATCH bpf-next 3/3] selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure Yonghong Song
@ 2025-07-26 1:40 ` patchwork-bot+netdevbpf
3 siblings, 0 replies; 10+ messages in thread
From: patchwork-bot+netdevbpf @ 2025-07-26 1:40 UTC (permalink / raw)
To: Yonghong Song; +Cc: bpf, ast, andrii, daniel, kernel-team, martin.lau
Hello:
This series was applied to bpf/bpf-next.git (master)
by Martin KaFai Lau <martin.lau@kernel.org>:
On Thu, 24 Jul 2025 21:34:25 -0700 you wrote:
> 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.
>
> Yonghong Song (3):
> selftests/bpf: Increase xdp data size for arm64 64K page size
> selftests/bpf: Fix test dynptr/test_dynptr_copy_xdp failure
> selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure
>
> [...]
Here is the summary with links:
- [bpf-next,1/3] selftests/bpf: Increase xdp data size for arm64 64K page size
https://git.kernel.org/bpf/bpf-next/c/4c82768e4134
- [bpf-next,2/3] selftests/bpf: Fix test dynptr/test_dynptr_copy_xdp failure
https://git.kernel.org/bpf/bpf-next/c/90f791a975af
- [bpf-next,3/3] selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure
https://git.kernel.org/bpf/bpf-next/c/4a5dcb337395
You are awesome, thank you!
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^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH bpf-next 3/3] selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure
2025-07-26 0:59 ` Yonghong Song
@ 2025-07-26 1:41 ` Martin KaFai Lau
0 siblings, 0 replies; 10+ messages in thread
From: Martin KaFai Lau @ 2025-07-26 1:41 UTC (permalink / raw)
To: Yonghong Song, Lorenzo Bianconi
Cc: Alexei Starovoitov, Andrii Nakryiko, Daniel Borkmann, kernel-team,
Martin KaFai Lau, bpf, Network Development
On 7/25/25 5:59 PM, Yonghong Song wrote:
>
>
> On 7/25/25 4:29 PM, Martin KaFai Lau wrote:
>> On 7/24/25 9:34 PM, Yonghong Song wrote:
>>> For arm64 64K page size, the xdp data size was set to be more than 64K
>>> in one of previous patches. This will cause failure for bpf_dynptr_memset().
>>> Since the failure of bpf_dynptr_memset() is expected with 64K page size,
>>> return success.
>>>
>>> Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
>>> ---
>>> tools/testing/selftests/bpf/progs/dynptr_success.c | 13 ++++++++++++-
>>> 1 file changed, 12 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/tools/testing/selftests/bpf/progs/dynptr_success.c b/tools/
>>> testing/selftests/bpf/progs/dynptr_success.c
>>> index 3094a1e4ee91..8315273cb900 100644
>>> --- a/tools/testing/selftests/bpf/progs/dynptr_success.c
>>> +++ b/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;
>>> @@ -821,8 +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()
>>
>> I don't think I understand why the test fixed in patch 1 (e.g.
>> test_probe_read_user_dynptr) can pass the bpf_xdp_pointer test on 0xffff. I
>> thought the bpf_probe_read_user_str_dynptr will eventually call the
>> __bpf_xdp_store_bytes which also does a bpf_xdp_pointer?
>
> For example, for test_probe_read_user_dynptr, for function test_dynptr_probe_xdp(),
> for this one:
> off = xdp_near_frag_end_offset();
>
> the off = 64928. Note that xdp_near_frag_end_offset() return value depends page
> size.
>
> __u32 xdp_near_frag_end_offset(void)
> {
> const __u32 headroom = 256;
> const __u32 max_frag_size = __PAGE_SIZE - headroom - sizeof(struct
> skb_shared_info);
> /* 32 bytes before the approximate end of the fragment */
> return max_frag_size - 32;
> }
>
> The 'len' depends on 'test_len[i]' and test_len is
> __u32 test_len[7] = {0/* placeholder */, 0, 1, 2, 255, 256, 257};
>
> In bpf_xdp_pointer, we have the following test
>
> if (unlikely(offset > 0xffff || len > 0xffff))
Thanks for the explanation. Applied. Thanks.
I wonder if the 0xffff check can be removed from bpf_xdp_pointer() and depend on
checking the xdp_get_buff_len(). The 0xffff check was also removed from the
bpf_skb_load_bytes some time ago. [cc: Lorenzo, netdev]
Otherwise, it is not very useful to be able to create such xdp buff from the
bpf_prog_test_run_xdp.
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2025-07-26 1:41 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-07-25 4:34 [PATCH bpf-next 0/3] selftests/bpf: Fix a few dynptr test failures with 64K page size Yonghong Song
2025-07-25 4:34 ` [PATCH bpf-next 1/3] selftests/bpf: Increase xdp data size for arm64 " Yonghong Song
2025-07-25 11:53 ` Mykyta Yatsenko
2025-07-25 4:34 ` [PATCH bpf-next 2/3] selftests/bpf: Fix test dynptr/test_dynptr_copy_xdp failure Yonghong Song
2025-07-25 11:53 ` Mykyta Yatsenko
2025-07-25 4:34 ` [PATCH bpf-next 3/3] selftests/bpf: Fix test dynptr/test_dynptr_memset_xdp_chunks failure Yonghong Song
2025-07-25 23:29 ` Martin KaFai Lau
2025-07-26 0:59 ` Yonghong Song
2025-07-26 1:41 ` Martin KaFai Lau
2025-07-26 1:40 ` [PATCH bpf-next 0/3] selftests/bpf: Fix a few dynptr test failures with 64K page size patchwork-bot+netdevbpf
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