* fentry/fexit attach to EXT type XDP program does not work
@ 2020-06-08 14:11 Eelco Chaudron
2020-06-08 16:58 ` Yonghong Song
0 siblings, 1 reply; 8+ messages in thread
From: Eelco Chaudron @ 2020-06-08 14:11 UTC (permalink / raw)
To: bpf; +Cc: netdev, ast, daniel, kafai, songliubraving, yhs, andriin, toke
I'm trying for a while to do a fentry/fexit trace an EXT program
attached to an XDP program. To make it easier to explain I've
created a test case (see patch below) to show the issue.
Without the changes to test_xdp_bpf2bpf.c I'll get the following error:
libbpf: -- BEGIN DUMP LOG ---
libbpf:
arg#0 type is not a struct
Unrecognized arg#0 type PTR
; int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
0: (79) r6 = *(u64 *)(r1 +0)
invalid bpf_context access off=0 size=8
processed 1 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
libbpf: -- END LOG --
libbpf: failed to load program 'fentry/FUNC'
libbpf: failed to load object 'test_xdp_bpf2bpf'
libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -4007
test_xdp_fentry_ext:FAIL:__load ftrace skeleton failed
#91 xdp_fentry_ext:FAIL
Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
With the change I get the following (but I do feel this change
should not be needed):
libbpf: -- BEGIN DUMP LOG ---
libbpf:
Unrecognized arg#0 type PTR
; int trace_on_entry(struct xdp_buff *xdp)
0: (bf) r6 = r1
; void *data = (void *)(long)xdp->data;
1: (79) r1 = *(u64 *)(r6 +0)
invalid bpf_context access off=0 size=8
processed 2 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
libbpf: -- END LOG --
libbpf: failed to load program 'fentry/FUNC'
libbpf: failed to load object 'test_xdp_bpf2bpf'
libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -4007
test_xdp_fentry_ext:FAIL:__load ftrace skeleton failed
#91 xdp_fentry_ext:FAIL
Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
Any idea what could be the case here? The same fentry/fexit attach
code works fine in the xdp_bpf2bpf.c tests case.
Cheers,
Eelco
---
.../selftests/bpf/prog_tests/xdp_fentry_ext.c | 95 ++++++++++++++++++++
1 file changed, 95 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_fentry_ext.c
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_fentry_ext.c b/tools/testing/selftests/bpf/prog_tests/xdp_fentry_ext.c
new file mode 100644
index 000000000000..68cd83fad632
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_fentry_ext.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include <network_helpers.h>
+
+#include "test_xdp_ext.skel.h"
+#include "test_xdp_bpf2bpf.skel.h"
+#include "xdp_dummy.skel.h"
+
+void test_xdp_fentry_ext(void)
+{
+ /* Using the skeleton framework does not work, as it does not like
+ * like the prog_replace() function to be noinline
+ */
+
+ __u32 duration = 0, retval, size;
+ const char *file = "./test_xdp_ext.o";
+ const char *ext_file = "./xdp_dummy.o";
+ struct bpf_program *prog;
+ struct bpf_program *ext_prog;
+ struct bpf_object *xdp_obj, *ext_obj = NULL;
+ struct test_xdp_bpf2bpf *ftrace_skel = NULL;
+ int err, xdp_fd, ext_fd;
+ char buf[128];
+
+ err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &xdp_obj, &xdp_fd);
+ if (CHECK_FAIL(err))
+ return;
+
+ /* Load the EXT program to attach to replace existing function */
+ ext_obj = bpf_object__open_file(ext_file, NULL);
+ if (CHECK(IS_ERR_OR_NULL(ext_obj), "obj_open",
+ "failed to open %s: %ld\n",
+ ext_file, PTR_ERR(ext_obj)))
+ goto out;
+
+ ext_prog = bpf_object__find_program_by_title(ext_obj, "xdp_dummy");
+ if (CHECK(!ext_prog, "find_prog", "xdp_dummy_prog not found\n"))
+ goto out;
+
+ err = bpf_program__set_attach_target(ext_prog, xdp_fd, "prog_replace");
+ if (CHECK(err, "set_attach", "err %d, errno %d\n", err, errno))
+ goto out;
+
+ bpf_program__set_type(ext_prog, BPF_PROG_TYPE_EXT);
+
+ err = bpf_object__load(ext_obj);
+ if (CHECK(err, "obj_load", "err %d\n", err))
+ goto out;
+
+ bpf_program__attach_trace(ext_prog);
+
+ ext_fd = bpf_program__fd(ext_prog);
+
+ /* Now try to attach an fentry trace to the EXT program above */
+
+ ftrace_skel = test_xdp_bpf2bpf__open();
+ if (CHECK(!ftrace_skel, "__open", "ftrace skeleton failed\n"))
+ goto out;
+
+ prog = ftrace_skel->progs.trace_on_entry;
+ bpf_program__set_expected_attach_type(prog, BPF_TRACE_FENTRY);
+ bpf_program__set_attach_target(prog, ext_fd, "xdp_dummy_prog");
+
+ prog = ftrace_skel->progs.trace_on_exit;
+ bpf_program__set_expected_attach_type(prog, BPF_TRACE_FEXIT);
+ bpf_program__set_attach_target(prog, ext_fd, "xdp_dummy_prog");
+
+ err = test_xdp_bpf2bpf__load(ftrace_skel);
+ if (CHECK(err, "__load", "ftrace skeleton failed\n"))
+ goto out;
+
+ err = test_xdp_bpf2bpf__attach(ftrace_skel);
+ if (CHECK(err, "ftrace_attach", "ftrace attach failed: %d\n", err))
+ goto out;
+
+
+ /* Execute the xdp program by sending a dummy packet */
+ err = bpf_prog_test_run(xdp_fd, 1, &pkt_v4, sizeof(pkt_v4),
+ buf, &size, &retval, &duration);
+
+ if (CHECK(err || retval != XDP_PASS , "packet",
+ "err %d, errno %d, retval %d %c= %d\n",
+ err, errno, retval, retval != XDP_PASS ? '!' : '=', XDP_PASS))
+ goto out;
+
+out:
+ bpf_object__close(xdp_obj);
+ if (ext_obj)
+ bpf_object__close(ext_obj);
+ if (ftrace_skel)
+ test_xdp_bpf2bpf__destroy(ftrace_skel);
+
+}
+
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c b/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
index a038e827f850..41b2a103c7ca 100644
--- a/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
@@ -42,7 +42,8 @@ struct {
__u64 test_result_fentry = 0;
SEC("fentry/FUNC")
-int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
+//int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
+int trace_on_entry(struct xdp_buff *xdp)
{
struct meta meta;
void *data_end = (void *)(long)xdp->data_end;
@@ -61,7 +62,8 @@ int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
__u64 test_result_fexit = 0;
SEC("fexit/FUNC")
-int BPF_PROG(trace_on_exit, struct xdp_buff *xdp, int ret)
+//int BPF_PROG(trace_on_exit, struct xdp_buff *xdp, int ret)
+int trace_on_exit(struct xdp_buff *xdp, int ret)
{
test_result_fexit = ret;
return 0;
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_ext.c b/tools/testing/selftests/bpf/progs/test_xdp_ext.c
new file mode 100644
index 000000000000..37bd16c95b36
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_ext.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+__u64 xdp_ext_called = 0;
+
+__attribute__ ((noinline))
+int prog_replace(struct xdp_md *ctx) {
+ volatile int ret = XDP_ABORTED;
+
+ return ret;
+}
+
+SEC("xdp_ext_call")
+int xdp_ext_call_func(struct xdp_md *ctx)
+{
+
+ return prog_replace(ctx);
+}
+
+char _license[] SEC("license") = "GPL";
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: fentry/fexit attach to EXT type XDP program does not work
2020-06-08 14:11 fentry/fexit attach to EXT type XDP program does not work Eelco Chaudron
@ 2020-06-08 16:58 ` Yonghong Song
2020-06-09 8:52 ` Eelco Chaudron
0 siblings, 1 reply; 8+ messages in thread
From: Yonghong Song @ 2020-06-08 16:58 UTC (permalink / raw)
To: Eelco Chaudron, bpf
Cc: netdev, ast, daniel, kafai, songliubraving, andriin, toke
On 6/8/20 7:11 AM, Eelco Chaudron wrote:
> I'm trying for a while to do a fentry/fexit trace an EXT program
> attached to an XDP program. To make it easier to explain I've
> created a test case (see patch below) to show the issue.
>
> Without the changes to test_xdp_bpf2bpf.c I'll get the following error:
>
> libbpf: -- BEGIN DUMP LOG ---
> libbpf:
> arg#0 type is not a struct
> Unrecognized arg#0 type PTR
> ; int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
> 0: (79) r6 = *(u64 *)(r1 +0)
> invalid bpf_context access off=0 size=8
> processed 1 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
>
> libbpf: -- END LOG --
> libbpf: failed to load program 'fentry/FUNC'
> libbpf: failed to load object 'test_xdp_bpf2bpf'
> libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -4007
> test_xdp_fentry_ext:FAIL:__load ftrace skeleton failed
> #91 xdp_fentry_ext:FAIL
> Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
>
> With the change I get the following (but I do feel this change
> should not be needed):
>
> libbpf: -- BEGIN DUMP LOG ---
> libbpf:
> Unrecognized arg#0 type PTR
> ; int trace_on_entry(struct xdp_buff *xdp)
> 0: (bf) r6 = r1
> ; void *data = (void *)(long)xdp->data;
> 1: (79) r1 = *(u64 *)(r6 +0)
> invalid bpf_context access off=0 size=8
> processed 2 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
>
> libbpf: -- END LOG --
> libbpf: failed to load program 'fentry/FUNC'
> libbpf: failed to load object 'test_xdp_bpf2bpf'
> libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -4007
> test_xdp_fentry_ext:FAIL:__load ftrace skeleton failed
> #91 xdp_fentry_ext:FAIL
> Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
>
> Any idea what could be the case here? The same fentry/fexit attach
> code works fine in the xdp_bpf2bpf.c tests case.
>
>
> Cheers,
>
>
> Eelco
> ---
> .../selftests/bpf/prog_tests/xdp_fentry_ext.c | 95 ++++++++++++++++++++
> 1 file changed, 95 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_fentry_ext.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_fentry_ext.c b/tools/testing/selftests/bpf/prog_tests/xdp_fentry_ext.c
> new file mode 100644
> index 000000000000..68cd83fad632
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_fentry_ext.c
> @@ -0,0 +1,95 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <test_progs.h>
> +#include <network_helpers.h>
> +
> +#include "test_xdp_ext.skel.h"
> +#include "test_xdp_bpf2bpf.skel.h"
> +#include "xdp_dummy.skel.h"
> +
> +void test_xdp_fentry_ext(void)
> +{
> + /* Using the skeleton framework does not work, as it does not like
> + * like the prog_replace() function to be noinline
> + */
> +
> + __u32 duration = 0, retval, size;
> + const char *file = "./test_xdp_ext.o";
> + const char *ext_file = "./xdp_dummy.o";
> + struct bpf_program *prog;
> + struct bpf_program *ext_prog;
> + struct bpf_object *xdp_obj, *ext_obj = NULL;
> + struct test_xdp_bpf2bpf *ftrace_skel = NULL;
> + int err, xdp_fd, ext_fd;
> + char buf[128];
> +
> + err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &xdp_obj, &xdp_fd);
> + if (CHECK_FAIL(err))
> + return;
> +
> + /* Load the EXT program to attach to replace existing function */
> + ext_obj = bpf_object__open_file(ext_file, NULL);
> + if (CHECK(IS_ERR_OR_NULL(ext_obj), "obj_open",
> + "failed to open %s: %ld\n",
> + ext_file, PTR_ERR(ext_obj)))
> + goto out;
> +
> + ext_prog = bpf_object__find_program_by_title(ext_obj, "xdp_dummy");
> + if (CHECK(!ext_prog, "find_prog", "xdp_dummy_prog not found\n"))
> + goto out;
> +
> + err = bpf_program__set_attach_target(ext_prog, xdp_fd, "prog_replace");
> + if (CHECK(err, "set_attach", "err %d, errno %d\n", err, errno))
> + goto out;
> +
> + bpf_program__set_type(ext_prog, BPF_PROG_TYPE_EXT);
> +
> + err = bpf_object__load(ext_obj);
> + if (CHECK(err, "obj_load", "err %d\n", err))
> + goto out;
> +
> + bpf_program__attach_trace(ext_prog);
> +
> + ext_fd = bpf_program__fd(ext_prog);
> +
> + /* Now try to attach an fentry trace to the EXT program above */
> +
> + ftrace_skel = test_xdp_bpf2bpf__open();
> + if (CHECK(!ftrace_skel, "__open", "ftrace skeleton failed\n"))
> + goto out;
I think this is not supported now. That is, you cannot attach a fentry trace
to the EXT program. The current implementation for fentry program simply
trying to find and match the signature of freplace program which by default
is a pointer to void.
It is doable in that in kernel we could recognize to-be-attached program is
a freplace and further trace down to find the real signature. The related
kernel function is btf_get_prog_ctx_type(). You can try to implement by
yourself
or I can have a patch for this once bpf-next opens.
> +
> + prog = ftrace_skel->progs.trace_on_entry;
> + bpf_program__set_expected_attach_type(prog, BPF_TRACE_FENTRY);
> + bpf_program__set_attach_target(prog, ext_fd, "xdp_dummy_prog");
> +
> + prog = ftrace_skel->progs.trace_on_exit;
> + bpf_program__set_expected_attach_type(prog, BPF_TRACE_FEXIT);
> + bpf_program__set_attach_target(prog, ext_fd, "xdp_dummy_prog");
> +
> + err = test_xdp_bpf2bpf__load(ftrace_skel);
> + if (CHECK(err, "__load", "ftrace skeleton failed\n"))
> + goto out;
> +
> + err = test_xdp_bpf2bpf__attach(ftrace_skel);
> + if (CHECK(err, "ftrace_attach", "ftrace attach failed: %d\n", err))
> + goto out;
> +
> +
> + /* Execute the xdp program by sending a dummy packet */
> + err = bpf_prog_test_run(xdp_fd, 1, &pkt_v4, sizeof(pkt_v4),
> + buf, &size, &retval, &duration);
> +
> + if (CHECK(err || retval != XDP_PASS , "packet",
> + "err %d, errno %d, retval %d %c= %d\n",
> + err, errno, retval, retval != XDP_PASS ? '!' : '=', XDP_PASS))
> + goto out;
> +
> +out:
> + bpf_object__close(xdp_obj);
> + if (ext_obj)
> + bpf_object__close(ext_obj);
> + if (ftrace_skel)
> + test_xdp_bpf2bpf__destroy(ftrace_skel);
> +
> +}
> +
> diff --git a/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c b/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
> index a038e827f850..41b2a103c7ca 100644
> --- a/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
> +++ b/tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
> @@ -42,7 +42,8 @@ struct {
>
> __u64 test_result_fentry = 0;
> SEC("fentry/FUNC")
> -int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
> +//int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
> +int trace_on_entry(struct xdp_buff *xdp)
> {
> struct meta meta;
> void *data_end = (void *)(long)xdp->data_end;
> @@ -61,7 +62,8 @@ int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
>
> __u64 test_result_fexit = 0;
> SEC("fexit/FUNC")
> -int BPF_PROG(trace_on_exit, struct xdp_buff *xdp, int ret)
> +//int BPF_PROG(trace_on_exit, struct xdp_buff *xdp, int ret)
> +int trace_on_exit(struct xdp_buff *xdp, int ret)
> {
> test_result_fexit = ret;
> return 0;
> diff --git a/tools/testing/selftests/bpf/progs/test_xdp_ext.c b/tools/testing/selftests/bpf/progs/test_xdp_ext.c
> new file mode 100644
> index 000000000000..37bd16c95b36
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_xdp_ext.c
> @@ -0,0 +1,21 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +
> +__u64 xdp_ext_called = 0;
> +
> +__attribute__ ((noinline))
> +int prog_replace(struct xdp_md *ctx) {
> + volatile int ret = XDP_ABORTED;
> +
> + return ret;
> +}
> +
> +SEC("xdp_ext_call")
> +int xdp_ext_call_func(struct xdp_md *ctx)
> +{
> +
> + return prog_replace(ctx);
> +}
> +
> +char _license[] SEC("license") = "GPL";
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: fentry/fexit attach to EXT type XDP program does not work
2020-06-08 16:58 ` Yonghong Song
@ 2020-06-09 8:52 ` Eelco Chaudron
2020-07-26 12:24 ` Jiri Olsa
0 siblings, 1 reply; 8+ messages in thread
From: Eelco Chaudron @ 2020-06-09 8:52 UTC (permalink / raw)
To: Yonghong Song
Cc: bpf, netdev, ast, daniel, kafai, songliubraving, andriin, toke
On 8 Jun 2020, at 18:58, Yonghong Song wrote:
> On 6/8/20 7:11 AM, Eelco Chaudron wrote:
>> I'm trying for a while to do a fentry/fexit trace an EXT program
>> attached to an XDP program. To make it easier to explain I've
>> created a test case (see patch below) to show the issue.
>>
>> Without the changes to test_xdp_bpf2bpf.c I'll get the following
>> error:
>>
>> libbpf: -- BEGIN DUMP LOG ---
>> libbpf:
>> arg#0 type is not a struct
>> Unrecognized arg#0 type PTR
>> ; int BPF_PROG(trace_on_entry, struct xdp_buff *xdp)
>> 0: (79) r6 = *(u64 *)(r1 +0)
>> invalid bpf_context access off=0 size=8
>> processed 1 insns (limit 1000000) max_states_per_insn 0
>> total_states 0 peak_states 0 mark_read 0
>>
>> libbpf: -- END LOG --
>> libbpf: failed to load program 'fentry/FUNC'
>> libbpf: failed to load object 'test_xdp_bpf2bpf'
>> libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -4007
>> test_xdp_fentry_ext:FAIL:__load ftrace skeleton failed
>> #91 xdp_fentry_ext:FAIL
>> Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
>>
>> With the change I get the following (but I do feel this change
>> should not be needed):
>>
>> libbpf: -- BEGIN DUMP LOG ---
>> libbpf:
>> Unrecognized arg#0 type PTR
>> ; int trace_on_entry(struct xdp_buff *xdp)
>> 0: (bf) r6 = r1
>> ; void *data = (void *)(long)xdp->data;
>> 1: (79) r1 = *(u64 *)(r6 +0)
>> invalid bpf_context access off=0 size=8
>> processed 2 insns (limit 1000000) max_states_per_insn 0
>> total_states 0 peak_states 0 mark_read 0
>>
>> libbpf: -- END LOG --
>> libbpf: failed to load program 'fentry/FUNC'
>> libbpf: failed to load object 'test_xdp_bpf2bpf'
>> libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -4007
>> test_xdp_fentry_ext:FAIL:__load ftrace skeleton failed
>> #91 xdp_fentry_ext:FAIL
>> Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
>>
>> Any idea what could be the case here? The same fentry/fexit attach
>> code works fine in the xdp_bpf2bpf.c tests case.
<SNIP>
>
> I think this is not supported now. That is, you cannot attach a fentry
> trace
> to the EXT program. The current implementation for fentry program
> simply
> trying to find and match the signature of freplace program which by
> default
> is a pointer to void.
>
> It is doable in that in kernel we could recognize to-be-attached
> program is
> a freplace and further trace down to find the real signature. The
> related
> kernel function is btf_get_prog_ctx_type(). You can try to implement
> by yourself
> or I can have a patch for this once bpf-next opens.
I’m not familiar with this area of the code, so if you could prepare a
patch that would nice.
You can also send it to me before bpf-next opens and I can verify it,
and clean up the self-test so it can be included as well.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: fentry/fexit attach to EXT type XDP program does not work
2020-06-09 8:52 ` Eelco Chaudron
@ 2020-07-26 12:24 ` Jiri Olsa
2020-07-27 7:59 ` Eelco Chaudron
0 siblings, 1 reply; 8+ messages in thread
From: Jiri Olsa @ 2020-07-26 12:24 UTC (permalink / raw)
To: Eelco Chaudron
Cc: Yonghong Song, bpf, netdev, ast, daniel, kafai, songliubraving,
andriin, toke
On Tue, Jun 09, 2020 at 10:52:34AM +0200, Eelco Chaudron wrote:
SNIP
> > > libbpf: failed to load object 'test_xdp_bpf2bpf'
> > > libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -4007
> > > test_xdp_fentry_ext:FAIL:__load ftrace skeleton failed
> > > #91 xdp_fentry_ext:FAIL
> > > Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
> > >
> > > Any idea what could be the case here? The same fentry/fexit attach
> > > code works fine in the xdp_bpf2bpf.c tests case.
>
> <SNIP>
> >
> > I think this is not supported now. That is, you cannot attach a fentry
> > trace
> > to the EXT program. The current implementation for fentry program simply
> > trying to find and match the signature of freplace program which by
> > default
> > is a pointer to void.
> >
> > It is doable in that in kernel we could recognize to-be-attached program
> > is
> > a freplace and further trace down to find the real signature. The
> > related
> > kernel function is btf_get_prog_ctx_type(). You can try to implement by
> > yourself
> > or I can have a patch for this once bpf-next opens.
>
> I’m not familiar with this area of the code, so if you could prepare a patch
> that would nice.
> You can also send it to me before bpf-next opens and I can verify it, and
> clean up the self-test so it can be included as well.
>
hi,
it seems that you cannot exten fentry/fexit programs,
but it's possible to attach fentry/fexit to ext program.
/* Program extensions can extend all program types
* except fentry/fexit. The reason is the following.
* The fentry/fexit programs are used for performance
* analysis, stats and can be attached to any program
* type except themselves. When extension program is
* replacing XDP function it is necessary to allow
* performance analysis of all functions. Both original
* XDP program and its program extension. Hence
* attaching fentry/fexit to BPF_PROG_TYPE_EXT is
* allowed. If extending of fentry/fexit was allowed it
* would be possible to create long call chain
* fentry->extension->fentry->extension beyond
* reasonable stack size. Hence extending fentry is not
* allowed.
*/
I changed fexit_bpf2bpf.c test just to do a quick check
and it seems to work:
# echo > /sys/kernel/debug/tracing/trace
# ./test_progs -t fexit_bpf2bpf
#25 fexit_bpf2bpf:OK
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
# cat /sys/kernel/debug/tracing/trace | tail -2
<...>-75365 [012] d... 313932.416780: bpf_trace_printk: ENTRY val 123
<...>-75365 [012] d... 313932.416784: bpf_trace_printk: EXIT val 123, ret 1
jirka
---
diff --git a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
index a895bfed55db..4b6c26ac2362 100644
--- a/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
+++ b/tools/testing/selftests/bpf/prog_tests/fexit_bpf2bpf.c
@@ -17,6 +17,7 @@ static void test_fexit_bpf2bpf_common(const char *obj_file,
struct bpf_map *data_map;
const int zero = 0;
u64 *result = NULL;
+ int ext_fd;
err = bpf_prog_load(target_obj_file, BPF_PROG_TYPE_UNSPEC,
&pkt_obj, &pkt_fd);
@@ -51,11 +52,50 @@ static void test_fexit_bpf2bpf_common(const char *obj_file,
link[i] = bpf_program__attach_trace(prog[i]);
if (CHECK(IS_ERR(link[i]), "attach_trace", "failed to link\n"))
goto close_prog;
+
+ if (!strcmp(prog_name[i], "freplace/get_constant"))
+ ext_fd = bpf_program__fd(prog[i]);
}
if (!run_prog)
goto close_prog;
+{
+ struct bpf_object *obj_trace = NULL;
+ struct bpf_program *prog_trace = NULL;
+ struct bpf_link *link_trace = NULL;
+
+ DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts_trace,
+ .attach_prog_fd = ext_fd,
+ );
+
+ obj_trace = bpf_object__open_file("trace_ext.o", &opts_trace);
+ if (CHECK(IS_ERR_OR_NULL(obj_trace), "obj_open",
+ "failed to open %s: %ld\n", obj_file,
+ PTR_ERR(obj_trace)))
+ goto close_prog;
+
+ err = bpf_object__load(obj_trace);
+ if (CHECK(err, "obj_load", "err %d\n", err))
+ goto close_prog;
+
+ prog_trace = bpf_object__find_program_by_title(obj_trace, "fexit/new_get_constant");
+ if (CHECK(!prog_trace, "find_prog", "prog %s not found\n", "fexit/new_get_constant"))
+ goto close_prog;
+
+ link_trace = bpf_program__attach_trace(prog_trace);
+ if (CHECK(IS_ERR(link_trace), "attach_trace", "failed to link\n"))
+ goto close_prog;
+
+ prog_trace = bpf_object__find_program_by_title(obj_trace, "fentry/new_get_constant");
+ if (CHECK(!prog_trace, "find_prog", "prog %s not found\n", "fentry/new_get_constant"))
+ goto close_prog;
+
+ link_trace = bpf_program__attach_trace(prog_trace);
+ if (CHECK(IS_ERR(link_trace), "attach_trace", "failed to link\n"))
+ goto close_prog;
+}
+
data_map = bpf_object__find_map_by_name(obj, "fexit_bp.bss");
if (CHECK(!data_map, "find_data_map", "data map not found\n"))
goto close_prog;
@@ -88,6 +128,7 @@ static void test_fexit_bpf2bpf_common(const char *obj_file,
free(result);
}
+#if 0
static void test_target_no_callees(void)
{
const char *prog_name[] = {
@@ -112,6 +153,7 @@ static void test_target_yes_callees(void)
ARRAY_SIZE(prog_name),
prog_name, true);
}
+#endif
static void test_func_replace(void)
{
@@ -130,6 +172,7 @@ static void test_func_replace(void)
prog_name, true);
}
+#if 0
static void test_func_replace_verify(void)
{
const char *prog_name[] = {
@@ -140,11 +183,9 @@ static void test_func_replace_verify(void)
ARRAY_SIZE(prog_name),
prog_name, false);
}
+#endif
void test_fexit_bpf2bpf(void)
{
- test_target_no_callees();
- test_target_yes_callees();
test_func_replace();
- test_func_replace_verify();
}
diff --git a/tools/testing/selftests/bpf/progs/trace_ext.c b/tools/testing/selftests/bpf/progs/trace_ext.c
new file mode 100644
index 000000000000..c7eaf30bf5ba
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/trace_ext.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <stddef.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_tracing.h>
+
+
+SEC("fentry/new_get_constant")
+int BPF_PROG(test_fentry_new_get_constant, long val)
+{
+ bpf_printk("ENTRY val %ld", val);
+ return 0;
+}
+
+SEC("fexit/new_get_constant")
+int BPF_PROG(test_fexit_new_get_constant, long val, int ret)
+{
+ bpf_printk("EXIT val %ld, ret %d", val, ret);
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: fentry/fexit attach to EXT type XDP program does not work
2020-07-26 12:24 ` Jiri Olsa
@ 2020-07-27 7:59 ` Eelco Chaudron
2020-07-27 14:53 ` Jiri Olsa
0 siblings, 1 reply; 8+ messages in thread
From: Eelco Chaudron @ 2020-07-27 7:59 UTC (permalink / raw)
To: Jiri Olsa
Cc: Yonghong Song, bpf, netdev, ast, daniel, kafai, songliubraving,
andriin, toke
On 26 Jul 2020, at 14:24, Jiri Olsa wrote:
> On Tue, Jun 09, 2020 at 10:52:34AM +0200, Eelco Chaudron wrote:
>
> SNIP
>
>>>> libbpf: failed to load object 'test_xdp_bpf2bpf'
>>>> libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -4007
>>>> test_xdp_fentry_ext:FAIL:__load ftrace skeleton failed
>>>> #91 xdp_fentry_ext:FAIL
>>>> Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
>>>>
>>>> Any idea what could be the case here? The same fentry/fexit attach
>>>> code works fine in the xdp_bpf2bpf.c tests case.
>>
>> <SNIP>
>>>
>>> I think this is not supported now. That is, you cannot attach a
>>> fentry
>>> trace
>>> to the EXT program. The current implementation for fentry program
>>> simply
>>> trying to find and match the signature of freplace program which by
>>> default
>>> is a pointer to void.
>>>
>>> It is doable in that in kernel we could recognize to-be-attached
>>> program
>>> is
>>> a freplace and further trace down to find the real signature. The
>>> related
>>> kernel function is btf_get_prog_ctx_type(). You can try to implement
>>> by
>>> yourself
>>> or I can have a patch for this once bpf-next opens.
>>
>> I’m not familiar with this area of the code, so if you could
>> prepare a patch
>> that would nice.
>> You can also send it to me before bpf-next opens and I can verify it,
>> and
>> clean up the self-test so it can be included as well.
>>
>
> hi,
> it seems that you cannot exten fentry/fexit programs,
> but it's possible to attach fentry/fexit to ext program.
>
> /* Program extensions can extend all program types
> * except fentry/fexit. The reason is the following.
> * The fentry/fexit programs are used for performance
> * analysis, stats and can be attached to any program
> * type except themselves. When extension program is
> * replacing XDP function it is necessary to allow
> * performance analysis of all functions. Both original
> * XDP program and its program extension. Hence
> * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
> * allowed. If extending of fentry/fexit was allowed it
> * would be possible to create long call chain
> * fentry->extension->fentry->extension beyond
> * reasonable stack size. Hence extending fentry is not
> * allowed.
> */
>
> I changed fexit_bpf2bpf.c test just to do a quick check
> and it seems to work:
Hi Jiri this is exactly what I’m trying, however when you do this
where the first argument is a pointer to some context data which you are
accessing it’s failing in the verifier.
This is a link to the original email, which has a test patch attached
that will show the failure when trying to load/attach the fentry
function and access the context:
https://lore.kernel.org/bpf/159162546868.10791.12432342618156330247.stgit@ebuild/
//Eelco
>
> # echo > /sys/kernel/debug/tracing/trace
> # ./test_progs -t fexit_bpf2bpf
> #25 fexit_bpf2bpf:OK
> Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
> # cat /sys/kernel/debug/tracing/trace | tail -2
> <...>-75365 [012] d... 313932.416780: bpf_trace_printk:
> ENTRY val 123
> <...>-75365 [012] d... 313932.416784: bpf_trace_printk:
> EXIT val 123, ret 1
>
< SNIP>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: fentry/fexit attach to EXT type XDP program does not work
2020-07-27 7:59 ` Eelco Chaudron
@ 2020-07-27 14:53 ` Jiri Olsa
2020-07-29 6:23 ` Eelco Chaudron
0 siblings, 1 reply; 8+ messages in thread
From: Jiri Olsa @ 2020-07-27 14:53 UTC (permalink / raw)
To: Eelco Chaudron
Cc: Yonghong Song, bpf, netdev, ast, daniel, kafai, songliubraving,
andriin, toke
On Mon, Jul 27, 2020 at 09:59:14AM +0200, Eelco Chaudron wrote:
>
>
> On 26 Jul 2020, at 14:24, Jiri Olsa wrote:
>
> > On Tue, Jun 09, 2020 at 10:52:34AM +0200, Eelco Chaudron wrote:
> >
> > SNIP
> >
> > > > > libbpf: failed to load object 'test_xdp_bpf2bpf'
> > > > > libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -4007
> > > > > test_xdp_fentry_ext:FAIL:__load ftrace skeleton failed
> > > > > #91 xdp_fentry_ext:FAIL
> > > > > Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
> > > > >
> > > > > Any idea what could be the case here? The same fentry/fexit attach
> > > > > code works fine in the xdp_bpf2bpf.c tests case.
> > >
> > > <SNIP>
> > > >
> > > > I think this is not supported now. That is, you cannot attach a
> > > > fentry
> > > > trace
> > > > to the EXT program. The current implementation for fentry
> > > > program simply
> > > > trying to find and match the signature of freplace program which by
> > > > default
> > > > is a pointer to void.
> > > >
> > > > It is doable in that in kernel we could recognize to-be-attached
> > > > program
> > > > is
> > > > a freplace and further trace down to find the real signature. The
> > > > related
> > > > kernel function is btf_get_prog_ctx_type(). You can try to
> > > > implement by
> > > > yourself
> > > > or I can have a patch for this once bpf-next opens.
> > >
> > > I’m not familiar with this area of the code, so if you could prepare
> > > a patch
> > > that would nice.
> > > You can also send it to me before bpf-next opens and I can verify
> > > it, and
> > > clean up the self-test so it can be included as well.
> > >
> >
> > hi,
> > it seems that you cannot exten fentry/fexit programs,
> > but it's possible to attach fentry/fexit to ext program.
> >
> > /* Program extensions can extend all program types
> > * except fentry/fexit. The reason is the following.
> > * The fentry/fexit programs are used for performance
> > * analysis, stats and can be attached to any program
> > * type except themselves. When extension program is
> > * replacing XDP function it is necessary to allow
> > * performance analysis of all functions. Both original
> > * XDP program and its program extension. Hence
> > * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
> > * allowed. If extending of fentry/fexit was allowed it
> > * would be possible to create long call chain
> > * fentry->extension->fentry->extension beyond
> > * reasonable stack size. Hence extending fentry is not
> > * allowed.
> > */
> >
> > I changed fexit_bpf2bpf.c test just to do a quick check
> > and it seems to work:
>
> Hi Jiri this is exactly what I’m trying, however when you do this where the
> first argument is a pointer to some context data which you are accessing
> it’s failing in the verifier.
> This is a link to the original email, which has a test patch attached that
> will show the failure when trying to load/attach the fentry function and
> access the context:
>
> https://lore.kernel.org/bpf/159162546868.10791.12432342618156330247.stgit@ebuild/
ok, I tried to trace ext program with __sk_buff argument and I can see
the issue as well.. can't acess the skb argument
patch below fixes it for me, I can access the skb pointer and its data
via probe read, like:
SEC("fexit/new_get_skb_ifindex")
int BPF_PROG(fexit_new_get_skb_ifindex, int val, struct __sk_buff *skb, int var, int ret)
{
__u32 data;
int err;
bpf_printk("EXIT skb %p", skb);
bpf_probe_read_kernel(&data, sizeof(data), &skb->data);
bpf_printk("EXIT ret %d, data %p", err, data);
return 0;
}
I think it should fix the xdp_md acess as well
jirka
---
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index ee36b7f60936..2145329f7b1b 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -3828,6 +3828,10 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
}
info->reg_type = PTR_TO_BTF_ID;
+
+ if (tgt_prog && tgt_prog->type == BPF_PROG_TYPE_EXT)
+ tgt_prog = tgt_prog->aux->linked_prog;
+
if (tgt_prog) {
ret = btf_translate_to_vmlinux(log, btf, t, tgt_prog->type, arg);
if (ret > 0) {
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: fentry/fexit attach to EXT type XDP program does not work
2020-07-27 14:53 ` Jiri Olsa
@ 2020-07-29 6:23 ` Eelco Chaudron
2020-07-29 8:09 ` Jiri Olsa
0 siblings, 1 reply; 8+ messages in thread
From: Eelco Chaudron @ 2020-07-29 6:23 UTC (permalink / raw)
To: Jiri Olsa
Cc: Yonghong Song, bpf, netdev, ast, daniel, kafai, songliubraving,
andriin, toke
On 27 Jul 2020, at 16:53, Jiri Olsa wrote:
> On Mon, Jul 27, 2020 at 09:59:14AM +0200, Eelco Chaudron wrote:
>>
>>
>> On 26 Jul 2020, at 14:24, Jiri Olsa wrote:
>>
>>> On Tue, Jun 09, 2020 at 10:52:34AM +0200, Eelco Chaudron wrote:
>>>
>>> SNIP
>>>
>>>>>> libbpf: failed to load object 'test_xdp_bpf2bpf'
>>>>>> libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -4007
>>>>>> test_xdp_fentry_ext:FAIL:__load ftrace skeleton failed
>>>>>> #91 xdp_fentry_ext:FAIL
>>>>>> Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
>>>>>>
>>>>>> Any idea what could be the case here? The same fentry/fexit
>>>>>> attach
>>>>>> code works fine in the xdp_bpf2bpf.c tests case.
>>>>
>>>> <SNIP>
>>>>>
>>>>> I think this is not supported now. That is, you cannot attach a
>>>>> fentry
>>>>> trace
>>>>> to the EXT program. The current implementation for fentry
>>>>> program simply
>>>>> trying to find and match the signature of freplace program which
>>>>> by
>>>>> default
>>>>> is a pointer to void.
>>>>>
>>>>> It is doable in that in kernel we could recognize to-be-attached
>>>>> program
>>>>> is
>>>>> a freplace and further trace down to find the real signature. The
>>>>> related
>>>>> kernel function is btf_get_prog_ctx_type(). You can try to
>>>>> implement by
>>>>> yourself
>>>>> or I can have a patch for this once bpf-next opens.
>>>>
>>>> I’m not familiar with this area of the code, so if you could
>>>> prepare
>>>> a patch
>>>> that would nice.
>>>> You can also send it to me before bpf-next opens and I can verify
>>>> it, and
>>>> clean up the self-test so it can be included as well.
>>>>
>>>
>>> hi,
>>> it seems that you cannot exten fentry/fexit programs,
>>> but it's possible to attach fentry/fexit to ext program.
>>>
>>> /* Program extensions can extend all program types
>>> * except fentry/fexit. The reason is the following.
>>> * The fentry/fexit programs are used for performance
>>> * analysis, stats and can be attached to any program
>>> * type except themselves. When extension program is
>>> * replacing XDP function it is necessary to allow
>>> * performance analysis of all functions. Both original
>>> * XDP program and its program extension. Hence
>>> * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
>>> * allowed. If extending of fentry/fexit was allowed it
>>> * would be possible to create long call chain
>>> * fentry->extension->fentry->extension beyond
>>> * reasonable stack size. Hence extending fentry is not
>>> * allowed.
>>> */
>>>
>>> I changed fexit_bpf2bpf.c test just to do a quick check
>>> and it seems to work:
>>
>> Hi Jiri this is exactly what I’m trying, however when you do this
>> where the
>> first argument is a pointer to some context data which you are
>> accessing
>> it’s failing in the verifier.
>> This is a link to the original email, which has a test patch attached
>> that
>> will show the failure when trying to load/attach the fentry function
>> and
>> access the context:
>>
>> https://lore.kernel.org/bpf/159162546868.10791.12432342618156330247.stgit@ebuild/
>
> ok, I tried to trace ext program with __sk_buff argument and I can see
> the issue as well.. can't acess the skb argument
>
> patch below fixes it for me, I can access the skb pointer and its data
> via probe read, like:
>
> SEC("fexit/new_get_skb_ifindex")
> int BPF_PROG(fexit_new_get_skb_ifindex, int val, struct __sk_buff
> *skb, int var, int ret)
> {
> __u32 data;
> int err;
>
> bpf_printk("EXIT skb %p", skb);
> bpf_probe_read_kernel(&data, sizeof(data), &skb->data);
> bpf_printk("EXIT ret %d, data %p", err, data);
> return 0;
> }
>
> I think it should fix the xdp_md acess as well
Excellent patch ;) It works with xdp_md as well, and even better it does
not require the bpf_probe_read_kernel(), so the test_xdp_bpf2bpf.c code
just works.
Are you planning to send the patch upstream?
> jirka
>
>
> ---
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index ee36b7f60936..2145329f7b1b 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -3828,6 +3828,10 @@ bool btf_ctx_access(int off, int size, enum
> bpf_access_type type,
> }
>
> info->reg_type = PTR_TO_BTF_ID;
> +
> + if (tgt_prog && tgt_prog->type == BPF_PROG_TYPE_EXT)
> + tgt_prog = tgt_prog->aux->linked_prog;
> +
> if (tgt_prog) {
> ret = btf_translate_to_vmlinux(log, btf, t, tgt_prog->type, arg);
> if (ret > 0) {
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: fentry/fexit attach to EXT type XDP program does not work
2020-07-29 6:23 ` Eelco Chaudron
@ 2020-07-29 8:09 ` Jiri Olsa
0 siblings, 0 replies; 8+ messages in thread
From: Jiri Olsa @ 2020-07-29 8:09 UTC (permalink / raw)
To: Eelco Chaudron
Cc: Yonghong Song, bpf, netdev, ast, daniel, kafai, songliubraving,
andriin, toke
On Wed, Jul 29, 2020 at 08:23:56AM +0200, Eelco Chaudron wrote:
SNIP
> > > > > a patch
> > > > > that would nice.
> > > > > You can also send it to me before bpf-next opens and I can verify
> > > > > it, and
> > > > > clean up the self-test so it can be included as well.
> > > > >
> > > >
> > > > hi,
> > > > it seems that you cannot exten fentry/fexit programs,
> > > > but it's possible to attach fentry/fexit to ext program.
> > > >
> > > > /* Program extensions can extend all program types
> > > > * except fentry/fexit. The reason is the following.
> > > > * The fentry/fexit programs are used for performance
> > > > * analysis, stats and can be attached to any program
> > > > * type except themselves. When extension program is
> > > > * replacing XDP function it is necessary to allow
> > > > * performance analysis of all functions. Both original
> > > > * XDP program and its program extension. Hence
> > > > * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
> > > > * allowed. If extending of fentry/fexit was allowed it
> > > > * would be possible to create long call chain
> > > > * fentry->extension->fentry->extension beyond
> > > > * reasonable stack size. Hence extending fentry is not
> > > > * allowed.
> > > > */
> > > >
> > > > I changed fexit_bpf2bpf.c test just to do a quick check
> > > > and it seems to work:
> > >
> > > Hi Jiri this is exactly what I’m trying, however when you do this
> > > where the
> > > first argument is a pointer to some context data which you are
> > > accessing
> > > it’s failing in the verifier.
> > > This is a link to the original email, which has a test patch
> > > attached that
> > > will show the failure when trying to load/attach the fentry function
> > > and
> > > access the context:
> > >
> > > https://lore.kernel.org/bpf/159162546868.10791.12432342618156330247.stgit@ebuild/
> >
> > ok, I tried to trace ext program with __sk_buff argument and I can see
> > the issue as well.. can't acess the skb argument
> >
> > patch below fixes it for me, I can access the skb pointer and its data
> > via probe read, like:
> >
> > SEC("fexit/new_get_skb_ifindex")
> > int BPF_PROG(fexit_new_get_skb_ifindex, int val, struct __sk_buff *skb,
> > int var, int ret)
> > {
> > __u32 data;
> > int err;
> >
> > bpf_printk("EXIT skb %p", skb);
> > bpf_probe_read_kernel(&data, sizeof(data), &skb->data);
> > bpf_printk("EXIT ret %d, data %p", err, data);
> > return 0;
> > }
> >
> > I think it should fix the xdp_md acess as well
>
> Excellent patch ;) It works with xdp_md as well, and even better it does not
> require the bpf_probe_read_kernel(), so the test_xdp_bpf2bpf.c code just
> works.
great ;-) will check on xdp_md
>
> Are you planning to send the patch upstream?
yep, I'll add some test for that and send it
thanks,
jirka
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2020-07-29 8:15 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-08 14:11 fentry/fexit attach to EXT type XDP program does not work Eelco Chaudron
2020-06-08 16:58 ` Yonghong Song
2020-06-09 8:52 ` Eelco Chaudron
2020-07-26 12:24 ` Jiri Olsa
2020-07-27 7:59 ` Eelco Chaudron
2020-07-27 14:53 ` Jiri Olsa
2020-07-29 6:23 ` Eelco Chaudron
2020-07-29 8:09 ` Jiri Olsa
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