* [RFC] bpf: Issue with bpf_fentry_test7 call
@ 2023-12-15 9:16 Jiri Olsa
2023-12-15 9:43 ` Jiri Olsa
2023-12-15 14:24 ` Jiri Olsa
0 siblings, 2 replies; 6+ messages in thread
From: Jiri Olsa @ 2023-12-15 9:16 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Yonghong Song
Cc: bpf, Martin KaFai Lau, Song Liu, John Fastabend, KP Singh,
Stanislav Fomichev, Hao Luo
hi,
The bpf CI is broken due to clang emitting 2 functions for
bpf_fentry_test7:
# cat available_filter_functions | grep bpf_fentry_test7
bpf_fentry_test7
bpf_fentry_test7.specialized.1
The tests attach to 'bpf_fentry_test7' while the function with
'.specialized.1' suffix is executed in bpf_prog_test_run_tracing.
It looks like clang optimalization that comes from passing 0
as argument and returning it directly in bpf_fentry_test7.
I'm not sure there's a way to disable this, so far I came
up with solution below that passes real pointer, but I think
that was not the original intention for the test.
We had issue with this function back in august:
32337c0a2824 bpf: Prevent inlining of bpf_fentry_test7()
I'm not sure why it started to show now? was clang updated for CI?
I'll try to find out more, but any clang ideas are welcome ;-)
thanks,
jirka
---
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index c9fdcc5cdce1..33208eec9361 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -543,7 +543,7 @@ struct bpf_fentry_test_t {
int noinline bpf_fentry_test7(struct bpf_fentry_test_t *arg)
{
asm volatile ("");
- return (long)arg;
+ return 0;
}
int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg)
@@ -668,7 +668,7 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
bpf_fentry_test4((void *)7, 8, 9, 10) != 34 ||
bpf_fentry_test5(11, (void *)12, 13, 14, 15) != 65 ||
bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111 ||
- bpf_fentry_test7((struct bpf_fentry_test_t *)0) != 0 ||
+ bpf_fentry_test7(&arg) != 0 ||
bpf_fentry_test8(&arg) != 0 ||
bpf_fentry_test9(&retval) != 0)
goto out;
diff --git a/tools/testing/selftests/bpf/progs/fentry_test.c b/tools/testing/selftests/bpf/progs/fentry_test.c
index 52a550d281d9..95c5c34ccaa8 100644
--- a/tools/testing/selftests/bpf/progs/fentry_test.c
+++ b/tools/testing/selftests/bpf/progs/fentry_test.c
@@ -64,7 +64,7 @@ __u64 test7_result = 0;
SEC("fentry/bpf_fentry_test7")
int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
{
- if (!arg)
+ if (arg)
test7_result = 1;
return 0;
}
diff --git a/tools/testing/selftests/bpf/progs/fexit_test.c b/tools/testing/selftests/bpf/progs/fexit_test.c
index 8f1ccb7302e1..ffb30236ca02 100644
--- a/tools/testing/selftests/bpf/progs/fexit_test.c
+++ b/tools/testing/selftests/bpf/progs/fexit_test.c
@@ -65,7 +65,7 @@ __u64 test7_result = 0;
SEC("fexit/bpf_fentry_test7")
int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
{
- if (!arg)
+ if (arg)
test7_result = 1;
return 0;
}
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [RFC] bpf: Issue with bpf_fentry_test7 call
2023-12-15 9:16 [RFC] bpf: Issue with bpf_fentry_test7 call Jiri Olsa
@ 2023-12-15 9:43 ` Jiri Olsa
2023-12-15 14:24 ` Jiri Olsa
1 sibling, 0 replies; 6+ messages in thread
From: Jiri Olsa @ 2023-12-15 9:43 UTC (permalink / raw)
To: Jiri Olsa
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Yonghong Song, bpf, Martin KaFai Lau, Song Liu, John Fastabend,
KP Singh, Stanislav Fomichev, Hao Luo
On Fri, Dec 15, 2023 at 10:16:27AM +0100, Jiri Olsa wrote:
> hi,
> The bpf CI is broken due to clang emitting 2 functions for
> bpf_fentry_test7:
>
> # cat available_filter_functions | grep bpf_fentry_test7
> bpf_fentry_test7
> bpf_fentry_test7.specialized.1
>
> The tests attach to 'bpf_fentry_test7' while the function with
> '.specialized.1' suffix is executed in bpf_prog_test_run_tracing.
>
> It looks like clang optimalization that comes from passing 0
> as argument and returning it directly in bpf_fentry_test7.
>
> I'm not sure there's a way to disable this, so far I came
> up with solution below that passes real pointer, but I think
> that was not the original intention for the test.
>
> We had issue with this function back in august:
> 32337c0a2824 bpf: Prevent inlining of bpf_fentry_test7()
>
> I'm not sure why it started to show now? was clang updated for CI?
>
> I'll try to find out more, but any clang ideas are welcome ;-)
fyi also there's probably another related usse in global_func17 test:
run_subtest:FAIL:unexpected_load_success unexpected success: 0
#290/17 test_global_funcs/global_func17:FAIL
looks like clang optimized the call out and returns the value directly:
Disassembly of section .text:
0000000000000000 <foo>:
0: b4 00 00 00 00 00 00 00 w0 = 0x0
1: 15 01 02 00 00 00 00 00 if r1 == 0x0 goto +0x2 <LBB0_2>
2: b4 00 00 00 2a 00 00 00 w0 = 0x2a
3: 63 01 00 00 00 00 00 00 *(u32 *)(r1 + 0x0) = r0
0000000000000020 <LBB0_2>:
4: 95 00 00 00 00 00 00 00 exit
Disassembly of section tc:
0000000000000000 <global_func17>:
0: b4 00 00 00 2a 00 00 00 w0 = 0x2a
1: 95 00 00 00 00 00 00 00 exit
jirka
>
> thanks,
> jirka
>
>
> ---
> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> index c9fdcc5cdce1..33208eec9361 100644
> --- a/net/bpf/test_run.c
> +++ b/net/bpf/test_run.c
> @@ -543,7 +543,7 @@ struct bpf_fentry_test_t {
> int noinline bpf_fentry_test7(struct bpf_fentry_test_t *arg)
> {
> asm volatile ("");
> - return (long)arg;
> + return 0;
> }
>
> int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg)
> @@ -668,7 +668,7 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
> bpf_fentry_test4((void *)7, 8, 9, 10) != 34 ||
> bpf_fentry_test5(11, (void *)12, 13, 14, 15) != 65 ||
> bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111 ||
> - bpf_fentry_test7((struct bpf_fentry_test_t *)0) != 0 ||
> + bpf_fentry_test7(&arg) != 0 ||
> bpf_fentry_test8(&arg) != 0 ||
> bpf_fentry_test9(&retval) != 0)
> goto out;
> diff --git a/tools/testing/selftests/bpf/progs/fentry_test.c b/tools/testing/selftests/bpf/progs/fentry_test.c
> index 52a550d281d9..95c5c34ccaa8 100644
> --- a/tools/testing/selftests/bpf/progs/fentry_test.c
> +++ b/tools/testing/selftests/bpf/progs/fentry_test.c
> @@ -64,7 +64,7 @@ __u64 test7_result = 0;
> SEC("fentry/bpf_fentry_test7")
> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> {
> - if (!arg)
> + if (arg)
> test7_result = 1;
> return 0;
> }
> diff --git a/tools/testing/selftests/bpf/progs/fexit_test.c b/tools/testing/selftests/bpf/progs/fexit_test.c
> index 8f1ccb7302e1..ffb30236ca02 100644
> --- a/tools/testing/selftests/bpf/progs/fexit_test.c
> +++ b/tools/testing/selftests/bpf/progs/fexit_test.c
> @@ -65,7 +65,7 @@ __u64 test7_result = 0;
> SEC("fexit/bpf_fentry_test7")
> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> {
> - if (!arg)
> + if (arg)
> test7_result = 1;
> return 0;
> }
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC] bpf: Issue with bpf_fentry_test7 call
2023-12-15 9:16 [RFC] bpf: Issue with bpf_fentry_test7 call Jiri Olsa
2023-12-15 9:43 ` Jiri Olsa
@ 2023-12-15 14:24 ` Jiri Olsa
2023-12-15 14:42 ` Yonghong Song
1 sibling, 1 reply; 6+ messages in thread
From: Jiri Olsa @ 2023-12-15 14:24 UTC (permalink / raw)
To: Jiri Olsa
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Yonghong Song, bpf, Martin KaFai Lau, Song Liu, John Fastabend,
KP Singh, Stanislav Fomichev, Hao Luo
On Fri, Dec 15, 2023 at 10:16:27AM +0100, Jiri Olsa wrote:
> hi,
> The bpf CI is broken due to clang emitting 2 functions for
> bpf_fentry_test7:
>
> # cat available_filter_functions | grep bpf_fentry_test7
> bpf_fentry_test7
> bpf_fentry_test7.specialized.1
>
> The tests attach to 'bpf_fentry_test7' while the function with
> '.specialized.1' suffix is executed in bpf_prog_test_run_tracing.
>
> It looks like clang optimalization that comes from passing 0
> as argument and returning it directly in bpf_fentry_test7.
>
> I'm not sure there's a way to disable this, so far I came
> up with solution below that passes real pointer, but I think
> that was not the original intention for the test.
>
> We had issue with this function back in august:
> 32337c0a2824 bpf: Prevent inlining of bpf_fentry_test7()
>
> I'm not sure why it started to show now? was clang updated for CI?
>
> I'll try to find out more, but any clang ideas are welcome ;-)
>
> thanks,
> jirka
hm, there seems to be fix in bpf-next for this one:
b16904fd9f01 bpf: Fix a few selftest failures due to llvm18 change
jirka
>
>
> ---
> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> index c9fdcc5cdce1..33208eec9361 100644
> --- a/net/bpf/test_run.c
> +++ b/net/bpf/test_run.c
> @@ -543,7 +543,7 @@ struct bpf_fentry_test_t {
> int noinline bpf_fentry_test7(struct bpf_fentry_test_t *arg)
> {
> asm volatile ("");
> - return (long)arg;
> + return 0;
> }
>
> int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg)
> @@ -668,7 +668,7 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
> bpf_fentry_test4((void *)7, 8, 9, 10) != 34 ||
> bpf_fentry_test5(11, (void *)12, 13, 14, 15) != 65 ||
> bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111 ||
> - bpf_fentry_test7((struct bpf_fentry_test_t *)0) != 0 ||
> + bpf_fentry_test7(&arg) != 0 ||
> bpf_fentry_test8(&arg) != 0 ||
> bpf_fentry_test9(&retval) != 0)
> goto out;
> diff --git a/tools/testing/selftests/bpf/progs/fentry_test.c b/tools/testing/selftests/bpf/progs/fentry_test.c
> index 52a550d281d9..95c5c34ccaa8 100644
> --- a/tools/testing/selftests/bpf/progs/fentry_test.c
> +++ b/tools/testing/selftests/bpf/progs/fentry_test.c
> @@ -64,7 +64,7 @@ __u64 test7_result = 0;
> SEC("fentry/bpf_fentry_test7")
> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> {
> - if (!arg)
> + if (arg)
> test7_result = 1;
> return 0;
> }
> diff --git a/tools/testing/selftests/bpf/progs/fexit_test.c b/tools/testing/selftests/bpf/progs/fexit_test.c
> index 8f1ccb7302e1..ffb30236ca02 100644
> --- a/tools/testing/selftests/bpf/progs/fexit_test.c
> +++ b/tools/testing/selftests/bpf/progs/fexit_test.c
> @@ -65,7 +65,7 @@ __u64 test7_result = 0;
> SEC("fexit/bpf_fentry_test7")
> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> {
> - if (!arg)
> + if (arg)
> test7_result = 1;
> return 0;
> }
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC] bpf: Issue with bpf_fentry_test7 call
2023-12-15 14:24 ` Jiri Olsa
@ 2023-12-15 14:42 ` Yonghong Song
2023-12-15 21:22 ` Andrii Nakryiko
0 siblings, 1 reply; 6+ messages in thread
From: Yonghong Song @ 2023-12-15 14:42 UTC (permalink / raw)
To: Jiri Olsa
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Yonghong Song, bpf, Martin KaFai Lau, Song Liu, John Fastabend,
KP Singh, Stanislav Fomichev, Hao Luo
On 12/15/23 6:24 AM, Jiri Olsa wrote:
> On Fri, Dec 15, 2023 at 10:16:27AM +0100, Jiri Olsa wrote:
>> hi,
>> The bpf CI is broken due to clang emitting 2 functions for
>> bpf_fentry_test7:
>>
>> # cat available_filter_functions | grep bpf_fentry_test7
>> bpf_fentry_test7
>> bpf_fentry_test7.specialized.1
>>
>> The tests attach to 'bpf_fentry_test7' while the function with
>> '.specialized.1' suffix is executed in bpf_prog_test_run_tracing.
>>
>> It looks like clang optimalization that comes from passing 0
>> as argument and returning it directly in bpf_fentry_test7.
>>
>> I'm not sure there's a way to disable this, so far I came
>> up with solution below that passes real pointer, but I think
>> that was not the original intention for the test.
>>
>> We had issue with this function back in august:
>> 32337c0a2824 bpf: Prevent inlining of bpf_fentry_test7()
>>
>> I'm not sure why it started to show now? was clang updated for CI?
>>
>> I'll try to find out more, but any clang ideas are welcome ;-)
>>
>> thanks,
>> jirka
>
> hm, there seems to be fix in bpf-next for this one:
>
> b16904fd9f01 bpf: Fix a few selftest failures due to llvm18 change
Maybe submit a patch to https://github.com/kernel-patches/vmtest/tree/master/ci/diffs?
That is typically the place to have temporary patches to workaround ci failures.
>
> jirka
>
>>
>> ---
>> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
>> index c9fdcc5cdce1..33208eec9361 100644
>> --- a/net/bpf/test_run.c
>> +++ b/net/bpf/test_run.c
>> @@ -543,7 +543,7 @@ struct bpf_fentry_test_t {
>> int noinline bpf_fentry_test7(struct bpf_fentry_test_t *arg)
>> {
>> asm volatile ("");
>> - return (long)arg;
>> + return 0;
>> }
>>
>> int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg)
>> @@ -668,7 +668,7 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
>> bpf_fentry_test4((void *)7, 8, 9, 10) != 34 ||
>> bpf_fentry_test5(11, (void *)12, 13, 14, 15) != 65 ||
>> bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111 ||
>> - bpf_fentry_test7((struct bpf_fentry_test_t *)0) != 0 ||
>> + bpf_fentry_test7(&arg) != 0 ||
>> bpf_fentry_test8(&arg) != 0 ||
>> bpf_fentry_test9(&retval) != 0)
>> goto out;
>> diff --git a/tools/testing/selftests/bpf/progs/fentry_test.c b/tools/testing/selftests/bpf/progs/fentry_test.c
>> index 52a550d281d9..95c5c34ccaa8 100644
>> --- a/tools/testing/selftests/bpf/progs/fentry_test.c
>> +++ b/tools/testing/selftests/bpf/progs/fentry_test.c
>> @@ -64,7 +64,7 @@ __u64 test7_result = 0;
>> SEC("fentry/bpf_fentry_test7")
>> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
>> {
>> - if (!arg)
>> + if (arg)
>> test7_result = 1;
>> return 0;
>> }
>> diff --git a/tools/testing/selftests/bpf/progs/fexit_test.c b/tools/testing/selftests/bpf/progs/fexit_test.c
>> index 8f1ccb7302e1..ffb30236ca02 100644
>> --- a/tools/testing/selftests/bpf/progs/fexit_test.c
>> +++ b/tools/testing/selftests/bpf/progs/fexit_test.c
>> @@ -65,7 +65,7 @@ __u64 test7_result = 0;
>> SEC("fexit/bpf_fentry_test7")
>> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
>> {
>> - if (!arg)
>> + if (arg)
>> test7_result = 1;
>> return 0;
>> }
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC] bpf: Issue with bpf_fentry_test7 call
2023-12-15 14:42 ` Yonghong Song
@ 2023-12-15 21:22 ` Andrii Nakryiko
2023-12-15 23:21 ` Jiri Olsa
0 siblings, 1 reply; 6+ messages in thread
From: Andrii Nakryiko @ 2023-12-15 21:22 UTC (permalink / raw)
To: Yonghong Song
Cc: Jiri Olsa, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Yonghong Song, bpf, Martin KaFai Lau, Song Liu, John Fastabend,
KP Singh, Stanislav Fomichev, Hao Luo
On Fri, Dec 15, 2023 at 6:42 AM Yonghong Song <yonghong.song@linux.dev> wrote:
>
>
> On 12/15/23 6:24 AM, Jiri Olsa wrote:
> > On Fri, Dec 15, 2023 at 10:16:27AM +0100, Jiri Olsa wrote:
> >> hi,
> >> The bpf CI is broken due to clang emitting 2 functions for
> >> bpf_fentry_test7:
> >>
> >> # cat available_filter_functions | grep bpf_fentry_test7
> >> bpf_fentry_test7
> >> bpf_fentry_test7.specialized.1
> >>
> >> The tests attach to 'bpf_fentry_test7' while the function with
> >> '.specialized.1' suffix is executed in bpf_prog_test_run_tracing.
> >>
> >> It looks like clang optimalization that comes from passing 0
> >> as argument and returning it directly in bpf_fentry_test7.
> >>
> >> I'm not sure there's a way to disable this, so far I came
> >> up with solution below that passes real pointer, but I think
> >> that was not the original intention for the test.
> >>
> >> We had issue with this function back in august:
> >> 32337c0a2824 bpf: Prevent inlining of bpf_fentry_test7()
> >>
> >> I'm not sure why it started to show now? was clang updated for CI?
> >>
> >> I'll try to find out more, but any clang ideas are welcome ;-)
> >>
> >> thanks,
> >> jirka
> >
> > hm, there seems to be fix in bpf-next for this one:
> >
> > b16904fd9f01 bpf: Fix a few selftest failures due to llvm18 change
>
> Maybe submit a patch to https://github.com/kernel-patches/vmtest/tree/master/ci/diffs?
> That is typically the place to have temporary patches to workaround ci failures.
>
To get bpf/master back to green CI I did it meanwhile ([0]). Jiri,
please check the PR to be familiar with the process for the future
similar mitigations, thanks.
[0] https://github.com/kernel-patches/vmtest/pull/258
> >
> > jirka
> >
> >>
> >> ---
> >> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> >> index c9fdcc5cdce1..33208eec9361 100644
> >> --- a/net/bpf/test_run.c
> >> +++ b/net/bpf/test_run.c
> >> @@ -543,7 +543,7 @@ struct bpf_fentry_test_t {
> >> int noinline bpf_fentry_test7(struct bpf_fentry_test_t *arg)
> >> {
> >> asm volatile ("");
> >> - return (long)arg;
> >> + return 0;
> >> }
> >>
> >> int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg)
> >> @@ -668,7 +668,7 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
> >> bpf_fentry_test4((void *)7, 8, 9, 10) != 34 ||
> >> bpf_fentry_test5(11, (void *)12, 13, 14, 15) != 65 ||
> >> bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111 ||
> >> - bpf_fentry_test7((struct bpf_fentry_test_t *)0) != 0 ||
> >> + bpf_fentry_test7(&arg) != 0 ||
> >> bpf_fentry_test8(&arg) != 0 ||
> >> bpf_fentry_test9(&retval) != 0)
> >> goto out;
> >> diff --git a/tools/testing/selftests/bpf/progs/fentry_test.c b/tools/testing/selftests/bpf/progs/fentry_test.c
> >> index 52a550d281d9..95c5c34ccaa8 100644
> >> --- a/tools/testing/selftests/bpf/progs/fentry_test.c
> >> +++ b/tools/testing/selftests/bpf/progs/fentry_test.c
> >> @@ -64,7 +64,7 @@ __u64 test7_result = 0;
> >> SEC("fentry/bpf_fentry_test7")
> >> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> >> {
> >> - if (!arg)
> >> + if (arg)
> >> test7_result = 1;
> >> return 0;
> >> }
> >> diff --git a/tools/testing/selftests/bpf/progs/fexit_test.c b/tools/testing/selftests/bpf/progs/fexit_test.c
> >> index 8f1ccb7302e1..ffb30236ca02 100644
> >> --- a/tools/testing/selftests/bpf/progs/fexit_test.c
> >> +++ b/tools/testing/selftests/bpf/progs/fexit_test.c
> >> @@ -65,7 +65,7 @@ __u64 test7_result = 0;
> >> SEC("fexit/bpf_fentry_test7")
> >> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> >> {
> >> - if (!arg)
> >> + if (arg)
> >> test7_result = 1;
> >> return 0;
> >> }
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC] bpf: Issue with bpf_fentry_test7 call
2023-12-15 21:22 ` Andrii Nakryiko
@ 2023-12-15 23:21 ` Jiri Olsa
0 siblings, 0 replies; 6+ messages in thread
From: Jiri Olsa @ 2023-12-15 23:21 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Yonghong Song, Jiri Olsa, Alexei Starovoitov, Daniel Borkmann,
Andrii Nakryiko, Yonghong Song, bpf, Martin KaFai Lau, Song Liu,
John Fastabend, KP Singh, Stanislav Fomichev, Hao Luo
On Fri, Dec 15, 2023 at 01:22:35PM -0800, Andrii Nakryiko wrote:
> On Fri, Dec 15, 2023 at 6:42 AM Yonghong Song <yonghong.song@linux.dev> wrote:
> >
> >
> > On 12/15/23 6:24 AM, Jiri Olsa wrote:
> > > On Fri, Dec 15, 2023 at 10:16:27AM +0100, Jiri Olsa wrote:
> > >> hi,
> > >> The bpf CI is broken due to clang emitting 2 functions for
> > >> bpf_fentry_test7:
> > >>
> > >> # cat available_filter_functions | grep bpf_fentry_test7
> > >> bpf_fentry_test7
> > >> bpf_fentry_test7.specialized.1
> > >>
> > >> The tests attach to 'bpf_fentry_test7' while the function with
> > >> '.specialized.1' suffix is executed in bpf_prog_test_run_tracing.
> > >>
> > >> It looks like clang optimalization that comes from passing 0
> > >> as argument and returning it directly in bpf_fentry_test7.
> > >>
> > >> I'm not sure there's a way to disable this, so far I came
> > >> up with solution below that passes real pointer, but I think
> > >> that was not the original intention for the test.
> > >>
> > >> We had issue with this function back in august:
> > >> 32337c0a2824 bpf: Prevent inlining of bpf_fentry_test7()
> > >>
> > >> I'm not sure why it started to show now? was clang updated for CI?
> > >>
> > >> I'll try to find out more, but any clang ideas are welcome ;-)
> > >>
> > >> thanks,
> > >> jirka
> > >
> > > hm, there seems to be fix in bpf-next for this one:
> > >
> > > b16904fd9f01 bpf: Fix a few selftest failures due to llvm18 change
> >
> > Maybe submit a patch to https://github.com/kernel-patches/vmtest/tree/master/ci/diffs?
> > That is typically the place to have temporary patches to workaround ci failures.
> >
>
> To get bpf/master back to green CI I did it meanwhile ([0]). Jiri,
> please check the PR to be familiar with the process for the future
> similar mitigations, thanks.
>
> [0] https://github.com/kernel-patches/vmtest/pull/258
great, thanks
jirka
>
> > >
> > > jirka
> > >
> > >>
> > >> ---
> > >> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> > >> index c9fdcc5cdce1..33208eec9361 100644
> > >> --- a/net/bpf/test_run.c
> > >> +++ b/net/bpf/test_run.c
> > >> @@ -543,7 +543,7 @@ struct bpf_fentry_test_t {
> > >> int noinline bpf_fentry_test7(struct bpf_fentry_test_t *arg)
> > >> {
> > >> asm volatile ("");
> > >> - return (long)arg;
> > >> + return 0;
> > >> }
> > >>
> > >> int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg)
> > >> @@ -668,7 +668,7 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog,
> > >> bpf_fentry_test4((void *)7, 8, 9, 10) != 34 ||
> > >> bpf_fentry_test5(11, (void *)12, 13, 14, 15) != 65 ||
> > >> bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111 ||
> > >> - bpf_fentry_test7((struct bpf_fentry_test_t *)0) != 0 ||
> > >> + bpf_fentry_test7(&arg) != 0 ||
> > >> bpf_fentry_test8(&arg) != 0 ||
> > >> bpf_fentry_test9(&retval) != 0)
> > >> goto out;
> > >> diff --git a/tools/testing/selftests/bpf/progs/fentry_test.c b/tools/testing/selftests/bpf/progs/fentry_test.c
> > >> index 52a550d281d9..95c5c34ccaa8 100644
> > >> --- a/tools/testing/selftests/bpf/progs/fentry_test.c
> > >> +++ b/tools/testing/selftests/bpf/progs/fentry_test.c
> > >> @@ -64,7 +64,7 @@ __u64 test7_result = 0;
> > >> SEC("fentry/bpf_fentry_test7")
> > >> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> > >> {
> > >> - if (!arg)
> > >> + if (arg)
> > >> test7_result = 1;
> > >> return 0;
> > >> }
> > >> diff --git a/tools/testing/selftests/bpf/progs/fexit_test.c b/tools/testing/selftests/bpf/progs/fexit_test.c
> > >> index 8f1ccb7302e1..ffb30236ca02 100644
> > >> --- a/tools/testing/selftests/bpf/progs/fexit_test.c
> > >> +++ b/tools/testing/selftests/bpf/progs/fexit_test.c
> > >> @@ -65,7 +65,7 @@ __u64 test7_result = 0;
> > >> SEC("fexit/bpf_fentry_test7")
> > >> int BPF_PROG(test7, struct bpf_fentry_test_t *arg)
> > >> {
> > >> - if (!arg)
> > >> + if (arg)
> > >> test7_result = 1;
> > >> return 0;
> > >> }
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-12-15 23:22 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-12-15 9:16 [RFC] bpf: Issue with bpf_fentry_test7 call Jiri Olsa
2023-12-15 9:43 ` Jiri Olsa
2023-12-15 14:24 ` Jiri Olsa
2023-12-15 14:42 ` Yonghong Song
2023-12-15 21:22 ` Andrii Nakryiko
2023-12-15 23:21 ` Jiri Olsa
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