In use_missing_map function, value is
initialized twice.There is no
connection between the two assignment.
This patch could fix this bug.
Signed-off-by: Wang Ming <[email protected]>
---
tools/testing/selftests/bpf/progs/test_log_fixup.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/test_log_fixup.c b/tools/testing/selftests/bpf/progs/test_log_fixup.c
index 1bd48feaaa42..1c49b2f9be6c 100644
--- a/tools/testing/selftests/bpf/progs/test_log_fixup.c
+++ b/tools/testing/selftests/bpf/progs/test_log_fixup.c
@@ -52,13 +52,9 @@ struct {
SEC("?raw_tp/sys_enter")
int use_missing_map(const void *ctx)
{
- int zero = 0, *value;
+ int zero = 0;
- value = bpf_map_lookup_elem(&existing_map, &zero);
-
- value = bpf_map_lookup_elem(&missing_map, &zero);
-
- return value != NULL;
+ return bpf_map_lookup_elem(&missing_map, &zero) != NULL;
}
extern int bpf_nonexistent_kfunc(void) __ksym __weak;
--
2.25.1
On 7/5/23 2:33 PM, Wang Ming wrote:
> In use_missing_map function, value is
> initialized twice.There is no
> connection between the two assignment.
> This patch could fix this bug.
Please never submit patches where you are just speculating and did not even
bother to run BPF selftests !
Otherwise you would have seen that your change is breaking it :
Error: #126 log_fixup
Error: #126/5 log_fixup/missing_map
Error: #126/5 log_fixup/missing_map
missing_map:PASS:skel_open 0 nsec
libbpf: prog 'use_missing_map': BPF program load failed: Invalid argument
libbpf: prog 'use_missing_map': failed to load: -22
libbpf: failed to load object 'test_log_fixup'
libbpf: failed to load BPF skeleton 'test_log_fixup': -22
missing_map:PASS:load_fail 0 nsec
missing_map:PASS:existing_map_autocreate 0 nsec
missing_map:PASS:missing_map_autocreate 0 nsec
missing_map:FAIL:log_buf unexpected log_buf: '8: <invalid BPF map reference>
BPF map 'missing_map' is referenced but wasn't created
' is not a substring of 'reg type unsupported for arg#0 function use_missing_map#20
0: R1=ctx(off=0,imm=0) R10=fp0
; int use_missing_map(const void *ctx)
0: (b4) w1 = 0 ; R1_w=0
; int zero = 0;
1: (63) *(u32 *)(r10 -4) = r1 ; R1_w=0 R10=fp0 fp-8=0000????
2: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
;
3: (07) r2 += -4 ; R2_w=fp-4
; return bpf_map_lookup_elem(&missing_map, &zero) != NULL;
4: <invalid BPF map reference>
BPF map 'missing_map' is referenced but wasn't created
processed 5 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
> Signed-off-by: Wang Ming <[email protected]>
> ---
> tools/testing/selftests/bpf/progs/test_log_fixup.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/test_log_fixup.c b/tools/testing/selftests/bpf/progs/test_log_fixup.c
> index 1bd48feaaa42..1c49b2f9be6c 100644
> --- a/tools/testing/selftests/bpf/progs/test_log_fixup.c
> +++ b/tools/testing/selftests/bpf/progs/test_log_fixup.c
> @@ -52,13 +52,9 @@ struct {
> SEC("?raw_tp/sys_enter")
> int use_missing_map(const void *ctx)
> {
> - int zero = 0, *value;
> + int zero = 0;
>
> - value = bpf_map_lookup_elem(&existing_map, &zero);
> -
> - value = bpf_map_lookup_elem(&missing_map, &zero);
> -
> - return value != NULL;
> + return bpf_map_lookup_elem(&missing_map, &zero) != NULL;
> }
>
> extern int bpf_nonexistent_kfunc(void) __ksym __weak;
>
Thank you, but I don't understand the error.
-----邮件原件-----
发件人: Daniel Borkmann <[email protected]>
发送时间: 2023年7月5日 21:32
收件人: 王明-软件底层技术部 <[email protected]>; Alexei Starovoitov <[email protected]>; Andrii Nakryiko <[email protected]>; Martin KaFai Lau <[email protected]>; Song Liu <[email protected]>; Yonghong Song <[email protected]>; John Fastabend <[email protected]>; KP Singh <[email protected]>; Stanislav Fomichev <[email protected]>; Hao Luo <[email protected]>; Jiri Olsa <[email protected]>; Mykola Lysenko <[email protected]>; Shuah Khan <[email protected]>; [email protected]; [email protected]; [email protected]
抄送: opensource.kernel <[email protected]>
主题: Re: [PATCH v1] selftests:bpf:Fix repeated initialization
On 7/5/23 2:33 PM, Wang Ming wrote:
> In use_missing_map function, value is
> initialized twice.There is no
> connection between the two assignment.
> This patch could fix this bug.
Please never submit patches where you are just speculating and did not even bother to run BPF selftests !
Otherwise you would have seen that your change is breaking it :
Error: #126 log_fixup
Error: #126/5 log_fixup/missing_map
Error: #126/5 log_fixup/missing_map
missing_map:PASS:skel_open 0 nsec
libbpf: prog 'use_missing_map': BPF program load failed: Invalid argument
libbpf: prog 'use_missing_map': failed to load: -22
libbpf: failed to load object 'test_log_fixup'
libbpf: failed to load BPF skeleton 'test_log_fixup': -22
missing_map:PASS:load_fail 0 nsec
missing_map:PASS:existing_map_autocreate 0 nsec
missing_map:PASS:missing_map_autocreate 0 nsec
missing_map:FAIL:log_buf unexpected log_buf: '8: <invalid BPF map reference>
BPF map 'missing_map' is referenced but wasn't created
' is not a substring of 'reg type unsupported for arg#0 function use_missing_map#20
0: R1=ctx(off=0,imm=0) R10=fp0
; int use_missing_map(const void *ctx)
0: (b4) w1 = 0 ; R1_w=0
; int zero = 0;
1: (63) *(u32 *)(r10 -4) = r1 ; R1_w=0 R10=fp0 fp-8=0000????
2: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
;
3: (07) r2 += -4 ; R2_w=fp-4
; return bpf_map_lookup_elem(&missing_map, &zero) != NULL;
4: <invalid BPF map reference>
BPF map 'missing_map' is referenced but wasn't created
processed 5 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0
> Signed-off-by: Wang Ming <[email protected]>
> ---
> tools/testing/selftests/bpf/progs/test_log_fixup.c | 8 ++------
> 1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/test_log_fixup.c
> b/tools/testing/selftests/bpf/progs/test_log_fixup.c
> index 1bd48feaaa42..1c49b2f9be6c 100644
> --- a/tools/testing/selftests/bpf/progs/test_log_fixup.c
> +++ b/tools/testing/selftests/bpf/progs/test_log_fixup.c
> @@ -52,13 +52,9 @@ struct {
> SEC("?raw_tp/sys_enter")
> int use_missing_map(const void *ctx)
> {
> - int zero = 0, *value;
> + int zero = 0;
>
> - value = bpf_map_lookup_elem(&existing_map, &zero);
> -
> - value = bpf_map_lookup_elem(&missing_map, &zero);
> -
> - return value != NULL;
> + return bpf_map_lookup_elem(&missing_map, &zero) != NULL;
> }
>
> extern int bpf_nonexistent_kfunc(void) __ksym __weak;
>