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| author | Alexei Starovoitov <ast@kernel.org> | 2023-02-15 02:50:51 +0300 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2023-02-15 20:24:59 +0300 |
| commit | 62d101d5f422cde39b269f7eb4cbbe2f1e26f9d4 (patch) | |
| tree | 59b808098f150e0f6ac994adcb30f2bae2c271b0 /tools/testing/selftests | |
| parent | 5e53e5c7edc6d69b8cb48b3b370cfe531e4b4132 (diff) | |
| download | linux-62d101d5f422cde39b269f7eb4cbbe2f1e26f9d4.tar.xz | |
selftests/bpf: Fix map_kptr test.
The compiler is optimizing out majority of unref_ptr read/writes, so the test
wasn't testing much. For example, one could delete '__kptr' tag from
'struct prog_test_ref_kfunc __kptr *unref_ptr;' and the test would still "pass".
Convert it to volatile stores. Confirmed by comparing bpf asm before/after.
Fixes: 2cbc469a6fc3 ("selftests/bpf: Add C tests for kptr")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230214235051.22938-1-alexei.starovoitov@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Diffstat (limited to 'tools/testing/selftests')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/map_kptr.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/tools/testing/selftests/bpf/progs/map_kptr.c b/tools/testing/selftests/bpf/progs/map_kptr.c index eb8217803493..228ec45365a8 100644 --- a/tools/testing/selftests/bpf/progs/map_kptr.c +++ b/tools/testing/selftests/bpf/progs/map_kptr.c @@ -62,21 +62,23 @@ extern struct prog_test_ref_kfunc * bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **p, int a, int b) __ksym; extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym; +#define WRITE_ONCE(x, val) ((*(volatile typeof(x) *) &(x)) = (val)) + static void test_kptr_unref(struct map_value *v) { struct prog_test_ref_kfunc *p; p = v->unref_ptr; /* store untrusted_ptr_or_null_ */ - v->unref_ptr = p; + WRITE_ONCE(v->unref_ptr, p); if (!p) return; if (p->a + p->b > 100) return; /* store untrusted_ptr_ */ - v->unref_ptr = p; + WRITE_ONCE(v->unref_ptr, p); /* store NULL */ - v->unref_ptr = NULL; + WRITE_ONCE(v->unref_ptr, NULL); } static void test_kptr_ref(struct map_value *v) @@ -85,7 +87,7 @@ static void test_kptr_ref(struct map_value *v) p = v->ref_ptr; /* store ptr_or_null_ */ - v->unref_ptr = p; + WRITE_ONCE(v->unref_ptr, p); if (!p) return; if (p->a + p->b > 100) @@ -99,7 +101,7 @@ static void test_kptr_ref(struct map_value *v) return; } /* store ptr_ */ - v->unref_ptr = p; + WRITE_ONCE(v->unref_ptr, p); bpf_kfunc_call_test_release(p); p = bpf_kfunc_call_test_acquire(&(unsigned long){0}); |