From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D347DBA46 for ; Tue, 7 Mar 2023 18:11:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E5D0C433D2; Tue, 7 Mar 2023 18:11:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678212674; bh=tpWQ3pQ0YRv95/CN5dI+MV41MpEypJwHkvMGlvUE/e8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eXw++bKdbYU3XUc9KT5PtTc7DJG42US93IzUrTL1P2qGNTTk7gZq9s7Me6oqXgYIJ UwX/HtbzYVCoWO9x7acPn3PoYI0uoKKPoQEQRJCF2yIARjCSQrB08h2RxloMsQkaU/ Op94u9gR2MiXSjs5sVZOrTQ95XG8ObiiWU74QsYM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexei Starovoitov , Stanislav Fomichev , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Sasha Levin Subject: [PATCH 6.1 243/885] selftests/bpf: Fix map_kptr test. Date: Tue, 7 Mar 2023 17:52:57 +0100 Message-Id: <20230307170012.580474372@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230307170001.594919529@linuxfoundation.org> References: <20230307170001.594919529@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Alexei Starovoitov [ Upstream commit 62d101d5f422cde39b269f7eb4cbbe2f1e26f9d4 ] 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 Acked-by: Stanislav Fomichev Acked-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20230214235051.22938-1-alexei.starovoitov@gmail.com Signed-off-by: Martin KaFai Lau Signed-off-by: Sasha Levin --- tools/testing/selftests/bpf/progs/map_kptr.c | 12 +++++++----- 1 file 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 eb82178034934..228ec45365a8d 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}); -- 2.39.2