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 148A715F3EE; Mon, 27 May 2024 14:16:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716819370; cv=none; b=COLuNuDVOHSsnDQ9+zwoZ12q7iXVyPXLC7M5wYx6Rkuvka2Eh114anSpUogsMR1UzTVjrgl2Lp9GyGgKhj5Fvk7o9iVQlcVjhgIjkcS6md3ioXwpAuoHYpFHtP9Ffz4lpzpT3tpsj+OY0iaXEma9UrVl8kA5I3VcTLHUyjYc6gw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716819370; c=relaxed/simple; bh=KYbDoBIOVemCSPjQliXQl6JYCRrMwP9/hPqHjp4Cy2I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ThJL07+lw+QyVAW40PQ+P57+3aLJ40BVVJsRyc42S2cbHwyUubFJ4NjX5mybdhkKfZ/oOzY4K6+xxXKAnVa0UR/ZionSfz5Ry8BfvfsuETyL/4V/yamplpodOVmLp2XZCgieUVlxx4js0Zp7W5cvagpcXWWuHXo4TUIQkDh+C00= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fTjrTgEc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fTjrTgEc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 570D0C32789; Mon, 27 May 2024 14:16:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716819369; bh=KYbDoBIOVemCSPjQliXQl6JYCRrMwP9/hPqHjp4Cy2I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fTjrTgEcbMmG6+x162TbYscWUugSyNEMAPixScFvddO7BbQvTxs8HV4KvKw+BYN5v C1XTJkgM6kJRSEOWd9kcc6mgoB1A5cm/XgvELk2rsqArOM3j3fNUAHLpg9ZWtuKSAt Lj9fNLoC4Nt2+bIZhCpmNi+EFUADCXxCB6AwREMnqkeyZq9tjOu0nmqSm4mgUXDmtN m+t1dbHa4xZ2NrPnWTzNMzrK/5VCb/7q/HdzB0xnbuWGpmYgoxREbJzYHzjsL8j+j4 UzXfDpIKmUIK+bc7BOiUa1Sn3IW8v5KylpI0eYsfF2odq++ljyLAsBS3LG3dx18hHT 7M8ObPwT3ESmw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yonghong Song , Daniel Borkmann , Sasha Levin , andrii@kernel.org, eddyz87@gmail.com, ast@kernel.org, shuah@kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH AUTOSEL 6.6 03/21] selftests/bpf: Fix flaky test btf_map_in_map/lookup_update Date: Mon, 27 May 2024 10:15:14 -0400 Message-ID: <20240527141551.3853516-3-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240527141551.3853516-1-sashal@kernel.org> References: <20240527141551.3853516-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.32 Content-Transfer-Encoding: 8bit From: Yonghong Song [ Upstream commit 14bb1e8c8d4ad5d9d2febb7d19c70a3cf536e1e5 ] Recently, I frequently hit the following test failure: [root@arch-fb-vm1 bpf]# ./test_progs -n 33/1 test_lookup_update:PASS:skel_open 0 nsec [...] test_lookup_update:PASS:sync_rcu 0 nsec test_lookup_update:FAIL:map1_leak inner_map1 leaked! #33/1 btf_map_in_map/lookup_update:FAIL #33 btf_map_in_map:FAIL In the test, after map is closed and then after two rcu grace periods, it is assumed that map_id is not available to user space. But the above assumption cannot be guaranteed. After zero or one or two rcu grace periods in different siturations, the actual freeing-map-work is put into a workqueue. Later on, when the work is dequeued, the map will be actually freed. See bpf_map_put() in kernel/bpf/syscall.c. By using workqueue, there is no ganrantee that map will be actually freed after a couple of rcu grace periods. This patch removed such map leak detection and then the test can pass consistently. Signed-off-by: Yonghong Song Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20240322061353.632136-1-yonghong.song@linux.dev Signed-off-by: Sasha Levin --- .../selftests/bpf/prog_tests/btf_map_in_map.c | 26 +------------------ 1 file changed, 1 insertion(+), 25 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c b/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c index a8b53b8736f01..f66ceccd7029c 100644 --- a/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c +++ b/tools/testing/selftests/bpf/prog_tests/btf_map_in_map.c @@ -25,7 +25,7 @@ static void test_lookup_update(void) int map1_fd, map2_fd, map3_fd, map4_fd, map5_fd, map1_id, map2_id; int outer_arr_fd, outer_hash_fd, outer_arr_dyn_fd; struct test_btf_map_in_map *skel; - int err, key = 0, val, i, fd; + int err, key = 0, val, i; skel = test_btf_map_in_map__open_and_load(); if (CHECK(!skel, "skel_open", "failed to open&load skeleton\n")) @@ -102,30 +102,6 @@ static void test_lookup_update(void) CHECK(map1_id == 0, "map1_id", "failed to get ID 1\n"); CHECK(map2_id == 0, "map2_id", "failed to get ID 2\n"); - test_btf_map_in_map__destroy(skel); - skel = NULL; - - /* we need to either wait for or force synchronize_rcu(), before - * checking for "still exists" condition, otherwise map could still be - * resolvable by ID, causing false positives. - * - * Older kernels (5.8 and earlier) freed map only after two - * synchronize_rcu()s, so trigger two, to be entirely sure. - */ - CHECK(kern_sync_rcu(), "sync_rcu", "failed\n"); - CHECK(kern_sync_rcu(), "sync_rcu", "failed\n"); - - fd = bpf_map_get_fd_by_id(map1_id); - if (CHECK(fd >= 0, "map1_leak", "inner_map1 leaked!\n")) { - close(fd); - goto cleanup; - } - fd = bpf_map_get_fd_by_id(map2_id); - if (CHECK(fd >= 0, "map2_leak", "inner_map2 leaked!\n")) { - close(fd); - goto cleanup; - } - cleanup: test_btf_map_in_map__destroy(skel); } -- 2.43.0