bpftool: Use sysfs vmlinux when dumping BTF by ID

.github/actions/vmtest/action.yml

@@ -0,0 +1,35 @@
+name: 'vmtest'
+description: 'Build + run vmtest'
+inputs:
+  arch:
+    description: 'what arch to test'
+    required: true
+    default: 'x86_64'
+runs:
+  using: "composite"
+  steps:
+    # 1. Setup environment
+    - name: Setup build environment
+      uses: libbpf/ci/setup-build-env@master
+    # 2. Build
+    - name: Build kernel image
+      shell: bash
+      run: ${GITHUB_ACTION_PATH}/build.sh ${{ inputs.arch }}
+    - name: Build selftests
+      shell: bash
+      run: ${GITHUB_ACTION_PATH}/build_selftests.sh
+      env:
+        VMLINUX_BTF: ${{ github.workspace }}/vmlinux
+    # 3. Test
+    - name: Prepare rootfs
+      uses: libbpf/ci/prepare-rootfs@master
+      with:
+        project-name: 'libbpf'
+        arch: ${{ inputs.arch }}
+        kernel-root: '.'
+    - name: Run selftests
+      uses: libbpf/ci/run-qemu@master
+      with:
+        arch: ${{ inputs.arch}}
+        img: '/tmp/root.img'
+        vmlinuz: '${{ github.workspace }}/vmlinuz'

.github/actions/vmtest/build.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+set -euo pipefail
+
+ARCH="$1"
+
+THISDIR="$(cd $(dirname $0) && pwd)"
+
+source "${THISDIR}"/helpers.sh
+
+travis_fold start build_kernel "Building kernel"
+
+cp ${GITHUB_WORKSPACE}/travis-ci/vmtest/configs/config-latest.${ARCH} .config
+
+make -j $((4*$(nproc))) olddefconfig all > /dev/null
+
+travis_fold end build_kernel

.github/actions/vmtest/build_selftests.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+
+set -euo pipefail
+
+THISDIR="$(cd $(dirname $0) && pwd)"
+
+source "${THISDIR}"/helpers.sh
+
+travis_fold start prepare_selftests "Building selftests"
+
+LLVM_VER=15
+LIBBPF_PATH="${REPO_ROOT}"
+
+PREPARE_SELFTESTS_SCRIPT=${THISDIR}/prepare_selftests-${KERNEL}.sh
+if [ -f "${PREPARE_SELFTESTS_SCRIPT}" ]; then
+	(cd "${REPO_ROOT}/${REPO_PATH}/tools/testing/selftests/bpf" && ${PREPARE_SELFTESTS_SCRIPT})
+fi
+
+if [[ "${KERNEL}" = 'LATEST' ]]; then
+	VMLINUX_H=
+else
+	VMLINUX_H=${THISDIR}/vmlinux.h
+fi
+
+cd ${REPO_ROOT}/${REPO_PATH}
+make \
+	CLANG=clang-${LLVM_VER} \
+	LLC=llc-${LLVM_VER} \
+	LLVM_STRIP=llvm-strip-${LLVM_VER} \
+	VMLINUX_BTF="${VMLINUX_BTF}" \
+	VMLINUX_H="${VMLINUX_H}" \
+	-C "${REPO_ROOT}/${REPO_PATH}/tools/testing/selftests/bpf" \
+	-j $((4*$(nproc))) > /dev/null
+cd -
+mkdir "${LIBBPF_PATH}"/selftests
+cp -R "${REPO_ROOT}/${REPO_PATH}/tools/testing/selftests/bpf" \
+	"${LIBBPF_PATH}"/selftests
+cd "${LIBBPF_PATH}"
+rm selftests/bpf/.gitignore
+git add selftests
+
+travis_fold end prepare_selftests

.github/actions/vmtest/helpers.sh

@@ -0,0 +1,44 @@
+# $1 - start or end
+# $2 - fold identifier, no spaces
+# $3 - fold section description
+travis_fold() {
+  local YELLOW='\033[1;33m'
+  local NOCOLOR='\033[0m'
+  if [ -z ${GITHUB_WORKFLOW+x} ]; then
+    echo travis_fold:$1:$2
+    if [ ! -z "${3:-}" ]; then
+      echo -e "${YELLOW}$3${NOCOLOR}"
+    fi
+    echo
+  else
+    if [ $1 = "start" ]; then
+      line="::group::$2"
+      if [ ! -z "${3:-}" ]; then
+        line="$line - ${YELLOW}$3${NOCOLOR}"
+      fi
+    else
+      line="::endgroup::"
+    fi
+    echo -e "$line"
+  fi
+}
+
+__print() {
+  local TITLE=""
+  if [[ -n $2 ]]; then
+      TITLE=" title=$2"
+  fi
+  echo "::$1${TITLE}::$3"
+}
+
+# $1 - title
+# $2 - message
+print_error() {
+  __print error $1 $2
+}
+
+# $1 - title
+# $2 - message
+print_notice() {
+  __print notice $1 $2
+}

.github/workflows/test.yml

@@ -0,0 +1,50 @@
+name: bpf-ci
+
+on:
+  pull_request:
+
+concurrency: 
+  group: ci-test-${{ github.head_ref }}
+  cancel-in-progress: true
+
+jobs:
+  VM_Test:
+    runs-on: ${{ matrix.runs_on }}
+    name: Kernel ${{ matrix.kernel }} on ${{ matrix.runs_on }} + selftests
+    timeout-minutes: 100
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - kernel: 'LATEST'
+            runs_on: ubuntu-latest
+            arch: 'x86_64'
+          - kernel: 'LATEST'
+            runs_on: z15
+            arch: 's390x'
+    env:
+      AUTHOR_EMAIL: "$(git log -1 --pretty=\"%aE\")"
+      KERNEL: LATEST
+      REPO_ROOT: ${{ github.workspace }}
+      REPO_PATH: ""
+    steps:
+      - uses: actions/checkout@v2
+      - if: ${{ github.repository != 'kernel-patches/bpf' && github.repository != 'kernel-patches/bpf-rc' }}
+        name: Download bpf-next tree
+        uses: libbpf/ci/get-linux-source@master
+        with:
+          dest: '.kernel'
+      - if: ${{ github.repository != 'kernel-patches/bpf' && github.repository != 'kernel-patches/bpf-rc' }}
+        name: Move linux source in place
+        shell: bash
+        run: |
+          rm -rf .kernel/.git
+          cp -rf .kernel/. .
+          rm -rf .kernel
+      - uses: libbpf/ci/patch-kernel@master
+        with:
+          patches-root: '${{ github.workspace }}/travis-ci/diffs'
+          repo-root: '${{ github.workspace }}'
+      - uses: ./.github/actions/vmtest
+        with:
+          arch: ${{ matrix.arch }}

README

@@ -1,18 +0,0 @@
-Linux kernel
-============
-
-There are several guides for kernel developers and users. These guides can
-be rendered in a number of formats, like HTML and PDF. Please read
-Documentation/admin-guide/README.rst first.
-
-In order to build the documentation, use ``make htmldocs`` or
-``make pdfdocs``.  The formatted documentation can also be read online at:
-
-    https://www.kernel.org/doc/html/latest/
-
-There are various text files in the Documentation/ subdirectory,
-several of them using the Restructured Text markup notation.
-
-Please read the Documentation/process/changes.rst file, as it contains the
-requirements for building and running the kernel, and information about
-the problems which may result by upgrading your kernel.

tools/bpf/bpftool/btf.c

@@ -459,6 +459,22 @@ static int dump_btf_c(const struct btf *btf,
 	return err;
 }
 
+static const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";
+
+static struct btf *get_vmlinux_btf_from_sysfs(void)
+{
+	struct btf *base;
+
+	base = btf__parse(sysfs_vmlinux, NULL);
+	if (libbpf_get_error(base)) {
+		p_err("failed to parse vmlinux BTF at '%s': %ld\n",
+		      sysfs_vmlinux, libbpf_get_error(base));
+		base = NULL;
+	}
+
+	return base;
+}
+
 static int do_dump(int argc, char **argv)
 {
 	struct btf *btf = NULL, *base = NULL;
@@ -536,18 +552,11 @@ static int do_dump(int argc, char **argv)
 		NEXT_ARG();
 	} else if (is_prefix(src, "file")) {
 		const char sysfs_prefix[] = "/sys/kernel/btf/";
-		const char sysfs_vmlinux[] = "/sys/kernel/btf/vmlinux";
 
 		if (!base_btf &&
 		    strncmp(*argv, sysfs_prefix, sizeof(sysfs_prefix) - 1) == 0 &&
-		    strcmp(*argv, sysfs_vmlinux) != 0) {
-			base = btf__parse(sysfs_vmlinux, NULL);
-			if (libbpf_get_error(base)) {
-				p_err("failed to parse vmlinux BTF at '%s': %ld\n",
-				      sysfs_vmlinux, libbpf_get_error(base));
-				base = NULL;
-			}
-		}
+		    strcmp(*argv, sysfs_vmlinux))
+			base = get_vmlinux_btf_from_sysfs();
 
 		btf = btf__parse_split(*argv, base ?: base_btf);
 		err = libbpf_get_error(btf);
@@ -593,6 +602,14 @@ static int do_dump(int argc, char **argv)
 	if (!btf) {
 		btf = btf__load_from_kernel_by_id_split(btf_id, base_btf);
 		err = libbpf_get_error(btf);
+		if (err == -EINVAL && !base_btf) {
+			btf__free(base);
+			base = get_vmlinux_btf_from_sysfs();
+			p_info("Warning: valid base BTF was not specified with -B option, falling back on standard base BTF (sysfs vmlinux)");
+			btf = btf__load_from_kernel_by_id_split(btf_id, base);
+			err = libbpf_get_error(btf);
+		}
+
 		if (err) {
 			p_err("get btf by id (%u): %s", btf_id, strerror(err));
 			goto done;

travis-ci/vmtest/configs/blacklist/BLACKLIST-latest

@@ -0,0 +1,2 @@
+# TEMPORARY
+

travis-ci/vmtest/configs/blacklist/BLACKLIST-latest.s390x

@@ -0,0 +1,65 @@
+# TEMPORARY
+atomics                                  # attach(add): actual -524 <= expected 0                                      (trampoline)
+bpf_iter_setsockopt                      # JIT does not support calling kernel function                                (kfunc)
+bloom_filter_map                         # failed to find kernel BTF type ID of '__x64_sys_getpgid': -3                (?)
+bpf_tcp_ca                               # JIT does not support calling kernel function                                (kfunc)
+bpf_loop                                 # attaches to __x64_sys_nanosleep
+bpf_mod_race                             # BPF trampoline
+bpf_nf                                   # JIT does not support calling kernel function
+core_read_macros                         # unknown func bpf_probe_read#4                                               (overlapping)
+d_path                                   # failed to auto-attach program 'prog_stat': -524                             (trampoline)
+dummy_st_ops                             # test_run unexpected error: -524 (errno 524)                                 (trampoline)
+fentry_fexit                             # fentry attach failed: -524                                                  (trampoline)
+fentry_test                              # fentry_first_attach unexpected error: -524                                  (trampoline)
+fexit_bpf2bpf                            # freplace_attach_trace unexpected error: -524                                (trampoline)
+fexit_sleep                              # fexit_skel_load fexit skeleton failed                                       (trampoline)
+fexit_stress                             # fexit attach failed prog 0 failed: -524                                     (trampoline)
+fexit_test                               # fexit_first_attach unexpected error: -524                                   (trampoline)
+get_func_args_test	                 # trampoline
+get_func_ip_test                         # get_func_ip_test__attach unexpected error: -524                             (trampoline)
+get_stack_raw_tp                         # user_stack corrupted user stack                                             (no backchain userspace)
+kfree_skb                                # attach fentry unexpected error: -524                                        (trampoline)
+kfunc_call                               # 'bpf_prog_active': not found in kernel BTF                                  (?)
+ksyms_module                             # test_ksyms_module__open_and_load unexpected error: -9                       (?)
+ksyms_module_libbpf                      # JIT does not support calling kernel function                                (kfunc)
+ksyms_module_lskel                       # test_ksyms_module_lskel__open_and_load unexpected error: -9                 (?)
+modify_return                            # modify_return attach failed: -524                                           (trampoline)
+module_attach                            # skel_attach skeleton attach failed: -524                                    (trampoline)
+kprobe_multi_test                        # relies on fentry
+netcnt                                   # failed to load BPF skeleton 'netcnt_prog': -7                               (?)
+probe_user                               # check_kprobe_res wrong kprobe res from probe read                           (?)
+recursion                                # skel_attach unexpected error: -524                                          (trampoline)
+ringbuf                                  # skel_load skeleton load failed                                              (?)
+sk_assign                                # Can't read on server: Invalid argument                                      (?)
+sk_lookup                                # endianness problem
+sk_storage_tracing                       # test_sk_storage_tracing__attach unexpected error: -524                      (trampoline)
+skc_to_unix_sock                         # could not attach BPF object unexpected error: -524                          (trampoline)
+socket_cookie                            # prog_attach unexpected error: -524                                          (trampoline)
+stacktrace_build_id                      # compare_map_keys stackid_hmap vs. stackmap err -2 errno 2                   (?)
+tailcalls                                # tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls      (?)
+task_local_storage                       # failed to auto-attach program 'trace_exit_creds': -524                      (trampoline)
+test_bpffs                               # bpffs test  failed 255                                                      (iterator)
+test_bprm_opts                           # failed to auto-attach program 'secure_exec': -524                           (trampoline)
+test_ima                                 # failed to auto-attach program 'ima': -524                                   (trampoline)
+test_local_storage                       # failed to auto-attach program 'unlink_hook': -524                           (trampoline)
+test_lsm                                 # failed to find kernel BTF type ID of '__x64_sys_setdomainname': -3          (?)
+test_overhead                            # attach_fentry unexpected error: -524                                        (trampoline)
+test_profiler                            # unknown func bpf_probe_read_str#45                                          (overlapping)
+timer                                    # failed to auto-attach program 'test1': -524                                 (trampoline)
+timer_crash                              # trampoline
+timer_mim                                # failed to auto-attach program 'test1': -524                                 (trampoline)
+trace_ext                                # failed to auto-attach program 'test_pkt_md_access_new': -524                (trampoline)
+trace_printk                             # trace_printk__load unexpected error: -2 (errno 2)                           (?)
+trace_vprintk                            # trace_vprintk__open_and_load unexpected error: -9                           (?)
+trampoline_count                         # prog 'prog1': failed to attach: ERROR: strerror_r(-524)=22                  (trampoline)
+verif_stats                              # trace_vprintk__open_and_load unexpected error: -9                           (?)
+vmlinux                                  # failed to auto-attach program 'handle__fentry': -524                        (trampoline)
+xdp_adjust_tail                          # case-128 err 0 errno 28 retval 1 size 128 expect-size 3520                  (?)
+xdp_bonding                              # failed to auto-attach program 'trace_on_entry': -524                        (trampoline)
+xdp_bpf2bpf                              # failed to auto-attach program 'trace_on_entry': -524                        (trampoline)
+map_kptr                                 # failed to open_and_load program: -524 (trampoline)
+bpf_cookie                               # failed to open_and_load program: -524 (trampoline)
+xdp_do_redirect                          # prog_run_max_size unexpected error: -22 (errno 22)
+send_signal                              # intermittently fails to receive signal
+select_reuseport                         # intermittently fails on new s390x setup
+tc_redirect/tc_redirect_dtime            # very flaky