@@ -832,9 +832,10 @@ $(OUTPUT)/veristat: $(OUTPUT)/veristat.o
# Linking uprobe_multi can fail due to relocation overflows on mips.
$(OUTPUT)/uprobe_multi: CFLAGS += $(if $(filter mips, $(ARCH)),-mxgot)
-$(OUTPUT)/uprobe_multi: uprobe_multi.c
+$(OUTPUT)/uprobe_multi: uprobe_multi.c uprobe_multi.ld
$(call msg,BINARY,,$@)
- $(Q)$(CC) $(CFLAGS) -O0 $(LDFLAGS) $^ $(LDLIBS) -o $@
+ $(Q)$(CC) $(CFLAGS) -Wl,-T,uprobe_multi.ld -O0 $(LDFLAGS) \
+ $(filter-out %.ld,$^) $(LDLIBS) -o $@
EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR) \
prog_tests/tests.h map_tests/tests.h verifier/tests.h \
new file mode 100644
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+#include <test_progs.h>
+
+#include "test_build_id.skel.h"
+
+static char build_id[BPF_BUILD_ID_SIZE];
+static int build_id_sz;
+
+static void print_stack(struct bpf_stack_build_id *stack, int frame_cnt)
+{
+ int i, j;
+
+ for (i = 0; i < frame_cnt; i++) {
+ printf("FRAME #%02d: ", i);
+ switch (stack[i].status) {
+ case BPF_STACK_BUILD_ID_EMPTY:
+ printf("<EMPTY>\n");
+ break;
+ case BPF_STACK_BUILD_ID_VALID:
+ printf("BUILD ID = ");
+ for (j = 0; j < BPF_BUILD_ID_SIZE; j++)
+ printf("%02hhx", (unsigned)stack[i].build_id[j]);
+ printf(" OFFSET = %llx", (unsigned long long)stack[i].offset);
+ break;
+ case BPF_STACK_BUILD_ID_IP:
+ printf("IP = %llx", (unsigned long long)stack[i].ip);
+ break;
+ default:
+ printf("UNEXPECTED STATUS %d ", stack[i].status);
+ break;
+ }
+ printf("\n");
+ }
+}
+
+static void subtest_nofault(bool build_id_resident)
+{
+ struct test_build_id *skel;
+ struct bpf_stack_build_id *stack;
+ int frame_cnt;
+
+ skel = test_build_id__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ return;
+
+ skel->links.uprobe_nofault = bpf_program__attach(skel->progs.uprobe_nofault);
+ if (!ASSERT_OK_PTR(skel->links.uprobe_nofault, "link"))
+ goto cleanup;
+
+ if (build_id_resident)
+ ASSERT_OK(system("./uprobe_multi uprobe-paged-in"), "trigger_uprobe");
+ else
+ ASSERT_OK(system("./uprobe_multi uprobe-paged-out"), "trigger_uprobe");
+
+ if (!ASSERT_GT(skel->bss->res_nofault, 0, "res"))
+ goto cleanup;
+
+ stack = skel->bss->stack_nofault;
+ frame_cnt = skel->bss->res_nofault / sizeof(struct bpf_stack_build_id);
+ if (env.verbosity >= VERBOSE_NORMAL)
+ print_stack(stack, frame_cnt);
+
+ if (build_id_resident) {
+ ASSERT_EQ(stack[0].status, BPF_STACK_BUILD_ID_VALID, "build_id_status");
+ ASSERT_EQ(memcmp(stack[0].build_id, build_id, build_id_sz), 0, "build_id_match");
+ } else {
+ ASSERT_EQ(stack[0].status, BPF_STACK_BUILD_ID_IP, "build_id_status");
+ }
+
+cleanup:
+ test_build_id__destroy(skel);
+}
+
+static void subtest_sleepable(void)
+{
+ struct test_build_id *skel;
+ struct bpf_stack_build_id *stack;
+ int frame_cnt;
+
+ skel = test_build_id__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "skel_open"))
+ return;
+
+ skel->links.uprobe_sleepable = bpf_program__attach(skel->progs.uprobe_sleepable);
+ if (!ASSERT_OK_PTR(skel->links.uprobe_sleepable, "link"))
+ goto cleanup;
+
+ /* force build ID to not be paged in */
+ ASSERT_OK(system("./uprobe_multi uprobe-paged-out"), "trigger_uprobe");
+
+ if (!ASSERT_GT(skel->bss->res_sleepable, 0, "res"))
+ goto cleanup;
+
+ stack = skel->bss->stack_sleepable;
+ frame_cnt = skel->bss->res_sleepable / sizeof(struct bpf_stack_build_id);
+ if (env.verbosity >= VERBOSE_NORMAL)
+ print_stack(stack, frame_cnt);
+
+ ASSERT_EQ(stack[0].status, BPF_STACK_BUILD_ID_VALID, "build_id_status");
+ ASSERT_EQ(memcmp(stack[0].build_id, build_id, build_id_sz), 0, "build_id_match");
+
+cleanup:
+ test_build_id__destroy(skel);
+}
+
+void serial_test_build_id(void)
+{
+ build_id_sz = read_build_id("uprobe_multi", build_id, sizeof(build_id));
+ ASSERT_EQ(build_id_sz, BPF_BUILD_ID_SIZE, "parse_build_id");
+
+ if (test__start_subtest("nofault-paged-out"))
+ subtest_nofault(false /* not resident */);
+ if (test__start_subtest("nofault-paged-in"))
+ subtest_nofault(true /* resident */);
+ if (test__start_subtest("sleepable"))
+ subtest_sleepable();
+}
new file mode 100644
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+struct bpf_stack_build_id stack_sleepable[128];
+int res_sleepable;
+
+struct bpf_stack_build_id stack_nofault[128];
+int res_nofault;
+
+SEC("uprobe.multi/./uprobe_multi:uprobe")
+int uprobe_nofault(struct pt_regs *ctx)
+{
+ res_nofault = bpf_get_stack(ctx, stack_nofault, sizeof(stack_nofault),
+ BPF_F_USER_STACK | BPF_F_USER_BUILD_ID);
+
+ return 0;
+}
+
+SEC("uprobe.multi.s/./uprobe_multi:uprobe")
+int uprobe_sleepable(struct pt_regs *ctx)
+{
+ res_sleepable = bpf_get_stack(ctx, stack_sleepable, sizeof(stack_sleepable),
+ BPF_F_USER_STACK | BPF_F_USER_BUILD_ID);
+
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
@@ -2,8 +2,21 @@
#include <stdio.h>
#include <string.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <sys/mman.h>
+#include <unistd.h>
#include <sdt.h>
+#ifndef MADV_POPULATE_READ
+#define MADV_POPULATE_READ 22
+#endif
+
+int __attribute__((weak)) uprobe(void)
+{
+ return 0;
+}
+
#define __PASTE(a, b) a##b
#define PASTE(a, b) __PASTE(a, b)
@@ -75,6 +88,30 @@ static int usdt(void)
return 0;
}
+extern char build_id_start[];
+extern char build_id_end[];
+
+int __attribute__((weak)) trigger_uprobe(bool build_id_resident)
+{
+ int page_sz = sysconf(_SC_PAGESIZE);
+ void *addr;
+
+ /* page-align build ID start */
+ addr = (void *)((uintptr_t)&build_id_start & ~(page_sz - 1));
+
+ /* to guarantee MADV_PAGEOUT work reliably, we need to ensure that
+ * memory range is mapped into current process, so we unconditionally
+ * do MADV_POPULATE_READ, and then MADV_PAGEOUT, if necessary
+ */
+ madvise(addr, page_sz, MADV_POPULATE_READ);
+ if (!build_id_resident)
+ madvise(addr, page_sz, MADV_PAGEOUT);
+
+ (void)uprobe();
+
+ return 0;
+}
+
int main(int argc, char **argv)
{
if (argc != 2)
@@ -84,6 +121,10 @@ int main(int argc, char **argv)
return bench();
if (!strcmp("usdt", argv[1]))
return usdt();
+ if (!strcmp("uprobe-paged-out", argv[1]))
+ return trigger_uprobe(false /* page-out build ID */);
+ if (!strcmp("uprobe-paged-in", argv[1]))
+ return trigger_uprobe(true /* page-in build ID */);
error:
fprintf(stderr, "usage: %s <bench|usdt>\n", argv[0]);
new file mode 100644
@@ -0,0 +1,11 @@
+SECTIONS
+{
+ . = ALIGN(4096);
+ .note.gnu.build-id : { *(.note.gnu.build-id) }
+ . = ALIGN(4096);
+}
+INSERT AFTER .text;
+
+build_id_start = ADDR(.note.gnu.build-id);
+build_id_end = ADDR(.note.gnu.build-id) + SIZEOF(.note.gnu.build-id);
+