selftests/bpf: Add uprobe/usdt syscall tests
Adding tests for optimized uprobe/usdt probes. Checking that we get expected trampoline and attached bpf programs get executed properly. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20250720112133.244369-15-jolsa@kernel.org
This commit is contained in:
Jiri Olsa
committed by
Peter Zijlstra
Peter Zijlstra
parent
7932c4cf57
commit
d5c86c3370
@@ -8,6 +8,7 @@
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#include <asm/ptrace.h>
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#include <linux/compiler.h>
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#include <linux/stringify.h>
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#include <linux/kernel.h>
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#include <sys/wait.h>
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#include <sys/syscall.h>
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#include <sys/prctl.h>
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@@ -15,6 +16,11 @@
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#include "uprobe_syscall.skel.h"
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#include "uprobe_syscall_executed.skel.h"
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#define USDT_NOP .byte 0x0f, 0x1f, 0x44, 0x00, 0x00
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#include "usdt.h"
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#pragma GCC diagnostic ignored "-Wattributes"
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__naked unsigned long uretprobe_regs_trigger(void)
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{
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asm volatile (
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@@ -305,6 +311,265 @@ cleanup:
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close(go[0]);
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}
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#define TRAMP "[uprobes-trampoline]"
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__attribute__((aligned(16)))
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__nocf_check __weak __naked void uprobe_test(void)
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{
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asm volatile (" \n"
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".byte 0x0f, 0x1f, 0x44, 0x00, 0x00 \n"
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"ret \n"
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);
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}
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__attribute__((aligned(16)))
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__nocf_check __weak void usdt_test(void)
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{
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USDT(optimized_uprobe, usdt);
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}
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static int find_uprobes_trampoline(void *tramp_addr)
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{
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void *start, *end;
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char line[128];
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int ret = -1;
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FILE *maps;
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maps = fopen("/proc/self/maps", "r");
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if (!maps) {
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fprintf(stderr, "cannot open maps\n");
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return -1;
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}
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while (fgets(line, sizeof(line), maps)) {
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int m = -1;
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/* We care only about private r-x mappings. */
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if (sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n", &start, &end, &m) != 2)
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continue;
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if (m < 0)
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continue;
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if (!strncmp(&line[m], TRAMP, sizeof(TRAMP)-1) && (start == tramp_addr)) {
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ret = 0;
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break;
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}
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}
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fclose(maps);
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return ret;
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}
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static unsigned char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
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static void *find_nop5(void *fn)
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{
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int i;
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for (i = 0; i < 10; i++) {
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if (!memcmp(nop5, fn + i, 5))
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return fn + i;
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}
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return NULL;
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}
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typedef void (__attribute__((nocf_check)) *trigger_t)(void);
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static bool shstk_is_enabled;
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static void *check_attach(struct uprobe_syscall_executed *skel, trigger_t trigger,
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void *addr, int executed)
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{
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struct __arch_relative_insn {
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__u8 op;
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__s32 raddr;
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} __packed *call;
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void *tramp = NULL;
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__u8 *bp;
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/* Uprobe gets optimized after first trigger, so let's press twice. */
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trigger();
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trigger();
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/* Make sure bpf program got executed.. */
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ASSERT_EQ(skel->bss->executed, executed, "executed");
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if (shstk_is_enabled) {
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/* .. and check optimization is disabled under shadow stack. */
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bp = (__u8 *) addr;
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ASSERT_EQ(*bp, 0xcc, "int3");
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} else {
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/* .. and check the trampoline is as expected. */
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call = (struct __arch_relative_insn *) addr;
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tramp = (void *) (call + 1) + call->raddr;
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ASSERT_EQ(call->op, 0xe8, "call");
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ASSERT_OK(find_uprobes_trampoline(tramp), "uprobes_trampoline");
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}
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return tramp;
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}
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static void check_detach(void *addr, void *tramp)
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{
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/* [uprobes_trampoline] stays after detach */
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ASSERT_OK(!shstk_is_enabled && find_uprobes_trampoline(tramp), "uprobes_trampoline");
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ASSERT_OK(memcmp(addr, nop5, 5), "nop5");
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}
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static void check(struct uprobe_syscall_executed *skel, struct bpf_link *link,
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trigger_t trigger, void *addr, int executed)
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{
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void *tramp;
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tramp = check_attach(skel, trigger, addr, executed);
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bpf_link__destroy(link);
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check_detach(addr, tramp);
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}
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static void test_uprobe_legacy(void)
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{
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struct uprobe_syscall_executed *skel = NULL;
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LIBBPF_OPTS(bpf_uprobe_opts, opts,
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.retprobe = true,
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);
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struct bpf_link *link;
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unsigned long offset;
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offset = get_uprobe_offset(&uprobe_test);
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if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
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goto cleanup;
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/* uprobe */
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skel = uprobe_syscall_executed__open_and_load();
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if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
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return;
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skel->bss->pid = getpid();
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link = bpf_program__attach_uprobe_opts(skel->progs.test_uprobe,
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0, "/proc/self/exe", offset, NULL);
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if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_opts"))
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goto cleanup;
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check(skel, link, uprobe_test, uprobe_test, 2);
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/* uretprobe */
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skel->bss->executed = 0;
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link = bpf_program__attach_uprobe_opts(skel->progs.test_uretprobe,
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0, "/proc/self/exe", offset, &opts);
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if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_opts"))
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goto cleanup;
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check(skel, link, uprobe_test, uprobe_test, 2);
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cleanup:
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uprobe_syscall_executed__destroy(skel);
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}
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static void test_uprobe_multi(void)
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{
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struct uprobe_syscall_executed *skel = NULL;
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LIBBPF_OPTS(bpf_uprobe_multi_opts, opts);
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struct bpf_link *link;
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unsigned long offset;
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offset = get_uprobe_offset(&uprobe_test);
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if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
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goto cleanup;
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opts.offsets = &offset;
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opts.cnt = 1;
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skel = uprobe_syscall_executed__open_and_load();
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if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
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return;
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skel->bss->pid = getpid();
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/* uprobe.multi */
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link = bpf_program__attach_uprobe_multi(skel->progs.test_uprobe_multi,
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0, "/proc/self/exe", NULL, &opts);
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if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
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goto cleanup;
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check(skel, link, uprobe_test, uprobe_test, 2);
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/* uretprobe.multi */
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skel->bss->executed = 0;
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opts.retprobe = true;
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link = bpf_program__attach_uprobe_multi(skel->progs.test_uretprobe_multi,
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0, "/proc/self/exe", NULL, &opts);
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if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
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goto cleanup;
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check(skel, link, uprobe_test, uprobe_test, 2);
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cleanup:
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uprobe_syscall_executed__destroy(skel);
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}
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static void test_uprobe_session(void)
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{
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struct uprobe_syscall_executed *skel = NULL;
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LIBBPF_OPTS(bpf_uprobe_multi_opts, opts,
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.session = true,
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);
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struct bpf_link *link;
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unsigned long offset;
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offset = get_uprobe_offset(&uprobe_test);
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if (!ASSERT_GE(offset, 0, "get_uprobe_offset"))
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goto cleanup;
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opts.offsets = &offset;
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opts.cnt = 1;
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skel = uprobe_syscall_executed__open_and_load();
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if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
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return;
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skel->bss->pid = getpid();
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link = bpf_program__attach_uprobe_multi(skel->progs.test_uprobe_session,
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0, "/proc/self/exe", NULL, &opts);
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if (!ASSERT_OK_PTR(link, "bpf_program__attach_uprobe_multi"))
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goto cleanup;
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check(skel, link, uprobe_test, uprobe_test, 4);
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cleanup:
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uprobe_syscall_executed__destroy(skel);
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}
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static void test_uprobe_usdt(void)
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{
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struct uprobe_syscall_executed *skel;
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struct bpf_link *link;
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void *addr;
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errno = 0;
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addr = find_nop5(usdt_test);
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if (!ASSERT_OK_PTR(addr, "find_nop5"))
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return;
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skel = uprobe_syscall_executed__open_and_load();
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if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load"))
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return;
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skel->bss->pid = getpid();
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link = bpf_program__attach_usdt(skel->progs.test_usdt,
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-1 /* all PIDs */, "/proc/self/exe",
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"optimized_uprobe", "usdt", NULL);
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if (!ASSERT_OK_PTR(link, "bpf_program__attach_usdt"))
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goto cleanup;
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check(skel, link, usdt_test, addr, 2);
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cleanup:
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uprobe_syscall_executed__destroy(skel);
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}
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/*
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* Borrowed from tools/testing/selftests/x86/test_shadow_stack.c.
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*
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@@ -347,11 +612,20 @@ static void test_uretprobe_shadow_stack(void)
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return;
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}
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/* Run all of the uretprobe tests. */
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/* Run all the tests with shadow stack in place. */
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shstk_is_enabled = true;
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test_uretprobe_regs_equal();
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test_uretprobe_regs_change();
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test_uretprobe_syscall_call();
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test_uprobe_legacy();
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test_uprobe_multi();
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test_uprobe_session();
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test_uprobe_usdt();
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shstk_is_enabled = false;
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ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK);
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}
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@@ -365,6 +639,14 @@ static void __test_uprobe_syscall(void)
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test_uretprobe_syscall_call();
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if (test__start_subtest("uretprobe_shadow_stack"))
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test_uretprobe_shadow_stack();
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if (test__start_subtest("uprobe_legacy"))
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test_uprobe_legacy();
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if (test__start_subtest("uprobe_multi"))
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test_uprobe_multi();
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if (test__start_subtest("uprobe_session"))
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test_uprobe_session();
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if (test__start_subtest("uprobe_usdt"))
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test_uprobe_usdt();
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}
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#else
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static void __test_uprobe_syscall(void)
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@@ -1,6 +1,8 @@
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// SPDX-License-Identifier: GPL-2.0
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/usdt.bpf.h>
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#include <string.h>
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struct pt_regs regs;
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@@ -10,6 +12,36 @@ char _license[] SEC("license") = "GPL";
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int executed = 0;
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int pid;
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SEC("uprobe")
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int BPF_UPROBE(test_uprobe)
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{
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if (bpf_get_current_pid_tgid() >> 32 != pid)
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return 0;
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executed++;
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return 0;
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}
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SEC("uretprobe")
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int BPF_URETPROBE(test_uretprobe)
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{
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if (bpf_get_current_pid_tgid() >> 32 != pid)
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return 0;
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executed++;
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return 0;
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}
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SEC("uprobe.multi")
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int test_uprobe_multi(struct pt_regs *ctx)
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{
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if (bpf_get_current_pid_tgid() >> 32 != pid)
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return 0;
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executed++;
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return 0;
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}
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SEC("uretprobe.multi")
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int test_uretprobe_multi(struct pt_regs *ctx)
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{
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@@ -19,3 +51,23 @@ int test_uretprobe_multi(struct pt_regs *ctx)
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executed++;
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return 0;
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}
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SEC("uprobe.session")
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int test_uprobe_session(struct pt_regs *ctx)
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{
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if (bpf_get_current_pid_tgid() >> 32 != pid)
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return 0;
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executed++;
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return 0;
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}
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SEC("usdt")
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int test_usdt(struct pt_regs *ctx)
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{
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if (bpf_get_current_pid_tgid() >> 32 != pid)
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return 0;
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executed++;
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return 0;
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}
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