From: Jiri Olsa <jolsa@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>
Cc: bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: [PATCH 4/7] selftests/bpf: Change uprobe syscall tests to use nop10
Date: Thu, 14 May 2026 15:53:39 +0200 [thread overview]
Message-ID: <20260514135342.22130-5-jolsa@kernel.org> (raw)
In-Reply-To: <20260514135342.22130-1-jolsa@kernel.org>
Optimized uprobes are now on top of 10-bytes nop instructions,
reflect that in existing tests.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
.../selftests/bpf/benchs/bench_trigger.c | 2 +-
.../selftests/bpf/prog_tests/uprobe_syscall.c | 29 ++++++++++---------
tools/testing/selftests/bpf/prog_tests/usdt.c | 25 +++++++++-------
tools/testing/selftests/bpf/usdt_2.c | 2 +-
4 files changed, 33 insertions(+), 25 deletions(-)
diff --git a/tools/testing/selftests/bpf/benchs/bench_trigger.c b/tools/testing/selftests/bpf/benchs/bench_trigger.c
index 2f22ec61667b..bcc4820c802e 100644
--- a/tools/testing/selftests/bpf/benchs/bench_trigger.c
+++ b/tools/testing/selftests/bpf/benchs/bench_trigger.c
@@ -398,7 +398,7 @@ static void *uprobe_producer_ret(void *input)
#ifdef __x86_64__
__nocf_check __weak void uprobe_target_nop5(void)
{
- asm volatile (".byte 0x0f, 0x1f, 0x44, 0x00, 0x00");
+ asm volatile (".byte 0x66, 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00");
}
static void *uprobe_producer_nop5(void *input)
diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
index 955a37751b52..c2e9e549c737 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c
@@ -17,7 +17,7 @@
#include "uprobe_syscall_executed.skel.h"
#include "bpf/libbpf_internal.h"
-#define USDT_NOP .byte 0x0f, 0x1f, 0x44, 0x00, 0x00
+#define USDT_NOP .byte 0x66, 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00
#include "usdt.h"
#pragma GCC diagnostic ignored "-Wattributes"
@@ -26,7 +26,7 @@ __attribute__((aligned(16)))
__nocf_check __weak __naked unsigned long uprobe_regs_trigger(void)
{
asm volatile (
- ".byte 0x0f, 0x1f, 0x44, 0x00, 0x00\n" /* nop5 */
+ ".byte 0x66, 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00\n" /* nop10 */
"movq $0xdeadbeef, %rax\n"
"ret\n"
);
@@ -345,9 +345,9 @@ static void test_uretprobe_syscall_call(void)
__attribute__((aligned(16)))
__nocf_check __weak __naked void uprobe_test(void)
{
- asm volatile (" \n"
- ".byte 0x0f, 0x1f, 0x44, 0x00, 0x00 \n"
- "ret \n"
+ asm volatile (
+ ".byte 0x66, 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00\n" /* nop10 */
+ "ret\n"
);
}
@@ -388,14 +388,16 @@ static int find_uprobes_trampoline(void *tramp_addr)
return ret;
}
-static unsigned char nop5[5] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
+static unsigned char jmp2B[2] = { 0xeb, 8 };
+static unsigned char nop10[10] = { 0x66, 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 };
+static unsigned char lea_rsp[5] = { 0x48, 0x8d, 0x64, 0x24, 0x80 };
-static void *find_nop5(void *fn)
+static void *find_nop10(void *fn)
{
int i;
- for (i = 0; i < 10; i++) {
- if (!memcmp(nop5, fn + i, 5))
+ for (i = 0; i < 128; i++) {
+ if (!memcmp(nop10, fn + i, 9))
return fn + i;
}
return NULL;
@@ -420,7 +422,8 @@ static void *check_attach(struct uprobe_syscall_executed *skel, trigger_t trigge
ASSERT_EQ(skel->bss->executed, executed, "executed");
/* .. and check the trampoline is as expected. */
- call = (struct __arch_relative_insn *) addr;
+ ASSERT_OK(memcmp(addr, lea_rsp, 4), "lea_rsp");
+ call = (struct __arch_relative_insn *)(addr + 5);
tramp = (void *) (call + 1) + call->raddr;
ASSERT_EQ(call->op, 0xe8, "call");
ASSERT_OK(find_uprobes_trampoline(tramp), "uprobes_trampoline");
@@ -432,7 +435,7 @@ static void check_detach(void *addr, void *tramp)
{
/* [uprobes_trampoline] stays after detach */
ASSERT_OK(find_uprobes_trampoline(tramp), "uprobes_trampoline");
- ASSERT_OK(memcmp(addr, nop5, 5), "nop5");
+ ASSERT_OK(memcmp(addr, jmp2B, 2), "jmp2B");
}
static void check(struct uprobe_syscall_executed *skel, struct bpf_link *link,
@@ -568,8 +571,8 @@ static void test_uprobe_usdt(void)
void *addr;
errno = 0;
- addr = find_nop5(usdt_test);
- if (!ASSERT_OK_PTR(addr, "find_nop5"))
+ addr = find_nop10(usdt_test);
+ if (!ASSERT_OK_PTR(addr, "find_nop10"))
return;
skel = uprobe_syscall_executed__open_and_load();
diff --git a/tools/testing/selftests/bpf/prog_tests/usdt.c b/tools/testing/selftests/bpf/prog_tests/usdt.c
index 69759b27794d..be34c4087ff5 100644
--- a/tools/testing/selftests/bpf/prog_tests/usdt.c
+++ b/tools/testing/selftests/bpf/prog_tests/usdt.c
@@ -252,7 +252,7 @@ extern void usdt_1(void);
extern void usdt_2(void);
static unsigned char nop1[1] = { 0x90 };
-static unsigned char nop1_nop5_combo[6] = { 0x90, 0x0f, 0x1f, 0x44, 0x00, 0x00 };
+static unsigned char nop1_nop10_combo[11] = { 0x90, 0x66, 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 };
static void *find_instr(void *fn, unsigned char *instr, size_t cnt)
{
@@ -271,17 +271,17 @@ static void subtest_optimized_attach(void)
__u8 *addr_1, *addr_2;
/* usdt_1 USDT probe has single nop instruction */
- addr_1 = find_instr(usdt_1, nop1_nop5_combo, 6);
- if (!ASSERT_NULL(addr_1, "usdt_1_find_nop1_nop5_combo"))
+ addr_1 = find_instr(usdt_1, nop1_nop10_combo, 6);
+ if (!ASSERT_NULL(addr_1, "usdt_1_find_nop1_nop10_combo"))
return;
addr_1 = find_instr(usdt_1, nop1, 1);
if (!ASSERT_OK_PTR(addr_1, "usdt_1_find_nop1"))
return;
- /* usdt_2 USDT probe has nop,nop5 instructions combo */
- addr_2 = find_instr(usdt_2, nop1_nop5_combo, 6);
- if (!ASSERT_OK_PTR(addr_2, "usdt_2_find_nop1_nop5_combo"))
+ /* usdt_2 USDT probe has nop,nop10 instructions combo */
+ addr_2 = find_instr(usdt_2, nop1_nop10_combo, 6);
+ if (!ASSERT_OK_PTR(addr_2, "usdt_2_find_nop1_nop10_combo"))
return;
skel = test_usdt__open_and_load();
@@ -309,12 +309,12 @@ static void subtest_optimized_attach(void)
bpf_link__destroy(skel->links.usdt_executed);
- /* we expect the nop5 ip */
+ /* we expect the nop10 ip */
skel->bss->expected_ip = (unsigned long) addr_2 + 1;
/*
* Attach program on top of usdt_2 which is probe defined on top
- * of nop1,nop5 combo, so the probe gets optimized on top of nop5.
+ * of nop1,nop10 combo, so the probe gets optimized on top of nop10.
*/
skel->links.usdt_executed = bpf_program__attach_usdt(skel->progs.usdt_executed,
0 /*self*/, "/proc/self/exe",
@@ -328,8 +328,13 @@ static void subtest_optimized_attach(void)
/* nop stays on addr_2 address */
ASSERT_EQ(*addr_2, 0x90, "nop");
- /* call is on addr_2 + 1 address */
- ASSERT_EQ(*(addr_2 + 1), 0xe8, "call");
+ /*
+ * lea -0x80(%rsp), %rsp
+ * call ...
+ */
+ static unsigned char expected[] = { 0x48, 0x8d, 0x64, 0x24, 0x80, 0xe8 };
+
+ ASSERT_MEMEQ(addr_2 + 1, expected, sizeof(expected), "lea_and_call");
ASSERT_EQ(skel->bss->executed, 4, "executed");
cleanup:
diff --git a/tools/testing/selftests/bpf/usdt_2.c b/tools/testing/selftests/bpf/usdt_2.c
index 789883aaca4c..b359b389f6c0 100644
--- a/tools/testing/selftests/bpf/usdt_2.c
+++ b/tools/testing/selftests/bpf/usdt_2.c
@@ -3,7 +3,7 @@
#if defined(__x86_64__)
/*
- * Include usdt.h with default nop,nop5 instructions combo.
+ * Include usdt.h with default nop,nop10 instructions combo.
*/
#include "usdt.h"
--
2.53.0
next prev parent reply other threads:[~2026-05-14 13:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-14 13:53 [PATCH 0/7] uprobes/x86: Fix red zone issue for optimized uprobes Jiri Olsa
2026-05-14 13:53 ` [PATCH 1/7] uprobes/x86: Move optimized uprobe from nop5 to nop10 Jiri Olsa
2026-05-14 16:54 ` Jakub Sitnicki
2026-05-14 20:05 ` sashiko-bot
2026-05-14 13:53 ` [PATCH 2/7] libbpf: Change has_nop_combo to work on top of nop10 Jiri Olsa
2026-05-14 14:55 ` bot+bpf-ci
2026-05-14 13:53 ` [PATCH 3/7] selftests/bpf: Emit nop,nop10 instructions combo for x86_64 arch Jiri Olsa
2026-05-14 13:53 ` Jiri Olsa [this message]
2026-05-14 13:53 ` [PATCH 5/7] selftests/bpf: Change uprobe/usdt trigger bench code to use nop10 Jiri Olsa
2026-05-14 13:53 ` [PATCH 6/7] selftests/bpf: Add reattach tests for uprobe syscall Jiri Olsa
2026-05-14 13:53 ` [PATCH 7/7] selftests/bpf: Add tests for uprobe nop10 red zone clobbering Jiri Olsa
2026-05-14 14:55 ` bot+bpf-ci
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