[bpf-next,v7,7/9] selftests/bpf: Add tracing prog private stack tests

Commit Message

Yonghong Song Oct. 29, 2024, 10:17 p.m. UTC

Some private stack tests are added including:
  - main prog only with stack size greater than BPF_PSTACK_MIN_SIZE.
  - main prog only with stack size smaller than BPF_PSTACK_MIN_SIZE.
  - prog with one subprog having MAX_BPF_STACK stack size and another
    subprog having non-zero small stack size.
  - prog with callback function.
  - prog with exception in main prog or subprog.
  - prog with async callback without nesting
  - prog with async callback with possible nesting

Signed-off-by: Yonghong Song <[e-mail]>
---
 .../selftests/bpf/prog_tests/verifier.c       |   2 +
 .../bpf/progs/verifier_private_stack.c        | 272 ++++++++++++++++++
 2 files changed, 274 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/verifier_private_stack.c

Patch

diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c
index 75f7a2ce334b..d9f65adb456b 100644
--- a/tools/testing/selftests/bpf/prog_tests/verifier.c
+++ b/tools/testing/selftests/bpf/prog_tests/verifier.c
@@ -61,6 +61,7 @@ 
 #include "verifier_or_jmp32_k.skel.h"
 #include "verifier_precision.skel.h"
 #include "verifier_prevent_map_lookup.skel.h"
+#include "verifier_private_stack.skel.h"
 #include "verifier_raw_stack.skel.h"
 #include "verifier_raw_tp_writable.skel.h"
 #include "verifier_reg_equal.skel.h"
@@ -188,6 +189,7 @@  void test_verifier_bpf_fastcall(void)         { RUN(verifier_bpf_fastcall); }
 void test_verifier_or_jmp32_k(void)           { RUN(verifier_or_jmp32_k); }
 void test_verifier_precision(void)            { RUN(verifier_precision); }
 void test_verifier_prevent_map_lookup(void)   { RUN(verifier_prevent_map_lookup); }
+void test_verifier_private_stack(void)        { RUN(verifier_private_stack); }
 void test_verifier_raw_stack(void)            { RUN(verifier_raw_stack); }
 void test_verifier_raw_tp_writable(void)      { RUN(verifier_raw_tp_writable); }
 void test_verifier_reg_equal(void)            { RUN(verifier_reg_equal); }
diff --git a/tools/testing/selftests/bpf/progs/verifier_private_stack.c b/tools/testing/selftests/bpf/progs/verifier_private_stack.c
new file mode 100644
index 000000000000..b1fbdf119553
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/verifier_private_stack.c
@@ -0,0 +1,272 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+#include "bpf_experimental.h"
+
+/* From include/linux/filter.h */
+#define MAX_BPF_STACK    512
+
+#if defined(__TARGET_ARCH_x86)
+
+struct elem {
+	struct bpf_timer t;
+	char pad[256];
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, int);
+	__type(value, struct elem);
+} array SEC(".maps");
+
+SEC("kprobe")
+__description("Private stack, single prog")
+__success
+__arch_x86_64
+__jited("	movabsq	$0x{{.*}}, %r9")
+__jited("	addq	%gs:0x{{.*}}, %r9")
+__jited("	movl	$0x2a, %edi")
+__jited("	movq	%rdi, -0x100(%r9)")
+__naked void private_stack_single_prog(void)
+{
+	asm volatile ("			\
+	r1 = 42;			\
+	*(u64 *)(r10 - 256) = r1;	\
+	r0 = 0;				\
+	exit;				\
+"	::: __clobber_all);
+}
+
+SEC("raw_tp")
+__description("No private stack")
+__success
+__arch_x86_64
+__jited("	subq	$0x8, %rsp")
+__naked void no_private_stack_nested(void)
+{
+	asm volatile ("			\
+	r1 = 42;			\
+	*(u64 *)(r10 - 8) = r1;		\
+	r0 = 0;				\
+	exit;				\
+"	::: __clobber_all);
+}
+
+__used
+__naked static void cumulative_stack_depth_subprog(void)
+{
+	asm volatile ("				\
+	r1 = 41;				\
+	*(u64 *)(r10 - 32) = r1;		\
+	call %[bpf_get_smp_processor_id];	\
+	exit;					\
+"	:
+	: __imm(bpf_get_smp_processor_id)
+	: __clobber_all);
+}
+
+SEC("kprobe")
+__description("Private stack, subtree > MAX_BPF_STACK")
+__success
+__arch_x86_64
+/* private stack fp for the main prog */
+__jited("	movabsq	$0x{{.*}}, %r9")
+__jited("	addq	%gs:0x{{.*}}, %r9")
+__jited("	movl	$0x2a, %edi")
+__jited("	movq	%rdi, -0x200(%r9)")
+__jited("	pushq	%r9")
+__jited("	callq	0x{{.*}}")
+__jited("	popq	%r9")
+__jited("	xorl	%eax, %eax")
+__naked void private_stack_nested_1(void)
+{
+	asm volatile ("				\
+	r1 = 42;				\
+	*(u64 *)(r10 - %[max_bpf_stack]) = r1;	\
+	call cumulative_stack_depth_subprog;	\
+	r0 = 0;					\
+	exit;					\
+"	:
+	: __imm_const(max_bpf_stack, MAX_BPF_STACK)
+	: __clobber_all);
+}
+
+__naked __noinline __used
+static unsigned long loop_callback(void)
+{
+	asm volatile ("				\
+	call %[bpf_get_prandom_u32];		\
+	r1 = 42;				\
+	*(u64 *)(r10 - 512) = r1;		\
+	call cumulative_stack_depth_subprog;	\
+	r0 = 0;					\
+	exit;					\
+"	:
+	: __imm(bpf_get_prandom_u32)
+	: __clobber_common);
+}
+
+SEC("raw_tp")
+__description("Private stack, callback")
+__success
+__arch_x86_64
+/* for func loop_callback */
+__jited("func #1")
+__jited("	endbr64")
+__jited("	nopl	(%rax,%rax)")
+__jited("	nopl	(%rax)")
+__jited("	pushq	%rbp")
+__jited("	movq	%rsp, %rbp")
+__jited("	endbr64")
+__jited("	movabsq	$0x{{.*}}, %r9")
+__jited("	addq	%gs:0x{{.*}}, %r9")
+__jited("	pushq	%r9")
+__jited("	callq")
+__jited("	popq	%r9")
+__jited("	movl	$0x2a, %edi")
+__jited("	movq	%rdi, -0x200(%r9)")
+__jited("	pushq	%r9")
+__jited("	callq")
+__jited("	popq	%r9")
+__naked void private_stack_callback(void)
+{
+	asm volatile ("			\
+	r1 = 1;				\
+	r2 = %[loop_callback];		\
+	r3 = 0;				\
+	r4 = 0;				\
+	call %[bpf_loop];		\
+	r0 = 0;				\
+	exit;				\
+"	:
+	: __imm_ptr(loop_callback),
+	  __imm(bpf_loop)
+	: __clobber_common);
+}
+
+SEC("fentry/bpf_fentry_test9")
+__description("Private stack, exception in main prog")
+__success __retval(0)
+__arch_x86_64
+__jited("	pushq	%r9")
+__jited("	callq")
+__jited("	popq	%r9")
+int private_stack_exception_main_prog(void)
+{
+	asm volatile ("			\
+	r1 = 42;			\
+	*(u64 *)(r10 - 512) = r1;	\
+"	::: __clobber_common);
+
+	bpf_throw(0);
+	return 0;
+}
+
+__used static int subprog_exception(void)
+{
+	bpf_throw(0);
+	return 0;
+}
+
+SEC("fentry/bpf_fentry_test9")
+__description("Private stack, exception in subprog")
+__success __retval(0)
+__arch_x86_64
+__jited("	movq	%rdi, -0x200(%r9)")
+__jited("	pushq	%r9")
+__jited("	callq")
+__jited("	popq	%r9")
+int private_stack_exception_sub_prog(void)
+{
+	asm volatile ("			\
+	r1 = 42;			\
+	*(u64 *)(r10 - 512) = r1;	\
+	call subprog_exception;		\
+"	::: __clobber_common);
+
+	return 0;
+}
+
+int glob;
+__noinline static void subprog2(int *val)
+{
+	glob += val[0] * 2;
+}
+
+__noinline static void subprog1(int *val)
+{
+	int tmp[64] = {};
+
+	tmp[0] = *val;
+	subprog2(tmp);
+}
+
+__noinline static int timer_cb1(void *map, int *key, struct bpf_timer *timer)
+{
+	subprog1(key);
+	return 0;
+}
+
+__noinline static int timer_cb2(void *map, int *key, struct bpf_timer *timer)
+{
+	return 0;
+}
+
+SEC("fentry/bpf_fentry_test9")
+__description("Private stack, async callback, not nested")
+__success __retval(0)
+__arch_x86_64
+__jited("	movabsq	$0x{{.*}}, %r9")
+int private_stack_async_callback_1(void)
+{
+	struct bpf_timer *arr_timer;
+	int array_key = 0;
+
+	arr_timer = bpf_map_lookup_elem(&array, &array_key);
+	if (!arr_timer)
+		return 0;
+
+	bpf_timer_init(arr_timer, &array, 1);
+	bpf_timer_set_callback(arr_timer, timer_cb2);
+	bpf_timer_start(arr_timer, 0, 0);
+	subprog1(&array_key);
+	return 0;
+}
+
+SEC("fentry/bpf_fentry_test9")
+__description("Private stack, async callback, potential nesting")
+__success __retval(0)
+__arch_x86_64
+__jited("	subq	$0x100, %rsp")
+int private_stack_async_callback_2(void)
+{
+	struct bpf_timer *arr_timer;
+	int array_key = 0;
+
+	arr_timer = bpf_map_lookup_elem(&array, &array_key);
+	if (!arr_timer)
+		return 0;
+
+	bpf_timer_init(arr_timer, &array, 1);
+	bpf_timer_set_callback(arr_timer, timer_cb1);
+	bpf_timer_start(arr_timer, 0, 0);
+	subprog1(&array_key);
+	return 0;
+}
+
+#else
+
+SEC("kprobe")
+__description("private stack is not supported, use a dummy test")
+__success
+int dummy_test(void)
+{
+	return 0;
+}
+
+#endif
+
+char _license[] SEC("license") = "GPL";