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selftests/bpf: Use at least 10 args in stack argument tests

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On arm64, the first 8 arguments are passed in registers (x0-x7), so
tests with 8 or fewer arguments never exercise the native stack argument
path in the JIT. Increase argument counts to at least 10 across all
BPF-to-BPF subprog and kfunc stack argument tests so that at least 2
arguments land on the arm64 stack.

For the two-callees test, bump foo1 from 8 to 10 and foo2 from 10 to 12
args to preserve the different-stack-depth flavor of the test.

The bpf_kfunc_call_stack_arg_mem kfunc is left unchanged at 7 args to
avoid breaking the precision backtracking test which relies on hardcoded
verifier log instruction indices.

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20260528161750.1900674-3-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Puranjay Mohan 2026-05-28 09:17:48 -07:00 committed by Alexei Starovoitov
parent 12a585e607
commit 157317ba66
5 changed files with 110 additions and 74 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
tools/testing/selftests/bpf/prog_tests/stack_arg.c
View File

@ -37,7 +37,7 @@ static void test_global_many(void)
if (!ASSERT_OK(stack_arg__load(skel), "load"))
goto out;
run_subtest(skel->progs.test_global_many_args, 36);
run_subtest(skel->progs.test_global_many_args, 55);
out:
stack_arg__destroy(skel);
@ -62,10 +62,10 @@ static void test_async_cb_many(void)
run_subtest(skel->progs.test_async_cb_many_args, 0);
/* Wait for the timer callback to fire and verify the result.
* 10+20+30+40+50+60+70+80 = 360
* 10+20+30+40+50+60+70+80+90+100 = 550
*/
usleep(50);
ASSERT_EQ(skel->bss->timer_result, 360, "timer_result");
ASSERT_EQ(skel->bss->timer_result, 550, "timer_result");
out:
stack_arg__destroy(skel);
@ -87,11 +87,11 @@ static void test_bpf2bpf(void)
if (!ASSERT_OK(stack_arg__load(skel), "load"))
goto out;
run_subtest(skel->progs.test_bpf2bpf_ptr_stack_arg, 45);
run_subtest(skel->progs.test_bpf2bpf_mix_stack_args, 51);
run_subtest(skel->progs.test_bpf2bpf_nesting_stack_arg, 50);
run_subtest(skel->progs.test_bpf2bpf_dynptr_stack_arg, 69);
run_subtest(skel->progs.test_two_callees, 91);
run_subtest(skel->progs.test_bpf2bpf_ptr_stack_arg, 75);
run_subtest(skel->progs.test_bpf2bpf_mix_stack_args, 66);
run_subtest(skel->progs.test_bpf2bpf_nesting_stack_arg, 84);
run_subtest(skel->progs.test_bpf2bpf_dynptr_stack_arg, 99);
run_subtest(skel->progs.test_two_callees, 133);
out:
stack_arg__destroy(skel);
@ -113,14 +113,14 @@ static void test_kfunc(void)
if (!ASSERT_OK(stack_arg_kfunc__load(skel), "load"))
goto out;
run_subtest(skel->progs.test_stack_arg_scalar, 36);
run_subtest(skel->progs.test_stack_arg_ptr, 45);
run_subtest(skel->progs.test_stack_arg_mix, 51);
run_subtest(skel->progs.test_stack_arg_dynptr, 69);
run_subtest(skel->progs.test_stack_arg_scalar, 55);
run_subtest(skel->progs.test_stack_arg_ptr, 75);
run_subtest(skel->progs.test_stack_arg_mix, 66);
run_subtest(skel->progs.test_stack_arg_dynptr, 99);
run_subtest(skel->progs.test_stack_arg_mem, 151);
run_subtest(skel->progs.test_stack_arg_iter, 115);
run_subtest(skel->progs.test_stack_arg_const_str, 15);
run_subtest(skel->progs.test_stack_arg_timer, 15);
run_subtest(skel->progs.test_stack_arg_iter, 145);
run_subtest(skel->progs.test_stack_arg_const_str, 45);
run_subtest(skel->progs.test_stack_arg_timer, 45);
out:
stack_arg_kfunc__destroy(skel);

94
tools/testing/selftests/bpf/progs/stack_arg.c
View File

@ -27,14 +27,16 @@ int timer_result;
const volatile bool has_stack_arg = true;
__noinline static int static_func_many_args(int a, int b, int c, int d,
int e, int f, int g, int h)
int e, int f, int g, int h,
int i, int j)
{
return a + b + c + d + e + f + g + h;
return a + b + c + d + e + f + g + h + i + j;
}
__noinline int global_calls_many_args(int a, int b, int c)
{
return static_func_many_args(a, b, c, 4, 5, 6, 7, 8);
return static_func_many_args(a, b, c, a + 3, a + 4, a + 5, a + 6,
a + 7, a + 8, a + 9);
}
SEC("tc")
@ -48,18 +50,20 @@ struct test_data {
long y;
};
/* 1 + 2 + 3 + 4 + 5 + 10 + 20 = 45 */
/* 1+2+3+4+5+6+7+8+9+10+20 = 75 */
__noinline static long func_with_ptr_stack_arg(long a, long b, long c, long d,
long e, struct test_data *p)
long e, long f, long g, long h,
long i, struct test_data *p)
{
return a + b + c + d + e + p->x + p->y;
return a + b + c + d + e + f + g + h + i + p->x + p->y;
}
__noinline long global_ptr_stack_arg(long a, long b, long c, long d, long e)
{
struct test_data data = { .x = 10, .y = 20 };
return func_with_ptr_stack_arg(a, b, c, d, e, &data);
return func_with_ptr_stack_arg(a, b, c, d, e, a + 5, a + 6, a + 7,
a + 8, &data);
}
SEC("tc")
@ -68,12 +72,13 @@ int test_bpf2bpf_ptr_stack_arg(void)
return global_ptr_stack_arg(1, 2, 3, 4, 5);
}
/* 1 + 2 + 3 + 4 + 5 + 10 + 6 + 20 = 51 */
/* 1+2+3+4+5+6+7+10+8+20 = 66 */
__noinline static long func_with_mix_stack_args(long a, long b, long c, long d,
long e, struct test_data *p,
long f, struct test_data *q)
long e, long f, long g,
struct test_data *p,
long h, struct test_data *q)
{
return a + b + c + d + e + p->x + f + q->y;
return a + b + c + d + e + f + g + p->x + h + q->y;
}
__noinline long global_mix_stack_args(long a, long b, long c, long d, long e)
@ -81,7 +86,8 @@ __noinline long global_mix_stack_args(long a, long b, long c, long d, long e)
struct test_data p = { .x = 10 };
struct test_data q = { .y = 20 };
return func_with_mix_stack_args(a, b, c, d, e, &p, e + 1, &q);
return func_with_mix_stack_args(a, b, c, d, e, e + 1, e + 2, &p,
e + 3, &q);
}
SEC("tc")
@ -94,26 +100,30 @@ int test_bpf2bpf_mix_stack_args(void)
* Nesting test: func_outer calls func_inner, both with struct pointer
* as stack arg.
*
* func_inner: (a+1) + (b+1) + (c+1) + (d+1) + (e+1) + p->x + p->y
* = 2 + 3 + 4 + 5 + 6 + 10 + 20 = 50
* func_inner: (a+1)+...+(i+1) + p->x + p->y
* = 2+3+4+5+6+7+8+9+10+10+20 = 84
*/
__noinline static long func_inner_ptr(long a, long b, long c, long d,
long e, struct test_data *p)
long e, long f, long g, long h,
long i, struct test_data *p)
{
return a + b + c + d + e + p->x + p->y;
return a + b + c + d + e + f + g + h + i + p->x + p->y;
}
__noinline static long func_outer_ptr(long a, long b, long c, long d,
long e, struct test_data *p)
long e, long f, long g, long h,
long i, struct test_data *p)
{
return func_inner_ptr(a + 1, b + 1, c + 1, d + 1, e + 1, p);
return func_inner_ptr(a + 1, b + 1, c + 1, d + 1, e + 1,
f + 1, g + 1, h + 1, i + 1, p);
}
__noinline long global_nesting_ptr(long a, long b, long c, long d, long e)
{
struct test_data data = { .x = 10, .y = 20 };
return func_outer_ptr(a, b, c, d, e, &data);
return func_outer_ptr(a, b, c, d, e, a + 5, a + 6, a + 7, a + 8,
&data);
}
SEC("tc")
@ -122,11 +132,12 @@ int test_bpf2bpf_nesting_stack_arg(void)
return global_nesting_ptr(1, 2, 3, 4, 5);
}
/* 1 + 2 + 3 + 4 + 5 + sizeof(pkt_v4) = 15 + 54 = 69 */
/* 1+2+3+4+5+6+7+8+9+sizeof(pkt_v4) = 45+54 = 99 */
__noinline static long func_with_dynptr(long a, long b, long c, long d,
long e, struct bpf_dynptr *ptr)
long e, long f, long g, long h,
long i, struct bpf_dynptr *ptr)
{
return a + b + c + d + e + bpf_dynptr_size(ptr);
return a + b + c + d + e + f + g + h + i + bpf_dynptr_size(ptr);
}
__noinline long global_dynptr_stack_arg(void *ctx __arg_ctx, long a, long b,
@ -135,7 +146,8 @@ __noinline long global_dynptr_stack_arg(void *ctx __arg_ctx, long a, long b,
struct bpf_dynptr ptr;
bpf_dynptr_from_skb(ctx, 0, &ptr);
return func_with_dynptr(a, b, c, d, d + 1, &ptr);
return func_with_dynptr(a, b, c, d, d + 1, d + 2, d + 3, d + 4,
d + 5, &ptr);
}
SEC("tc")
@ -144,24 +156,25 @@ int test_bpf2bpf_dynptr_stack_arg(struct __sk_buff *skb)
return global_dynptr_stack_arg(skb, 1, 2, 3, 4);
}
/* foo1: a+b+c+d+e+f+g+h */
__noinline static int foo1(int a, int b, int c, int d,
int e, int f, int g, int h)
{
return a + b + c + d + e + f + g + h;
}
/* foo2: a+b+c+d+e+f+g+h+i+j */
__noinline static int foo2(int a, int b, int c, int d, int e,
/* foo1: a+b+c+d+e+f+g+h+i+j */
__noinline static int foo1(int a, int b, int c, int d, int e,
int f, int g, int h, int i, int j)
{
return a + b + c + d + e + f + g + h + i + j;
}
/* global_two_callees calls foo1 (3 stack args) and foo2 (5 stack args).
/* foo2: a+b+c+d+e+f+g+h+i+j+k+l */
__noinline static int foo2(int a, int b, int c, int d, int e,
int f, int g, int h, int i, int j,
int k, int l)
{
return a + b + c + d + e + f + g + h + i + j + k + l;
}
/* global_two_callees calls foo1 (5 stack args) and foo2 (7 stack args).
* The outgoing stack arg area is sized for foo2 (the larger callee).
* Stores for foo1 are a subset of the area used by foo2.
* Result: foo1(1,2,3,4,5,6,7,8) + foo2(1,2,3,4,5,6,7,8,9,10) = 36 + 55 = 91
* Result: foo1(1..10) + foo2(1..12) = 55 + 78 = 133
*
* Pass a-e through so the compiler can't constant-fold the stack args away.
*/
@ -169,8 +182,9 @@ __noinline int global_two_callees(int a, int b, int c, int d, int e)
{
int ret;
ret = foo1(a, b, c, d, e, a + 5, a + 6, a + 7);
ret += foo2(a, b, c, d, e, a + 5, a + 6, a + 7, a + 8, a + 9);
ret = foo1(a, b, c, d, e, a + 5, a + 6, a + 7, a + 8, a + 9);
ret += foo2(a, b, c, d, e, a + 5, a + 6, a + 7, a + 8, a + 9,
a + 10, a + 11);
return ret;
}
@ -180,9 +194,15 @@ int test_two_callees(void)
return global_two_callees(1, 2, 3, 4, 5);
}
const volatile int timer_base = 10;
static int timer_cb_many_args(void *map, int *key, struct bpf_timer *timer)
{
timer_result = static_func_many_args(10, 20, 30, 40, 50, 60, 70, 80);
int v = timer_base;
timer_result = static_func_many_args(v, v * 2, v * 3, v * 4, v * 5,
v * 6, v * 7, v * 8, v * 9,
v * 10);
return 0;
}

24
tools/testing/selftests/bpf/progs/stack_arg_kfunc.c
View File

@ -33,7 +33,7 @@ struct {
SEC("tc")
int test_stack_arg_scalar(struct __sk_buff *skb)
{
return bpf_kfunc_call_stack_arg(1, 2, 3, 4, 5, 6, 7, 8);
return bpf_kfunc_call_stack_arg(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
}
SEC("tc")
@ -41,7 +41,7 @@ int test_stack_arg_ptr(struct __sk_buff *skb)
{
struct prog_test_pass1 p = { .x0 = 10, .x1 = 20 };
return bpf_kfunc_call_stack_arg_ptr(1, 2, 3, 4, 5, &p);
return bpf_kfunc_call_stack_arg_ptr(1, 2, 3, 4, 5, 6, 7, 8, 9, &p);
}
SEC("tc")
@ -50,17 +50,17 @@ int test_stack_arg_mix(struct __sk_buff *skb)
struct prog_test_pass1 p = { .x0 = 10 };
struct prog_test_pass1 q = { .x1 = 20 };
return bpf_kfunc_call_stack_arg_mix(1, 2, 3, 4, 5, &p, 6, &q);
return bpf_kfunc_call_stack_arg_mix(1, 2, 3, 4, 5, 6, 7, &p, 8, &q);
}
/* 1 + 2 + 3 + 4 + 5 + sizeof(pkt_v4) = 15 + 54 = 69 */
/* 1+2+3+4+5+6+7+8+9+sizeof(pkt_v4) = 45+54 = 99 */
SEC("tc")
int test_stack_arg_dynptr(struct __sk_buff *skb)
{
struct bpf_dynptr ptr;
bpf_dynptr_from_skb(skb, 0, &ptr);
return bpf_kfunc_call_stack_arg_dynptr(1, 2, 3, 4, 5, &ptr);
return bpf_kfunc_call_stack_arg_dynptr(1, 2, 3, 4, 5, 6, 7, 8, 9, &ptr);
}
/* 1 + 2 + 3 + 4 + 5 + (1 + 2 + ... + 16) = 15 + 136 = 151 */
@ -72,7 +72,7 @@ int test_stack_arg_mem(struct __sk_buff *skb)
return bpf_kfunc_call_stack_arg_mem(1, 2, 3, 4, 5, buf, sizeof(buf));
}
/* 1 + 2 + 3 + 4 + 5 + 100 = 115 */
/* 1+2+3+4+5+6+7+8+9+100 = 145 */
SEC("tc")
int test_stack_arg_iter(struct __sk_buff *skb)
{
@ -80,21 +80,22 @@ int test_stack_arg_iter(struct __sk_buff *skb)
u64 ret;
bpf_iter_testmod_seq_new(&it, 100, 10);
ret = bpf_kfunc_call_stack_arg_iter(1, 2, 3, 4, 5, &it);
ret = bpf_kfunc_call_stack_arg_iter(1, 2, 3, 4, 5, 6, 7, 8, 9, &it);
bpf_iter_testmod_seq_destroy(&it);
return ret;
}
const char cstr[] = "hello";
/* 1 + 2 + 3 + 4 + 5 = 15 */
/* 1+2+3+4+5+6+7+8+9 = 45 */
SEC("tc")
int test_stack_arg_const_str(struct __sk_buff *skb)
{
return bpf_kfunc_call_stack_arg_const_str(1, 2, 3, 4, 5, cstr);
return bpf_kfunc_call_stack_arg_const_str(1, 2, 3, 4, 5, 6, 7, 8, 9,
cstr);
}
/* 1 + 2 + 3 + 4 + 5 = 15 */
/* 1+2+3+4+5+6+7+8+9 = 45 */
SEC("tc")
int test_stack_arg_timer(struct __sk_buff *skb)
{
@ -104,7 +105,8 @@ int test_stack_arg_timer(struct __sk_buff *skb)
val = bpf_map_lookup_elem(&kfunc_timer_map, &key);
if (!val)
return 0;
return bpf_kfunc_call_stack_arg_timer(1, 2, 3, 4, 5, &val->timer);
return bpf_kfunc_call_stack_arg_timer(1, 2, 3, 4, 5, 6, 7, 8, 9,
&val->timer);
}
#else

25
tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
View File

@ -826,30 +826,34 @@ __bpf_kfunc int bpf_kfunc_call_test5(u8 a, u16 b, u32 c)
}
__bpf_kfunc u64 bpf_kfunc_call_stack_arg(u64 a, u64 b, u64 c, u64 d,
u64 e, u64 f, u64 g, u64 h)
u64 e, u64 f, u64 g, u64 h,
u64 i, u64 j)
{
return a + b + c + d + e + f + g + h;
return a + b + c + d + e + f + g + h + i + j;
}
__bpf_kfunc u64 bpf_kfunc_call_stack_arg_ptr(u64 a, u64 b, u64 c, u64 d, u64 e,
u64 f, u64 g, u64 h, u64 i,
struct prog_test_pass1 *p)
{
return a + b + c + d + e + p->x0 + p->x1;
return a + b + c + d + e + f + g + h + i + p->x0 + p->x1;
}
__bpf_kfunc u64 bpf_kfunc_call_stack_arg_mix(u64 a, u64 b, u64 c, u64 d, u64 e,
struct prog_test_pass1 *p, u64 f,
u64 f, u64 g,
struct prog_test_pass1 *p, u64 h,
struct prog_test_pass1 *q)
{
return a + b + c + d + e + p->x0 + f + q->x1;
return a + b + c + d + e + f + g + p->x0 + h + q->x1;
}
__bpf_kfunc u64 bpf_kfunc_call_stack_arg_dynptr(u64 a, u64 b, u64 c, u64 d, u64 e,
u64 f, u64 g, u64 h, u64 i,
struct bpf_dynptr *ptr)
{
const struct bpf_dynptr_kern *kern_ptr = (void *)ptr;
return a + b + c + d + e + (kern_ptr->size & 0xFFFFFF);
return a + b + c + d + e + f + g + h + i + (kern_ptr->size & 0xFFFFFF);
}
__bpf_kfunc u64 bpf_kfunc_call_stack_arg_mem(u64 a, u64 b, u64 c, u64 d, u64 e,
@ -865,21 +869,24 @@ __bpf_kfunc u64 bpf_kfunc_call_stack_arg_mem(u64 a, u64 b, u64 c, u64 d, u64 e,
}
__bpf_kfunc u64 bpf_kfunc_call_stack_arg_iter(u64 a, u64 b, u64 c, u64 d, u64 e,
u64 f, u64 g, u64 h, u64 i,
struct bpf_iter_testmod_seq *it__iter)
{
return a + b + c + d + e + it__iter->value;
return a + b + c + d + e + f + g + h + i + it__iter->value;
}
__bpf_kfunc u64 bpf_kfunc_call_stack_arg_const_str(u64 a, u64 b, u64 c, u64 d, u64 e,
u64 f, u64 g, u64 h, u64 i,
const char *str__str)
{
return a + b + c + d + e;
return a + b + c + d + e + f + g + h + i;
}
__bpf_kfunc u64 bpf_kfunc_call_stack_arg_timer(u64 a, u64 b, u64 c, u64 d, u64 e,
u64 f, u64 g, u64 h, u64 i,
struct bpf_timer *timer)
{
return a + b + c + d + e;
return a + b + c + d + e + f + g + h + i;
}
__bpf_kfunc u64 bpf_kfunc_call_stack_arg_big(u64 a, u64 b, u64 c, u64 d, u64 e,

11
tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h
View File

@ -119,21 +119,28 @@ struct sock *bpf_kfunc_call_test3(struct sock *sk) __ksym;
long bpf_kfunc_call_test4(signed char a, short b, int c, long d) __ksym;
int bpf_kfunc_call_test5(__u8 a, __u16 b, __u32 c) __ksym;
__u64 bpf_kfunc_call_stack_arg(__u64 a, __u64 b, __u64 c, __u64 d,
__u64 e, __u64 f, __u64 g, __u64 h) __ksym;
__u64 e, __u64 f, __u64 g, __u64 h,
__u64 i, __u64 j) __ksym;
__u64 bpf_kfunc_call_stack_arg_ptr(__u64 a, __u64 b, __u64 c, __u64 d, __u64 e,
__u64 f, __u64 g, __u64 h, __u64 i,
struct prog_test_pass1 *p) __ksym;
__u64 bpf_kfunc_call_stack_arg_mix(__u64 a, __u64 b, __u64 c, __u64 d, __u64 e,
struct prog_test_pass1 *p, __u64 f,
__u64 f, __u64 g,
struct prog_test_pass1 *p, __u64 h,
struct prog_test_pass1 *q) __ksym;
__u64 bpf_kfunc_call_stack_arg_dynptr(__u64 a, __u64 b, __u64 c, __u64 d, __u64 e,
__u64 f, __u64 g, __u64 h, __u64 i,
struct bpf_dynptr *ptr) __ksym;
__u64 bpf_kfunc_call_stack_arg_mem(__u64 a, __u64 b, __u64 c, __u64 d, __u64 e,
void *mem, int mem__sz) __ksym;
__u64 bpf_kfunc_call_stack_arg_iter(__u64 a, __u64 b, __u64 c, __u64 d, __u64 e,
__u64 f, __u64 g, __u64 h, __u64 i,
struct bpf_iter_testmod_seq *it__iter) __ksym;
__u64 bpf_kfunc_call_stack_arg_const_str(__u64 a, __u64 b, __u64 c, __u64 d, __u64 e,
__u64 f, __u64 g, __u64 h, __u64 i,
const char *str__str) __ksym;
__u64 bpf_kfunc_call_stack_arg_timer(__u64 a, __u64 b, __u64 c, __u64 d, __u64 e,
__u64 f, __u64 g, __u64 h, __u64 i,
struct bpf_timer *timer) __ksym;
__u64 bpf_kfunc_call_stack_arg_big(__u64 a, __u64 b, __u64 c, __u64 d, __u64 e,
struct prog_test_big_arg s) __ksym;