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selftests/bpf: Add testcases for callback with tailcall

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Add 2 testcases for callback with tailcall:
1. failure case: callback->subprog->tailcall.
2. success case: subprog with tailcall do not affect
   no-tailcall callback.

Signed-off-by: Pu Lehui <pulehui@huawei.com>
Link: https://patch.msgid.link/20260716120157.835937-4-pulehui@huaweicloud.com
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
This commit is contained in:
Pu Lehui
2026-07-16 12:01:57 +00:00
committed by Eduard Zingerman
parent a41d0c30d7
commit 42bfd21a8b
2 changed files with 88 additions and 0 deletions
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7
tools/testing/selftests/bpf/prog_tests/tailcalls.c
View File

@@ -12,6 +12,7 @@
#include "tailcall_cgrp_storage_no_storage.skel.h"
#include "tailcall_cgrp_storage.skel.h"
#include "tailcall_sleepable.skel.h"
#include "tailcall_callback.skel.h"
/* test_tailcall_1 checks basic functionality by patching multiple locations
* in a single program for a single tail call slot with nop->jmp, jmp->nop
@@ -1901,6 +1902,11 @@ static void test_tailcall_sleepable(void)
tailcall_sleepable__destroy(skel);
}
static void test_tailcall_callback(void)
{
RUN_TESTS(tailcall_callback);
}
void test_tailcalls(void)
{
if (test__start_subtest("tailcall_1"))
@@ -1967,4 +1973,5 @@ void test_tailcalls(void)
test_tailcall_cgrp_storage_no_storage_leaf();
if (test__start_subtest("tailcall_cgrp_storage_no_storage_bridge"))
test_tailcall_cgrp_storage_no_storage_bridge();
test_tailcall_callback();
}

81
tools/testing/selftests/bpf/progs/tailcall_callback.c Normal file
View File

@@ -0,0 +1,81 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
#include "bpf_test_utils.h"
int classifier_0(struct __sk_buff *skb);
struct {
__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
__uint(max_entries, 1);
__uint(key_size, sizeof(__u32));
__array(values, void (void));
} jmp_table SEC(".maps") = {
.values = {
[0] = (void *) &classifier_0,
},
};
__auxiliary
SEC("tc")
int classifier_0(struct __sk_buff *skb)
{
return 0;
}
static __noinline
int subprog_tail0(struct __sk_buff *skb)
{
int ret = 0;
bpf_tail_call_static(skb, &jmp_table, 0);
barrier_var(ret);
return ret;
}
static __noinline
int callback_loop(int index, void **cb_ctx)
{
int ret;
ret = subprog_tail0(*cb_ctx);
barrier_var(ret);
return ret ? 1 : 0;
}
static __noinline
int callback_empty(int index, void *data)
{
return 0;
}
/* callback involving subprog with tail call is rejected */
SEC("tc")
__failure __msg("cannot tail call within callback")
int tailcall_callback_1(struct __sk_buff *skb)
{
clobber_regs_stack();
bpf_loop(1, callback_loop, &skb, 0);
return 0;
}
/* subprogs with tailcall do not affect no-tailcall callback */
SEC("tc")
__success
__retval(0)
int tailcall_callback_2(struct __sk_buff *skb)
{
int ret;
clobber_regs_stack();
ret = subprog_tail0(skb);
__sink(ret);
bpf_loop(1, callback_empty, NULL, 0);
return 0;
}
char __license[] SEC("license") = "GPL";