bybrooklyn/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-04-18 06:44:00 -04:00
Code Issues Packages Projects Releases Wiki Activity

selftests/bpf: add test for softlock when modifying hashmap while iterating

Browse Source 
Add test that modifies the map while it's being iterated in such a way that
hangs the kernel thread unless the _safe fix is applied to
bpf_for_each_hash_elem.

Signed-off-by: Brandon Kammerdiener <brandon.kammerdiener@intel.com>
Link: https://lore.kernel.org/r/20250424153246.141677-3-brandon.kammerdiener@intel.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Hou Tao <houtao1@huawei.com>
This commit is contained in:
Brandon Kammerdiener
2025-04-24 11:32:55 -04:00
committed by Alexei Starovoitov
parent 75673fda0c
commit 3d9c463f95
2 changed files with 67 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
tools/testing/selftests/bpf/prog_tests/for_each.c
View File

@@ -6,6 +6,7 @@
#include "for_each_array_map_elem.skel.h"
#include "for_each_map_elem_write_key.skel.h"
#include "for_each_multi_maps.skel.h"
#include "for_each_hash_modify.skel.h"
static unsigned int duration;
@@ -203,6 +204,40 @@ out:
for_each_multi_maps__destroy(skel);
}
static void test_hash_modify(void)
{
struct for_each_hash_modify *skel;
int max_entries, i, err;
__u64 key, val;
LIBBPF_OPTS(bpf_test_run_opts, topts,
.data_in = &pkt_v4,
.data_size_in = sizeof(pkt_v4),
.repeat = 1
);
skel = for_each_hash_modify__open_and_load();
if (!ASSERT_OK_PTR(skel, "for_each_hash_modify__open_and_load"))
return;
max_entries = bpf_map__max_entries(skel->maps.hashmap);
for (i = 0; i < max_entries; i++) {
key = i;
val = i;
err = bpf_map__update_elem(skel->maps.hashmap, &key, sizeof(key),
&val, sizeof(val), BPF_ANY);
if (!ASSERT_OK(err, "map_update"))
goto out;
}
err = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.test_pkt_access), &topts);
ASSERT_OK(err, "bpf_prog_test_run_opts");
ASSERT_OK(topts.retval, "retval");
out:
for_each_hash_modify__destroy(skel);
}
void test_for_each(void)
{
if (test__start_subtest("hash_map"))
@@ -213,4 +248,6 @@ void test_for_each(void)
test_write_map_key();
if (test__start_subtest("multi_maps"))
test_multi_maps();
if (test__start_subtest("hash_modify"))
test_hash_modify();
}

30
tools/testing/selftests/bpf/progs/for_each_hash_modify.c Normal file
View File

@@ -0,0 +1,30 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Intel Corporation */
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
char _license[] SEC("license") = "GPL";
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, 128);
__type(key, __u64);
__type(value, __u64);
} hashmap SEC(".maps");
static int cb(struct bpf_map *map, __u64 *key, __u64 *val, void *arg)
{
bpf_map_delete_elem(map, key);
bpf_map_update_elem(map, key, val, 0);
return 0;
}
SEC("tc")
int test_pkt_access(struct __sk_buff *skb)
{
(void)skb;
bpf_for_each_map_elem(&hashmap, cb, NULL, 0);
return 0;
}