selftests/bpf: Add a local kptr test with no special fields

Add a local kptr test with no special fields in the struct. Without the previous patch, the following warning will hit: [ 44.683877] WARNING: CPU: 3 PID: 485 at kernel/bpf/syscall.c:660 bpf_obj_free_fields+0x220/0x240 [ 44.684640] Modules linked in: bpf_testmod(OE) [ 44.685044] CPU: 3 PID: 485 Comm: kworker/u8:5 Tainted: G OE 6.5.0-rc5-01703-g260d855e9b90 torvalds#248 [ 44.685827] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 44.686693] Workqueue: events_unbound bpf_map_free_deferred [ 44.687297] RIP: 0010:bpf_obj_free_fields+0x220/0x240 [ 44.687775] Code: e8 55 17 1f 00 49 8b 74 24 08 4c 89 ef e8 e8 14 05 00 e8 a3 da e2 ff e9 55 fe ff ff 0f 0b e9 4e fe ff ff 0f 0b e9 47 fe ff ff <0f> 0b e8 d9 d9 e2 ff 31 f6 eb d5 48 83 c4 10 5b 41 5c e [ 44.689353] RSP: 0018:ffff888106467cb8 EFLAGS: 00010246 [ 44.689806] RAX: 0000000000000000 RBX: ffff888112b3a200 RCX: 0000000000000001 [ 44.690433] RDX: 0000000000000000 RSI: dffffc0000000000 RDI: ffff8881128ad988 [ 44.691094] RBP: 0000000000000002 R08: ffffffff81370bd0 R09: 1ffff110216231a5 [ 44.691643] R10: dffffc0000000000 R11: ffffed10216231a6 R12: ffff88810d68a488 [ 44.692245] R13: ffff88810767c288 R14: ffff88810d68a400 R15: ffff88810d68a418 [ 44.692829] FS: 0000000000000000(0000) GS:ffff8881f7580000(0000) knlGS:0000000000000000 [ 44.693484] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 44.693964] CR2: 000055c7f2afce28 CR3: 000000010fee4002 CR4: 0000000000370ee0 [ 44.694513] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 44.695102] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 44.695747] Call Trace: [ 44.696001] <TASK> [ 44.696183] ? __warn+0xfe/0x270 [ 44.696447] ? bpf_obj_free_fields+0x220/0x240 [ 44.696817] ? report_bug+0x220/0x2d0 [ 44.697180] ? handle_bug+0x3d/0x70 [ 44.697507] ? exc_invalid_op+0x1a/0x50 [ 44.697887] ? asm_exc_invalid_op+0x1a/0x20 [ 44.698282] ? btf_find_struct_meta+0xd0/0xd0 [ 44.698634] ? bpf_obj_free_fields+0x220/0x240 [ 44.699027] ? bpf_obj_free_fields+0x1e2/0x240 [ 44.699414] array_map_free+0x1a3/0x260 [ 44.699763] bpf_map_free_deferred+0x7b/0xe0 [ 44.700154] process_one_work+0x46d/0x750 [ 44.700523] worker_thread+0x49e/0x900 [ 44.700892] ? pr_cont_work+0x270/0x270 [ 44.701224] kthread+0x1ae/0x1d0 [ 44.701516] ? kthread_blkcg+0x50/0x50 [ 44.701860] ret_from_fork+0x34/0x50 [ 44.702178] ? kthread_blkcg+0x50/0x50 [ 44.702508] ret_from_fork_asm+0x11/0x20 [ 44.702880] </TASK> With the previous patch, there is no warnings. Signed-off-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]>
intel-lab-lkp · Aug 24, 2023 · 001feda · 001feda
1 parent 393dc4b
commit 001feda
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diff --git a/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c b/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c
@@ -27,6 +27,27 @@ static void test_local_kptr_stash_simple(void)
 	local_kptr_stash__destroy(skel);
 }
 
+static void test_local_kptr_stash_plain(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, opts,
+		    .data_in = &pkt_v4,
+		    .data_size_in = sizeof(pkt_v4),
+		    .repeat = 1,
+	);
+	struct local_kptr_stash *skel;
+	int ret;
+
+	skel = local_kptr_stash__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "local_kptr_stash__open_and_load"))
+		return;
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.stash_plain), &opts);
+	ASSERT_OK(ret, "local_kptr_stash_add_plain run");
+	ASSERT_OK(opts.retval, "local_kptr_stash_add_plain retval");
+
+	local_kptr_stash__destroy(skel);
+}
+
 static void test_local_kptr_stash_unstash(void)
 {
 	LIBBPF_OPTS(bpf_test_run_opts, opts,
@@ -61,6 +82,8 @@ void test_local_kptr_stash(void)
 {
 	if (test__start_subtest("local_kptr_stash_simple"))
 		test_local_kptr_stash_simple();
+	if (test__start_subtest("local_kptr_stash_plain"))
+		test_local_kptr_stash_plain();
 	if (test__start_subtest("local_kptr_stash_unstash"))
 		test_local_kptr_stash_unstash();
 	if (test__start_subtest("local_kptr_stash_fail"))

diff --git a/tools/testing/selftests/bpf/progs/local_kptr_stash.c b/tools/testing/selftests/bpf/progs/local_kptr_stash.c
@@ -14,10 +14,16 @@ struct node_data {
 	struct bpf_rb_node node;
 };
 
+struct plain_local {
+	long key;
+	long data;
+};
+
 struct map_value {
 	struct prog_test_ref_kfunc *not_kptr;
 	struct prog_test_ref_kfunc __kptr *val;
 	struct node_data __kptr *node;
+	struct plain_local __kptr *plain;
 };
 
 /* This is necessary so that LLVM generates BTF for node_data struct
@@ -66,6 +72,28 @@ long stash_rb_nodes(void *ctx)
 	return create_and_stash(0, 41) ?: create_and_stash(1, 42);
 }
 
+SEC("tc")
+long stash_plain(void *ctx)
+{
+	struct map_value *mapval;
+	struct plain_local *res;
+	int idx = 0;
+
+	mapval = bpf_map_lookup_elem(&some_nodes, &idx);
+	if (!mapval)
+		return 1;
+
+	res = bpf_obj_new(typeof(*res));
+	if (!res)
+		return 1;
+	res->key = 41;
+
+	res = bpf_kptr_xchg(&mapval->plain, res);
+	if (res)
+		bpf_obj_drop(res);
+	return 0;
+}
+
 SEC("tc")
 long unstash_rb_node(void *ctx)
 {