From: David Vernet <void@manifault.com>
To: bpf@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
martin.lau@linux.dev, song@kernel.org, yhs@meta.com,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org,
linux-kernel@vger.kernel.org, kernel-team@meta.com
Subject: [PATCH bpf-next 3/5] bpf/selftests: Test using global cpumask kptr with RCU
Date: Wed, 15 Mar 2023 20:41:20 -0500 [thread overview]
Message-ID: <20230316014122.678082-4-void@manifault.com> (raw)
In-Reply-To: <20230316014122.678082-1-void@manifault.com>
Now that struct bpf_cpumask * is considered an RCU-safe type according
to the verifier, we should add tests that validate its common usages.
This patch adds those tests to the cpumask test suite. A subsequent
changes will remove bpf_cpumask_kptr_get(), and will adjust the selftest
and BPF documentation accordingly.
Signed-off-by: David Vernet <void@manifault.com>
---
.../selftests/bpf/prog_tests/cpumask.c | 1 +
.../selftests/bpf/progs/cpumask_common.h | 6 ++
.../selftests/bpf/progs/cpumask_failure.c | 62 +++++++++++++++++++
.../selftests/bpf/progs/cpumask_success.c | 33 ++++++++++
4 files changed, 102 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/cpumask.c b/tools/testing/selftests/bpf/prog_tests/cpumask.c
index 5fbe457c4ebe..6c0fe23498c7 100644
--- a/tools/testing/selftests/bpf/prog_tests/cpumask.c
+++ b/tools/testing/selftests/bpf/prog_tests/cpumask.c
@@ -17,6 +17,7 @@ static const char * const cpumask_success_testcases[] = {
"test_insert_leave",
"test_insert_remove_release",
"test_insert_kptr_get_release",
+ "test_global_mask_rcu",
};
static void verify_success(const char *prog_name)
diff --git a/tools/testing/selftests/bpf/progs/cpumask_common.h b/tools/testing/selftests/bpf/progs/cpumask_common.h
index 65e5496ca1b2..7623782fbd62 100644
--- a/tools/testing/selftests/bpf/progs/cpumask_common.h
+++ b/tools/testing/selftests/bpf/progs/cpumask_common.h
@@ -9,6 +9,9 @@
int err;
+#define private(name) SEC(".bss." #name) __hidden __attribute__((aligned(8)))
+private(MASK) static struct bpf_cpumask __kptr * global_mask;
+
struct __cpumask_map_value {
struct bpf_cpumask __kptr * cpumask;
};
@@ -51,6 +54,9 @@ void bpf_cpumask_copy(struct bpf_cpumask *dst, const struct cpumask *src) __ksym
u32 bpf_cpumask_any(const struct cpumask *src) __ksym;
u32 bpf_cpumask_any_and(const struct cpumask *src1, const struct cpumask *src2) __ksym;
+void bpf_rcu_read_lock(void) __ksym;
+void bpf_rcu_read_unlock(void) __ksym;
+
static inline const struct cpumask *cast(struct bpf_cpumask *cpumask)
{
return (const struct cpumask *)cpumask;
diff --git a/tools/testing/selftests/bpf/progs/cpumask_failure.c b/tools/testing/selftests/bpf/progs/cpumask_failure.c
index cfe83f0ef9e2..9f726d55f747 100644
--- a/tools/testing/selftests/bpf/progs/cpumask_failure.c
+++ b/tools/testing/selftests/bpf/progs/cpumask_failure.c
@@ -127,3 +127,65 @@ int BPF_PROG(test_cpumask_null, struct task_struct *task, u64 clone_flags)
return 0;
}
+
+SEC("tp_btf/task_newtask")
+__failure __msg("R2 must be a rcu pointer")
+int BPF_PROG(test_global_mask_out_of_rcu, struct task_struct *task, u64 clone_flags)
+{
+ struct bpf_cpumask *local, *prev;
+
+ local = create_cpumask();
+ if (!local)
+ return 0;
+
+ prev = bpf_kptr_xchg(&global_mask, local);
+ if (prev) {
+ bpf_cpumask_release(prev);
+ err = 3;
+ return 0;
+ }
+
+ bpf_rcu_read_lock();
+ local = global_mask;
+ if (!local) {
+ err = 4;
+ bpf_rcu_read_unlock();
+ return 0;
+ }
+
+ bpf_rcu_read_unlock();
+
+ /* RCU region is exited before calling KF_RCU kfunc. */
+
+ bpf_cpumask_test_cpu(0, (const struct cpumask *)local);
+
+ return 0;
+}
+
+SEC("tp_btf/task_newtask")
+__failure __msg("NULL pointer passed to trusted arg1")
+int BPF_PROG(test_global_mask_no_null_check, struct task_struct *task, u64 clone_flags)
+{
+ struct bpf_cpumask *local, *prev;
+
+ local = create_cpumask();
+ if (!local)
+ return 0;
+
+ prev = bpf_kptr_xchg(&global_mask, local);
+ if (prev) {
+ bpf_cpumask_release(prev);
+ err = 3;
+ return 0;
+ }
+
+ bpf_rcu_read_lock();
+ local = global_mask;
+
+ /* No NULL check is performed on global cpumask kptr. */
+ bpf_cpumask_test_cpu(0, (const struct cpumask *)local);
+
+ bpf_rcu_read_unlock();
+
+ return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/cpumask_success.c b/tools/testing/selftests/bpf/progs/cpumask_success.c
index 97ed08c4ff03..fe928ff72a06 100644
--- a/tools/testing/selftests/bpf/progs/cpumask_success.c
+++ b/tools/testing/selftests/bpf/progs/cpumask_success.c
@@ -423,3 +423,36 @@ int BPF_PROG(test_insert_kptr_get_release, struct task_struct *task, u64 clone_f
return 0;
}
+
+SEC("tp_btf/task_newtask")
+int BPF_PROG(test_global_mask_rcu, struct task_struct *task, u64 clone_flags)
+{
+ struct bpf_cpumask *local, *prev;
+
+ if (!is_test_task())
+ return 0;
+
+ local = create_cpumask();
+ if (!local)
+ return 0;
+
+ prev = bpf_kptr_xchg(&global_mask, local);
+ if (prev) {
+ bpf_cpumask_release(prev);
+ err = 3;
+ return 0;
+ }
+
+ bpf_rcu_read_lock();
+ local = global_mask;
+ if (!local) {
+ err = 4;
+ bpf_rcu_read_unlock();
+ return 0;
+ }
+
+ bpf_cpumask_test_cpu(0, (const struct cpumask *)local);
+ bpf_rcu_read_unlock();
+
+ return 0;
+}
--
2.39.0
next prev parent reply other threads:[~2023-03-16 1:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-16 1:41 [PATCH bpf-next 0/5] Make struct bpf_cpumask RCU safe David Vernet
2023-03-16 1:41 ` [PATCH bpf-next 1/5] bpf: Free struct bpf_cpumask in call_rcu handler David Vernet
2023-03-16 1:41 ` [PATCH bpf-next 2/5] bpf: Mark struct bpf_cpumask as RCU protected David Vernet
2023-03-16 1:41 ` David Vernet [this message]
2023-03-16 1:41 ` [PATCH bpf-next 4/5] bpf: Remove bpf_cpumask_kptr_get() kfunc David Vernet
2023-03-16 1:41 ` [PATCH bpf-next 5/5] bpf,docs: Remove bpf_cpumask_kptr_get() from documentation David Vernet
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230316014122.678082-4-void@manifault.com \
--to=void@manifault.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=haoluo@google.com \
--cc=john.fastabend@gmail.com \
--cc=jolsa@kernel.org \
--cc=kernel-team@meta.com \
--cc=kpsingh@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=martin.lau@linux.dev \
--cc=sdf@google.com \
--cc=song@kernel.org \
--cc=yhs@meta.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox