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Message-ID: <20250121213402.1754762-1-mjeanson@efficios.com>
Date: Tue, 21 Jan 2025 16:33:52 -0500
From: Michael Jeanson <mjeanson@...icios.com>
To: linux-kernel@...r.kernel.org
Cc: Michael Jeanson <mjeanson@...icios.com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
Shuah Khan <skhan@...uxfoundation.org>
Subject: [PATCH] selftests/rseq: add rseq syscall errors test
This test adds coverage of expected errors during rseq registration and
unregistration, it disables glibc integration and will thus always
exercise the rseq syscall explictly.
Signed-off-by: Michael Jeanson <mjeanson@...icios.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Shuah Khan <skhan@...uxfoundation.org>
---
tools/testing/selftests/rseq/.gitignore | 1 +
tools/testing/selftests/rseq/Makefile | 9 +-
tools/testing/selftests/rseq/rseq.c | 6 +-
tools/testing/selftests/rseq/rseq.h | 5 +
.../selftests/rseq/run_syscall_errors_test.sh | 5 +
.../selftests/rseq/syscall_errors_test.c | 124 ++++++++++++++++++
6 files changed, 145 insertions(+), 5 deletions(-)
create mode 100755 tools/testing/selftests/rseq/run_syscall_errors_test.sh
create mode 100644 tools/testing/selftests/rseq/syscall_errors_test.c
diff --git a/tools/testing/selftests/rseq/.gitignore b/tools/testing/selftests/rseq/.gitignore
index 16496de5f6ce..0fda241fa62b 100644
--- a/tools/testing/selftests/rseq/.gitignore
+++ b/tools/testing/selftests/rseq/.gitignore
@@ -9,3 +9,4 @@ param_test_compare_twice
param_test_mm_cid
param_test_mm_cid_benchmark
param_test_mm_cid_compare_twice
+syscall_errors_test
diff --git a/tools/testing/selftests/rseq/Makefile b/tools/testing/selftests/rseq/Makefile
index 5a3432fceb58..0d0a5fae5954 100644
--- a/tools/testing/selftests/rseq/Makefile
+++ b/tools/testing/selftests/rseq/Makefile
@@ -16,11 +16,12 @@ OVERRIDE_TARGETS = 1
TEST_GEN_PROGS = basic_test basic_percpu_ops_test basic_percpu_ops_mm_cid_test param_test \
param_test_benchmark param_test_compare_twice param_test_mm_cid \
- param_test_mm_cid_benchmark param_test_mm_cid_compare_twice
+ param_test_mm_cid_benchmark param_test_mm_cid_compare_twice \
+ syscall_errors_test
TEST_GEN_PROGS_EXTENDED = librseq.so
-TEST_PROGS = run_param_test.sh
+TEST_PROGS = run_param_test.sh run_syscall_errors_test.sh
TEST_FILES := settings
@@ -54,3 +55,7 @@ $(OUTPUT)/param_test_mm_cid_benchmark: param_test.c $(TEST_GEN_PROGS_EXTENDED) \
$(OUTPUT)/param_test_mm_cid_compare_twice: param_test.c $(TEST_GEN_PROGS_EXTENDED) \
rseq.h rseq-*.h
$(CC) $(CFLAGS) -DBUILDOPT_RSEQ_PERCPU_MM_CID -DRSEQ_COMPARE_TWICE $< $(LDLIBS) -lrseq -o $@
+
+$(OUTPUT)/syscall_errors_test: syscall_errors_test.c $(TEST_GEN_PROGS_EXTENDED) \
+ rseq.h rseq-*.h
+ $(CC) $(CFLAGS) $< $(LDLIBS) -lrseq -o $@
diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c
index 5b9772cdf265..4c06b8f61fe5 100644
--- a/tools/testing/selftests/rseq/rseq.c
+++ b/tools/testing/selftests/rseq/rseq.c
@@ -88,7 +88,7 @@ static int sys_getcpu(unsigned *cpu, unsigned *node)
return syscall(__NR_getcpu, cpu, node, NULL);
}
-int rseq_available(void)
+bool rseq_available(void)
{
int rc;
@@ -97,9 +97,9 @@ int rseq_available(void)
abort();
switch (errno) {
case ENOSYS:
- return 0;
+ return false;
case EINVAL:
- return 1;
+ return true;
default:
abort();
}
diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h
index 4e217b620e0c..7c3c018d2ba0 100644
--- a/tools/testing/selftests/rseq/rseq.h
+++ b/tools/testing/selftests/rseq/rseq.h
@@ -150,6 +150,11 @@ int32_t rseq_fallback_current_cpu(void);
*/
int32_t rseq_fallback_current_node(void);
+/*
+ * Returns true if rseq is supported.
+ */
+bool rseq_available(void);
+
/*
* Values returned can be either the current CPU number, -1 (rseq is
* uninitialized), or -2 (rseq initialization has failed).
diff --git a/tools/testing/selftests/rseq/run_syscall_errors_test.sh b/tools/testing/selftests/rseq/run_syscall_errors_test.sh
new file mode 100755
index 000000000000..9272246b39f2
--- /dev/null
+++ b/tools/testing/selftests/rseq/run_syscall_errors_test.sh
@@ -0,0 +1,5 @@
+#!/bin/bash
+# SPDX-License-Identifier: MIT
+# SPDX-FileCopyrightText: 2024 Michael Jeanson <mjeanson@...icios.com>
+
+GLIBC_TUNABLES="${GLIBC_TUNABLES:-}:glibc.pthread.rseq=0" ./syscall_errors_test
diff --git a/tools/testing/selftests/rseq/syscall_errors_test.c b/tools/testing/selftests/rseq/syscall_errors_test.c
new file mode 100644
index 000000000000..a5d9e1f8a2dc
--- /dev/null
+++ b/tools/testing/selftests/rseq/syscall_errors_test.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: MIT
+// SPDX-FileCopyrightText: 2024 Michael Jeanson <mjeanson@...icios.com>
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <assert.h>
+#include <stdint.h>
+#include <syscall.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "rseq.h"
+
+static int sys_rseq(void *rseq_abi, uint32_t rseq_len,
+ int flags, uint32_t sig)
+{
+ return syscall(__NR_rseq, rseq_abi, rseq_len, flags, sig);
+}
+
+/*
+ * Check the value of errno on some expected failures of the rseq syscall.
+ */
+
+int main(void)
+{
+ struct rseq_abi *global_rseq = rseq_get_abi();
+ int ret;
+ int errno_copy;
+
+ if (!rseq_available()) {
+ fprintf(stderr, "rseq syscall unavailable");
+ goto error;
+ }
+
+ /* The current thread is NOT registered. */
+
+ /* EINVAL */
+ errno = 0;
+ ret = sys_rseq(global_rseq, 32, -1, RSEQ_SIG);
+ errno_copy = errno;
+ fprintf(stderr, "Registration with invalid flag fails with errno set to EINVAL (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
+ if (ret == 0 || errno_copy != EINVAL)
+ goto error;
+
+ errno = 0;
+ ret = sys_rseq((char *) global_rseq + 1, 32, 0, RSEQ_SIG);
+ errno_copy = errno;
+ fprintf(stderr, "Registration with unaligned rseq_abi fails with errno set to EINVAL (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
+ if (ret == 0 || errno_copy != EINVAL)
+ goto error;
+
+ errno = 0;
+ ret = sys_rseq(global_rseq, 31, 0, RSEQ_SIG);
+ errno_copy = errno;
+ fprintf(stderr, "Registration with invalid size fails with errno set to EINVAL (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
+ if (ret == 0 || errno_copy != EINVAL)
+ goto error;
+
+
+#if defined(__LP64__) && (!defined(__s390__) && !defined(__s390x__))
+ /*
+ * We haven't found a reliable way to find an invalid address when
+ * running a 32bit userspace on a 64bit kernel, so only run this test
+ * on 64bit builds for the moment.
+ *
+ * Also exclude architectures that select
+ * CONFIG_ALTERNATE_USER_ADDRESS_SPACE where the kernel and userspace
+ * have their own address space and this failure can't happen.
+ */
+
+ /* EFAULT */
+ errno = 0;
+ ret = sys_rseq((void *) -4096UL, 32, 0, RSEQ_SIG);
+ errno_copy = errno;
+ fprintf(stderr, "Registration with invalid address fails with errno set to EFAULT (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
+ if (ret == 0 || errno_copy != EFAULT)
+ goto error;
+#endif
+
+ errno = 0;
+ ret = sys_rseq(global_rseq, 32, 0, RSEQ_SIG);
+ errno_copy = errno;
+ fprintf(stderr, "Registration succeeds for the current thread (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
+ if (ret != 0 && errno != 0)
+ goto error;
+
+ /* The current thread is registered. */
+
+ /* EBUSY */
+ errno = 0;
+ ret = sys_rseq(global_rseq, 32, 0, RSEQ_SIG);
+ errno_copy = errno;
+ fprintf(stderr, "Double registration fails with errno set to EBUSY (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
+ if (ret == 0 || errno_copy != EBUSY)
+ goto error;
+
+ /* EPERM */
+ errno = 0;
+ ret = sys_rseq(global_rseq, 32, RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG + 1);
+ errno_copy = errno;
+ fprintf(stderr, "Unregistration with wrong RSEQ_SIG fails with errno to EPERM (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
+ if (ret == 0 || errno_copy != EPERM)
+ goto error;
+
+ errno = 0;
+ ret = sys_rseq(global_rseq, 32, RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG);
+ errno_copy = errno;
+ fprintf(stderr, "Unregistration succeeds for the current thread (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
+ if (ret != 0)
+ goto error;
+
+ errno = 0;
+ ret = sys_rseq(global_rseq, 32, RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG);
+ errno_copy = errno;
+ fprintf(stderr, "Double unregistration fails with errno set to EINVAL (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
+ if (ret == 0 || errno_copy != EINVAL)
+ goto error;
+
+ return 0;
+error:
+ return -1;
+}
--
2.43.0
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