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mjeansonIngo Molnar
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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 <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Reviewed-by: Mathieu Desnoyers <[email protected]> Cc: Shuah Khan <[email protected]> Link: https://lore.kernel.org/r/[email protected]
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-5
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6 files changed

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‎tools/testing/selftests/rseq/.gitignore

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Original file line numberDiff line numberDiff line change
@@ -9,3 +9,4 @@ param_test_compare_twice
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param_test_mm_cid
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param_test_mm_cid_benchmark
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param_test_mm_cid_compare_twice
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syscall_errors_test

‎tools/testing/selftests/rseq/Makefile

Lines changed: 7 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -16,11 +16,12 @@ OVERRIDE_TARGETS = 1
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TEST_GEN_PROGS = basic_test basic_percpu_ops_test basic_percpu_ops_mm_cid_test param_test \
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param_test_benchmark param_test_compare_twice param_test_mm_cid \
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param_test_mm_cid_benchmark param_test_mm_cid_compare_twice
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param_test_mm_cid_benchmark param_test_mm_cid_compare_twice \
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syscall_errors_test
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TEST_GEN_PROGS_EXTENDED = librseq.so
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23-
TEST_PROGS = run_param_test.sh
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TEST_PROGS = run_param_test.sh run_syscall_errors_test.sh
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TEST_FILES := settings
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@@ -54,3 +55,7 @@ $(OUTPUT)/param_test_mm_cid_benchmark: param_test.c $(TEST_GEN_PROGS_EXTENDED) \
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$(OUTPUT)/param_test_mm_cid_compare_twice: param_test.c $(TEST_GEN_PROGS_EXTENDED) \
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rseq.h rseq-*.h
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$(CC) $(CFLAGS) -DBUILDOPT_RSEQ_PERCPU_MM_CID -DRSEQ_COMPARE_TWICE $< $(LDLIBS) -lrseq -o $@
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$(OUTPUT)/syscall_errors_test: syscall_errors_test.c $(TEST_GEN_PROGS_EXTENDED) \
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rseq.h rseq-*.h
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$(CC) $(CFLAGS) $< $(LDLIBS) -lrseq -o $@

‎tools/testing/selftests/rseq/rseq.c

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -87,7 +87,7 @@ static int sys_getcpu(unsigned *cpu, unsigned *node)
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return syscall(__NR_getcpu, cpu, node, NULL);
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}
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90-
int rseq_available(void)
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bool rseq_available(void)
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{
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int rc;
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@@ -96,9 +96,9 @@ int rseq_available(void)
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abort();
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switch (errno) {
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case ENOSYS:
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return 0;
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return false;
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case EINVAL:
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return 1;
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return true;
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default:
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abort();
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}

‎tools/testing/selftests/rseq/rseq.h

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@@ -159,6 +159,11 @@ int32_t rseq_fallback_current_cpu(void);
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*/
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int32_t rseq_fallback_current_node(void);
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/*
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* Returns true if rseq is supported.
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*/
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bool rseq_available(void);
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162167
/*
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* Values returned can be either the current CPU number, -1 (rseq is
164169
* uninitialized), or -2 (rseq initialization has failed).

‎tools/testing/selftests/rseq/run_syscall_errors_test.sh

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,5 @@
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#!/bin/bash
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# SPDX-License-Identifier: MIT
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# SPDX-FileCopyrightText: 2024 Michael Jeanson <[email protected]>
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GLIBC_TUNABLES="${GLIBC_TUNABLES:-}:glibc.pthread.rseq=0" ./syscall_errors_test

‎tools/testing/selftests/rseq/syscall_errors_test.c

Lines changed: 124 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,124 @@
1+
// SPDX-License-Identifier: MIT
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// SPDX-FileCopyrightText: 2024 Michael Jeanson <[email protected]>
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#ifndef _GNU_SOURCE
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#define _GNU_SOURCE
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#endif
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#include <assert.h>
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#include <stdint.h>
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#include <syscall.h>
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#include <string.h>
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#include <unistd.h>
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#include "rseq.h"
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static int sys_rseq(void *rseq_abi, uint32_t rseq_len,
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int flags, uint32_t sig)
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{
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return syscall(__NR_rseq, rseq_abi, rseq_len, flags, sig);
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}
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/*
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* Check the value of errno on some expected failures of the rseq syscall.
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*/
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int main(void)
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{
28+
struct rseq_abi *global_rseq = rseq_get_abi();
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int ret;
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int errno_copy;
31+
32+
if (!rseq_available()) {
33+
fprintf(stderr, "rseq syscall unavailable");
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goto error;
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}
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/* The current thread is NOT registered. */
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/* EINVAL */
40+
errno = 0;
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ret = sys_rseq(global_rseq, 32, -1, RSEQ_SIG);
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errno_copy = errno;
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fprintf(stderr, "Registration with invalid flag fails with errno set to EINVAL (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
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if (ret == 0 || errno_copy != EINVAL)
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goto error;
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47+
errno = 0;
48+
ret = sys_rseq((char *) global_rseq + 1, 32, 0, RSEQ_SIG);
49+
errno_copy = errno;
50+
fprintf(stderr, "Registration with unaligned rseq_abi fails with errno set to EINVAL (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
51+
if (ret == 0 || errno_copy != EINVAL)
52+
goto error;
53+
54+
errno = 0;
55+
ret = sys_rseq(global_rseq, 31, 0, RSEQ_SIG);
56+
errno_copy = errno;
57+
fprintf(stderr, "Registration with invalid size fails with errno set to EINVAL (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
58+
if (ret == 0 || errno_copy != EINVAL)
59+
goto error;
60+
61+
62+
#if defined(__LP64__) && (!defined(__s390__) && !defined(__s390x__))
63+
/*
64+
* We haven't found a reliable way to find an invalid address when
65+
* running a 32bit userspace on a 64bit kernel, so only run this test
66+
* on 64bit builds for the moment.
67+
*
68+
* Also exclude architectures that select
69+
* CONFIG_ALTERNATE_USER_ADDRESS_SPACE where the kernel and userspace
70+
* have their own address space and this failure can't happen.
71+
*/
72+
73+
/* EFAULT */
74+
errno = 0;
75+
ret = sys_rseq((void *) -4096UL, 32, 0, RSEQ_SIG);
76+
errno_copy = errno;
77+
fprintf(stderr, "Registration with invalid address fails with errno set to EFAULT (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
78+
if (ret == 0 || errno_copy != EFAULT)
79+
goto error;
80+
#endif
81+
82+
errno = 0;
83+
ret = sys_rseq(global_rseq, 32, 0, RSEQ_SIG);
84+
errno_copy = errno;
85+
fprintf(stderr, "Registration succeeds for the current thread (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
86+
if (ret != 0 && errno != 0)
87+
goto error;
88+
89+
/* The current thread is registered. */
90+
91+
/* EBUSY */
92+
errno = 0;
93+
ret = sys_rseq(global_rseq, 32, 0, RSEQ_SIG);
94+
errno_copy = errno;
95+
fprintf(stderr, "Double registration fails with errno set to EBUSY (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
96+
if (ret == 0 || errno_copy != EBUSY)
97+
goto error;
98+
99+
/* EPERM */
100+
errno = 0;
101+
ret = sys_rseq(global_rseq, 32, RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG + 1);
102+
errno_copy = errno;
103+
fprintf(stderr, "Unregistration with wrong RSEQ_SIG fails with errno to EPERM (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
104+
if (ret == 0 || errno_copy != EPERM)
105+
goto error;
106+
107+
errno = 0;
108+
ret = sys_rseq(global_rseq, 32, RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG);
109+
errno_copy = errno;
110+
fprintf(stderr, "Unregistration succeeds for the current thread (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
111+
if (ret != 0)
112+
goto error;
113+
114+
errno = 0;
115+
ret = sys_rseq(global_rseq, 32, RSEQ_ABI_FLAG_UNREGISTER, RSEQ_SIG);
116+
errno_copy = errno;
117+
fprintf(stderr, "Double unregistration fails with errno set to EINVAL (ret = %d, errno = %s)\n", ret, strerrorname_np(errno_copy));
118+
if (ret == 0 || errno_copy != EINVAL)
119+
goto error;
120+
121+
return 0;
122+
error:
123+
return -1;
124+
}

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