[LTP] [PATCH v2] futex: Add error coverage tests for wait, wake and cmp_requeue

[Michael Menasherov via ltp <ltp@lists.linux.it>]

Improve error handling coverage for futex syscalls by adding tests
for missing error conditions that were previously untested.

futex_wait06 verifies EFAULT is returned when uaddr or timeout
points to unmapped memory.

futex_wait07 verifies EINTR is returned when futex_wait() is
interrupted by a signal.

futex_wake05 verifies EFAULT is returned when uaddr points to
unmapped or PROT_NONE memory.

futex_cmp_requeue03 verifies EFAULT is returned when uaddr or
uaddr2 points to unmapped memory, and EACCES or EFAULT when uaddr
points to memory without read permission (PROT_NONE). The EACCES
behavior was introduced in kernel 5.9.
---
v2: Use TST_EXP_FAIL macro as requested.
    Store address directly in testcase structs and not using flags.
    Use SAFE_MMAP and not raw as requested, also added a sign off.
 runtest/syscalls                              |   4 +
 testcases/kernel/syscalls/futex/.gitignore    |   4 +
 .../syscalls/futex/futex_cmp_requeue03.c      |  96 ++++++++++++++
 .../kernel/syscalls/futex/futex_wait06.c      |  73 +++++++++++
 .../kernel/syscalls/futex/futex_wait07.c      | 117 ++++++++++++++++++
 .../kernel/syscalls/futex/futex_wake05.c      |  86 +++++++++++++
 6 files changed, 380 insertions(+)
 create mode 100644 testcases/kernel/syscalls/futex/futex_cmp_requeue03.c
 create mode 100644 testcases/kernel/syscalls/futex/futex_wait06.c
 create mode 100644 testcases/kernel/syscalls/futex/futex_wait07.c
 create mode 100644 testcases/kernel/syscalls/futex/futex_wake05.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 6ba0227a8..6c12dc225 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -1859,11 +1859,14 @@ perf_event_open02 perf_event_open02
 
 futex_cmp_requeue01 futex_cmp_requeue01
 futex_cmp_requeue02 futex_cmp_requeue02
+futex_cmp_requeue03 futex_cmp_requeue03
 futex_wait01 futex_wait01
 futex_wait02 futex_wait02
 futex_wait03 futex_wait03
 futex_wait04 futex_wait04
 futex_wait05 futex_wait05
+futex_wait06 futex_wait06
+futex_wait07 futex_wait07
 futex_waitv01 futex_waitv01
 futex_waitv02 futex_waitv02
 futex_waitv03 futex_waitv03
@@ -1871,6 +1874,7 @@ futex_wake01 futex_wake01
 futex_wake02 futex_wake02
 futex_wake03 futex_wake03
 futex_wake04 futex_wake04
+futex_wake05 futex_wake05
 futex_wait_bitset01 futex_wait_bitset01
 
 memfd_create01 memfd_create01
diff --git a/testcases/kernel/syscalls/futex/.gitignore b/testcases/kernel/syscalls/futex/.gitignore
index 9d08ba7d3..c47d39b5b 100644
--- a/testcases/kernel/syscalls/futex/.gitignore
+++ b/testcases/kernel/syscalls/futex/.gitignore
@@ -1,15 +1,19 @@
 /futex_cmp_requeue01
 /futex_cmp_requeue02
+/futex_cmp_requeue03
 /futex_wait01
 /futex_wait02
 /futex_wait03
 /futex_wait04
 /futex_wait05
+/futex_wait06
+/futex_wait07
 /futex_wait_bitset01
 /futex_wake01
 /futex_wake02
 /futex_wake03
 /futex_wake04
+/futex_wake05
 /futex_waitv01
 /futex_waitv02
 /futex_waitv03
diff --git a/testcases/kernel/syscalls/futex/futex_cmp_requeue03.c b/testcases/kernel/syscalls/futex/futex_cmp_requeue03.c
new file mode 100644
index 000000000..099d5e35c
--- /dev/null
+++ b/testcases/kernel/syscalls/futex/futex_cmp_requeue03.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 Red Hat, Inc.
+ */
+
+/*\
+ * Check that futex(FUTEX_CMP_REQUEUE) returns EFAULT when uaddr or
+ * uaddr2 points to unmapped memory, and EACCES (or EFAULT on older kernels)
+ * when uaddr points to memory without read permission (PROT_NONE).
+ *
+ * The EACCES behavior for PROT_NONE was introduced in kernel 5.9.
+ */
+
+#include <errno.h>
+#include <sys/mman.h>
+
+#include "futextest.h"
+
+static futex_t futex_var = FUTEX_INITIALIZER;
+static futex_t *prot_none_addr;
+
+static struct futex_test_variants variants[] = {
+#if (__NR_futex != __LTP__NR_INVALID_SYSCALL)
+	{ .fntype = FUTEX_FN_FUTEX, .desc = "syscall with old kernel spec"},
+#endif
+
+#if (__NR_futex_time64 != __LTP__NR_INVALID_SYSCALL)
+	{ .fntype = FUTEX_FN_FUTEX64, .desc = "syscall time64 with kernel spec"},
+#endif
+};
+
+static struct testcase {
+	const char *desc;
+	futex_t *uaddr;
+	futex_t *uaddr2;
+	int exp_errno;
+} testcases[3];
+
+static void run(unsigned int n)
+{
+	struct futex_test_variants *tv = &variants[tst_variant];
+	struct testcase *tc = &testcases[n];
+
+	TST_EXP_FAIL(futex_cmp_requeue(tv->fntype, tc->uaddr, futex_var,
+		tc->uaddr2, 1, 1, 0), tc->exp_errno, "%s", tc->desc);
+}
+
+static void setup(void)
+{
+	struct futex_test_variants *tv = &variants[tst_variant];
+	size_t pagesize = getpagesize();
+	futex_t *unmapped;
+
+	tst_res(TINFO, "Testing variant: %s", tv->desc);
+	futex_supported_by_kernel(tv->fntype);
+
+	unmapped = SAFE_MMAP(NULL, pagesize, PROT_READ | PROT_WRITE,
+		MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	SAFE_MUNMAP(unmapped, pagesize);
+
+	prot_none_addr = SAFE_MMAP(NULL, pagesize, PROT_NONE,
+		MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+	testcases[0] = (struct testcase){
+		.desc = "uaddr unmapped",
+		.uaddr = unmapped,
+		.uaddr2 = &futex_var,
+		.exp_errno = EFAULT,
+	};
+	testcases[1] = (struct testcase){
+		.desc = "uaddr2 unmapped",
+		.uaddr = &futex_var,
+		.uaddr2 = unmapped,
+		.exp_errno = EFAULT,
+	};
+	testcases[2] = (struct testcase){
+		.desc = "uaddr PROT_NONE",
+		.uaddr = prot_none_addr,
+		.uaddr2 = &futex_var,
+		.exp_errno = tst_kvercmp(5, 9, 0) >= 0 ? EACCES : EFAULT,
+	};
+}
+
+static void cleanup(void)
+{
+	if (prot_none_addr)
+		SAFE_MUNMAP(prot_none_addr, getpagesize());
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.test = run,
+	.tcnt = ARRAY_SIZE(testcases),
+	.test_variants = ARRAY_SIZE(variants),
+};
diff --git a/testcases/kernel/syscalls/futex/futex_wait06.c b/testcases/kernel/syscalls/futex/futex_wait06.c
new file mode 100644
index 000000000..8bb563fb2
--- /dev/null
+++ b/testcases/kernel/syscalls/futex/futex_wait06.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 Red Hat, Inc.
+ */
+
+/*\
+ * Check that futex(FUTEX_WAIT) returns EFAULT when:
+ *
+ * 1) uaddr points to unmapped memory
+ * 2) timeout points to unmapped memory
+ */
+#include <errno.h>
+#include <sys/mman.h>
+
+#include "futextest.h"
+
+static futex_t futex = FUTEX_INITIALIZER;
+
+static struct futex_test_variants variants[] = {
+#if (__NR_futex != __LTP__NR_INVALID_SYSCALL)
+	{ .fntype = FUTEX_FN_FUTEX, .tstype = TST_KERN_OLD_TIMESPEC, .desc = "syscall with old kernel spec"},
+#endif
+
+#if (__NR_futex_time64 != __LTP__NR_INVALID_SYSCALL)
+	{ .fntype = FUTEX_FN_FUTEX64, .tstype = TST_KERN_TIMESPEC, .desc = "syscall time64 with kernel spec"},
+#endif
+};
+
+static struct testcase {
+	const char *desc;
+	futex_t *uaddr;
+	void *timeout;
+} testcases[2];
+
+static void run(unsigned int n)
+{
+	struct futex_test_variants *tv = &variants[tst_variant];
+	struct testcase *tc = &testcases[n];
+
+	TST_EXP_FAIL(futex_syscall(tv->fntype, tc->uaddr, FUTEX_WAIT, futex,
+		tc->timeout, NULL, 0, 0), EFAULT, "%s", tc->desc);
+}
+
+static void setup(void)
+{
+	struct futex_test_variants *tv = &variants[tst_variant];
+	void *bad;
+
+	tst_res(TINFO, "Testing variant: %s", tv->desc);
+	futex_supported_by_kernel(tv->fntype);
+
+	bad = SAFE_MMAP(NULL, getpagesize(), PROT_READ | PROT_WRITE,
+		MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	SAFE_MUNMAP(bad, getpagesize());
+
+	testcases[0] = (struct testcase){
+		.desc = "uaddr points to unmapped memory",
+		.uaddr = bad,
+		.timeout = NULL,
+	};
+	testcases[1] = (struct testcase){
+		.desc = "timeout points to unmapped memory",
+		.uaddr = &futex,
+		.timeout = bad,
+	};
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.test = run,
+	.tcnt = ARRAY_SIZE(testcases),
+	.test_variants = ARRAY_SIZE(variants),
+};
diff --git a/testcases/kernel/syscalls/futex/futex_wait07.c b/testcases/kernel/syscalls/futex/futex_wait07.c
new file mode 100644
index 000000000..a3c1c153d
--- /dev/null
+++ b/testcases/kernel/syscalls/futex/futex_wait07.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 Red Hat, Inc.
+ */
+
+/*\
+ * Check that futex(FUTEX_WAIT) returns EINTR when interrupted by a signal.
+ * A child process blocks on futex_wait() with a long timeout. The parent
+ * waits for the child to enter sleep state, then sends SIGUSR1 to it.
+ * The child verifies it received EINTR and exits accordingly.
+ */
+
+#include <errno.h>
+#include <signal.h>
+#include <sys/wait.h>
+
+#include "futextest.h"
+
+static futex_t *futex;
+
+static struct futex_test_variants variants[] = {
+#if (__NR_futex != __LTP__NR_INVALID_SYSCALL)
+	{ .fntype = FUTEX_FN_FUTEX, .tstype = TST_KERN_OLD_TIMESPEC, .desc = "syscall with old kernel spec"},
+#endif
+
+#if (__NR_futex_time64 != __LTP__NR_INVALID_SYSCALL)
+	{ .fntype = FUTEX_FN_FUTEX64, .tstype = TST_KERN_TIMESPEC, .desc = "syscall time64 with kernel spec"},
+#endif
+};
+
+/* We need a handler so SIGUSR1 is caught instead of killing the process.
+ * The empty body is needed, just receiving the signal is enough to
+ * interrupt futex_wait() and make it return into EINTR -1 status.
+ */
+static void sigusr1_handler(int sig LTP_ATTRIBUTE_UNUSED)
+{
+}
+
+static void do_child(void)
+{
+	struct futex_test_variants *tv = &variants[tst_variant];
+	struct sigaction sa;
+	struct tst_ts timeout;
+	int res;
+
+	/* Set up the signal handler for SIGUSR1 */
+	sa.sa_handler = sigusr1_handler;
+	sa.sa_flags = 0;
+	SAFE_SIGEMPTYSET(&sa.sa_mask);
+	SAFE_SIGACTION(SIGUSR1, &sa, NULL);
+
+	/* Create a timeout for 5 sec for this variant.
+	 * if no one wakes the child before 5 sec, futex_wait() will return
+	 * on its own with ETIMEDOUT and will not wait any longer
+	 */
+	timeout = tst_ts_from_ms(tv->tstype, 5000);
+	res = futex_wait(tv->fntype, futex, *futex, &timeout, 0);
+
+	if (res != -1) {
+		tst_res(TFAIL, "futex_wait() should have failed with EINTR but returned success instead");
+		exit(1);
+	}
+	if (errno != EINTR) {
+		tst_res(TFAIL | TERRNO, "futex_wait() expected EINTR but got something else, errno");
+		exit(1);
+	}
+	tst_res(TPASS | TERRNO, "futex_wait() returned EINTR as expected");
+	exit(0);
+}
+
+static void run(void)
+{
+	pid_t child;
+	int status;
+
+	child = SAFE_FORK();
+
+	if (child == 0) {
+		do_child();
+	}
+	/* Wait until child is sleeping before sending signal */
+	TST_PROCESS_STATE_WAIT(child, 'S', 0);
+	/* Wake up the child so it will return EINTR -1 status */
+	SAFE_KILL(child, SIGUSR1);
+	SAFE_WAITPID(child, &status, 0);
+	/* Check if the child finished everything as it should */
+	if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+		tst_res(TFAIL, "child exited abnormally");
+	}
+}
+
+static void setup(void)
+{
+	struct futex_test_variants *tv = &variants[tst_variant];
+
+	tst_res(TINFO, "Testing variant: %s", tv->desc);
+	futex_supported_by_kernel(tv->fntype);
+
+	/* Futex needs to be in a shared memory so the parent and the child can access into it */
+	futex = SAFE_MMAP(NULL, sizeof(*futex), PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_SHARED, -1, 0);
+	*futex = FUTEX_INITIALIZER;
+}
+
+static void cleanup(void)
+{
+	if (futex) {
+		SAFE_MUNMAP((void *)futex, sizeof(*futex));
+	}
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.test_all = run,
+	.test_variants = ARRAY_SIZE(variants),
+	.forks_child = 1,
+};
diff --git a/testcases/kernel/syscalls/futex/futex_wake05.c b/testcases/kernel/syscalls/futex/futex_wake05.c
new file mode 100644
index 000000000..1e9bd6435
--- /dev/null
+++ b/testcases/kernel/syscalls/futex/futex_wake05.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2026 Red Hat, Inc.
+ */
+
+/*\
+ * Check that futex(FUTEX_WAKE) returns EFAULT when uaddr points to
+ * unmapped or PROT_NONE memory.
+ *
+ * Note: FUTEX_WAKE never reads *uaddr, so PROT_NONE triggers EFAULT
+ * (not EACCES). The EACCES behavior only applies to syscalls that read
+ * *uaddr (e.g. FUTEX_WAIT, FUTEX_CMP_REQUEUE).
+ */
+
+#include <errno.h>
+#include <sys/mman.h>
+#include "futextest.h"
+
+static futex_t *prot_none_addr;
+
+static struct futex_test_variants variants[] = {
+#if (__NR_futex != __LTP__NR_INVALID_SYSCALL)
+	{ .fntype = FUTEX_FN_FUTEX, .desc = "syscall with old kernel spec"},
+#endif
+
+#if (__NR_futex_time64 != __LTP__NR_INVALID_SYSCALL)
+	{ .fntype = FUTEX_FN_FUTEX64, .desc = "syscall time64 with kernel spec"},
+#endif
+};
+
+static struct testcase {
+	const char *desc;
+	futex_t *addr;
+	int exp_errno;
+} testcases[2];
+
+static void run(unsigned int n)
+{
+	struct futex_test_variants *tv = &variants[tst_variant];
+	struct testcase *tc = &testcases[n];
+
+	TST_EXP_FAIL(futex_wake(tv->fntype, tc->addr, 1, 0),
+		tc->exp_errno, "%s", tc->desc);
+}
+
+static void setup(void)
+{
+	struct futex_test_variants *tv = &variants[tst_variant];
+	size_t pagesize = getpagesize();
+	futex_t *unmapped;
+
+	tst_res(TINFO, "Testing variant: %s", tv->desc);
+	futex_supported_by_kernel(tv->fntype);
+
+	unmapped = SAFE_MMAP(NULL, pagesize, PROT_READ | PROT_WRITE,
+		MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	SAFE_MUNMAP(unmapped, pagesize);
+
+	prot_none_addr = SAFE_MMAP(NULL, pagesize, PROT_NONE,
+		MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+
+	testcases[0] = (struct testcase){
+		.desc = "uaddr unmapped",
+		.addr = unmapped,
+		.exp_errno = EFAULT,
+	};
+	testcases[1] = (struct testcase){
+		.desc = "uaddr PROT_NONE",
+		.addr = prot_none_addr,
+		.exp_errno = EFAULT,
+	};
+}
+
+static void cleanup(void)
+{
+	if (prot_none_addr)
+		SAFE_MUNMAP(prot_none_addr, getpagesize());
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.test = run,
+	.tcnt = ARRAY_SIZE(testcases),
+	.test_variants = ARRAY_SIZE(variants),
+};
-- 
2.53.0


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