tests/perf_pmu: Handle CPU hotplug failures better

new file mode 100644
index 000000000000..fe3d2e344ff1
@@ -0,0 +1,22 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/reboot.h>
+
+#include "igt_core.h"
+
+#include "igt_sysrq.h"
+
+void igt_sysrq_reboot(void)
+{
+	sync();
+
+	/* Try to be nice at first, and if that fails pull the trigger */
+	if (reboot(RB_AUTOBOOT)) {
+		int fd = open("/proc/sysrq-trigger", O_WRONLY);
+		igt_ignore_warn(write(fd, "b", 2));
+		close(fd);
+	}
+
+	abort();
+}

new file mode 100644
index 000000000000..422473d2a480
@@ -0,0 +1,30 @@
+/*
+ * Copyright © 2018 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __IGT_SYSRQ_H__
+#define __IGT_SYSRQ_H__
+
+void igt_sysrq_reboot(void) __attribute__((noreturn));
+
+#endif /* __IGT_SYSRQ_H__ */

83 lines not on this page · raw message

index c292343de09e..3fd9f529f09f 100644
@@ -70,6 +70,7 @@
 #include "igt_core.h"
 #include "igt_aux.h"
 #include "igt_sysfs.h"
+#include "igt_sysrq.h"
 #include "igt_rc.h"
 
 #define UNW_LOCAL_ONLY

@@ -1136,6 +1137,28 @@ void igt_fail(int exitcode)
 	}
 }
 
+/**
+ * igt_fatal_error:
+ *
+ * Stop test execution or optionally, if the IGT_REBOOT_ON_FATAL_ERROR
+ * environment variable is set, reboot the machine.
+ *
+ * Since out test runner (piglit) does support fatal test exit codes, we
+ * implement the default behaviour by waiting endlessly.
+ */
+void  __attribute__((noreturn)) igt_fatal_error(void)
+{
+	if (igt_check_boolean_env_var("IGT_REBOOT_ON_FATAL_ERROR", false)) {
+		igt_warn("FATAL ERROR - REBOOTING");
+		igt_sysrq_reboot();
+	} else {
+		igt_warn("FATAL ERROR");
+		for (;;)
+			sleep(60);
+	}
+}
+
+
 /**
  * igt_can_fail:
  *

index 7af2b4c109fe..66523a208c31 100644
@@ -311,6 +311,7 @@ void __igt_fail_assert(const char *domain, const char *file,
 		       const char *format, ...)
 	__attribute__((noreturn));
 void igt_exit(void) __attribute__((noreturn));
+void igt_fatal_error(void) __attribute__((noreturn));
 
 /**
  * igt_ignore_warn:

new file mode 100644
index 000000000000..fe3d2e344ff1
@@ -0,0 +1,22 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/reboot.h>
+
+#include "igt_core.h"
+
+#include "igt_sysrq.h"
+
+void igt_sysrq_reboot(void)
+{
+	sync();
+
+	/* Try to be nice at first, and if that fails pull the trigger */
+	if (reboot(RB_AUTOBOOT)) {
+		int fd = open("/proc/sysrq-trigger", O_WRONLY);
+		igt_ignore_warn(write(fd, "b", 2));
+		close(fd);
+	}
+
+	abort();
+}

new file mode 100644
index 000000000000..422473d2a480
@@ -0,0 +1,30 @@
+/*
+ * Copyright © 2018 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __IGT_SYSRQ_H__
+#define __IGT_SYSRQ_H__
+
+void igt_sysrq_reboot(void) __attribute__((noreturn));
+
+#endif /* __IGT_SYSRQ_H__ */

index 3bbb18d2f216..8c75b0641785 100644
@@ -965,6 +965,7 @@ static void cpu_hotplug(int gem_fd)
 	int link[2];
 	int fd, ret;
 	int cur = 0;
+	char buf;
 
 	igt_skip_on(IS_BROXTON(intel_get_drm_devid(gem_fd)));
 	igt_require(cpu0_hotplug_support());

@@ -1011,9 +1012,32 @@ static void cpu_hotplug(int gem_fd)
 			}
 
 			/* Offline followed by online a CPU. */
-			igt_assert_eq(write(cpufd, "0", 2), 2);
+
+			ret = write(cpufd, "0", 2);
+			if (ret < 0) {
+				/*
+				 * If we failed to offline a CPU we don't want
+				 * to proceed.
+				 */
+				igt_warn("Failed to offline cpu%u! (%d)\n",
+					 cpu, errno);
+				igt_assert_eq(write(link[1], "s", 1), 1);
+				break;
+			}
+
 			usleep(1e6);
-			igt_assert_eq(write(cpufd, "1", 2), 2);
+
+			ret = write(cpufd, "1", 2);
+			if (ret < 0) {
+				/*
+				 * Failed to bring a CPU back online is fatal
+				 * for the sanity of a test run so reboot
+				 * immediately.
+				 */
+				igt_warn("Failed to online cpu%u! (%d)\n",
+					 cpu, errno);
+				igt_fatal_error();
+			}
 
 			close(cpufd);
 			cpu++;

@@ -1027,15 +1051,12 @@ static void cpu_hotplug(int gem_fd)
 	 * until the CPU core shuffler finishes one loop.
 	 */
 	for (;;) {
-		char buf;
-		int ret2;
-
 		usleep(500e3);
 		end_spin(gem_fd, spin[cur], 0);
 
 		/* Check if the child is signaling completion. */
-		ret2 = read(link[0], &buf, 1);
-		if ( ret2 == 1 || (ret2 < 0 && errno != EAGAIN))
+		ret = read(link[0], &buf, 1);
+		if ( ret == 1 || (ret < 0 && errno != EAGAIN))
 			break;
 
 		igt_spin_batch_free(gem_fd, spin[cur]);

@@ -1054,6 +1075,9 @@ static void cpu_hotplug(int gem_fd)
 	close(fd);
 	close(link[0]);
 
+	/* Skip if child signals a problem with offlining a CPU. */
+	igt_skip_on(buf == 's');
+
 	assert_within_epsilon(val, ts[1] - ts[0], tolerance);
 }
 

index c292343de09e..d64c25e1217b 100644
@@ -70,6 +70,7 @@
 #include "igt_core.h"
 #include "igt_aux.h"
 #include "igt_sysfs.h"
+#include "igt_sysrq.h"
 #include "igt_rc.h"
 
 #define UNW_LOCAL_ONLY

@@ -1136,6 +1137,28 @@ void igt_fail(int exitcode)
 	}
 }
 
+/**
+ * igt_fatal_error: Stop test execution on fatal errors
+ *
+ * Stop test execution or optionally, if the IGT_REBOOT_ON_FATAL_ERROR
+ * environment variable is set, reboot the machine.
+ *
+ * Since out test runner (piglit) does support fatal test exit codes, we
+ * implement the default behaviour by waiting endlessly.
+ */
+void  __attribute__((noreturn)) igt_fatal_error(void)
+{
+	if (igt_check_boolean_env_var("IGT_REBOOT_ON_FATAL_ERROR", false)) {
+		igt_warn("FATAL ERROR - REBOOTING");
+		igt_sysrq_reboot();
+	} else {
+		igt_warn("FATAL ERROR");
+		for (;;)
+			sleep(60);
+	}
+}
+
+
 /**
  * igt_can_fail:
  *

index 7af2b4c109fe..66523a208c31 100644
@@ -311,6 +311,7 @@ void __igt_fail_assert(const char *domain, const char *file,
 		       const char *format, ...)
 	__attribute__((noreturn));
 void igt_exit(void) __attribute__((noreturn));
+void igt_fatal_error(void) __attribute__((noreturn));
 
 /**
  * igt_ignore_warn:

new file mode 100644
index 000000000000..3bda321f7c5b
@@ -0,0 +1,27 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/reboot.h>
+
+#include "igt_core.h"
+
+#include "igt_sysrq.h"
+
+/**
+ * igt_sysrq_reboot: Reboots the machine
+ *
+ * Syncs filesystems and immediately reboots the machine.
+ */
+void igt_sysrq_reboot(void)
+{
+	sync();
+
+	/* Try to be nice at first, and if that fails pull the trigger */
+	if (reboot(RB_AUTOBOOT)) {
+		int fd = open("/proc/sysrq-trigger", O_WRONLY);
+		igt_ignore_warn(write(fd, "b", 2));
+		close(fd);
+	}
+
+	abort();
+}

new file mode 100644
index 000000000000..422473d2a480
@@ -0,0 +1,30 @@
+/*
+ * Copyright © 2018 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __IGT_SYSRQ_H__
+#define __IGT_SYSRQ_H__
+
+void igt_sysrq_reboot(void) __attribute__((noreturn));
+
+#endif /* __IGT_SYSRQ_H__ */

index 3bbb18d2f216..87e7e782d05e 100644
@@ -965,6 +965,7 @@ static void cpu_hotplug(int gem_fd)
 	int link[2];
 	int fd, ret;
 	int cur = 0;
+	char buf;
 
 	igt_skip_on(IS_BROXTON(intel_get_drm_devid(gem_fd)));
 	igt_require(cpu0_hotplug_support());

@@ -1011,9 +1012,32 @@ static void cpu_hotplug(int gem_fd)
 			}
 
 			/* Offline followed by online a CPU. */
-			igt_assert_eq(write(cpufd, "0", 2), 2);
+
+			ret = write(cpufd, "0", 2);
+			if (ret < 0) {
+				/*
+				 * If we failed to offline a CPU we don't want
+				 * to proceed.
+				 */
+				igt_warn("Failed to offline cpu%u! (%d)\n",
+					 cpu, errno);
+				igt_assert_eq(write(link[1], "s", 1), 1);
+				break;
+			}
+
 			usleep(1e6);
-			igt_assert_eq(write(cpufd, "1", 2), 2);
+
+			ret = write(cpufd, "1", 2);
+			if (ret < 0) {
+				/*
+				 * Failed to bring a CPU back online is fatal
+				 * for the sanity of a test run so stop further
+				 * testing.
+				 */
+				igt_warn("Failed to online cpu%u! (%d)\n",
+					 cpu, errno);
+				igt_fatal_error();
+			}
 
 			close(cpufd);
 			cpu++;

@@ -1027,15 +1051,12 @@ static void cpu_hotplug(int gem_fd)
 	 * until the CPU core shuffler finishes one loop.
 	 */
 	for (;;) {
-		char buf;
-		int ret2;
-
 		usleep(500e3);
 		end_spin(gem_fd, spin[cur], 0);
 
 		/* Check if the child is signaling completion. */
-		ret2 = read(link[0], &buf, 1);
-		if ( ret2 == 1 || (ret2 < 0 && errno != EAGAIN))
+		ret = read(link[0], &buf, 1);
+		if ( ret == 1 || (ret < 0 && errno != EAGAIN))
 			break;
 
 		igt_spin_batch_free(gem_fd, spin[cur]);

@@ -1054,6 +1075,9 @@ static void cpu_hotplug(int gem_fd)
 	close(fd);
 	close(link[0]);
 
+	/* Skip if child signals a problem with offlining a CPU. */
+	igt_skip_on(buf == 's');
+
 	assert_within_epsilon(val, ts[1] - ts[0], tolerance);
 }
 

index c292343de09e..46285ac32432 100644
@@ -70,6 +70,7 @@
 #include "igt_core.h"
 #include "igt_aux.h"
 #include "igt_sysfs.h"
+#include "igt_sysrq.h"
 #include "igt_rc.h"
 
 #define UNW_LOCAL_ONLY

@@ -1136,6 +1137,28 @@ void igt_fail(int exitcode)
 	}
 }
 
+/**
+ * igt_fatal_error: Stop test execution on fatal errors
+ *
+ * Stop test execution or optionally, if the IGT_REBOOT_ON_FATAL_ERROR
+ * environment variable is set, reboot the machine.
+ *
+ * Since out test runner (piglit) does support fatal test exit codes, we
+ * implement the default behaviour by waiting endlessly.
+ */
+void  __attribute__((noreturn)) igt_fatal_error(void)
+{
+	if (igt_check_boolean_env_var("IGT_REBOOT_ON_FATAL_ERROR", false)) {
+		igt_warn("FATAL ERROR - REBOOTING");
+		igt_sysrq_reboot();
+	} else {
+		igt_warn("FATAL ERROR");
+		for (;;)
+			pause();
+	}
+}
+
+
 /**
  * igt_can_fail:
  *

index 7af2b4c109fe..66523a208c31 100644
@@ -311,6 +311,7 @@ void __igt_fail_assert(const char *domain, const char *file,
 		       const char *format, ...)
 	__attribute__((noreturn));
 void igt_exit(void) __attribute__((noreturn));
+void igt_fatal_error(void) __attribute__((noreturn));
 
 /**
  * igt_ignore_warn:

new file mode 100644
index 000000000000..3bda321f7c5b
@@ -0,0 +1,27 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/reboot.h>
+
+#include "igt_core.h"
+
+#include "igt_sysrq.h"
+
+/**
+ * igt_sysrq_reboot: Reboots the machine
+ *
+ * Syncs filesystems and immediately reboots the machine.
+ */
+void igt_sysrq_reboot(void)
+{
+	sync();
+
+	/* Try to be nice at first, and if that fails pull the trigger */
+	if (reboot(RB_AUTOBOOT)) {
+		int fd = open("/proc/sysrq-trigger", O_WRONLY);
+		igt_ignore_warn(write(fd, "b", 2));
+		close(fd);
+	}
+
+	abort();
+}

new file mode 100644
index 000000000000..422473d2a480
@@ -0,0 +1,30 @@
+/*
+ * Copyright © 2018 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __IGT_SYSRQ_H__
+#define __IGT_SYSRQ_H__
+
+void igt_sysrq_reboot(void) __attribute__((noreturn));
+
+#endif /* __IGT_SYSRQ_H__ */

index 3bbb18d2f216..87e7e782d05e 100644
@@ -965,6 +965,7 @@ static void cpu_hotplug(int gem_fd)
 	int link[2];
 	int fd, ret;
 	int cur = 0;
+	char buf;
 
 	igt_skip_on(IS_BROXTON(intel_get_drm_devid(gem_fd)));
 	igt_require(cpu0_hotplug_support());

@@ -1011,9 +1012,32 @@ static void cpu_hotplug(int gem_fd)
 			}
 
 			/* Offline followed by online a CPU. */
-			igt_assert_eq(write(cpufd, "0", 2), 2);
+
+			ret = write(cpufd, "0", 2);
+			if (ret < 0) {
+				/*
+				 * If we failed to offline a CPU we don't want
+				 * to proceed.
+				 */
+				igt_warn("Failed to offline cpu%u! (%d)\n",
+					 cpu, errno);
+				igt_assert_eq(write(link[1], "s", 1), 1);
+				break;
+			}
+
 			usleep(1e6);
-			igt_assert_eq(write(cpufd, "1", 2), 2);
+
+			ret = write(cpufd, "1", 2);
+			if (ret < 0) {
+				/*
+				 * Failed to bring a CPU back online is fatal
+				 * for the sanity of a test run so stop further
+				 * testing.
+				 */
+				igt_warn("Failed to online cpu%u! (%d)\n",
+					 cpu, errno);
+				igt_fatal_error();
+			}
 
 			close(cpufd);
 			cpu++;

@@ -1027,15 +1051,12 @@ static void cpu_hotplug(int gem_fd)
 	 * until the CPU core shuffler finishes one loop.
 	 */
 	for (;;) {
-		char buf;
-		int ret2;
-
 		usleep(500e3);
 		end_spin(gem_fd, spin[cur], 0);
 
 		/* Check if the child is signaling completion. */
-		ret2 = read(link[0], &buf, 1);
-		if ( ret2 == 1 || (ret2 < 0 && errno != EAGAIN))
+		ret = read(link[0], &buf, 1);
+		if ( ret == 1 || (ret < 0 && errno != EAGAIN))
 			break;
 
 		igt_spin_batch_free(gem_fd, spin[cur]);

@@ -1054,6 +1075,9 @@ static void cpu_hotplug(int gem_fd)
 	close(fd);
 	close(link[0]);
 
+	/* Skip if child signals a problem with offlining a CPU. */
+	igt_skip_on(buf == 's');
+
 	assert_within_epsilon(val, ts[1] - ts[0], tolerance);
 }
 

index c292343de09e..e52b806bdb01 100644
@@ -70,6 +70,7 @@
 #include "igt_core.h"
 #include "igt_aux.h"
 #include "igt_sysfs.h"
+#include "igt_sysrq.h"
 #include "igt_rc.h"
 
 #define UNW_LOCAL_ONLY

@@ -1136,6 +1137,28 @@ void igt_fail(int exitcode)
 	}
 }
 
+/**
+ * igt_fatal_error: Stop test execution on fatal errors
+ *
+ * Stop test execution or optionally, if the IGT_REBOOT_ON_FATAL_ERROR
+ * environment variable is set, reboot the machine.
+ *
+ * Since out test runner (piglit) does support fatal test exit codes, we
+ * implement the default behaviour by waiting endlessly.
+ */
+void  __attribute__((noreturn)) igt_fatal_error(void)
+{
+	if (igt_check_boolean_env_var("IGT_REBOOT_ON_FATAL_ERROR", false)) {
+		igt_warn("FATAL ERROR - REBOOTING\n");
+		igt_sysrq_reboot();
+	} else {
+		igt_warn("FATAL ERROR\n");
+		for (;;)
+			pause();
+	}
+}
+
+
 /**
  * igt_can_fail:
  *

index 7af2b4c109fe..66523a208c31 100644
@@ -311,6 +311,7 @@ void __igt_fail_assert(const char *domain, const char *file,
 		       const char *format, ...)
 	__attribute__((noreturn));
 void igt_exit(void) __attribute__((noreturn));
+void igt_fatal_error(void) __attribute__((noreturn));
 
 /**
  * igt_ignore_warn:

new file mode 100644
index 000000000000..3bda321f7c5b
@@ -0,0 +1,27 @@
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/reboot.h>
+
+#include "igt_core.h"
+
+#include "igt_sysrq.h"
+
+/**
+ * igt_sysrq_reboot: Reboots the machine
+ *
+ * Syncs filesystems and immediately reboots the machine.
+ */
+void igt_sysrq_reboot(void)
+{
+	sync();
+
+	/* Try to be nice at first, and if that fails pull the trigger */
+	if (reboot(RB_AUTOBOOT)) {
+		int fd = open("/proc/sysrq-trigger", O_WRONLY);
+		igt_ignore_warn(write(fd, "b", 2));
+		close(fd);
+	}
+
+	abort();
+}

new file mode 100644
index 000000000000..422473d2a480
@@ -0,0 +1,30 @@
+/*
+ * Copyright © 2018 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#ifndef __IGT_SYSRQ_H__
+#define __IGT_SYSRQ_H__
+
+void igt_sysrq_reboot(void) __attribute__((noreturn));
+
+#endif /* __IGT_SYSRQ_H__ */

index 3bbb18d2f216..87e7e782d05e 100644
@@ -965,6 +965,7 @@ static void cpu_hotplug(int gem_fd)
 	int link[2];
 	int fd, ret;
 	int cur = 0;
+	char buf;
 
 	igt_skip_on(IS_BROXTON(intel_get_drm_devid(gem_fd)));
 	igt_require(cpu0_hotplug_support());

@@ -1011,9 +1012,32 @@ static void cpu_hotplug(int gem_fd)
 			}
 
 			/* Offline followed by online a CPU. */
-			igt_assert_eq(write(cpufd, "0", 2), 2);
+
+			ret = write(cpufd, "0", 2);
+			if (ret < 0) {
+				/*
+				 * If we failed to offline a CPU we don't want
+				 * to proceed.
+				 */
+				igt_warn("Failed to offline cpu%u! (%d)\n",
+					 cpu, errno);
+				igt_assert_eq(write(link[1], "s", 1), 1);
+				break;
+			}
+
 			usleep(1e6);
-			igt_assert_eq(write(cpufd, "1", 2), 2);
+
+			ret = write(cpufd, "1", 2);
+			if (ret < 0) {
+				/*
+				 * Failed to bring a CPU back online is fatal
+				 * for the sanity of a test run so stop further
+				 * testing.
+				 */
+				igt_warn("Failed to online cpu%u! (%d)\n",
+					 cpu, errno);
+				igt_fatal_error();
+			}
 
 			close(cpufd);
 			cpu++;

@@ -1027,15 +1051,12 @@ static void cpu_hotplug(int gem_fd)
 	 * until the CPU core shuffler finishes one loop.
 	 */
 	for (;;) {
-		char buf;
-		int ret2;
-
 		usleep(500e3);
 		end_spin(gem_fd, spin[cur], 0);
 
 		/* Check if the child is signaling completion. */
-		ret2 = read(link[0], &buf, 1);
-		if ( ret2 == 1 || (ret2 < 0 && errno != EAGAIN))
+		ret = read(link[0], &buf, 1);
+		if ( ret == 1 || (ret < 0 && errno != EAGAIN))
 			break;
 
 		igt_spin_batch_free(gem_fd, spin[cur]);

@@ -1054,6 +1075,9 @@ static void cpu_hotplug(int gem_fd)
 	close(fd);
 	close(link[0]);
 
+	/* Skip if child signals a problem with offlining a CPU. */
+	igt_skip_on(buf == 's');
+
 	assert_within_epsilon(val, ts[1] - ts[0], tolerance);
 }