tests/tcg/multiarch/signals.c | 149 ++++++++++++++++++++++++++++ tests/tcg/multiarch/Makefile.target | 2 + 2 files changed, 151 insertions(+) create mode 100644 tests/tcg/multiarch/signals.c
This adds a simple signal test that combines the POSIX timer_create
with signal delivery across multiple threads.
[AJB: So I wrote this in an attempt to flush out issues with the
s390x-linux-user handling. However I suspect I've done something wrong
or opened a can of signal handling worms.
Nominally this runs fine on real hardware but I variously get failures
when running it under translation and while debugging QEMU running the
test. I've also exposed a shortcomming with the gdb stub when dealing
with guest TLS data so yay ;-). So I post this as an RFC in case
anyone else can offer insight or can verify they are seeing the same
strange behaviour?]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
tests/tcg/multiarch/signals.c | 149 ++++++++++++++++++++++++++++
tests/tcg/multiarch/Makefile.target | 2 +
2 files changed, 151 insertions(+)
create mode 100644 tests/tcg/multiarch/signals.c
diff --git a/tests/tcg/multiarch/signals.c b/tests/tcg/multiarch/signals.c
new file mode 100644
index 0000000000..998c8fdefd
--- /dev/null
+++ b/tests/tcg/multiarch/signals.c
@@ -0,0 +1,149 @@
+/*
+ * linux-user signal handling tests.
+ *
+ * Copyright (c) 2021 Linaro Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <pthread.h>
+#include <string.h>
+#include <signal.h>
+#include <time.h>
+#include <sys/time.h>
+
+static void error1(const char *filename, int line, const char *fmt, ...)
+{
+ va_list ap;
+ va_start(ap, fmt);
+ fprintf(stderr, "%s:%d: ", filename, line);
+ vfprintf(stderr, fmt, ap);
+ fprintf(stderr, "\n");
+ va_end(ap);
+ exit(1);
+}
+
+static int __chk_error(const char *filename, int line, int ret)
+{
+ if (ret < 0) {
+ error1(filename, line, "%m (ret=%d, errno=%d/%s)",
+ ret, errno, strerror(errno));
+ }
+ return ret;
+}
+
+#define error(fmt, ...) error1(__FILE__, __LINE__, fmt, ## __VA_ARGS__)
+
+#define chk_error(ret) __chk_error(__FILE__, __LINE__, (ret))
+
+/*
+ * Thread handling
+ */
+typedef struct ThreadJob ThreadJob;
+
+struct ThreadJob {
+ int number;
+ int sleep;
+ int count;
+};
+
+static pthread_t *threads;
+static int max_threads = 10;
+__thread int signal_count;
+int total_signal_count;
+
+static void *background_thread_func(void *arg)
+{
+ ThreadJob *job = (ThreadJob *) arg;
+
+ printf("thread%d: started\n", job->number);
+ while (total_signal_count < job->count) {
+ usleep(job->sleep);
+ }
+ printf("thread%d: saw %d alarms from %d\n", job->number,
+ signal_count, total_signal_count);
+ return NULL;
+}
+
+static void spawn_threads(void)
+{
+ int i;
+ threads = calloc(sizeof(pthread_t), max_threads);
+
+ for (i = 0; i < max_threads; i++) {
+ ThreadJob *job = calloc(sizeof(ThreadJob), 1);
+ job->number = i;
+ job->sleep = i * 1000;
+ job->count = i * 100;
+ pthread_create(threads + i, NULL, background_thread_func, job);
+ }
+}
+
+static void close_threads(void)
+{
+ int i;
+ for (i = 0; i < max_threads; i++) {
+ pthread_join(threads[i], NULL);
+ }
+ free(threads);
+ threads = NULL;
+}
+
+static void sig_alarm(int sig, siginfo_t *info, void *puc)
+{
+ if (sig != SIGRTMIN) {
+ error("unexpected signal");
+ }
+ signal_count++;
+ __atomic_fetch_add(&total_signal_count, 1, __ATOMIC_SEQ_CST);
+}
+
+static void test_signals(void)
+{
+ struct sigaction act;
+ struct itimerspec it;
+ timer_t tid;
+ struct sigevent sev;
+
+ /* Set up SIG handler */
+ act.sa_sigaction = sig_alarm;
+ sigemptyset(&act.sa_mask);
+ act.sa_flags = SA_SIGINFO;
+ chk_error(sigaction(SIGRTMIN, &act, NULL));
+
+ /* Create POSIX timer */
+ sev.sigev_notify = SIGEV_SIGNAL;
+ sev.sigev_signo = SIGRTMIN;
+ sev.sigev_value.sival_ptr = &tid;
+ chk_error(timer_create(CLOCK_REALTIME, &sev, &tid));
+
+ it.it_interval.tv_sec = 0;
+ it.it_interval.tv_nsec = 1000000;
+ it.it_value.tv_sec = 0;
+ it.it_value.tv_nsec = 1000000;
+ chk_error(timer_settime(tid, 0, &it, NULL));
+
+ spawn_threads();
+
+ do {
+ usleep(1000);
+ } while (total_signal_count < 2000);
+
+ printf("shutting down after: %d signals\n", total_signal_count);
+
+ close_threads();
+
+ chk_error(timer_delete(tid));
+}
+
+int main(int argc, char **argv)
+{
+ test_signals();
+ return 0;
+}
diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target
index a3a751723d..3f283eabe6 100644
--- a/tests/tcg/multiarch/Makefile.target
+++ b/tests/tcg/multiarch/Makefile.target
@@ -30,6 +30,8 @@ testthread: LDFLAGS+=-lpthread
threadcount: LDFLAGS+=-lpthread
+signals: LDFLAGS+=-lrt -lpthread
+
# We define the runner for test-mmap after the individual
# architectures have defined their supported pages sizes. If no
# additional page sizes are defined we only run the default test.
--
2.20.1
+Laurent On 4/21/21 3:29 PM, Alex Bennée wrote: > This adds a simple signal test that combines the POSIX timer_create > with signal delivery across multiple threads. > > [AJB: So I wrote this in an attempt to flush out issues with the > s390x-linux-user handling. However I suspect I've done something wrong > or opened a can of signal handling worms. > > Nominally this runs fine on real hardware but I variously get failures > when running it under translation and while debugging QEMU running the > test. I've also exposed a shortcomming with the gdb stub when dealing > with guest TLS data so yay ;-). So I post this as an RFC in case > anyone else can offer insight or can verify they are seeing the same > strange behaviour?] > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > --- > tests/tcg/multiarch/signals.c | 149 ++++++++++++++++++++++++++++ > tests/tcg/multiarch/Makefile.target | 2 + > 2 files changed, 151 insertions(+) > create mode 100644 tests/tcg/multiarch/signals.c > > diff --git a/tests/tcg/multiarch/signals.c b/tests/tcg/multiarch/signals.c > new file mode 100644 > index 0000000000..998c8fdefd > --- /dev/null > +++ b/tests/tcg/multiarch/signals.c > @@ -0,0 +1,149 @@ > +/* > + * linux-user signal handling tests. > + * > + * Copyright (c) 2021 Linaro Ltd > + * > + * SPDX-License-Identifier: GPL-2.0-or-later > + */ > + > +#include <stdarg.h> > +#include <stdint.h> > +#include <stdio.h> > +#include <stdlib.h> > +#include <unistd.h> > +#include <errno.h> > +#include <pthread.h> > +#include <string.h> > +#include <signal.h> > +#include <time.h> > +#include <sys/time.h> > + > +static void error1(const char *filename, int line, const char *fmt, ...) > +{ > + va_list ap; > + va_start(ap, fmt); > + fprintf(stderr, "%s:%d: ", filename, line); > + vfprintf(stderr, fmt, ap); > + fprintf(stderr, "\n"); > + va_end(ap); > + exit(1); > +} > + > +static int __chk_error(const char *filename, int line, int ret) > +{ > + if (ret < 0) { > + error1(filename, line, "%m (ret=%d, errno=%d/%s)", > + ret, errno, strerror(errno)); > + } > + return ret; > +} > + > +#define error(fmt, ...) error1(__FILE__, __LINE__, fmt, ## __VA_ARGS__) > + > +#define chk_error(ret) __chk_error(__FILE__, __LINE__, (ret)) > + > +/* > + * Thread handling > + */ > +typedef struct ThreadJob ThreadJob; > + > +struct ThreadJob { > + int number; > + int sleep; > + int count; > +}; > + > +static pthread_t *threads; > +static int max_threads = 10; > +__thread int signal_count; > +int total_signal_count; > + > +static void *background_thread_func(void *arg) > +{ > + ThreadJob *job = (ThreadJob *) arg; > + > + printf("thread%d: started\n", job->number); > + while (total_signal_count < job->count) { > + usleep(job->sleep); > + } > + printf("thread%d: saw %d alarms from %d\n", job->number, > + signal_count, total_signal_count); > + return NULL; > +} > + > +static void spawn_threads(void) > +{ > + int i; > + threads = calloc(sizeof(pthread_t), max_threads); > + > + for (i = 0; i < max_threads; i++) { > + ThreadJob *job = calloc(sizeof(ThreadJob), 1); > + job->number = i; > + job->sleep = i * 1000; > + job->count = i * 100; > + pthread_create(threads + i, NULL, background_thread_func, job); > + } > +} > + > +static void close_threads(void) > +{ > + int i; > + for (i = 0; i < max_threads; i++) { > + pthread_join(threads[i], NULL); > + } > + free(threads); > + threads = NULL; > +} > + > +static void sig_alarm(int sig, siginfo_t *info, void *puc) > +{ > + if (sig != SIGRTMIN) { > + error("unexpected signal"); > + } > + signal_count++; > + __atomic_fetch_add(&total_signal_count, 1, __ATOMIC_SEQ_CST); > +} > + > +static void test_signals(void) > +{ > + struct sigaction act; > + struct itimerspec it; > + timer_t tid; > + struct sigevent sev; > + > + /* Set up SIG handler */ > + act.sa_sigaction = sig_alarm; > + sigemptyset(&act.sa_mask); > + act.sa_flags = SA_SIGINFO; > + chk_error(sigaction(SIGRTMIN, &act, NULL)); > + > + /* Create POSIX timer */ > + sev.sigev_notify = SIGEV_SIGNAL; > + sev.sigev_signo = SIGRTMIN; > + sev.sigev_value.sival_ptr = &tid; > + chk_error(timer_create(CLOCK_REALTIME, &sev, &tid)); > + > + it.it_interval.tv_sec = 0; > + it.it_interval.tv_nsec = 1000000; > + it.it_value.tv_sec = 0; > + it.it_value.tv_nsec = 1000000; > + chk_error(timer_settime(tid, 0, &it, NULL)); > + > + spawn_threads(); > + > + do { > + usleep(1000); > + } while (total_signal_count < 2000); > + > + printf("shutting down after: %d signals\n", total_signal_count); > + > + close_threads(); > + > + chk_error(timer_delete(tid)); > +} > + > +int main(int argc, char **argv) > +{ > + test_signals(); > + return 0; > +} > diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target > index a3a751723d..3f283eabe6 100644 > --- a/tests/tcg/multiarch/Makefile.target > +++ b/tests/tcg/multiarch/Makefile.target > @@ -30,6 +30,8 @@ testthread: LDFLAGS+=-lpthread > > threadcount: LDFLAGS+=-lpthread > > +signals: LDFLAGS+=-lrt -lpthread > + > # We define the runner for test-mmap after the individual > # architectures have defined their supported pages sizes. If no > # additional page sizes are defined we only run the default test. >
Alex Bennée <alex.bennee@linaro.org> writes: > This adds a simple signal test that combines the POSIX timer_create > with signal delivery across multiple threads. > > [AJB: So I wrote this in an attempt to flush out issues with the > s390x-linux-user handling. However I suspect I've done something wrong > or opened a can of signal handling worms. > > Nominally this runs fine on real hardware but I variously get failures > when running it under translation and while debugging QEMU running the > test. I've also exposed a shortcomming with the gdb stub when dealing > with guest TLS data so yay ;-). So I post this as an RFC in case > anyone else can offer insight or can verify they are seeing the same > strange behaviour?] To further document my confusion: gdb --args $QEMU ./tests/tcg/$ARCH/signals will SEGV in generated code for every target I've run. This seems to be some sort of change of behaviour by running inside a debug environment. Architectures that fail running normally: ./qemu-alpha tests/tcg/alpha-linux-user/signals fish: “./qemu-alpha tests/tcg/alpha-li…” terminated by signal SIGILL (Illegal instruction) ./qemu-sparc64 tests/tcg/sparc64-linux-user/signals thread0: started thread1: started thread2: started thread3: started thread4: started thread5: started thread6: started thread7: started thread8: started thread9: started thread0: saw 0 alarms from 0 ... (and hangs) ./qemu-s390x ./tests/tcg/s390x-linux-user/signals fish: “./qemu-s390x ./tests/tcg/s390x-…” terminated by signal SIGSEGV (Address boundary error) ./qemu-sh4 ./tests/tcg/sh4-linux-user/signals thread0: saw 87 alarms from 238 thread1: started thread1: saw 0 alarms from 331 thread2: started thread2: saw 0 alarms from 17088 thread3: started thread3: saw 0 alarms from 17093 thread4: started thread4: saw 0 alarms from 17098 thread5: started thread5: saw 2 alarms from 17106 thread6: started thread6: saw 0 alarms from 17108 thread7: started thread7: saw 1 alarms from 17114 thread8: started thread8: saw 0 alarms from 17118 thread9: started thread9: saw 0 alarms from 17122 qemu: uncaught target signal 11 (Segmentation fault) - core dumped fish: “./qemu-sh4 ./tests/tcg/sh4-linu…” terminated by signal SIGSEGV (Address boundary error) And another completely random data point while most arches see most signals delivered to the main thread qemu-i386 actually sees quite a few delivered to the other threads which is weird because I though the signal delivery would be more of a host feature than anything else. ./qemu-i386 ./tests/tcg/i386-linux-user/signals thread0: started thread0: saw 134 alarms from 177 thread1: started thread1: saw 0 alarms from 254 thread2: started thread2: saw 1 alarms from 300 thread3: started thread3: saw 1 alarms from 305 thread4: started thread5: started thread6: started thread7: started thread8: started thread9: started thread4: saw 80 alarms from 423 thread5: saw 7 alarms from 525 thread6: saw 4 alarms from 631 thread7: saw 6 alarms from 758 thread8: saw 4 alarms from 822 thread9: saw 635 alarms from 978 -- Alex Bennée
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