tests/qtest/vhost-user-blk-test.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-)
In the vhost-user-blk-test, as of now there is nothing stoping
vhost-user-blk in QEMU writing to the socket right after forking off the
storage daemon before it has a chance to come up properly, leaving the
test hanging forever. This intermittently hanging test has caused QEMU
automation failures reported multiple times on the mailing list [1].
This change makes the storage-daemon notify the vhost-user-blk-test
that it is fully initialized and ready to handle client connections by
creating a pidfile on initialiation. This ensures that the storage-daemon
backend won't miss vhost-user messages and thereby resolves the hang.
[1] https://lore.kernel.org/qemu-devel/CAFEAcA8kYpz9LiPNxnWJAPSjc=nv532bEdyfynaBeMeohqBp3A@mail.gmail.com/
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
---
Accidentally left a raw free() in v3. Converted it to g_free() here.
tests/qtest/vhost-user-blk-test.c | 27 ++++++++++++++++++++++++++-
1 file changed, 26 insertions(+), 1 deletion(-)
diff --git a/tests/qtest/vhost-user-blk-test.c b/tests/qtest/vhost-user-blk-test.c
index 6f108a1b62..6898f55f11 100644
--- a/tests/qtest/vhost-user-blk-test.c
+++ b/tests/qtest/vhost-user-blk-test.c
@@ -24,6 +24,7 @@
#define TEST_IMAGE_SIZE (64 * 1024 * 1024)
#define QVIRTIO_BLK_TIMEOUT_US (30 * 1000 * 1000)
#define PCI_SLOT_HP 0x06
+#define PIDFILE_RETRIES 5
typedef struct {
pid_t pid;
@@ -885,7 +886,8 @@ static void start_vhost_user_blk(GString *cmd_line, int vus_instances,
int num_queues)
{
const char *vhost_user_blk_bin = qtest_qemu_storage_daemon_binary();
- int i;
+ int i, retries;
+ char *daemon_pidfile_path;
gchar *img_path;
GString *storage_daemon_command = g_string_new(NULL);
QemuStorageDaemonState *qsd;
@@ -898,6 +900,9 @@ static void start_vhost_user_blk(GString *cmd_line, int vus_instances,
" -object memory-backend-memfd,id=mem,size=256M,share=on "
" -M memory-backend=mem -m 256M ");
+ daemon_pidfile_path = g_strdup_printf("/tmp/daemon-%d", getpid());
+ g_assert_cmpint((uintptr_t) daemon_pidfile_path, !=, (uintptr_t) NULL);
+
for (i = 0; i < vus_instances; i++) {
int fd;
char *sock_path = create_listen_socket(&fd);
@@ -914,6 +919,9 @@ static void start_vhost_user_blk(GString *cmd_line, int vus_instances,
i + 1, sock_path);
}
+ g_string_append_printf(storage_daemon_command, "--pidfile %s ",
+ daemon_pidfile_path);
+
g_test_message("starting vhost-user backend: %s",
storage_daemon_command->str);
pid_t pid = fork();
@@ -930,7 +938,24 @@ static void start_vhost_user_blk(GString *cmd_line, int vus_instances,
execlp("/bin/sh", "sh", "-c", storage_daemon_command->str, NULL);
exit(1);
}
+
+ /*
+ * Ensure the storage-daemon has come up properly before allowing the
+ * test to proceed.
+ */
+ retries = 0;
+ while (access(daemon_pidfile_path, F_OK) != 0) {
+ g_assert_cmpint(retries, <, PIDFILE_RETRIES);
+
+ retries++;
+ g_usleep(1000);
+ }
+
g_string_free(storage_daemon_command, true);
+ if (access(daemon_pidfile_path, F_OK) == 0) {
+ unlink(daemon_pidfile_path);
+ }
+ g_free(daemon_pidfile_path);
qsd = g_new(QemuStorageDaemonState, 1);
qsd->pid = pid;
--
2.20.1
On Thu, Sep 23, 2021 at 03:16:17PM +0000, Raphael Norwitz wrote: > In the vhost-user-blk-test, as of now there is nothing stoping > vhost-user-blk in QEMU writing to the socket right after forking off the > storage daemon before it has a chance to come up properly, leaving the > test hanging forever. This intermittently hanging test has caused QEMU > automation failures reported multiple times on the mailing list [1]. > > This change makes the storage-daemon notify the vhost-user-blk-test > that it is fully initialized and ready to handle client connections by > creating a pidfile on initialiation. This ensures that the storage-daemon > backend won't miss vhost-user messages and thereby resolves the hang. > > [1] https://lore.kernel.org/qemu-devel/CAFEAcA8kYpz9LiPNxnWJAPSjc=nv532bEdyfynaBeMeohqBp3A@mail.gmail.com/ > > Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com> > --- > Accidentally left a raw free() in v3. Converted it to g_free() here. > > tests/qtest/vhost-user-blk-test.c | 27 ++++++++++++++++++++++++++- > 1 file changed, 26 insertions(+), 1 deletion(-) > > diff --git a/tests/qtest/vhost-user-blk-test.c b/tests/qtest/vhost-user-blk-test.c > index 6f108a1b62..6898f55f11 100644 > --- a/tests/qtest/vhost-user-blk-test.c > +++ b/tests/qtest/vhost-user-blk-test.c > @@ -24,6 +24,7 @@ > #define TEST_IMAGE_SIZE (64 * 1024 * 1024) > #define QVIRTIO_BLK_TIMEOUT_US (30 * 1000 * 1000) > #define PCI_SLOT_HP 0x06 > +#define PIDFILE_RETRIES 5 > > typedef struct { > pid_t pid; > @@ -885,7 +886,8 @@ static void start_vhost_user_blk(GString *cmd_line, int vus_instances, > int num_queues) > { > const char *vhost_user_blk_bin = qtest_qemu_storage_daemon_binary(); > - int i; > + int i, retries; > + char *daemon_pidfile_path; > gchar *img_path; > GString *storage_daemon_command = g_string_new(NULL); > QemuStorageDaemonState *qsd; > @@ -898,6 +900,9 @@ static void start_vhost_user_blk(GString *cmd_line, int vus_instances, > " -object memory-backend-memfd,id=mem,size=256M,share=on " > " -M memory-backend=mem -m 256M "); > > + daemon_pidfile_path = g_strdup_printf("/tmp/daemon-%d", getpid()); > + g_assert_cmpint((uintptr_t) daemon_pidfile_path, !=, (uintptr_t) NULL); Feels verbose compared to: g_assert(daemon_pidfile_path) For that matter, can g_strdup_printf() ever return NULL? On memory error, it exit()s rather than returning. So this assert feels like overkill. Otherwise, Reviewed-by: Eric Blake <eblake@redhat.com> -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
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