Wed Aug 7 02:56:35 PDT 2013

1 files changed, 141 insertions, 0 deletions

diff --git a/core/libusbx/0002-hotplug-Remove-use-of-pthread_cancel-from-linux_udev.patch b/core/libusbx/0002-hotplug-Remove-use-of-pthread_cancel-from-linux_udev.patch
new file mode 100644
index 000000000..5342fbe70
--- /dev/null
+++ b/core/libusbx/0002-hotplug-Remove-use-of-pthread_cancel-from-linux_udev.patch
@@ -0,0 +1,141 @@
+From 852efb5a3e82de43cf6288e9904cb254ff636aa0 Mon Sep 17 00:00:00 2001
+From: Chris Dickens <christopher.a.dickens@gmail.com>
+Date: Sat, 20 Jul 2013 13:01:41 -0700
+Subject: [PATCH 2/2] hotplug: Remove use of pthread_cancel from linux_udev
+
+Using pthread_cancel() presents the opportunity for deadlock, so
+use a control pipe to cause the event thread to gracefully exit.
+
+Signed-off-by: Hans de Goede <hdegoede@redhat.com>
+---
+ libusb/os/linux_udev.c | 63 ++++++++++++++++++++++++++++++++++++++------------
+ libusb/version_nano.h  |  2 +-
+ 2 files changed, 49 insertions(+), 16 deletions(-)
+
+diff --git a/libusb/os/linux_udev.c b/libusb/os/linux_udev.c
+index 5a2aadf..70f632d 100644
+--- a/libusb/os/linux_udev.c
++++ b/libusb/os/linux_udev.c
+@@ -46,6 +46,7 @@
+ /* udev context */
+ static struct udev *udev_ctx = NULL;
+ static int udev_monitor_fd = -1;
++static int udev_control_pipe[2] = {-1, -1};
+ static struct udev_monitor *udev_monitor = NULL;
+ static pthread_t linux_event_thread;
+ 
+@@ -95,14 +96,23 @@ int linux_udev_start_event_monitor(void)
+ 		goto err_free_monitor;
+ 	}
+ 
++	r = usbi_pipe(udev_control_pipe);
++	if (r) {
++		usbi_err(NULL, "could not create udev control pipe");
++		goto err_free_monitor;
++	}
++
+ 	r = pthread_create(&linux_event_thread, NULL, linux_udev_event_thread_main, NULL);
+ 	if (r) {
+ 		usbi_err(NULL, "creating hotplug event thread (%d)", r);
+-		goto err_free_monitor;
++		goto err_close_pipe;
+ 	}
+ 
+ 	return LIBUSB_SUCCESS;
+ 
++err_close_pipe:
++	close(udev_control_pipe[0]);
++	close(udev_control_pipe[1]);
+ err_free_monitor:
+ 	udev_monitor_unref(udev_monitor);
+ 	udev_monitor = NULL;
+@@ -115,14 +125,19 @@ err_free_ctx:
+ 
+ int linux_udev_stop_event_monitor(void)
+ {
++	char dummy = 1;
++	int r;
++
+ 	assert(udev_ctx != NULL);
+ 	assert(udev_monitor != NULL);
+ 	assert(udev_monitor_fd != -1);
+ 
+-	/* Cancel the event thread. This is the only way to guarantee the
+-	   thread exits since closing the monitor fd won't necessarily cause
+-	   poll to return. */
+-	pthread_cancel(linux_event_thread);
++	/* Write some dummy data to the control pipe and
++	 * wait for the thread to exit */
++	r = usbi_write(udev_control_pipe[1], &dummy, sizeof(dummy));
++	if (r <= 0) {
++		usbi_warn(NULL, "udev control pipe signal failed");
++	}
+ 	pthread_join(linux_event_thread, NULL);
+ 
+ 	/* Release the udev monitor */
+@@ -134,27 +149,45 @@ int linux_udev_stop_event_monitor(void)
+ 	udev_unref(udev_ctx);
+ 	udev_ctx = NULL;
+ 
++	/* close and reset control pipe */
++	close(udev_control_pipe[0]);
++	close(udev_control_pipe[1]);
++	udev_control_pipe[0] = -1;
++	udev_control_pipe[1] = -1;
++
+ 	return LIBUSB_SUCCESS;
+ }
+ 
+ static void *linux_udev_event_thread_main(void *arg)
+ {
++	char dummy;
++	int r;
+ 	struct udev_device* udev_dev;
+-	struct pollfd fds = {.fd = udev_monitor_fd,
+-			     .events = POLLIN};
++	struct pollfd fds[] = {
++		{.fd = udev_control_pipe[0],
++		 .events = POLLIN},
++		{.fd = udev_monitor_fd,
++		 .events = POLLIN},
++	};
+ 
+ 	usbi_dbg("udev event thread entering.");
+ 
+-	while (1 == poll(&fds, 1, -1)) {
+-		if (NULL == udev_monitor || POLLIN != fds.revents) {
++	while (poll(fds, 2, -1) >= 0) {
++		if (fds[0].revents & POLLIN) {
++			/* activity on control pipe, read the byte and exit */
++			r = usbi_read(udev_control_pipe[0], &dummy, sizeof(dummy));
++			if (r <= 0) {
++				usbi_warn(NULL, "udev control pipe read failed");
++			}
+ 			break;
+ 		}
+-
+-		usbi_mutex_static_lock(&linux_hotplug_lock);
+-		udev_dev = udev_monitor_receive_device(udev_monitor);
+-		if (udev_dev)
+-			udev_hotplug_event(udev_dev);
+-		usbi_mutex_static_unlock(&linux_hotplug_lock);
++		if (fds[1].revents & POLLIN) {
++			usbi_mutex_static_lock(&linux_hotplug_lock);
++			udev_dev = udev_monitor_receive_device(udev_monitor);
++			if (udev_dev)
++				udev_hotplug_event(udev_dev);
++			usbi_mutex_static_unlock(&linux_hotplug_lock);
++		}
+ 	}
+ 
+ 	usbi_dbg("udev event thread exiting");
+diff --git a/libusb/version_nano.h b/libusb/version_nano.h
+index 34e26ff..39ad7e3 100644
+--- a/libusb/version_nano.h
++++ b/libusb/version_nano.h
+@@ -1 +1 @@
+-#define LIBUSB_NANO 10777
++#define LIBUSB_NANO 10778
+-- 
+1.8.3.1
+