From b7d2dcfdb924359a7bdb0614960df38e6e4a9feb Mon Sep 17 00:00:00 2001 From: root Date: Wed, 7 Aug 2013 03:03:38 -0700 Subject: Wed Aug 7 02:56:35 PDT 2013 --- ...ove-use-of-pthread_cancel-from-linux_udev.patch | 141 +++++++++++++++++++++ 1 file changed, 141 insertions(+) create mode 100644 core/libusbx/0002-hotplug-Remove-use-of-pthread_cancel-from-linux_udev.patch (limited to 'core/libusbx/0002-hotplug-Remove-use-of-pthread_cancel-from-linux_udev.patch') 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 +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 +--- + 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 + -- cgit v1.2.3-54-g00ecf