[Libusbx-devel] Reverting atexit call of libusb_exit from libusb-compat ?
Hi, As discussed in much detail here: https://bugzilla.redhat.com/show_bug.cgi?id=1003193 Calling libusb_exit from atexit from libusb-compat-0.1.5 causes some apps to break. The app in question is the scanimage app from sane-backends, which uses atexit for cleanup itself. So what happens is the libusb-compat atexit handler runs first, and then the scanimage atexit cleanup code runs, and tries to cleanly shutdown the scanner (which may require communicating to it). This results in logs with LIBUSB_DEBUG=4 like this: [ 9.641307] [6300] libusbx: debug [libusb_exit] [ 9.641312] [6300] libusbx: debug [libusb_exit] destroying default context [ 9.641317] [6300] libusbx: warning [libusb_exit] application left some devices open libusbx: warning [add_to_flying_list] failed to arm first timerfd (errno 9) libusbx: warning [add_to_flying_list] failed to arm first timerfd (errno 9) libusbx: warning [add_to_flying_list] failed to arm first timerfd (errno 9) libusbx: warning [libusb_close] internal signalling write failed, closing anyway scanimage: received signal 2 scanimage: trying to stop scanner libusbx: warning [add_to_flying_list] failed to arm first timerfd (errno 9) libusbx: warning [add_to_flying_list] failed to arm first timerfd (errno 9) libusbx: warning [add_to_flying_list] failed to arm first timerfd (errno 9) scanimage: received signal 2 scanimage: aborting Note that errno 9 is EBADFD, which is caused by the fd already being closed by libusb_exit. I consider this behavior with some old apps a way bigger problem then the memory / resource leak we had before, therefor I suggest reverting the atexit changes to libusb-compat. Regards, Hans -- Learn the latest--Visual Studio 2012, SharePoint 2013, SQL 2012, more! Discover the easy way to master current and previous Microsoft technologies and advance your career. Get an incredible 1,500+ hours of step-by-step tutorial videos with LearnDevNow. Subscribe today and save! http://pubads.g.doubleclick.net/gampad/clk?id=58040911&iu=/4140/ostg.clktrk ___ libusbx-devel mailing list libusbx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libusbx-devel
Re: [Libusbx-devel] Reverting atexit call of libusb_exit from libusb-compat ?
On Thu, Sep 5, 2013 at 3:26 AM, Hans de Goede wrote: > Hi, > > As discussed in much detail here: > https://bugzilla.redhat.com/show_bug.cgi?id=1003193 > > Calling libusb_exit from atexit from libusb-compat-0.1.5 causes > some apps to break. > > The app in question is the scanimage app from sane-backends, which > uses atexit for cleanup itself. > > So what happens is the libusb-compat atexit handler runs first, and > then the scanimage atexit cleanup code runs, and tries to cleanly > shutdown the scanner (which may require communicating to it). > ... > I consider this behavior with some old apps a way bigger problem then the > memory / resource leak we had before, therefor I suggest reverting the > atexit changes to libusb-compat. > I agree. On the other hand, maybe we then have to document this limitation of libusb-compat. BTW, do we need to replicate the libusb.org libusb-compat tickets in libusbx github? Only Ticket 110 and 32 need to be copied as other tickets have been closed. http://www.libusb.org/report/10 If yes, then I will copy the two tickets and add "Compat" in the beginning of the description to distinguish them from libusbx tickets. -- Xiaofan -- Learn the latest--Visual Studio 2012, SharePoint 2013, SQL 2012, more! Discover the easy way to master current and previous Microsoft technologies and advance your career. Get an incredible 1,500+ hours of step-by-step tutorial videos with LearnDevNow. Subscribe today and save! http://pubads.g.doubleclick.net/gampad/clk?id=58041391&iu=/4140/ostg.clktrk ___ libusbx-devel mailing list libusbx-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libusbx-devel
