From 66139a48cee1530c91f37c145384b4ee7043f0b7 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Sat, 6 Dec 2014 18:02:55 +0100 Subject: [PATCH] ALSA: usb-audio: Don't resubmit pending URBs at MIDI error recovery In snd_usbmidi_error_timer(), the driver tries to resubmit MIDI input URBs to reactivate the MIDI stream, but this causes the error when some of URBs are still pending like: WARNING: CPU: 0 PID: 0 at ../drivers/usb/core/urb.c:339 usb_submit_urb+0x5f/0x70() URB ef705c40 submitted while active CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.16.6-2-desktop #1 Hardware name: FOXCONN TPS01/TPS01, BIOS 080015 03/23/2010 c0984bfa f4009ed4 c078deaf f4009ee4 c024c884 c09a135c f4009f00 00000000 c0984bfa 00000153 c061ac4f c061ac4f 00000009 00000001 ef705c40 e854d1c0 f4009eec c024c8d3 00000009 f4009ee4 c09a135c f4009f00 f4009f04 c061ac4f Call Trace: [] try_stack_unwind+0x156/0x170 [] dump_trace+0x5a/0x1b0 [] show_trace_log_lvl+0x46/0x50 [] show_stack_log_lvl+0x51/0xe0 [] show_stack+0x27/0x50 [] dump_stack+0x45/0x65 [] warn_slowpath_common+0x84/0xa0 [] warn_slowpath_fmt+0x33/0x40 [] usb_submit_urb+0x5f/0x70 [] snd_usbmidi_submit_urb+0x14/0x60 [snd_usbmidi_lib] [] snd_usbmidi_error_timer+0x6a/0xa0 [snd_usbmidi_lib] [] call_timer_fn+0x30/0x130 [] run_timer_softirq+0x1c2/0x260 [] __do_softirq+0xc3/0x270 [] do_softirq_own_stack+0x22/0x30 [] irq_exit+0x8d/0xa0 [] smp_apic_timer_interrupt+0x38/0x50 [] apic_timer_interrupt+0x34/0x3c [] cpuidle_enter_state+0x3e/0xd0 [] cpu_idle_loop+0x29d/0x3e0 [] cpu_startup_entry+0x53/0x60 [] start_kernel+0x415/0x41a For avoiding these errors, check the pending URBs and skip resubmitting such ones. Reported-and-tested-by: Stefan Seyfried Acked-by: Clemens Ladisch Cc: Signed-off-by: Takashi Iwai --- sound/usb/midi.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/sound/usb/midi.c b/sound/usb/midi.c index d3d49525a16b..5bfb695547f8 100644 --- a/sound/usb/midi.c +++ b/sound/usb/midi.c @@ -365,6 +365,8 @@ static void snd_usbmidi_error_timer(unsigned long data) if (in && in->error_resubmit) { in->error_resubmit = 0; for (j = 0; j < INPUT_URBS; ++j) { + if (atomic_read(&in->urbs[j]->use_count)) + continue; in->urbs[j]->dev = umidi->dev; snd_usbmidi_submit_urb(in->urbs[j], GFP_ATOMIC); } -- 2.39.2