Re: commit 554f76962d3a6eb5110415f1591aca83f96a84ae hangs USB for vmware 7.0.1

Oliver Neukum
2010-03-06T11:13:18Z

Am Samstag, 6. März 2010 10:33:07 schrieb Dmitry Torokhov:
> I did not have issues with bringing VMware GUI with
> 64096c17417380d8a472d096645f4cbc9406c987 as tip of Linus's tree (which
> is a believe the latest published), but got the following traces when
> yanked USB keyboard out:
>
> [ 1784.954389] usb 5-1: USB disconnect, address 2
> [ 1784.954394] usb 5-1.3: USB disconnect, address 3
> [ 1920.558046] INFO: task khubd:27 blocked for more than 120 seconds.
> [ 1920.558051] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> [ 1920.558054] khubd D 0000000000000202 0 27 2 0x00000000
> [ 1920.558060] ffff88011ba29960 0000000000000046 ffff88000260eec0 ffff88011ba20000
> [ 1920.558067] ffff88011ba28000 ffff88011ba29fd8 ffff88011ba29fd8 ffff88011ba20000
> [ 1920.558073] ffff88011ba29fd8 0000000000013d80 0000000000013d80 0000000000013d80
> [ 1920.558079] Call Trace:
> [ 1920.558088] [<ffffffff81478591>] __mutex_lock_common+0x1a1/0x4a0
> [ 1920.558094] [<ffffffff8136f922>] ? usbfs_conn_disc_event+0x12/0x40
> [ 1920.558099] [<ffffffff8107eb7d>] ? trace_hardirqs_on+0xd/0x10
> [ 1920.558103] [<ffffffff8136f922>] ? usbfs_conn_disc_event+0x12/0x40
> [ 1920.558107] [<ffffffff8147896e>] mutex_lock_nested+0x3e/0x50
> [ 1920.558111] [<ffffffff8136f922>] usbfs_conn_disc_event+0x12/0x40
> [ 1920.558115] [<ffffffff81371184>] usbfs_notify+0xa4/0x240

Thanks, seems like a lock is taken twice.
Dmitry, can you test this patch, too?

Regards
Oliver

>From e58722a5fc0c00bceaea1f70d5024f6325ac3a6c Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oliver@neukum.org>
Date: Sat, 6 Mar 2010 12:09:41 +0100
Subject: [PATCH] usb: usbfs: Fix deadlock of khubd

The caller of usbfs_conn_disc_event() already holds usbfs_mutex.
Don't take it again.

Signed-off-by: Oliver Neukum <neukum@b1-systems.de>
---
drivers/usb/core/devices.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/devices.c b/drivers/usb/core/devices.c
index c83c975..08def6b 100644
--- a/drivers/usb/core/devices.c
+++ b/drivers/usb/core/devices.c
@@ -155,11 +155,10 @@ static const struct class_info clas_info[] =

/*****************************************************************/

+/* the caller holds usbfs_mutex */
void usbfs_conn_disc_event(void)
{
- mutex_lock(&usbfs_mutex);
conndiscevcnt++;
- mutex_unlock(&usbfs_mutex);
wake_up(&deviceconndiscwq);
}

--
1.6.4.2