kern/63621: USB MemoryStick Reader stalls/crashes system

Herve Quiroz herve.quiroz at
Wed Nov 3 15:10:32 PST 2004

The following reply was made to PR kern/63621; it has been noted by GNATS.

From: Herve Quiroz <herve.quiroz at>
To: freebsd-gnats-submit at, marck at
Subject: Re: kern/63621: USB MemoryStick Reader stalls/crashes system
Date: Thu, 4 Nov 2004 00:03:34 +0100

 I was able to reproduce this error on 5.2.1-RELEASE-p11.
 In fact I had already encountered this problem but it occured while
 using Subversion. Each time I boot my machine, then plug my USB memory
 stick [1], then do a simple checkout from a repository located on the
 USB device, the stick hangs. Worse, even my USB mouse gets off in the
 process. From this point, nothing can be done to avoid a panic.
 Indeed, if a leave everything as-is for a while, the system lags then
 crash after a few minutes.
 OTOH it is impossible to umount the device and if I try to unplug the
 stick without unmounting it, I get a panic (as reported in many other
 PRs [2]). If I simply shutdown the system, I get the same output as you
 in the console: a problem while syncing some buffer.
 I found a workaround though. A tricky one that is. The first time I plug
 my memory stick after a fresh reboot, I do a simple cat(1) of some text
 file in the partition I just mounted (UFS2 BTW) and wait a few seconds
 before doing anything else with the stick. Then, most of the time, the
 subsequent subversion operations I perform are successful and nothing
 Better yet, if I umount, unplug and then re-plug and re-mount the memory
 stick, I don't need to 'cat' the file anymore to have my subversion
 operations working. So, as long as I don't reboot my system, my memory
 stick is now running fine and I can do anything on the filesystem on it.
 I recently tried to upgrade to 5.3-BETA (BETA5 or BETA6 -- I can't
 remember unfortunately) and experienced the same problem.
 BTW, I am experiencing this problem either with UHCI [3] or OHCI [4] on
 different systems.
 Just as you, I'm looking for a fix... I just hope this follow-up will
 help identify the cause of the problem.
 [1] USB Memory Stick (with some UFS2 partition):
 umass0: USB Flash Disk, rev 2.00/2.00, addr 3
 GEOM: create disk da0 dp=0xc4b83450
 da0 at umass-sim0 bus 0 target 0 lun 0
 da0: <USB BAR 2.00> Removable Direct Access SCSI-2 device 
 da0: 1.000MB/s transfers
 da0: 249MB (511744 512 byte sectors: 64H 32S/T 249C)
 [2] Panic when unplugging mounted USB mass storage device
 PRs:	kern/72119
 [3] UHCI
 uhci0: <Intel 82801EB (ICH5) USB controller USB-A> port 0xff80-0xff9f irq 16 at device 29.0 on pci0
 usb0: <Intel 82801EB (ICH5) USB controller USB-A> on uhci0
 usb0: USB revision 1.0
 uhub0: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
 uhub0: 2 ports with 2 removable, self powered
 [4] OHCI
 ohci0: <SiS 5571 USB controller> mem 0xea000000-0xea000fff irq 4 at device 3.0 on pci0
 usb0: OHCI version 1.0, legacy support
 usb0: <SiS 5571 USB controller> on ohci0
 usb0: USB revision 1.0
 uhub0: SiS OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
 uhub0: 2 ports with 2 removable, self powered

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