Bug 5164 - pl2303 when unplugged while device is open leaks semaphore
Summary: pl2303 when unplugged while device is open leaks semaphore
Alias: None
Product: Drivers
Classification: Unclassified
Component: USB (show other bugs)
Hardware: i386 Linux
: P2 normal
Assignee: Greg Kroah-Hartman
Depends on:
Blocks: USB
  Show dependency tree
Reported: 2005-08-31 13:12 UTC by Andi Kleen
Modified: 2006-02-14 17:40 UTC (History)
2 users (show)

See Also:
Kernel Version: 2.6.13
Tree: Mainline
Regression: ---


Description Andi Kleen 2005-08-31 13:12:07 UTC
Most recent kernel where this bug did not occur:
Distribution: suse 9.3
Hardware Environment:athlon64 / x86-64 VIA chipset OHCI 
Software Environment:
Problem Description:

Steps to reproduce:

I had a serialconnection open to a pl2303 ttyUSB0 device. Then the USB cable
was unplugged. The serial connection was closed as expected, but afterwards
lsusb hangs. Plugging in the cable again also doesn't make the device
available again.

Backtrace of lsusb:
lsusb         D ffff810065046b30     0 22153  26510               22152 (NOTLB)
ffff8100522fdde8 0000000000000082 0000000000000d19 ffff810065046b30 
       ffffffff803f3780 ffff81000d0fbae8 ffff8100721152a8 6db6db6db6db6db7 
       0000000000000001 ffff81002c4a1030 
Call Trace:<ffffffff8033598e>{__down+222}
       <ffffffff883db4c8>{:usbcore:usbdev_read+72} <ffffffff80178a44>{filp_open+68}
       <ffffffff801797c5>{vfs_read+229} <ffffffff80179fa3>{sys_read+83}
Comment 1 Alan Stern 2005-09-01 06:54:26 UTC
My guess is that the semaphore isn't "leaked", but instead the disconnect
routine either crashes or hangs while holding the semaphore.  What does your
stack dump show for the khubd thread?
Comment 2 Alan Stern 2005-09-28 13:28:49 UTC
Has there been any progress chasing this bug?  Does it still occur in the latest
Comment 3 Greg Kroah-Hartman 2005-10-05 10:39:31 UTC
Please test 2.6.14-rc3 or later.  If it still happens, please reopen this bug.
Comment 4 Greg Kroah-Hartman 2005-10-06 15:11:54 UTC
Note, I can't duplicate this at all on 2.6.14-rc3.  This is on i386 though...
Comment 5 Greg Kroah-Hartman 2006-02-14 17:40:03 UTC
Am marking closed.  If you still have this problem on the 2.6.16 kernel, please
reopen it and let us know.

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