android_kernel_motorola_sm6225/drivers/usb
Brandon Philips ad0b65efd1 USB: cdc-acm.c: fix recursive lock in acm_start_wb error path
Fixes an obvious bug in cdc-acm by avoiding a recursive lock on
acm_start_wb()'s error path. Should apply towards 2.6.27 stable and
2.6.28.

=============================================
[ INFO: possible recursive locking detected ]
2.6.27-2-pae #109
---------------------------------------------
python/31449 is trying to acquire lock:
 (&acm->write_lock){++..}, at: [<f89a0348>] acm_start_wb+0x5c/0x7b [cdc_acm]

but task is already holding lock:
 (&acm->write_lock){++..}, at: [<f89a04fb>] acm_tty_write+0xe1/0x167 [cdc_acm]

other info that might help us debug this:
2 locks held by python/31449:
 #0:  (&tty->atomic_write_lock){--..}, at: [<c0260fae>] tty_write_lock+0x14/0x3b
 #1:  (&acm->write_lock){++..}, at: [<f89a04fb>] acm_tty_write+0xe1/0x167 [cdc_acm]

stack backtrace:
Pid: 31449, comm: python Not tainted 2.6.27-2-pae #109
 [<c030f42f>] ? printk+0xf/0x18
 [<c0149f33>] __lock_acquire+0xc7b/0x1316
 [<c014a63e>] lock_acquire+0x70/0x97
 [<f89a0348>] ? acm_start_wb+0x5c/0x7b [cdc_acm]
 [<c0312109>] _spin_lock_irqsave+0x37/0x47
 [<f89a0348>] ? acm_start_wb+0x5c/0x7b [cdc_acm]
 [<f89a0348>] acm_start_wb+0x5c/0x7b [cdc_acm]
 [<f89a055d>] acm_tty_write+0x143/0x167 [cdc_acm]
 [<c0262a98>] write_chan+0x1cd/0x297
 [<c012527e>] ? default_wake_function+0x0/0xd
 [<c026111e>] tty_write+0x149/0x1b9
 [<c02628cb>] ? write_chan+0x0/0x297
 [<c01912c5>] ? rw_verify_area+0x76/0x98
 [<c0260fd5>] ? tty_write+0x0/0x1b9
 [<c01919ba>] vfs_write+0x8c/0x136
 [<c0191afd>] sys_write+0x3b/0x60
 [<c0103beb>] sysenter_do_call+0x12/0x3f
 =======================

Signed-off-by: Brandon Philips <bphilips@suse.de>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-11-13 14:45:02 -08:00
..
atm USB: Speedtouch: add pre_reset and post_reset routines 2008-10-22 10:05:28 -07:00
c67x00 usb/c67x00 endianness annotations 2008-06-04 08:06:01 -07:00
class USB: cdc-acm.c: fix recursive lock in acm_start_wb error path 2008-11-13 14:45:02 -08:00
core USB: mention URB_FREE_BUFFER in usb_free_urb documentation 2008-11-13 14:45:02 -08:00
gadget saner FASYNC handling on file close 2008-11-01 09:49:46 -07:00
host Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6 2008-10-23 10:09:50 -07:00
image USB: remove err() macro from more usb drivers 2008-10-17 14:41:14 -07:00
misc USB: vstusb: fix compiler warning on x86-64 2008-11-13 14:45:00 -08:00
mon usbmon: fix tiny race exposed by the fastboot patches 2008-10-17 14:40:57 -07:00
musb usb: musb: fix BULK request on different available endpoints 2008-11-13 14:45:01 -08:00
serial USB: CP2101 Add device ID for AMB2560 2008-11-13 14:45:02 -08:00
storage USB: add Nikon D300 camera to unusual_devs 2008-11-13 14:45:00 -08:00
wusbcore uwb: don't use printk_ratelimit() so often 2008-10-16 13:56:53 +01:00
Kconfig Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6 2008-10-23 10:09:50 -07:00
Makefile wusb: add HWA host controller driver 2008-09-17 16:54:31 +01:00
README USB: fix directory references in usb/README 2007-11-28 13:58:34 -08:00
usb-skeleton.c USB: remove unnecessary type casting of urb->context 2008-04-24 21:16:55 -07:00

To understand all the Linux-USB framework, you'll use these resources:

    * This source code.  This is necessarily an evolving work, and
      includes kerneldoc that should help you get a current overview.
      ("make pdfdocs", and then look at "usb.pdf" for host side and
      "gadget.pdf" for peripheral side.)  Also, Documentation/usb has
      more information.

    * The USB 2.0 specification (from www.usb.org), with supplements
      such as those for USB OTG and the various device classes.
      The USB specification has a good overview chapter, and USB
      peripherals conform to the widely known "Chapter 9".

    * Chip specifications for USB controllers.  Examples include
      host controllers (on PCs, servers, and more); peripheral
      controllers (in devices with Linux firmware, like printers or
      cell phones); and hard-wired peripherals like Ethernet adapters.

    * Specifications for other protocols implemented by USB peripheral
      functions.  Some are vendor-specific; others are vendor-neutral
      but just standardized outside of the www.usb.org team.

Here is a list of what each subdirectory here is, and what is contained in
them.

core/		- This is for the core USB host code, including the
		  usbfs files and the hub class driver ("khubd").

host/		- This is for USB host controller drivers.  This
		  includes UHCI, OHCI, EHCI, and others that might
		  be used with more specialized "embedded" systems.

gadget/		- This is for USB peripheral controller drivers and
		  the various gadget drivers which talk to them.


Individual USB driver directories.  A new driver should be added to the
first subdirectory in the list below that it fits into.

image/		- This is for still image drivers, like scanners or
		  digital cameras.
../input/	- This is for any driver that uses the input subsystem,
		  like keyboard, mice, touchscreens, tablets, etc.
../media/	- This is for multimedia drivers, like video cameras,
		  radios, and any other drivers that talk to the v4l
		  subsystem.
../net/		- This is for network drivers.
serial/		- This is for USB to serial drivers.
storage/	- This is for USB mass-storage drivers.
class/		- This is for all USB device drivers that do not fit
		  into any of the above categories, and work for a range
		  of USB Class specified devices. 
misc/		- This is for all USB device drivers that do not fit
		  into any of the above categories.