Bin Liu
1dc3a068cc
commitbc1e215454upstream. The DSPS glue calls del_timer_sync() in its musb_platform_disable() implementation, which requires the caller to not hold a lock. But musb_remove() calls musb_platform_disable() will musb->lock held. This could causes spinlock deadlock. So change musb_remove() to call musb_platform_disable() without holds musb->lock. This doesn't impact the musb_platform_disable implementation in other glue drivers. root@am335x-evm:~# modprobe -r musb-dsps [ 126.134879] musb-hdrc musb-hdrc.1: remove, state 1 [ 126.140465] usb usb2: USB disconnect, device number 1 [ 126.146178] usb 2-1: USB disconnect, device number 2 [ 126.416985] musb-hdrc musb-hdrc.1: USB bus 2 deregistered [ 126.423943] [ 126.425525] ====================================================== [ 126.431997] [ INFO: possible circular locking dependency detected ] [ 126.438564] 4.11.0-rc1-00003-g1557f13bca04-dirty #77 Not tainted [ 126.444852] ------------------------------------------------------- [ 126.451414] modprobe/778 is trying to acquire lock: [ 126.456523] (((&glue->timer))){+.-...}, at: [<c01b8788>] del_timer_sync+0x0/0xd0 [ 126.464403] [ 126.464403] but task is already holding lock: [ 126.470511] (&(&musb->lock)->rlock){-.-...}, at: [<bf30b7f8>] musb_remove+0x50/0x1 30 [musb_hdrc] [ 126.479965] [ 126.479965] which lock already depends on the new lock. [ 126.479965] [ 126.488531] [ 126.488531] the existing dependency chain (in reverse order) is: [ 126.496368] [ 126.496368] -> #1 (&(&musb->lock)->rlock){-.-...}: [ 126.502968] otg_timer+0x80/0xec [musb_dsps] [ 126.507990] call_timer_fn+0xb4/0x390 [ 126.512372] expire_timers+0xf0/0x1fc [ 126.516754] run_timer_softirq+0x80/0x178 [ 126.521511] __do_softirq+0xc4/0x554 [ 126.525802] irq_exit+0xe8/0x158 [ 126.529735] __handle_domain_irq+0x58/0xb8 [ 126.534583] __irq_usr+0x54/0x80 [ 126.538507] [ 126.538507] -> #0 (((&glue->timer))){+.-...}: [ 126.544636] del_timer_sync+0x40/0xd0 [ 126.549066] musb_remove+0x6c/0x130 [musb_hdrc] [ 126.554370] platform_drv_remove+0x24/0x3c [ 126.559206] device_release_driver_internal+0x14c/0x1e0 [ 126.565225] bus_remove_device+0xd8/0x108 [ 126.569970] device_del+0x1e4/0x308 [ 126.574170] platform_device_del+0x24/0x8c [ 126.579006] platform_device_unregister+0xc/0x20 [ 126.584394] dsps_remove+0x14/0x30 [musb_dsps] [ 126.589595] platform_drv_remove+0x24/0x3c [ 126.594432] device_release_driver_internal+0x14c/0x1e0 [ 126.600450] driver_detach+0x38/0x6c [ 126.604740] bus_remove_driver+0x4c/0xa0 [ 126.609407] SyS_delete_module+0x11c/0x1e4 [ 126.614252] __sys_trace_return+0x0/0x10 Fixes:ea2f35c01d("usb: musb: Fix sleeping function called from invalid context for hdrc glue") Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Bin Liu <b-liu@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 ("hub_wq").
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.