Ming Lei c825bab0ce usb: storage: fix lockdep warning inside usb_stor_pre_reset(v2) ... This patch fixes one lockdep warning[1] inside usb_stor_pre_reset. If the current configuration includes multiple mass storage interfaces, the 'AA' lockdep warning will be triggered since the lock class of 'us->dev_mutex' is acquired two times in .reset path. It isn't a real deadlock, so just take the lockdep_set_class annotation to remove the warning. [1], lockdep warning log :[ INFO: possible recursive locking detected ] :3.3.0-0.rc5.git3.1.fc17.x86_64 #1 Tainted: G W :--------------------------------------------- :usb-storage/14846 is trying to acquire lock: : (&(us->dev_mutex)){+.+.+.}, at: [<ffffffffa0481c0c>] usb_stor_pre_reset+0x1c/0x20 [usb_storage] :but task is already holding lock: : (&(us->dev_mutex)){+.+.+.}, at: [<ffffffffa0481c0c>] usb_stor_pre_reset+0x1c/0x20 [usb_storage] :other info that might help us debug this: : Possible unsafe locking scenario: : CPU0 : ---- : lock(&(us->dev_mutex)); : lock(&(us->dev_mutex)); : *** DEADLOCK *** : May be due to missing lock nesting notation :2 locks held by usb-storage/14846: : #0: (&__lockdep_no_validate__){......}, at: [<ffffffff8147e6a5>] usb_lock_device_for_reset+0x95/0x100 : #1: (&(us->dev_mutex)){+.+.+.}, at: [<ffffffffa0481c0c>] usb_stor_pre_reset+0x1c/0x20 [usb_storage] :stack backtrace: :Pid: 14846, comm: usb-storage Tainted: G W 3.3.0-0.rc5.git3.1.fc17.x86_64 #1 :Call Trace: : [<ffffffff810cbdaf>] __lock_acquire+0x168f/0x1bb0 : [<ffffffff81021083>] ? native_sched_clock+0x13/0x80 : [<ffffffff810210f9>] ? sched_clock+0x9/0x10 : [<ffffffff810210f9>] ? sched_clock+0x9/0x10 : [<ffffffff810a2975>] ? sched_clock_local+0x25/0xa0 : [<ffffffff810cc9a1>] lock_acquire+0xa1/0x1e0 : [<ffffffffa0481c0c>] ? usb_stor_pre_reset+0x1c/0x20 [usb_storage] : [<ffffffff81699c86>] mutex_lock_nested+0x76/0x3a0 : [<ffffffffa0481c0c>] ? usb_stor_pre_reset+0x1c/0x20 [usb_storage] : [<ffffffffa0481c0c>] ? usb_stor_pre_reset+0x1c/0x20 [usb_storage] : [<ffffffffa0481c0c>] usb_stor_pre_reset+0x1c/0x20 [usb_storage] : [<ffffffff8148184d>] usb_reset_device+0x7d/0x190 : [<ffffffffa048119c>] usb_stor_port_reset+0x7c/0x80 [usb_storage] : [<ffffffffa0481234>] usb_stor_invoke_transport+0x94/0x560 [usb_storage] : [<ffffffff810cd3b2>] ? mark_held_locks+0xb2/0x130 : [<ffffffff8169dbd0>] ? _raw_spin_unlock_irq+0x30/0x50 : [<ffffffffa047fe3e>] usb_stor_transparent_scsi_command+0xe/0x10 [usb_storage] : [<ffffffffa0481ae3>] usb_stor_control_thread+0x173/0x280 [usb_storage] : [<ffffffffa0481970>] ? fill_inquiry_response+0x20/0x20 [usb_storage] : [<ffffffff8108a3f7>] kthread+0xb7/0xc0 : [<ffffffff816a7d34>] kernel_thread_helper+0x4/0x10 : [<ffffffff8169e0f4>] ? retint_restore_args+0x13/0x13 : [<ffffffff8108a340>] ? kthread_worker_fn+0x1a0/0x1a0 : [<ffffffff816a7d30>] ? gs_change+0x13/0x13 Reported-By: Dave Jones <davej@redhat.com> Signed-off-by: Ming Lei <tom.leiming@gmail.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2012-04-06 13:54:00 -07:00
..
alauda.c
cypress_atacb.c
datafab.c
debug.c
debug.h
ene_ub6250.c	usb/storage: redefine US_BULK_FLAG_IN and use it	2012-02-28 11:07:42 -08:00
freecom.c
initializers.c
initializers.h
isd200.c
jumpshot.c
karma.c
Kconfig	Documentation: remove references to /etc/modprobe.conf	2012-03-30 16:03:15 -07:00
libusual.c
Makefile
onetouch.c
option_ms.c
option_ms.h
protocol.c
protocol.h
realtek_cr.c	usb/storage: redefine US_BULK_FLAG_IN and use it	2012-02-28 11:07:42 -08:00
scsiglue.c
scsiglue.h
sddr09.c
sddr55.c
shuttle_usbat.c
sierra_ms.c
sierra_ms.h
transport.c	usb/storage: redefine US_BULK_FLAG_IN and use it	2012-02-28 11:07:42 -08:00
transport.h	usb/storage: a couple defines from drivers/usb/storage/transport.h to include/linux/usb/storage.h	2012-02-28 11:05:18 -08:00
uas.c
unusual_alauda.h
unusual_cypress.h
unusual_datafab.h
unusual_devs.h
unusual_ene_ub6250.h
unusual_freecom.h
unusual_isd200.h
unusual_jumpshot.h
unusual_karma.h
unusual_onetouch.h
unusual_realtek.h
unusual_sddr09.h
unusual_sddr55.h
unusual_usbat.h
usb.c	usb: storage: fix lockdep warning inside usb_stor_pre_reset(v2)	2012-04-06 13:54:00 -07:00
usb.h
usual-tables.c