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alistair23-linux/drivers/usb/class
Jiri Slaby 19cd80a214 usblp: do not set TASK_INTERRUPTIBLE before lock
It is not permitted to set task state before lock. usblp_wwait sets
the state to TASK_INTERRUPTIBLE and calls mutex_lock_interruptible.
Upon return from that function, the state will be TASK_RUNNING again.

This is clearly a bug and a warning is generated with LOCKDEP too:
WARNING: CPU: 1 PID: 5109 at kernel/sched/core.c:7404 __might_sleep+0x7d/0x90()
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffffa0c588d0>] usblp_wwait+0xa0/0x310 [usblp]
Modules linked in: ...
CPU: 1 PID: 5109 Comm: captmon Tainted: G        W       4.2.5-0.gef2823b-default #1
Hardware name: LENOVO 23252SG/23252SG, BIOS G2ET33WW (1.13 ) 07/24/2012
 ffffffff81a4edce ffff880236ec7ba8 ffffffff81716651 0000000000000000
 ffff880236ec7bf8 ffff880236ec7be8 ffffffff8106e146 0000000000000282
 ffffffff81a50119 000000000000028b 0000000000000000 ffff8802dab7c508
Call Trace:
...
 [<ffffffff8106e1c6>] warn_slowpath_fmt+0x46/0x50
 [<ffffffff8109a8bd>] __might_sleep+0x7d/0x90
 [<ffffffff8171b20f>] mutex_lock_interruptible_nested+0x2f/0x4b0
 [<ffffffffa0c588fc>] usblp_wwait+0xcc/0x310 [usblp]
 [<ffffffffa0c58bb2>] usblp_write+0x72/0x350 [usblp]
 [<ffffffff8121ed98>] __vfs_write+0x28/0xf0
...

Commit 7f477358e2 (usblp: Implement the
ENOSPC convention) moved the set prior locking. So move it back after
the lock.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: 7f477358e2 ("usblp: Implement the ENOSPC convention")
Acked-By: Pete Zaitcev <zaitcev@yahoo.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-11-19 16:31:42 -08:00
..
Kconfig USB: regroup all depends on USB within an if USB block 2013-04-09 16:49:07 -07:00
Makefile USB: add USB test and measurement class driver 2008-10-17 14:40:51 -07:00
cdc-acm.c cdc-acm: Destroy acm_minors IDR on module exit 2015-07-22 14:49:42 -07:00
cdc-acm.h cdc-acm: Add support of ATOL FPrint fiscal printers 2015-06-08 14:01:13 -07:00
cdc-wdm.c cdc-wdm: error returns need to be translated 2015-03-26 10:51:57 +01:00
usblp.c usblp: do not set TASK_INTERRUPTIBLE before lock 2015-11-19 16:31:42 -08:00
usbtmc.c USB: usbtmc: add device quirk for Rigol DS6104 2015-06-02 11:49:45 +09:00