• Jiri Slaby's avatar
    usblp: do not set TASK_INTERRUPTIBLE before lock · 19cd80a2
    Jiri Slaby authored
    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 7f477358 (usblp: Implement the
    ENOSPC convention) moved the set prior locking. So move it back after
    the lock.
    Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
    Fixes: 7f477358 ("usblp: Implement the ENOSPC convention")
    Acked-By: default avatarPete Zaitcev <zaitcev@yahoo.com>
    Cc: stable <stable@vger.kernel.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
usblp.c 39.7 KB