Hi Gianluca / Marcel,
Sorry for the resend, but i had a typo in the mailinglist address.
Here a splat i just encountered on boot:
[ 78.248869] BUG: spinlock wrong CPU on CPU#3, krfcommd/1500
[ 78.255126] lock: 0xffff880056d8ded8, .magic: dead4ead, .owner: krfcommd/1500, .owner_cpu: 0
[ 78.261375] CPU: 3 PID: 1500 Comm: krfcommd Not tainted 3.15.0-rc3-20140501-nbdebug5+ #1
[ 78.267767] Hardware name: MSI MS-7640/890FXA-GD70 (MS-7640) , BIOS V1.8B1 09/13/2010
[ 78.274173] ffff880056d8ded8 ffff880057217d18 ffffffff81b8d666 ffff88005f6cfd88
[ 78.280707] ffff880056c3a3c0 ffff880057217d38 ffffffff81b8974c ffff880056d8ded8
[ 78.287091] ffffffff81f56fab ffff880057217d58 ffffffff81b89777 ffff880056d8ded8
[ 78.293371] Call Trace:
[ 78.299496] [<ffffffff81b8d666>] dump_stack+0x46/0x58
[ 78.305601] [<ffffffff81b8974c>] spin_dump+0x91/0x96
[ 78.311662] [<ffffffff81b89777>] spin_bug+0x26/0x2b
[ 78.317599] [<ffffffff8111a5ce>] do_raw_spin_unlock+0xae/0x100
[ 78.323557] [<ffffffff81b974cb>] _raw_spin_unlock+0x2b/0x40
[ 78.329571] [<ffffffff81b636d3>] rfcomm_run+0x1063/0x1310
[ 78.335608] [<ffffffff81b9754d>] ? _raw_spin_unlock_irqrestore+0x6d/0x90
[ 78.341715] [<ffffffff81b62670>] ? rfcomm_check_accept+0xc0/0xc0
[ 78.347830] [<ffffffff810ee1a4>] kthread+0xe4/0x100
[ 78.353916] [<ffffffff810ee0c0>] ? __init_kthread_worker+0x70/0x70
[ 78.360121] [<ffffffff81b9893c>] ret_from_fork+0x7c/0xb0
[ 78.366191] [<ffffffff810ee0c0>] ? __init_kthread_worker+0x70/0x70
--
Sander