Hi Peter, I get this missing-lockdep-annotation warning which I haven't seen before when booting with a usb-serial console on 3.18-rc5. It's been a while since I last tested this, though, and the tty_ldisc_ref wasn't introduced until 833efc0ed19c ("USB: serial: invoke dcd_change ldisc's handler."). [ 10.575225] usbserial: USB Serial support registered for pl2303 [ 10.575561] pl2303 1-2.1:1.0: pl2303 converter detected [ 10.627563] usb 1-2.1: pl2303 converter now attached to ttyUSB0 [ 10.650939] INFO: trying to register non-static key. [ 10.651000] the code is fine but needs lockdep annotation. [ 10.651000] turning off the locking correctness validator. [ 10.651031] CPU: 0 PID: 68 Comm: udevd Tainted: G W 3.18.0-rc5 #10 [ 10.651092] [<c0016f04>] (unwind_backtrace) from [<c0013978>] (show_stack+0x20/0x24) [ 10.651123] [<c0013978>] (show_stack) from [<c0449794>] (dump_stack+0x24/0x28) [ 10.651184] [<c0449794>] (dump_stack) from [<c006f730>] (__lock_acquire+0x1e50/0x2004) [ 10.651214] [<c006f730>] (__lock_acquire) from [<c0070128>] (lock_acquire+0xe4/0x18c) [ 10.651245] [<c0070128>] (lock_acquire) from [<c027c6f8>] (ldsem_down_read_trylock+0x78/0x90) [ 10.651275] [<c027c6f8>] (ldsem_down_read_trylock) from [<c027a1cc>] (tty_ldisc_ref+0x24/0x58) [ 10.651306] [<c027a1cc>] (tty_ldisc_ref) from [<c0340760>] (usb_serial_handle_dcd_change+0x48/0xe8) [ 10.651367] [<c0340760>] (usb_serial_handle_dcd_change) from [<bf000484>] (pl2303_read_int_callback+0x210/0x220 [pl2303]) [ 10.651428] [<bf000484>] (pl2303_read_int_callback [pl2303]) from [<c031624c>] (__usb_hcd_giveback_urb+0x80/0x140) [ 10.651458] [<c031624c>] (__usb_hcd_giveback_urb) from [<c0316fc0>] (usb_giveback_urb_bh+0x98/0xd4) [ 10.651489] [<c0316fc0>] (usb_giveback_urb_bh) from [<c0042e44>] (tasklet_hi_action+0x9c/0x108) [ 10.651519] [<c0042e44>] (tasklet_hi_action) from [<c0042380>] (__do_softirq+0x148/0x42c) [ 10.651550] [<c0042380>] (__do_softirq) from [<c00429cc>] (irq_exit+0xd8/0x114) [ 10.651580] [<c00429cc>] (irq_exit) from [<c007ae58>] (__handle_domain_irq+0x84/0xdc) [ 10.651611] [<c007ae58>] (__handle_domain_irq) from [<c000879c>] (omap_intc_handle_irq+0xd8/0xe0) [ 10.651641] [<c000879c>] (omap_intc_handle_irq) from [<c0014544>] (__irq_svc+0x44/0x7c) [ 10.651641] Exception stack(0xdf4e7f08 to 0xdf4e7f50) [ 10.651672] 7f00: debc0b80 df4e7f5c 00000000 00000000 debc0b80 be8da96c [ 10.651702] 7f20: 00000000 00000128 c000fc84 df4e6000 00000000 df4e7f94 00000004 df4e7f50 [ 10.651702] 7f40: c038ebc0 c038d74c 600f0013 ffffffff [ 10.651733] [<c0014544>] (__irq_svc) from [<c038d74c>] (___sys_sendmsg.part.29+0x0/0x2e0) [ 10.651763] [<c038d74c>] (___sys_sendmsg.part.29) from [<c038ec08>] (SyS_sendmsg+0x18/0x1c) [ 10.651794] [<c038ec08>] (SyS_sendmsg) from [<c000fa00>] (ret_fast_syscall+0x0/0x48) [ 10.692871] console [ttyUSB0] enabled Johan -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html