On 02/01/2014 07:48 AM, Beat Bolli wrote:
Hi
Hi Beat,
Firstly, I hope that my analysis of the stack trace is correct and this is really a serial driver problem. Anyway, here goes: I have a serial GPS with PPS on the RTS pin attached to my Atom N270 motherboard, using it, besides being my home server and Internet gateway, as a Stratum 0 NTP server. Recently[1], the kernel started producing BUGs as follows: [10671.576706] BUG: scheduling while atomic: blosxom.cgi/8118/0x10010000
<snip>
[10671.578517] Call Trace: [10671.578538] [<c13fe5a9>] ? dump_stack+0x3e/0x4e [10671.578549] [<c13fc1c8>] ? __schedule_bug+0x4d/0x5e [10671.578561] [<c140113c>] ? __schedule+0x6fc/0x710 [10671.578573] [<c1076170>] ? wake_up_state+0x10/0x10 [10671.578584] [<c114fba0>] ? poll_select_copy_remaining+0x110/0x110 [10671.578595] [<c1070676>] ? __wake_up_common+0x46/0x70 [10671.578606] [<c1074593>] ? __cond_resched+0x13/0x30 [10671.578615] [<c140145d>] ? _cond_resched+0x1d/0x30 [10671.578624] [<c1400758>] ? down_read+0x8/0x20 [10671.578636] [<c12b59dc>] ? n_tty_receive_buf2+0x2c/0xb0 [10671.578656] [<c12b59b0>] ? __receive_buf+0x7b0/0x7b0 [10671.578666] [<c12b89ba>] ? flush_to_ldisc+0xba/0x110
You can't use low_latency; only devices that receive data in non-interrupt contexts (such as USB serial devices) can.
[10671.578678] [<c12cea51>] ? serial8250_rx_chars+0xa1/0x1b0 [10671.578688] [<c12cebb5>] ? serial8250_handle_irq.part.13+0x55/0x90 [10671.578698] [<c12cdf04>] ? serial8250_interrupt+0x44/0xb0 [10671.578710] [<c109124c>] ? handle_irq_event_percpu+0x2c/0x1a0 [10671.578721] [<c10913e2>] ? handle_irq_event+0x22/0x40 [10671.578731] [<c109342e>] ? handle_edge_irq+0x5e/0xf0 [10671.578743] [<c1010a10>] ? handle_irq+0x30/0x80 [10671.578752] [<c10103f1>] ? do_IRQ+0x31/0xa0 [10671.578764] [<c1409bb3>] ? common_interrupt+0x33/0x38 [10671.578774] [<c140007b>] ? __ww_mutex_lock_slowpath+0x9e/0x203 [10976.065431] pps pps0: removed This is a stock Debian kernel, current as of today in Debian testing.
Regards, Peter Hurley -- 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
