On Sat, Feb 01, 2014 at 09:42:57AM -0500, Peter Hurley wrote: > 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. USB serial devices get their data in interrupt context, until we fix USB callbacks to be threaded, which might happen one day... greg k-h -- 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
