On Tue, Apr 22, 2014 at 11:55:52AM +0100, One Thousand Gnomes wrote: > On Fri, 18 Apr 2014 10:10:17 +0200 > Manfred Schlaegl <manfred.schla...@gmx.at> wrote: > > > On 2014-04-08 14:42, Manfred Schlaegl wrote: > > > The race was introduced while development of linux-3.11 by > > > e8437d7ecbc50198705331449367d401ebb3181f and > > > e9975fdec0138f1b2a85b9624e41660abd9865d4. > > > Originally it was found and reproduced on linux-3.12.15 and > > > linux-3.12.15-rt25, by sending 500 byte blocks with 115kbaud to the > > > target uart in a loop with 100 milliseconds delay. > > > > > > In short: > > > 1. The consumer flush_to_ldisc is on to remove the head tty_buffer. > > > 2. The producer adds a number of bytes, so that a new tty_buffer must > > > be allocated and added by __tty_buffer_request_room. > > > 3. The consumer removes the head tty_buffer element, without handling > > > newly committed data. > > > > Hi! > > > > Reminder: The Problem is still existent in linux-3.11, 3.12, 3.13. 3.14 and > > pre 3.15 kernels. > > > > The lastly delivered patch cleanly applies to pre 3.15 (torvalds tree) and > > 3.14(.1). > > Greg ?? what is happening about this one. We can't just ignore losing > bytes caused by incorrect lock removal. We are seeing breakages in things > like bluetooth over serial which are quite probably down to this problem.
It's in my queue, sorry, been traveling... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
