> On Nov 9, 2014, at 2:21 PM, erik quanstrom <[email protected]> wrote: > > On Sun Nov 9 14:51:37 EST 2014, [email protected] wrote: >> >>> On Nov 9, 2014, at 1:42 PM, erik quanstrom <[email protected]> wrote: >>> >>> the aside leads me to believe that there is something wrong with the segment >>> copy on fork. since the semaphore in question is in the data segment, >>> i'm going to guess that you're running the labs kernel, and you're hitting >>> the >>> page caching issue we've seen before. does this happen on an atom kernel? >> >> Only happens in the labs ARM kernel. The labs mips and 386 kernels work fine >> in this situation. > > my thinking is that this isn't a defect in the arch-specific bits but rather > a timing > bug. in that case, only manifesting on certain hardware is not diagnostic. > > do you have any reason to believe this is not a timing bug? it does fit the > pattern > rarely seen on x86 systems. (actually (cf. the console appliance) there were > ways > to really make x86 systems suffer by forking fast enough on slow hardware.)
Well, sys/src/libc/9sys/time.c did change about the time I started seeing this bug on my old dreamplug. -jas
