Avi Kivity wrote: > Gerald Britton wrote: >> On Thu, Aug 23, 2007 at 01:08:27PM +0200, Michael Smith wrote: >> >>> Hi, >>> >>> We've been seeing some strange behaviour on some of our applications >>> recently. I've tracked this down to gettimeofday() returning spurious >>> values occasionally. >>> >>> Specifically, gettimeofday() will suddenly, for a single call, return >>> a value about 4398 seconds (~1 hour 13 minutes) in the future. The >>> following call goes back to a normal value. >>> >> >> I have seen this as well (on a 2.6.20.4 kernel). The value returned was >> always identical each time the glitch occured (just a little over 4398 >> seconds). I saw it watching packet receive timestamps and on the >> system in >> question, it would generally hit this problem around once a minute. When >> moving forward to a 2.6.21 kernel, the problem seemed to go away (also >> back >> to 2.6.17, unfortunately I didn't have any sample points inbetween). >> I didn't have free time to spend bisecting attempting to find when the >> behavior started or stopped. > > That value, in nanoseconds, is 0x3fffd3a4c00. The next second is > 0x40038d51600. Is the wraparound at (0x400 << 32) significant? >
This would be consistent with an off-by-2^32 error. In particular, if either a CPU bug or a code bug could at some point produce 0x400fxxxxxxx in between then that would produce exactly the observed characteristics. -hpa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/