Hi David, On Jul 20 16:16, David Allsopp wrote: > I've pushed a repro case for this to > https://github.com/dra27/cygwin-nanosleep-bug.git > > Originally noticed as the main CI system for OCaml has been failing > sporadically for the signal.ml test mentioned in that repo. This morning I > tried hammering that test on my dev machine and discovered that it fails > very frequently. No idea if that's drivers, Windows 10 updates, number of > cores or what, but it was definitely happening, and easily. > > Drilling further, it appears that NtQueryTimer is able to return a negative > value in the TimeRemaining field even when SignalState is false. The values > I've seen have always been < 15ms - i.e. less than the timer resolution, so > I wonder if there is a point at which the timer has elapsed but has not been > signalled, but WaitForMultipleObjects returns because of the EINTR signal. > Mildly surprising that it seems to be so reproducible. > > Anyway, a patch is attached which simply guards a negative return value. The > test on tbi.SignalState is in theory unnecessary.
Thanks for the patch, I think your patch is fine. However, I'd like to dig a bit into this to see what exactly happens. Do you have a very simple testcase in plain C, by any chance? Thanks, Corinna
