On Fri, Oct 18, 2019 at 1:21 AM Tom Lane <t...@sss.pgh.pa.us> wrote: > Thomas Munro <thomas.mu...@gmail.com> writes: > > On Tue, Oct 15, 2019 at 1:55 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > >> and now prairiedog has shown it too: > >> https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=prairiedog&dt=2019-10-14%2021%3A45%3A47 > >> which is positively fascinating, because prairiedog is running a > >> bronze-age version of macOS that surely never heard of APFS. > >> So this makes it look like this is a basic macOS bug that's not > >> as filesystem-dependent as one might think. > > > Does https://github.com/macdice/unlinktest show the problem on that system? > > It does, though with a very low frequency: > > $ ./unlinktest > $ ./unlinktest 10000 > read 0 bytes, unexpected > $ ./unlinktest 10000 > read 0 bytes, unexpected > read 0 bytes, unexpected > $ ./unlinktest 10000 > $ > > The failure rate on my recent-vintage laptop is more like one > failure every five loops.
Wow. Ok, I'll add a note to the bug report to say it's reproducible on "Darwin Kernel Version 8.11.0: Wed Oct 10 18:26:00 PDT 2007; root:xnu-792.24.17~1/RELEASE_PPC" next time I'm near an Apple device that will let me log into the bug thing. On the off-chance that someone from Apple stumbles on this and is interested, the Radar number is rdar://46318934 and the title is "unlink(2) is not atomic (kernel/file system bug)".
