$ findflakes -grep 'RaceAsFunc3 *FAILED'
First observed 445c685 22 Jan 01:13 2016 (38 commits ago)
Last observed b4c9d01 26 Jan 16:27 2016 (2 commits ago)
56% chance failure is still happening
25% failure probability (10 of 37 commits)
25% 445c685 cmd/compile: remove unused (dead) fields
19% 0760023 runtime: skip TestSignalExitStatus on NetBSD
14% c7f5831 lib/time: update to IANA release 2015g.
11% 123510b runtime: save context value in NetBSD sigtramp
8% 4c4476c runtime: on NetBSD and DragonFly drop signal stack in new thread
6% 489f65b net: improve netsh usage in Windows unit tests
4% b203f88 crypto/tls: note in comment that Certificate.Leaf is nil after parsing.
3% 754216d text/template: fix documentation for pipelines
3% f8f4cfa net/http: make Client propagate Request.Cancel over redirected requests
ea7be51 02 Mar 17:52 2015 to 9626561 07 May 21:08 2015
0.73% failure probability (9 of 1097 commits)
I ran stress -p1 ./race.test on linux/amd64 from tip and got 8 / 32 failures. Then I reverted the most obvious candidate I could think of -- c5f0f88 ("runtime/race: update race runtime") -- and I've had 0 / 16 failures. And as I was about to submit this comment, it ticked over to 1 / 22 :-) but it still seems like the update didn't help.
Ran some longer tests, seems less clear. I guess it should be possible to bisect over the last few months of development given that it was a cm/dist problem preventing the tests from being run rather than anything preventing go test -race runtime/race from working. Would take a while though.