os/signal: timeout in TestAllThreadsSyscallSignals [1.16 backport]

[gopherbot]

@ianlancetaylor requested issue #44193 to be considered for backport to the next 1.16 minor release.

@gopherbot Please open backport to 1.16

This bug can cause a rare deadlock if a signal is received during a call to syscall.Setuid or various similar functions on GNU/Linux.

[toothrot]

Approved. This is a serious issue with no workaround.

[cagedmantis]

@AndrewGMorgan Would it be possible to create the cherry-pick CL before the upcoming release?

[AndrewGMorgan]

Sure, happy to.

I've not done this before. Do I checkout the 1.16 branch and cherry pick to that, or are you asking if it is safe for a robot to just do it?

[ianlancetaylor]

You can cherry pick entirely in Gerrit. See https://golang.org/wiki/MinorReleases.

[gopherbot]

Change https://golang.org/cl/316869 mentions this issue: [release-branch.go1.16] syscall: syscall.AllThreadsSyscall signal handling fixes

[AndrewGMorgan]

That cherry pick fails to complete ./all.bash for me. It fails with:

--- FAIL: TestDependencies (1.18s)
    deps_test.go:584: unexpected dependency: internal/buildcfg imports [runtime]
FAIL
FAIL    go/build        1.697s

That particular failure, however, does not seem to be related to my cherry pick since it fails with the HEAD^ commit too on this branch. I'll see if I can figure out what introduced the failure.

[AndrewGMorgan]

I guess I must be holding it wrong. For me. this seems to fail for all go1.16 release tags, when my bootstrap is using go1.16.3. I guess all of these release tags can't have been used if this is a general problem. I'll try again with something a lot older.

[AndrewGMorgan]

For completeness, starting over from scratch works fine:

$ git clone https://go.googlesource.com/go
$ cd go/src/
$ git fetch https://go.googlesource.com/go refs/changes/69/316869/2 && git checkout -b change-316869 FETCH_HEAD
$ ./all.bash 

Perhaps there is something left over from compiling at HEAD that is confusing the all.bash script in this branch? That is, this fails:

$ git clone https://go.googlesource.com/go
$ cd go/src/
$ ./all.bash && git checkout -b test1.16.3 go1.16.3 && ./all.bash