intel/llvm
1
0
Fork 0
mirror of https://github.com/intel/llvm.git synced 2026-01-20 01:58:44 +08:00
Code Issues Packages Projects Releases Wiki Activity

[libc] Resolve race condition in sub-process test runner.

Browse Source 
Summary:
There seems to be a race condition between the pipe closing and the child process death. Likely these two events are not atomic on some versions of linux.

With the removal of `WNOHANG` we eliminate the race condition, however if the child closes the pipe intentionally then it could result in the test runner hanging. I find this situation less likely, where as I experience failures locally with this race condition rather consistently.

Reviewers: sivachandra, abrachet

Reviewed By: sivachandra, abrachet

Subscribers: MaskRay, jfb, tschuett, libc-commits

Tags: #libc-project

Differential Revision: https://reviews.llvm.org/D76267
This commit is contained in:
Paula Toth
2020-03-17 12:59:21 -07:00
parent 2bd1ca28c1
commit 17566573b2
1 changed files with 6 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
libc/utils/testutils/ExecuteFunctionUnix.cpp
View File

@@ -67,8 +67,12 @@ ProcessStatus invokeInSubprocess(FunctionCaller *Func, unsigned timeoutMS) {
}
int WStatus = 0;
int status = ::waitpid(Pid, &WStatus, WNOHANG);
assert(status == Pid && "wait call should not block here");
// Wait on the pid of the subprocess here so it gets collected by the system
// and doesn't turn into a zombie.
pid_t status = ::waitpid(Pid, &WStatus, 0);
if (status == -1)
return ProcessStatus::Error("waitpid(2) failed");
assert(status == Pid);
(void)status;
return {WStatus};
}