[ruby-cvs:73271] normal:r66171 (trunk): process.c: fix ETXTBUSY from MJIT compiler process
normal at ruby-lang.org
normal at ruby-lang.org
Tue Dec 4 04:49:54 JST 2018
normal 2018-12-04 04:49:54 +0900 (Tue, 04 Dec 2018)
New Revision: 66171
https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=66171
Log:
process.c: fix ETXTBUSY from MJIT compiler process
This affects test/ruby/test_process.rb (test_execopt_env_path).
Since MJIT uses vfork+execve in a separate thread, there can be
small window in-between vfork and execve where tmp_script.cmd is
held open by the vforked child. vfork only pauses the MJIT
thread, not any Ruby Threads, so our call to Process.spawn will
hit ETXTBUSY in that window unless we fork.
main thread | MJIT thread
----------------------------------------------------
fd = open(tmp) | |
| vfork for CC | CC running
write | | ---------------
fchmod | | sees "fd" here
close(fd) | |
Process.spawn called | |
vfork (spawn)| (new process) | |
| execve => TXTBUSY | |
| | | execve (FD_CLOEXEC on fd)
| | vfork returns |
Holding the waitpid_lock whenever we intend to spawn a process
prevents the MJIT thread from spawning a process while we are
spawning in Ruby-land.
Modified files:
trunk/process.c
trunk/test/ruby/test_process.rb
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