[musl] [bug] Ctrl-Z when process is doing posix_spawn makes the process hard to kill

[Askar Safin <safinaskar@zohomail.com>]

I found a bug both in glibc and musl.

If a process does posix_spawn+waitpid, then attempting to pause it using Ctrl-Z
sometimes doesn't work and, worse, makes the process unkillable by usual Ctrl-Z or Ctrl-C.

The bug is described in full in this glibc issue: https://sourceware.org/bugzilla/show_bug.cgi?id=32565 .

It is reproducible with musl on the same system I used to reproduce it with glibc (see the link).

I compiled the code using "x86_64-linux-musl-gcc" wrapper provided by Debian.

Please, CC me when replying.

Output of some commands:

# dpkg -l musl
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name           Version      Architecture Description
+++-==============-============-============-=================================
ii  musl:amd64     1.2.5-1.1    amd64        standard C library
# /lib/x86_64-linux-musl/libc.so 
musl libc (x86_64)
Version 1.2.5
Dynamic Program Loader
Usage: /lib/x86_64-linux-musl/libc.so [options] [--] pathname [args]

--
Askar Safin
https://types.pl/@safinaskar