We have another hung build:

https://autobuilder.yoctoproject.org/typhoon/#/builders/79/builds/2805

[pokybuild@centos8-ty-1 ~]$ pstree -p 3610382
Worker(3610382)─┬─linux-yocto:com(3686989)───run.do_compile.(3687229)───make(3687234)───make(3687235)───make(3700121)───make(3703528)───sh(3703566)
└─{Worker}(3610616)

3610382 ? Sl 0:28 python3 /home/pokybuild/yocto-worker/oe-selftest-centos/build/bitbake/bin/bitbake-worker decafbad
3614645 ? S 0:00 /home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/sysroots-components/x86_64/pseudo-native/usr/bin/pseudo bitbake-worker decafbadbeef
3614650 ? Sl 0:27 python3 /home/pokybuild/yocto-worker/oe-selftest-centos/build/bitbake/bin/bitbake-worker decafbadbeef
3686989 ? SNs 0:02 python3 /home/pokybuild/yocto-worker/oe-selftest-centos/build/bitbake/bin/bitbake-worker decafbad
3687229 ? SN 0:00 /bin/sh /home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/temp/run.do_compile.3686989
3687234 ? SN 0:00 make -j 16 -l 52 HOSTCC=gcc HOSTCFLAGS=-isystem/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/recipe-sysroot-native/usr/include -O2 -pipe HOSTLDFLAGS=-L/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/recipe-sysroot-native/usr/lib -L/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/recipe-sysroot-native/lib -Wl,--enable-new-dtags -Wl,-rpath-link,/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/recipe-sysroot-native/usr/lib -Wl,-rpath-link,/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/recipe-sysroot-native/lib -Wl,-rpath,/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/recipe-sysroot-native/usr/lib -Wl,-rpath,/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/recipe-sysroot-native/lib -Wl,-O1 -Wl,--allow-shlib-undefined -Wl,--dynamic-linker=/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/sysroots-uninative/x86_64-linux/lib/ld-linux-x86-64.so.2 HOSTCPP=gcc -E HOSTCXX=g++ HOSTCXXFLAGS=-isystem/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/recipe-sysroot-native/usr/include -O2 -pipe bzImage CC=x86_64-poky-linux-gcc -fuse-ld=bfd -fmacro-prefix-map=/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0=/usr/src/debug/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0 -fdebug-prefix-map=/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0=/usr/src/debug/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0 -fdebug-prefix-map=/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/recipe-sysroot= -fdebug-prefix-map=/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/recipe-sysroot-native= -fdebug-prefix-map=/home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work-shared/qemux86-64/kernel-source=/usr/src/kernel LD=x86_64-poky-linux-ld.bfd
3687235 ? SN 0:00 make -C /home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work/qemux86_64-poky-linux/linux-yocto/5.14.15+gitAUTOINC+edb4dc09c5_f04b30fc15-r0/linux-qemux86_64-standard-build -f /home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work-shared/qemux86-64/kernel-source/Makefile bzImage
3700121 ? SN 0:00 make -f /home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work-shared/qemux86-64/kernel-source/scripts/Makefile.build obj=lib single-build= need-builtin=1 need-modorder=1
3703528 ? SN 0:00 make -f /home/pokybuild/yocto-worker/oe-selftest-centos/build/build-st-2484929/tmp/work-shared/qemux86-64/kernel-source/scripts/Makefile.build obj=lib/crypto need-builtin=1 need-modorder=1
3703566 ? ZN 0:00 [sh] <defunct>

Once again we have a zombie subprocess with make waiting on nothing. This is on
a linux-yocto build within an oe-selftest. It is once again on centos8 with make
4.2.1, similar to the perl build failure earlier in the week.

I suspect if I send a SIGCHLD to make, it will continue as if nothing happened
like the previous issue. 

Does anyone have any ideas what to do about this (or any better debugging we can
do whilst it is hung)?

Cheers,

Richard