See https://chromium-swarm.appspot.com/task?id=3475af9044c05210&refresh=10&show_raw=1 for example;


11:13:00.787 1520 	
11:13:00.787 1520 	
11:13:00.787 1520 	
Failed to delete e:\b\swarm_slave\w\irp6r7e1 (11 files remaining).
  Maybe the test has a subprocess outliving it.
  Sleeping 2 seconds.
Failed to delete e:\b\swarm_slave\w\irp6r7e1 (11 files remaining).
  Maybe the test has a subprocess outliving it.
  Sleeping 4 seconds.
Failed to delete e:\b\swarm_slave\w\irp6r7e1. The following files remain:
- \\?\e:\b\swarm_slave\w\irp6r7e1\out\Release\AHEM____.TTF
- \\?\e:\b\swarm_slave\w\irp6r7e1\out\Release\content_shell.exe
- \\?\e:\b\swarm_slave\w\irp6r7e1\out\Release\content_shell.log
- \\?\e:\b\swarm_slave\w\irp6r7e1\out\Release\content_shell.pak
- \\?\e:\b\swarm_slave\w\irp6r7e1\out\Release\icudtl.dat
- \\?\e:\b\swarm_slave\w\irp6r7e1\out\Release\natives_blob.bin
- \\?\e:\b\swarm_slave\w\irp6r7e1\out\Release\osmesa.dll
- \\?\e:\b\swarm_slave\w\irp6r7e1\out\Release\snapshot_blob.bin
- \\?\e:\b\swarm_slave\w\irp6r7e1\out\Release
- \\?\e:\b\swarm_slave\w\irp6r7e1\out
- \\?\e:\b\swarm_slave\w\irp6r7e1
Enumerating processes:
- pid 2768; Handles: 154; Exe: e:\b\swarm_slave\w\irp6r7e1\out\Release\content_shell.exe; Cmd: "e:\b\swarm_slave\w\irp6r7e1\out\Release\content_shell.exe" --type=gpu-process --disable-gpu-rasterization --enable-logging --run-layout-test --enable-crash-reporter --crash-dumps-dir="e:\b\swarm_slave\w\irp6r7e1\out\Release\crash-dumps" --register-font-files="e:\b\swarm_slave\w\irp6r7e1\out\Release\/AHEM____.TTF" --use-gl=osmesa --supports-dual-gpus=false --gpu-vendor-id=0x0000 --gpu-device-id=0x0000 --gpu-driver-vendor --gpu-driver-version --gpu-driver-date --run-layout-test --enable-crash-reporter --crash-dumps-dir="e:\b\swarm_slave\w\irp6r7e1\out\Release\crash-dumps" --register-font-files="e:\b\swarm_slave\w\irp6r7e1\out\Release\/AHEM____.TTF" --enable-logging --service-request-channel-token=09C6EAC4F13F4DE7DFD8B15E0D88CDDC --mojo-platform-channel-handle=1244 --ignored=" --type=renderer " /prefetch:2
- pid 4068; Handles: 252; Exe: e:\b\swarm_slave\w\irp6r7e1\out\Release\content_shell.exe; Cmd: "e:\b\swarm_slave\w\irp6r7e1\out\Release\content_shell.exe" --type=renderer --disable-display-list-2d-canvas --disable-gesture-requirement-for-media-playback --disable-threaded-compositing --enable-experimental-web-platform-features --enable-inband-text-tracks --enable-logging --enable-precise-memory-info --force-device-scale-factor=1.0 --register-pepper-plugins="e:\b\swarm_slave\w\irp6r7e1\out\Release\blink_test_plugin.dll#Blink Test Plugin#Interesting description.#0.8;application/x-blink-test-plugin#blinktestplugin,e:\b\swarm_slave\w\irp6r7e1\out\Release\blink_deprecated_test_plugin.dll#Blink Deprecated Test Plugin#Description#0.1;application/x-blink-deprecated-test-plugin#blinkdeprecatedtestplugin" --touch-events=enabled --use-gl=osmesa --disable-threaded-animation --enable-gpu-benchmarking --primordial-pipe-token=9530546FDB7D2873044542638E5F8BEB --lang=en-US --run-layout-test --enable-crash-reporter --crash-dumps-dir="e:\b\swarm_slave\w\irp6r7e1\out\Release\crash-dumps" --register-font-files="e:\b\swarm_slave\w\irp6r7e1\out\Release\/AHEM____.TTF" --enable-pinch --device-scale-factor=1 --num-raster-threads=4 --enable-main-frame-before-activation --content-image-texture-target=0,0,3553;0,1,3553;0,2,3553;0,3,3553;0,4,3553;0,5,3553;0,6,3553;0,7,3553;0,8,3553;0,9,3553;0,10,3553;0,11,3553;0,12,3553;0,13,3553;0,14,3553;0,15,3553;1,0,3553;1,1,3553;1,2,3553;1,3,3553;1,4,3553;1,5,3553;1,6,3553;1,7,3553;1,8,3553;1,9,3553;1,10,3553;1,11,3553;1,12,3553;1,13,3553;1,14,3553;1,15,3553;2,0,3553;2,1,3553;2,2,3553;2,3,3553;2,4,3553;2,5,3553;2,6,3553;2,7,3553;2,8,3553;2,9,3553;2,10,3553;2,11,3553;2,12,3553;2,13,3553;2,14,3553;2,15,3553;3,0,3553;3,1,3553;3,2,3553;3,3,3553;3,4,3553;3,5,3553;3,6,3553;3,7,3553;3,8,3553;3,9,3553;3,10,3553;3,11,3553;3,12,3553;3,13,3553;3,14,3553;3,15,3553 --service-request-channel-token=9530546FDB7D2873044542638E5F8BEB --renderer-client-id=3 --mojo-platform-channel-handle=1320 /prefetch:1
- pid 5516; Handles: 466; Exe: e:\b\swarm_slave\w\irp6r7e1\out\Release\content_shell.exe; Cmd: e:\b\swarm_slave\w\irp6r7e1\out\Release\content_shell.exe --run-layout-test --enable-direct-write --enable-crash-reporter --crash-dumps-dir=e:\b\swarm_slave\w\irp6r7e1\out\Release\crash-dumps -
Terminating 3 processes.
- 2768 killed
- 4068 killed
- 5516 killed
Enumerating processes:
Failed to delete the run directory, forcibly failing
the task because of it. No zombie process can outlive a
successful task run and still be marked as successful.
Fix your stuff.