commit f8c6db4cf4a6ec183586ca8ec071c153a7613a72
author LaMont Jones <lamontjones@chromium.org> Wed May 15 07:43:23 2019 -0600
committer Commit Bot <commit-bot@chromium.org> Wed May 15 18:26:49 2019 +0000
tree f837129fc7a26d2a05ed5eb91fe6e08b65dba3dc
parent 683b4fc53186d4a190c870aa7050ebfb9d62cf6f

cros_sdk_lib: extra logging for CleanupChrootMount

Add extra logging in CleanupChrootMount when UmountTree fails to help
find the lingering process.

BUG=chromium:923432
TEST=Manually verified

Change-Id: I183ab7afb43858a3a377f090bc08b94615286a2c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1613317
Tested-by: LaMont Jones <lamontjones@chromium.org>
Reviewed-by: Jason Clinton <jclinton@chromium.org>
Commit-Queue: LaMont Jones <lamontjones@chromium.org>

lib/cros_sdk_lib.py

diff --git a/lib/cros_sdk_lib.py b/lib/cros_sdk_lib.py
index 8b257e7..358706c 100644
--- a/lib/cros_sdk_lib.py
+++ b/lib/cros_sdk_lib.py
@@ -394,7 +394,18 @@
   # unmount it.
   vg_name, _ = FindChrootMountSource(chroot, proc_mounts=proc_mounts)
 
-  osutils.UmountTree(chroot)
+  try:
+    osutils.UmountTree(chroot)
+  except cros_build_lib.RunCommandError as e:
+    # TODO(lamontjones): Dump some information to help find the process still
+    # inside the chroot, causing crbug.com/923432.  In the end, this is likely
+    # to become fuser -k.
+    fuser = cros_build_lib.SudoRunCommand(['fuser', chroot], error_code_ok=True)
+    lsof = cros_build_lib.SudoRunCommand(['lsof', chroot], error_code_ok=True)
+    ps = cros_build_lib.RunCommand(['ps', 'auxf'], error_code_ok=True)
+    raise Error(
+        'Umount failed: %s.\nfuser output=%s\nlsof output=%s\nps output=%s\n',
+        e.result.error, fuser.output, lsof.output, ps.output)
 
   # Find the loopback device by either matching the VG or the image.
   chroot_dev = None