Index: libcxx/utils/ci/run-buildbot-container
===================================================================
--- libcxx/utils/ci/run-buildbot-container
+++ libcxx/utils/ci/run-buildbot-container
@@ -8,9 +8,9 @@
 # `run-buildbot` script.
 #
 # This script must be run from within the LLVM monorepo. Furthermore, the
-# monorepo will be mounted as `/llvm` inside the container. Be careful, the
-# state in `/llvm` is shared between the container and the host machine, which
-# is useful for editing files on the host machine and re-running the build bot
+# monorepo will be read-only mounted as `/llvm` inside the container. Be careful,
+# the state in `/llvm` is shared between the container and the host machine,
+# which is useful for editing files on the host machine and re-running the build bot
 # in the container.
 
 set -e
@@ -21,4 +21,5 @@
     exit 1
 fi
 docker pull ldionne/libcxx-builder
+# Add "--cap-add=SYS_PTRACE" here if you need to ptrace within the container
 docker run -it --volume "${MONOREPO_ROOT}:/llvm" --workdir "/llvm" ldionne/libcxx-builder bash