Skip to content

WCOW: restore support for client-mounted roots with process-isolated containers#2595

Open
corhere wants to merge 1 commit intomicrosoft:mainfrom
corhere:fix-docker-compat
Open

WCOW: restore support for client-mounted roots with process-isolated containers#2595
corhere wants to merge 1 commit intomicrosoft:mainfrom
corhere:fix-docker-compat

Conversation

@corhere
Copy link

@corhere corhere commented Feb 5, 2026

#2029 broke starting process-isolated containers when Root.Path is set in the container spec. Root.Path is set by clients such as Docker which mount and unmount the container's root filesystem themselves. Mounting is skipped, which also skips over setting coi.mountedWCOWLayers. The hcsoci.createWindowsContainerDocument function unconditionally dereferences that field, resulting in a nil-dereference panic when mounting is skipped. Restore the old behaviour by synthesizing the MountedWCOWLayers when Root.Path is set.

Commit 00ca088 broke starting
process-isolated containers when Root.Path is set in the container spec.
Root.Path is set by clients such as Docker which mount and unmount the
container's root filesystem themselves. Mounting is skipped, which also
skips over setting coi.mountedWCOWLayers. The
hcsoci.createWindowsContainerDocument function unconditionally
dereferences that field, resulting in a nil-dereference panic when
mounting is skipped. Restore the old behaviour by synthesizing the
MountedWCOWLayers when Root.Path is set.

Signed-off-by: Cory Snider <csnider@mirantis.com>
@corhere corhere requested a review from a team as a code owner February 5, 2026 00:01
@thaJeztah
Copy link
Contributor

@ambarve PTAL - this unblocks us with running docker with containerd 2.2 ❤️

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

nil dereference in createWindowsContainerDocument when starting container with process isolation

4 participants