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[hardknott,31/39] initramfs-framework: unmount automounts before switch_root

Message ID 999883990235251127b65f2277dcb40004e7f657.1646056612.git.anuj.mittal@intel.com
State Accepted, archived
Commit 999883990235251127b65f2277dcb40004e7f657
Headers show
Series [hardknott,01/39] virglrenderer: fix CVE-2022-0135 and -0175 | expand

Commit Message

Mittal, Anuj Feb. 28, 2022, 2 p.m. UTC 
From: Justin Bronder <jsbronder@cold-front.org>

If mounts are left lingering, then after we switch_root, attempts to
modify the block devices will result in an EBUSY with no way to unmount
them.  As we're about to switch_root anyways, there isn't much use to
keep anything mounted unless it has the new rootfs.

Signed-off-by: Justin Bronder <jsbronder@cold-front.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 4dc7af6d25597ea10ea43e76c7c3d7251462c0e5)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
(cherry picked from commit 991631492f4fafc1852113a34a60b025342518b6)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
---
 .../initrdscripts/initramfs-framework/finish         | 12 ++++++++++++
 1 file changed, 12 insertions(+)
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Patch

diff --git a/meta/recipes-core/initrdscripts/initramfs-framework/finish b/meta/recipes-core/initrdscripts/initramfs-framework/finish
index 717383ebac..f08a920867 100755
--- a/meta/recipes-core/initrdscripts/initramfs-framework/finish
+++ b/meta/recipes-core/initrdscripts/initramfs-framework/finish
@@ -12,6 +12,18 @@  finish_run() {
 			fatal "ERROR: There's no '/dev' on rootfs."
 		fi
 
+		# Unmount anything that was automounted by busybox via mdev-mount.sh.
+		# We're about to switch_root, and leaving anything mounted will prevent
+		# the next rootfs from modifying the block device.  Ignore ROOT_DISK,
+		# if it was set by setup-live, because it'll be mounted over loopback
+		# to ROOTFS_DIR.
+		local dev
+		for dev in /run/media/*; do
+			if mountpoint -q "${dev}" && [ "${dev##*/}" != "${ROOT_DISK}" ]; then
+				umount -f "${dev}" || debug "Failed to unmount ${dev}"
+			fi
+		done
+
 		info "Switching root to '$ROOTFS_DIR'..."
 
 		debug "Moving /dev, /proc and /sys onto rootfs..."