Merge pull request #60237 from mayflower/kexec-no-clobber

nixos/kexec: don't clobber existing kexec-loaded kernel

nixos/modules/system/boot/kexec.nix

@@ -13,8 +13,18 @@
         path = [ pkgs.kexectools ];
         script =
           ''
+            # Don't load the current system profile if we already have a kernel loaded
+            if [[ 1 = "$(</sys/kernel/kexec_loaded)" ]] ; then
+              echo "kexec kernel has already been loaded, prepare-kexec skipped"
+              exit 0
+            fi
+
             p=$(readlink -f /nix/var/nix/profiles/system)
-            if ! [ -d $p ]; then exit 1; fi
+            if ! [[ -d $p ]]; then
+              echo "Could not find system profile for prepare-kexec"
+              exit 1
+            fi
+            echo "Loading NixOS system via kexec."
             exec kexec --load $p/kernel --initrd=$p/initrd --append="$(cat $p/kernel-params) init=$p/init"
           '';
       };