From 3db198a018f694842f095febbda6a9d3562964cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Thalheim?= <joerg@thalheim.io>
Date: Mon, 15 May 2023 11:15:15 +0200
Subject: [PATCH] kexec-installer: print dmesg if kexec --load fails

In some cases dmesg contains interesting errors
---
 nix/kexec-installer/kexec-run.sh | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/nix/kexec-installer/kexec-run.sh b/nix/kexec-installer/kexec-run.sh
index c56fb7c..09d9d33 100644
--- a/nix/kexec-installer/kexec-run.sh
+++ b/nix/kexec-installer/kexec-run.sh
@@ -53,9 +53,13 @@ done
 find . | cpio -o -H newc | gzip -9 >> "$SCRIPT_DIR/initrd"
 
 # Dropped --kexec-syscall-auto because it broke on GCP...
-"$SCRIPT_DIR/kexec" --load "$SCRIPT_DIR/bzImage" \
+if ! "$SCRIPT_DIR/kexec" --load "$SCRIPT_DIR/bzImage" \
   --initrd="$SCRIPT_DIR/initrd" --no-checks \
-  --command-line "init=$init $kernelParams"
+  --command-line "init=$init $kernelParams"; then
+  echo "kexec failed, dumping dmesg"
+  dmesg | tail -n 100
+  exit 1
+fi
 
 # Disconnect our background kexec from the terminal
 echo "machine will boot into nixos in in 6s..."