From e9c71d971f7ec6379284ac58b3ea236996fb7b39 Mon Sep 17 00:00:00 2001
From: nikstur <nikstur@outlook.com>
Date: Tue, 29 Jul 2025 13:27:28 +0200
Subject: [PATCH] nixos/filesystem: remove mount-pstore

Ever since fb49d81b2541bd06fbaef6f516906381e7356947 we set
CONFIG_PSTORE=y in the config because we set CONIFG_ACPI_APEI=y in the
kernel. This means we always have pstore built right into the kernel.

systemd thus always mounts `/sys/fs/pstore` which makes our custom unit
superfluous and redudant.
---
 nixos/modules/tasks/filesystems.nix | 39 -----------------------------
 nixos/tests/all-tests.nix           |  1 +
 nixos/tests/systemd-pstore.nix      | 14 +++++++++++
 3 files changed, 15 insertions(+), 39 deletions(-)
 create mode 100644 nixos/tests/systemd-pstore.nix

diff --git a/nixos/modules/tasks/filesystems.nix b/nixos/modules/tasks/filesystems.nix
index 0cf83ca62d44..5e52591a560b 100644
--- a/nixos/modules/tasks/filesystems.nix
+++ b/nixos/modules/tasks/filesystems.nix
@@ -509,45 +509,6 @@ in
       ];
     };
 
-    systemd.services = {
-      # Mount /sys/fs/pstore for evacuating panic logs and crashdumps from persistent storage onto the disk using systemd-pstore.
-      # This cannot be done with the other special filesystems because the pstore module (which creates the mount point) is not loaded then.
-      "mount-pstore" = {
-        serviceConfig = {
-          Type = "oneshot";
-          # skip on kernels without the pstore module
-          ExecCondition = "${pkgs.kmod}/bin/modprobe -b pstore";
-          ExecStart = pkgs.writeShellScript "mount-pstore.sh" ''
-            set -eu
-            # if the pstore module is builtin it will have mounted the persistent store automatically. it may also be already mounted for other reasons.
-            ${pkgs.util-linux}/bin/mountpoint -q /sys/fs/pstore || ${pkgs.util-linux}/bin/mount -t pstore -o nosuid,noexec,nodev pstore /sys/fs/pstore
-            # wait up to 1.5 seconds for the backend to be registered and the files to appear. a systemd path unit cannot detect this happening; and succeeding after a restart would not start dependent units.
-            TRIES=15
-            while [ "$(cat /sys/module/pstore/parameters/backend)" = "(null)" ]; do
-              if (( $TRIES )); then
-                sleep 0.1
-                TRIES=$((TRIES-1))
-              else
-                echo "Persistent Storage backend was not registered in time." >&2
-                break
-              fi
-            done
-          '';
-          RemainAfterExit = true;
-        };
-        unitConfig = {
-          ConditionVirtualization = "!container";
-          DefaultDependencies = false; # needed to prevent a cycle
-        };
-        before = [
-          "systemd-pstore.service"
-          "shutdown.target"
-        ];
-        conflicts = [ "shutdown.target" ];
-        wantedBy = [ "systemd-pstore.service" ];
-      };
-    };
-
     systemd.tmpfiles.rules = [
       "d /run/keys 0750 root ${toString config.ids.gids.keys}"
       "z /run/keys 0750 root ${toString config.ids.gids.keys}"
diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index a2dcd4c7ffd7..567d438ef897 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -1437,6 +1437,7 @@ in
   systemd-nspawn-configfile = runTest ./systemd-nspawn-configfile.nix;
   systemd-oomd = runTest ./systemd-oomd.nix;
   systemd-portabled = runTest ./systemd-portabled.nix;
+  systemd-pstore = runTest ./systemd-pstore.nix;
   systemd-repart = handleTest ./systemd-repart.nix { };
   systemd-resolved = runTest ./systemd-resolved.nix;
   systemd-ssh-proxy = runTest ./systemd-ssh-proxy.nix;
diff --git a/nixos/tests/systemd-pstore.nix b/nixos/tests/systemd-pstore.nix
new file mode 100644
index 000000000000..7eeb7209e4a4
--- /dev/null
+++ b/nixos/tests/systemd-pstore.nix
@@ -0,0 +1,14 @@
+{
+  name = "systemd-pstore";
+
+  nodes.machine = { };
+
+  testScript = ''
+    with subtest("pstore API fs is mounted"):
+      machine.succeed("stat /sys/fs/pstore")
+
+    with subtest("systemd-pstore.service doesn't run because nothing crashed"):
+      output = machine.execute("systemctl status systemd-pstore.service", check_return=False)[1]
+      t.assertIn("condition unmet", output)
+  '';
+}