From b9d0cd4a4debfc761c85f1d3027520a37ecc6a07 Mon Sep 17 00:00:00 2001
From: Ajeem Khan K <ajeemkhank@Ajeems-MacBook-Air.local>
Date: Sun, 29 Mar 2026 22:38:24 +0530
Subject: [PATCH 1/2] Guard snapshot process signals in GUI

---
 qt/app.py | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/qt/app.py b/qt/app.py
index 90c261343..bd04b9581 100644
--- a/qt/app.py
+++ b/qt/app.py
@@ -490,11 +490,11 @@ def _create_actions(self):
                 _('Use checksums for file change detection.')),
             'act_pause_take_snapshot': (
                 icon.PAUSE, _('Pause backup process'),
-                lambda: os.kill(self.snapshots.pid(), signal.SIGSTOP), None,
+                lambda: self._signal_snapshot_process(signal.SIGSTOP), None,
                 None),
             'act_resume_take_snapshot': (
                 icon.RESUME, _('Resume backup process'),
-                lambda: os.kill(self.snapshots.pid(), signal.SIGCONT), None,
+                lambda: self._signal_snapshot_process(signal.SIGCONT), None,
                 None),
             'act_stop_take_snapshot': (
                 icon.STOP, _('Stop backup process'),
@@ -1848,12 +1848,29 @@ def _create_backup(self, checksum: bool) -> None:
         backintime.takeSnapshotAsync(self.config, checksum=checksum)
         self._update_backup_status(True)
 
+    def _signal_snapshot_process(self, sig: signal.Signals) -> bool:
+        pid = self.snapshots.pid()
+
+        if not tools.processAlive(pid):
+            self._update_backup_status(True)
+            return False
+
+        try:
+            os.kill(pid, sig)
+        except ProcessLookupError:
+            logger.debug(f'Ignoring signal {sig} for vanished snapshot process {pid}.')
+            self._update_backup_status(True)
+            return False
+
+        return True
+
     def _slot_backup_stop(self):
-        os.kill(self.snapshots.pid(), signal.SIGKILL)
+        if self._signal_snapshot_process(signal.SIGKILL):
+            self.snapshots.setTakeSnapshotMessage(0, 'Backup terminated')
+
         self.act_stop_take_snapshot.setEnabled(False)
         self.act_pause_take_snapshot.setEnabled(False)
         self.act_resume_take_snapshot.setEnabled(False)
-        self.snapshots.setTakeSnapshotMessage(0, 'Backup terminated')
 
     # |---------|
     # | Restore |

From f124ce2538040a210e84fff29f12166da89894ca Mon Sep 17 00:00:00 2001
From: Ajeem Khan K <ajeemkhank@Ajeems-MacBook-Air.local>
Date: Mon, 30 Mar 2026 17:29:14 +0530
Subject: [PATCH 2/2] Wrap debug log line for lint compliance

---
 qt/app.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/qt/app.py b/qt/app.py
index bd04b9581..386b58db6 100644
--- a/qt/app.py
+++ b/qt/app.py
@@ -1858,7 +1858,8 @@ def _signal_snapshot_process(self, sig: signal.Signals) -> bool:
         try:
             os.kill(pid, sig)
         except ProcessLookupError:
-            logger.debug(f'Ignoring signal {sig} for vanished snapshot process {pid}.')
+            logger.debug(
+                f'Ignoring signal {sig} for vanished snapshot process {pid}.')
             self._update_backup_status(True)
             return False