From 27b92fb175d0fc380be92474f9526e81609d11dc Mon Sep 17 00:00:00 2001
From: Felix Weiglhofer <felix.weiglhofer@cern.ch>
Date: Thu, 23 Apr 2026 11:34:15 +0200
Subject: [PATCH] GPU/TPC: Fix row overflow in Pad Filter.

---
 GPU/GPUTracking/TPCClusterFinder/GPUTPCCFCheckPadBaseline.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/GPU/GPUTracking/TPCClusterFinder/GPUTPCCFCheckPadBaseline.h b/GPU/GPUTracking/TPCClusterFinder/GPUTPCCFCheckPadBaseline.h
index c47de7f79d424..7638b95ee7f0b 100644
--- a/GPU/GPUTracking/TPCClusterFinder/GPUTPCCFCheckPadBaseline.h
+++ b/GPU/GPUTracking/TPCClusterFinder/GPUTPCCFCheckPadBaseline.h
@@ -63,8 +63,10 @@ class GPUTPCCFCheckPadBaseline : public GPUKernelTemplate
 
   static int32_t GetNBlocks(bool isGPU)
   {
-    const int32_t nBlocks = TPC_CLUSTERER_STRIDED_PAD_COUNT / PadsPerCacheline;
-    return isGPU ? GPUTPCGeometry::NROWS : nBlocks;
+    // Important to exclude rightmost padding from Pad Filter.
+    // There's nothing to filter there and padding is counted as start of a row, so it causes an overflow in the row count.
+    const int32_t nBlocksCPU = (TPC_CLUSTERER_STRIDED_PAD_COUNT - GPUCF_PADDING_PAD) / PadsPerCacheline;
+    return isGPU ? GPUTPCGeometry::NROWS : nBlocksCPU;
   }
 
   template <int32_t iKernel = defaultKernel>