[v4,7/7] ipa: simple: agc: Prevent division by zero in AGC
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Message ID 20250925192856.77881-8-mzamazal@redhat.com
State New
Headers show
Series
  • Fix stats related problems in software ISP
Related show

Commit Message

Milan Zamazal Sept. 25, 2025, 7:28 p.m. UTC 
If the histogram size is non-zero but lower than the number of bins,
yHistValsPerBin is zero and then the AGC processing crashes on division
by it.  Let's check yHistValsPerBin for being zero and stop AGC
processing in such a case.  The condition also covers the cases where
histogramSize or yHistValsPerBinMod are zero.

Tested-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
---
 src/ipa/simple/algorithms/agc.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

Patch
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diff --git a/src/ipa/simple/algorithms/agc.cpp b/src/ipa/simple/algorithms/agc.cpp
index c46bb0ebe..e47949ec4 100644
--- a/src/ipa/simple/algorithms/agc.cpp
+++ b/src/ipa/simple/algorithms/agc.cpp
@@ -124,6 +124,12 @@  void Agc::process(IPAContext &context,
 	unsigned int denom = 0;
 	unsigned int num = 0;
 
+	if (yHistValsPerBin == 0) {
+		LOG(IPASoftExposure, Debug)
+			<< "Not adjusting exposure due to insufficient histogram data";
+		return;
+	}
+
 	for (unsigned int i = 0; i < histogramSize; i++) {
 		unsigned int idx = (i - (i / yHistValsPerBinMod)) / yHistValsPerBin;
 		exposureBins[idx] += histogram[blackLevelHistIdx + i];