From 0e92eb6c7b2dc4a948af1606cb10b3402bec20d4 Mon Sep 17 00:00:00 2001
From: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Date: Thu, 9 Dec 2021 20:41:24 -0800
Subject: drm/i915/display: Fix an unsigned subtraction which can never be
negative.
Git-commit: 53b3495273282aa844c4613d19c3b30558c70c84
Patch-mainline: v5.16-rc6
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225
Alt-commit: 87bb2a410dcfb617b88e4695edf4beb6336dc314
smatch warning:
drivers/gpu/drm/i915/display/intel_dmc.c:601 parse_dmc_fw() warn:
unsigned 'fw->size - offset' is never less than zero
Firmware size is size_t and offset is u32. So the subtraction is
unsigned which can never be less than zero.
Fixes: 3d5928a168a9 ("drm/i915/xelpd: Pipe A DMC plugging")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211210044129.12422-1-harshit.m.mogalapalli@oracle.com
(cherry picked from commit 87bb2a410dcfb617b88e4695edf4beb6336dc314)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
drivers/gpu/drm/i915/display/intel_dmc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c
index 2dc9d632969d..aef69522f0be 100644
--- a/drivers/gpu/drm/i915/display/intel_dmc.c
+++ b/drivers/gpu/drm/i915/display/intel_dmc.c
@@ -596,7 +596,7 @@ static void parse_dmc_fw(struct drm_i915_private *dev_priv,
continue;
offset = readcount + dmc->dmc_info[id].dmc_offset * 4;
- if (fw->size - offset < 0) {
+ if (offset > fw->size) {
drm_err(&dev_priv->drm, "Reading beyond the fw_size\n");
continue;
}
--
2.38.1