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Date:   Sat,  4 Sep 2021 17:41:06 +0200
From:   Len Baker <>
To:     Alex Deucher <>,
        Christian K├Ânig <>,
        "Pan, Xinhui" <>,
        David Airlie <>,
        Daniel Vetter <>
Cc:     Len Baker <>, Kees Cook <>,,,,
Subject: [PATCH] drm/radeon: Prefer kcalloc over open coded arithmetic

As noted in the "Deprecated Interfaces, Language Features, Attributes,
and Conventions" documentation [1], size calculations (especially
multiplication) should not be performed in memory allocator (or similar)
function arguments due to the risk of them overflowing. This could lead
to values wrapping around and a smaller allocation being made than the
caller was expecting. Using those allocations could lead to linear
overflows of heap memory and other misbehaviors.

So, refactor the code a bit to use the purpose specific kcalloc()
function instead of the calculated size argument in the kzalloc()


Signed-off-by: Len Baker <>
 drivers/gpu/drm/radeon/r600_dpm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/radeon/r600_dpm.c b/drivers/gpu/drm/radeon/r600_dpm.c
index 35b77c944701..fd4226b99862 100644
--- a/drivers/gpu/drm/radeon/r600_dpm.c
+++ b/drivers/gpu/drm/radeon/r600_dpm.c
@@ -820,12 +820,12 @@ union fan_info {
 static int r600_parse_clk_voltage_dep_table(struct radeon_clock_voltage_dependency_table *radeon_table,
 					    ATOM_PPLIB_Clock_Voltage_Dependency_Table *atom_table)
-	u32 size = atom_table->ucNumEntries *
-		sizeof(struct radeon_clock_voltage_dependency_entry);
 	int i;
 	ATOM_PPLIB_Clock_Voltage_Dependency_Record *entry;

-	radeon_table->entries = kzalloc(size, GFP_KERNEL);
+	radeon_table->entries = kcalloc(atom_table->ucNumEntries,
+					sizeof(struct radeon_clock_voltage_dependency_entry),
+					GFP_KERNEL);
 	if (!radeon_table->entries)
 		return -ENOMEM;


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