[PATCH] arm64: topology: fix possible overflow in amu_fie_setup()

Sergey Shtylyov s.shtylyov at omp.ru
Fri Sep 16 13:17:07 PDT 2022


cpufreq_get_hw_max_freq() returns max frequency in kHz as *unsigned int*,
while freq_inv_set_max_ratio() gets passed this frequency in Hz as 'u64'.
Multiplying max frequency by 1000 can potentially result in overflow --
multiplying by 1000ULL instead should avoid that...

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Fixes: cd0ed03a8903 ("arm64: use activity monitors for frequency invariance")
Signed-off-by: Sergey Shtylyov <s.shtylyov at omp.ru>

---
The patch is against the 'for-next/fixes' branch of the ARM64 repo...

 arch/arm64/kernel/topology.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux/arch/arm64/kernel/topology.c
===================================================================
--- linux.orig/arch/arm64/kernel/topology.c
+++ linux/arch/arm64/kernel/topology.c
@@ -237,7 +237,7 @@ static void amu_fie_setup(const struct c
 	for_each_cpu(cpu, cpus) {
 		if (!freq_counters_valid(cpu) ||
 		    freq_inv_set_max_ratio(cpu,
-					   cpufreq_get_hw_max_freq(cpu) * 1000,
+					   cpufreq_get_hw_max_freq(cpu) * 1000ULL,
 					   arch_timer_get_rate()))
 			return;
 	}



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