[ Upstream commit ea136a112d89bade596314a1ae49f748902f4727 ]
The left shift of unsigned int cpu_khz will overflow for large values of cpu_khz, so cast it to a long long before shifting it to avoid overvlow. For example, this can happen when cpu_khz is 4194305, i.e. ~4.2 GHz.
Addresses-Coverity: ("Unintentional integer overflow") Fixes: 8c3ba8d04924 ("x86, apic: ack all pending irqs when crashed/on kexec") Signed-off-by: Colin Ian King colin.king@canonical.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Borislav Petkov bp@alien8.de Cc: "H . Peter Anvin" hpa@zytor.com Cc: kernel-janitors@vger.kernel.org Link: https://lkml.kernel.org/r/20190619181446.13635-1-colin.king@canonical.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/apic/apic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index b7bcdd781651..ec6225cb94f9 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1458,7 +1458,8 @@ static void apic_pending_intr_clear(void) if (queued) { if (boot_cpu_has(X86_FEATURE_TSC) && cpu_khz) { ntsc = rdtsc(); - max_loops = (cpu_khz << 10) - (ntsc - tsc); + max_loops = (long long)cpu_khz << 10; + max_loops -= ntsc - tsc; } else { max_loops--; }