Commit 99a40d66 authored by Colin Ian King's avatar Colin Ian King Committed by Greg Kroah-Hartman

x86/apic: Fix integer overflow on 10 bit left shift of cpu_khz

[ Upstream commit ea136a11 ]

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: 8c3ba8d0 ("x86, apic: ack all pending irqs when crashed/on kexec")
Signed-off-by: default avatarColin Ian King <colin.king@canonical.com>
Signed-off-by: default avatarThomas 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.comSigned-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 5f7bb2a5
......@@ -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--;
}
......
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