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authorColin Ian King <colin.king@canonical.com>2019-06-19 19:14:46 +0100
committerThomas Gleixner <tglx@linutronix.de>2019-06-22 11:59:31 +0200
commitea136a112d89bade596314a1ae49f748902f4727 (patch)
treeaaf91cd28e72da9cbaaf5bef2f9cf28e5ee72b56
parent32f010deab575199df4ebe7b6aec20c17bb7eccd (diff)
x86/apic: Fix integer overflow on 10 bit left shift of cpu_khz
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
-rw-r--r--arch/x86/kernel/apic/apic.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 177aa8ef2afa..85be316665b4 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1464,7 +1464,8 @@ 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--;
}