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authorColin Ian King2019-06-19 20:14:46 +0200
committerGreg Kroah-Hartman2019-07-21 09:03:06 +0200
commit2a6ee36917f02682e387d3e127af06bcb4a66aad (patch)
tree4b261b94bab625dd582fd2aba23ec30ed55b4597
parentafs: Fix uninitialised spinlock afs_volume::cb_break_lock (diff)
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x86/apic: Fix integer overflow on 10 bit left shift of cpu_khz
[ 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>
-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 84132eddb5a8..2646234380cc 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -1452,7 +1452,8 @@ 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--;
}