3.16.75-rc1 review patch. If anyone has any objections, please let me know.
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From: Colin Ian King colin.king@canonical.com
commit ea136a112d89bade596314a1ae49f748902f4727 upstream.
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 [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- arch/x86/kernel/apic/apic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -1403,7 +1403,8 @@ void setup_local_APIC(void) if (queued) { if (cpu_has_tsc && cpu_khz) { rdtscll(ntsc); - max_loops = (cpu_khz << 10) - (ntsc - tsc); + max_loops = (long long)cpu_khz << 10; + max_loops -= ntsc - tsc; } else max_loops--; }