diff --git a/grub-core/kern/i386/tsc_pmtimer.c b/grub-core/kern/i386/tsc_pmtimer.c index 5c03c510a..dd044590d 100644 --- a/grub-core/kern/i386/tsc_pmtimer.c +++ b/grub-core/kern/i386/tsc_pmtimer.c @@ -143,5 +143,15 @@ grub_tsc_calibrate_from_pmtimer (void) if (tsc_diff == 0) return 0; grub_tsc_rate = grub_divmod64 ((1ULL << 32), tsc_diff, 0); + /* + * Specifically, when the tsc_diff (end_tsc - start_tsc) is greater than (1ULL << 32), + * the result of grub_divmod64() becomes zero, causing grub_tsc_rate to always be zero. + * As a result, grub_tsc_get_time_ms() consistently returns zero, and the GRUB menu + * countdown gets stuck. To resolve this, we return 0 to proceed to the next calibration + * function when grub_tsc_rate is zero. + */ + if (grub_tsc_rate == 0) + return 0; + return 1; }