From 2e850b832f5d2adb9b230d191277d67c00caaab9 Mon Sep 17 00:00:00 2001 From: Josef 'Jeff' Sipek Date: Tue, 16 Apr 2024 19:01:28 -0400 Subject: [PATCH] acpi_battery: avoid divide-by-zero when no devices have capacity info On laptops with builtin batteries, disconnecting the battery may show up as a battery without any capacity information. (The theory is that one is disconnecting the cells but the electronics identifying the battery are still connected.) As a result, the loop over all batteries in acpi_battery_get_battinfo results in total_lfcap == 0. So, just check that total_lfcap is non-zero to avoid a division by zero (triggerable by sysctl hw.acpi.battery). Reported by: Stefano Marinelli Tested by: Stefano Marinelli Reviewed by: emaste Differential Revision: https://reviews.freebsd.org/D44818 --- sys/dev/acpica/acpi_battery.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/sys/dev/acpica/acpi_battery.c b/sys/dev/acpica/acpi_battery.c index 7455c6afc6a..cfd8261d5ea 100644 --- a/sys/dev/acpica/acpi_battery.c +++ b/sys/dev/acpica/acpi_battery.c @@ -266,7 +266,14 @@ acpi_battery_get_battinfo(device_t dev, struct acpi_battinfo *battinfo) */ if (valid_units > 0) { if (dev == NULL) { - battinfo->cap = (total_cap * 100) / total_lfcap; + /* + * Avoid division by zero if none of the batteries had valid + * capacity info. + */ + if (total_lfcap > 0) + battinfo->cap = (total_cap * 100) / total_lfcap; + else + battinfo->cap = 0; battinfo->min = total_min; battinfo->state = batt_stat; battinfo->rate = valid_rate;