From a4e3f91b98d86ae0b5c816fe45190bb29ac32f71 Mon Sep 17 00:00:00 2001 From: Daniel Mack Date: Thu, 12 Mar 2009 14:31:30 -0700 Subject: ds2760_battery.c: fix division by zero The 'battery remaining capacity' calculation in drivers/power/ds2760_battery.c lacks a parameter check to a division operation which causes the kernel to oops on my board. [ 21.233750] Division by zero in kernel. [ 21.237646] [] (__div0+0x0/0x20) from [] (Ldiv0+0x8/0x10) [ 21.244816] [] (ds2760_battery_read_status+0x0/0x2a4) from [] (ds2760_battery_get_property+0x30/0xdc) [ 21.255803] r8:c03a22c0 r7:c7886100 r6:00000009 r5:c782fe7c r4:c7886084 [ 21.262518] [] (ds2760_battery_get_property+0x0/0xdc) from [] (power_supply_show_property+0x48/0x114) [ 21.273480] r6:c7996000 r5:00000009 r4:00000000 [ 21.278111] [] (power_supply_show_property+0x0/0x114) from [] (power_supply_uevent+0x188/0x280) [ 21.288537] r8:00000001 r7:c7886100 r6:c7996000 r5:000000b4 r4:00000000 [ 21.295222] [] (power_supply_uevent+0x0/0x280) from [] (dev_uevent+0xd4/0x10c) [ 21.304199] [] (dev_uevent+0x0/0x10c) from [] (kobject_uevent_env+0x180/0x390) [ 21.313170] r5:00000000 r4:c78860ac [ 21.316725] [] (kobject_uevent_env+0x0/0x390) from [] (kobject_uevent+0x14/0x18) [ 21.325850] [] (kobject_uevent+0x0/0x18) from [] (power_supply_changed_work+0x5c/0x70) [ 21.335506] [] (power_supply_changed_work+0x0/0x70) from [] (run_workqueue+0xbc/0x144) [ 21.345167] r4:c7812040 [ 21.347716] [] (run_workqueue+0x0/0x144) from [] (worker_thread+0xa8/0xbc) [ 21.356296] r7:c7812040 r6:c7820b00 r5:c782ffa4 r4:c7812048 [ 21.361957] [] (worker_thread+0x0/0xbc) from [] (kthread+0x5c/0x94) [ 21.369971] r7:00000000 r6:c004d8a4 r5:c7812040 r4:c782e000 [ 21.375612] [] (kthread+0x0/0x94) from [] (do_exit+0x0/0x688) Signed-off-by: Daniel Mack Cc: Szabolcs Gyurko Acked-by: Matt Reimer Acked-by: Anton Vorontsov Cc: David Woodhouse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/power/ds2760_battery.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'drivers/power/ds2760_battery.c') diff --git a/drivers/power/ds2760_battery.c b/drivers/power/ds2760_battery.c index 1d768928e0bb..a52d4a11652d 100644 --- a/drivers/power/ds2760_battery.c +++ b/drivers/power/ds2760_battery.c @@ -180,10 +180,13 @@ static int ds2760_battery_read_status(struct ds2760_device_info *di) di->empty_uAh = battery_interpolate(scale, di->temp_C / 10); di->empty_uAh *= 1000; /* convert to µAh */ - /* From Maxim Application Note 131: remaining capacity = - * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */ - di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) / - (di->full_active_uAh - di->empty_uAh); + if (di->full_active_uAh == di->empty_uAh) + di->rem_capacity = 0; + else + /* From Maxim Application Note 131: remaining capacity = + * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */ + di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) / + (di->full_active_uAh - di->empty_uAh); if (di->rem_capacity < 0) di->rem_capacity = 0; -- cgit v1.2.3