From: brian-sy yang brian-sy.yang@mediatek.com
commit 34ab17cc6c2c1ac93d7e5d53bb972df9a968f085 upstream.
Slab OOB issue is scanned by KASAN in cpu_power_to_freq(). If power is limited below the power of OPP0 in EM table, it will cause slab out-of-bound issue with negative array index.
Return the lowest frequency if limited power cannot found a suitable OPP in EM table to fix this issue.
Backtrace: [<ffffffd02d2a37f0>] die+0x104/0x5ac [<ffffffd02d2a5630>] bug_handler+0x64/0xd0 [<ffffffd02d288ce4>] brk_handler+0x160/0x258 [<ffffffd02d281e5c>] do_debug_exception+0x248/0x3f0 [<ffffffd02d284488>] el1_dbg+0x14/0xbc [<ffffffd02d75d1d4>] __kasan_report+0x1dc/0x1e0 [<ffffffd02d75c2e0>] kasan_report+0x10/0x20 [<ffffffd02d75def8>] __asan_report_load8_noabort+0x18/0x28 [<ffffffd02e6fce5c>] cpufreq_power2state+0x180/0x43c [<ffffffd02e6ead80>] power_actor_set_power+0x114/0x1d4 [<ffffffd02e6fac24>] allocate_power+0xaec/0xde0 [<ffffffd02e6f9f80>] power_allocator_throttle+0x3ec/0x5a4 [<ffffffd02e6ea888>] handle_thermal_trip+0x160/0x294 [<ffffffd02e6edd08>] thermal_zone_device_check+0xe4/0x154 [<ffffffd02d351cb4>] process_one_work+0x5e4/0xe28 [<ffffffd02d352f44>] worker_thread+0xa4c/0xfac [<ffffffd02d360124>] kthread+0x33c/0x358 [<ffffffd02d289940>] ret_from_fork+0xc/0x18
Fixes: 371a3bc79c11b ("thermal/drivers/cpufreq_cooling: Fix wrong frequency converted from power") Signed-off-by: brian-sy yang brian-sy.yang@mediatek.com Signed-off-by: Michael Kao michael.kao@mediatek.com Reviewed-by: Lukasz Luba lukasz.luba@arm.com Cc: stable@vger.kernel.org #v5.7 Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org Link: https://lore.kernel.org/r/20201229050831.19493-1-michael.kao@mediatek.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/thermal/cpufreq_cooling.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/thermal/cpufreq_cooling.c +++ b/drivers/thermal/cpufreq_cooling.c @@ -123,7 +123,7 @@ static u32 cpu_power_to_freq(struct cpuf { int i;
- for (i = cpufreq_cdev->max_level; i >= 0; i--) { + for (i = cpufreq_cdev->max_level; i > 0; i--) { if (power >= cpufreq_cdev->em->table[i].power) break; }