From 34ab17cc6c2c1ac93d7e5d53bb972df9a968f085 Mon Sep 17 00:00:00 2001 From: brian-sy yang Date: Tue, 29 Dec 2020 13:08:31 +0800 Subject: [PATCH] thermal/drivers/cpufreq_cooling: Fix slab OOB issue 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: [] die+0x104/0x5ac [] bug_handler+0x64/0xd0 [] brk_handler+0x160/0x258 [] do_debug_exception+0x248/0x3f0 [] el1_dbg+0x14/0xbc [] __kasan_report+0x1dc/0x1e0 [] kasan_report+0x10/0x20 [] __asan_report_load8_noabort+0x18/0x28 [] cpufreq_power2state+0x180/0x43c [] power_actor_set_power+0x114/0x1d4 [] allocate_power+0xaec/0xde0 [] power_allocator_throttle+0x3ec/0x5a4 [] handle_thermal_trip+0x160/0x294 [] thermal_zone_device_check+0xe4/0x154 [] process_one_work+0x5e4/0xe28 [] worker_thread+0xa4c/0xfac [] kthread+0x33c/0x358 [] ret_from_fork+0xc/0x18 Fixes: 371a3bc79c11b ("thermal/drivers/cpufreq_cooling: Fix wrong frequency converted from power") Signed-off-by: brian-sy yang Signed-off-by: Michael Kao Reviewed-by: Lukasz Luba Cc: stable@vger.kernel.org #v5.7 Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20201229050831.19493-1-michael.kao@mediatek.com --- drivers/thermal/cpufreq_cooling.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c index f3d308427665..eeb4e4b76c0b 100644 --- a/drivers/thermal/cpufreq_cooling.c +++ b/drivers/thermal/cpufreq_cooling.c @@ -116,7 +116,7 @@ static u32 cpu_power_to_freq(struct cpufreq_cooling_device *cpufreq_cdev, { 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; }