| From 332fdf951df8b870e3da86b122ae304e2aabe88c Mon Sep 17 00:00:00 2001 |
| From: Ido Schimmel <idosch@nvidia.com> |
| Date: Tue, 12 Oct 2021 20:49:55 +0300 |
| Subject: mlxsw: thermal: Fix out-of-bounds memory accesses |
| |
| From: Ido Schimmel <idosch@nvidia.com> |
| |
| commit 332fdf951df8b870e3da86b122ae304e2aabe88c upstream. |
| |
| Currently, mlxsw allows cooling states to be set above the maximum |
| cooling state supported by the driver: |
| |
| # cat /sys/class/thermal/thermal_zone2/cdev0/type |
| mlxsw_fan |
| # cat /sys/class/thermal/thermal_zone2/cdev0/max_state |
| 10 |
| # echo 18 > /sys/class/thermal/thermal_zone2/cdev0/cur_state |
| # echo $? |
| 0 |
| |
| This results in out-of-bounds memory accesses when thermal state |
| transition statistics are enabled (CONFIG_THERMAL_STATISTICS=y), as the |
| transition table is accessed with a too large index (state) [1]. |
| |
| According to the thermal maintainer, it is the responsibility of the |
| driver to reject such operations [2]. |
| |
| Therefore, return an error when the state to be set exceeds the maximum |
| cooling state supported by the driver. |
| |
| To avoid dead code, as suggested by the thermal maintainer [3], |
| partially revert commit a421ce088ac8 ("mlxsw: core: Extend cooling |
| device with cooling levels") that tried to interpret these invalid |
| cooling states (above the maximum) in a special way. The cooling levels |
| array is not removed in order to prevent the fans going below 20% PWM, |
| which would cause them to get stuck at 0% PWM. |
| |
| [1] |
| BUG: KASAN: slab-out-of-bounds in thermal_cooling_device_stats_update+0x271/0x290 |
| Read of size 4 at addr ffff8881052f7bf8 by task kworker/0:0/5 |
| |
| CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.15.0-rc3-custom-45935-gce1adf704b14 #122 |
| Hardware name: Mellanox Technologies Ltd. "MSN2410-CB2FO"/"SA000874", BIOS 4.6.5 03/08/2016 |
| Workqueue: events_freezable_power_ thermal_zone_device_check |
| Call Trace: |
| dump_stack_lvl+0x8b/0xb3 |
| print_address_description.constprop.0+0x1f/0x140 |
| kasan_report.cold+0x7f/0x11b |
| thermal_cooling_device_stats_update+0x271/0x290 |
| __thermal_cdev_update+0x15e/0x4e0 |
| thermal_cdev_update+0x9f/0xe0 |
| step_wise_throttle+0x770/0xee0 |
| thermal_zone_device_update+0x3f6/0xdf0 |
| process_one_work+0xa42/0x1770 |
| worker_thread+0x62f/0x13e0 |
| kthread+0x3ee/0x4e0 |
| ret_from_fork+0x1f/0x30 |
| |
| Allocated by task 1: |
| kasan_save_stack+0x1b/0x40 |
| __kasan_kmalloc+0x7c/0x90 |
| thermal_cooling_device_setup_sysfs+0x153/0x2c0 |
| __thermal_cooling_device_register.part.0+0x25b/0x9c0 |
| thermal_cooling_device_register+0xb3/0x100 |
| mlxsw_thermal_init+0x5c5/0x7e0 |
| __mlxsw_core_bus_device_register+0xcb3/0x19c0 |
| mlxsw_core_bus_device_register+0x56/0xb0 |
| mlxsw_pci_probe+0x54f/0x710 |
| local_pci_probe+0xc6/0x170 |
| pci_device_probe+0x2b2/0x4d0 |
| really_probe+0x293/0xd10 |
| __driver_probe_device+0x2af/0x440 |
| driver_probe_device+0x51/0x1e0 |
| __driver_attach+0x21b/0x530 |
| bus_for_each_dev+0x14c/0x1d0 |
| bus_add_driver+0x3ac/0x650 |
| driver_register+0x241/0x3d0 |
| mlxsw_sp_module_init+0xa2/0x174 |
| do_one_initcall+0xee/0x5f0 |
| kernel_init_freeable+0x45a/0x4de |
| kernel_init+0x1f/0x210 |
| ret_from_fork+0x1f/0x30 |
| |
| The buggy address belongs to the object at ffff8881052f7800 |
| which belongs to the cache kmalloc-1k of size 1024 |
| The buggy address is located 1016 bytes inside of |
| 1024-byte region [ffff8881052f7800, ffff8881052f7c00) |
| The buggy address belongs to the page: |
| page:0000000052355272 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1052f0 |
| head:0000000052355272 order:3 compound_mapcount:0 compound_pincount:0 |
| flags: 0x200000000010200(slab|head|node=0|zone=2) |
| raw: 0200000000010200 ffffea0005034800 0000000300000003 ffff888100041dc0 |
| raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 |
| page dumped because: kasan: bad access detected |
| |
| Memory state around the buggy address: |
| ffff8881052f7a80: 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc fc |
| ffff8881052f7b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| >ffff8881052f7b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| ^ |
| ffff8881052f7c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| ffff8881052f7c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| |
| [2] https://lore.kernel.org/linux-pm/9aca37cb-1629-5c67-1895-1fdc45c0244e@linaro.org/ |
| [3] https://lore.kernel.org/linux-pm/af9857f2-578e-de3a-e62b-6baff7e69fd4@linaro.org/ |
| |
| CC: Daniel Lezcano <daniel.lezcano@linaro.org> |
| Fixes: a50c1e35650b ("mlxsw: core: Implement thermal zone") |
| Fixes: a421ce088ac8 ("mlxsw: core: Extend cooling device with cooling levels") |
| Signed-off-by: Ido Schimmel <idosch@nvidia.com> |
| Tested-by: Vadim Pasternak <vadimp@nvidia.com> |
| Link: https://lore.kernel.org/r/20211012174955.472928-1-idosch@idosch.org |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/net/ethernet/mellanox/mlxsw/core_thermal.c | 52 ++------------------- |
| 1 file changed, 5 insertions(+), 47 deletions(-) |
| |
| --- a/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c |
| +++ b/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c |
| @@ -25,16 +25,8 @@ |
| #define MLXSW_THERMAL_ZONE_MAX_NAME 16 |
| #define MLXSW_THERMAL_TEMP_SCORE_MAX GENMASK(31, 0) |
| #define MLXSW_THERMAL_MAX_STATE 10 |
| +#define MLXSW_THERMAL_MIN_STATE 2 |
| #define MLXSW_THERMAL_MAX_DUTY 255 |
| -/* Minimum and maximum fan allowed speed in percent: from 20% to 100%. Values |
| - * MLXSW_THERMAL_MAX_STATE + x, where x is between 2 and 10 are used for |
| - * setting fan speed dynamic minimum. For example, if value is set to 14 (40%) |
| - * cooling levels vector will be set to 4, 4, 4, 4, 4, 5, 6, 7, 8, 9, 10 to |
| - * introduce PWM speed in percent: 40, 40, 40, 40, 40, 50, 60. 70, 80, 90, 100. |
| - */ |
| -#define MLXSW_THERMAL_SPEED_MIN (MLXSW_THERMAL_MAX_STATE + 2) |
| -#define MLXSW_THERMAL_SPEED_MAX (MLXSW_THERMAL_MAX_STATE * 2) |
| -#define MLXSW_THERMAL_SPEED_MIN_LEVEL 2 /* 20% */ |
| |
| /* External cooling devices, allowed for binding to mlxsw thermal zones. */ |
| static char * const mlxsw_thermal_external_allowed_cdev[] = { |
| @@ -635,49 +627,16 @@ static int mlxsw_thermal_set_cur_state(s |
| struct mlxsw_thermal *thermal = cdev->devdata; |
| struct device *dev = thermal->bus_info->dev; |
| char mfsc_pl[MLXSW_REG_MFSC_LEN]; |
| - unsigned long cur_state, i; |
| int idx; |
| - u8 duty; |
| int err; |
| |
| + if (state > MLXSW_THERMAL_MAX_STATE) |
| + return -EINVAL; |
| + |
| idx = mlxsw_get_cooling_device_idx(thermal, cdev); |
| if (idx < 0) |
| return idx; |
| |
| - /* Verify if this request is for changing allowed fan dynamical |
| - * minimum. If it is - update cooling levels accordingly and update |
| - * state, if current state is below the newly requested minimum state. |
| - * For example, if current state is 5, and minimal state is to be |
| - * changed from 4 to 6, thermal->cooling_levels[0 to 5] will be changed |
| - * all from 4 to 6. And state 5 (thermal->cooling_levels[4]) should be |
| - * overwritten. |
| - */ |
| - if (state >= MLXSW_THERMAL_SPEED_MIN && |
| - state <= MLXSW_THERMAL_SPEED_MAX) { |
| - state -= MLXSW_THERMAL_MAX_STATE; |
| - for (i = 0; i <= MLXSW_THERMAL_MAX_STATE; i++) |
| - thermal->cooling_levels[i] = max(state, i); |
| - |
| - mlxsw_reg_mfsc_pack(mfsc_pl, idx, 0); |
| - err = mlxsw_reg_query(thermal->core, MLXSW_REG(mfsc), mfsc_pl); |
| - if (err) |
| - return err; |
| - |
| - duty = mlxsw_reg_mfsc_pwm_duty_cycle_get(mfsc_pl); |
| - cur_state = mlxsw_duty_to_state(duty); |
| - |
| - /* If current fan state is lower than requested dynamical |
| - * minimum, increase fan speed up to dynamical minimum. |
| - */ |
| - if (state < cur_state) |
| - return 0; |
| - |
| - state = cur_state; |
| - } |
| - |
| - if (state > MLXSW_THERMAL_MAX_STATE) |
| - return -EINVAL; |
| - |
| /* Normalize the state to the valid speed range. */ |
| state = thermal->cooling_levels[state]; |
| mlxsw_reg_mfsc_pack(mfsc_pl, idx, mlxsw_state_to_duty(state)); |
| @@ -980,8 +939,7 @@ int mlxsw_thermal_init(struct mlxsw_core |
| |
| /* Initialize cooling levels per PWM state. */ |
| for (i = 0; i < MLXSW_THERMAL_MAX_STATE; i++) |
| - thermal->cooling_levels[i] = max(MLXSW_THERMAL_SPEED_MIN_LEVEL, |
| - i); |
| + thermal->cooling_levels[i] = max(MLXSW_THERMAL_MIN_STATE, i); |
| |
| thermal->polling_delay = bus_info->low_frequency ? |
| MLXSW_THERMAL_SLOW_POLL_INT : |