CVE-2021-47441: In the Linux kernel, the following vulnerability has been resolved:  mlxsw: thermal: Fix out-of-bounds memory accesses  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- ---truncated---