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  1. 14 Nov, 2022 7 commits
    • Guenter Roeck's avatar
      thermal/core: Protect sysfs accesses to thermal operations with thermal zone mutex · 05eeee2b
      Guenter Roeck authored 
      Protect access to thermal operations against thermal zone removal by
acquiring the thermal zone device mutex. After acquiring the mutex, check
if the thermal zone device is registered and abort the operation if not.

With this change, we can call __thermal_zone_device_update() instead of
thermal_zone_device_update() from trip_point_temp_store() and from
emul_temp_store(). Similar, we can call __thermal_zone_set_trips() instead
of thermal_zone_set_trips() from trip_point_hyst_store().
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      05eeee2b
    • Guenter Roeck's avatar
      thermal/core: Protect hwmon accesses to thermal operations with thermal zone mutex · ea37bec5
      Guenter Roeck authored 
      In preparation to protecting access to thermal operations against thermal
zone device removal, protect hwmon accesses to thermal zone operations
with the thermal zone mutex. After acquiring the mutex, ensure that the
thermal zone device is registered before proceeding.
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      ea37bec5
    • Guenter Roeck's avatar
      thermal/core: Introduce locked version of thermal_zone_device_update · 1c439dec
      Guenter Roeck authored 
      In thermal_zone_device_set_mode(), the thermal zone mutex is released only
to be reacquired in the subsequent call to thermal_zone_device_update().

Introduce __thermal_zone_device_update(), which is similar to
thermal_zone_device_update() but has to be called with the thermal device
mutex held. Call the new function from thermal_zone_device_set_mode()
to avoid the extra thermal device mutex release/acquire sequence in that
function.

With the new function in place, re-implement thermal_zone_device_update()
as wrapper around __thermal_zone_device_update() to acquire and release
the thermal device mutex.
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      1c439dec
    • Guenter Roeck's avatar
      thermal/core: Move parameter validation from __thermal_zone_get_temp to thermal_zone_get_temp · ed97d10a
      Guenter Roeck authored 
      All callers of __thermal_zone_get_temp() already validated the
thermal zone parameters. Move validation to thermal_zone_get_temp()
where it is actually needed. Also add kernel documentation for
__thermal_zone_get_temp(), listing the requirement that the
function must be called with validated parameters and with thermal
device mutex held.
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      ed97d10a
    • Guenter Roeck's avatar
      thermal/core: Ensure that thermal device is registered in thermal_zone_get_temp · 1c6b3006
      Guenter Roeck authored 
      Calls to thermal_zone_get_temp() are not protected against thermal zone
device removal. As result, it is possible that the thermal zone operations
callbacks are no longer valid when thermal_zone_get_temp() is called.
This may result in crashes such as

BUG: unable to handle page fault for address: ffffffffc04ef420
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
PGD 5d60e067 P4D 5d60e067 PUD 5d610067 PMD 110197067 PTE 0
Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 3209 Comm: cat Tainted: G        W         5.10.136-19389-g615abc6eb807 #1 02df41ac0b12f3a64f4b34245188d8875bb3bce1
Hardware name: Google Coral/Coral, BIOS Google_Coral.10068.92.0 11/27/2018
RIP: 0010:thermal_zone_get_temp+0x26/0x73
Code: 89 c3 eb d3 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 53 48 85 ff 74 50 48 89 fb 48 81 ff 00 f0 ff ff 77 44 48 8b 83 98 03 00 00 <48> 83 78 10 00 74 36 49 89 f6 4c 8d bb d8 03 00 00 4c 89 ff e8 9f
RSP: 0018:ffffb3758138fd38 EFLAGS: 00010287
RAX: ffffffffc04ef410 RBX: ffff98f14d7fb000 RCX: 0000000000000000
RDX: ffff98f17cf90000 RSI: ffffb3758138fd64 RDI: ffff98f14d7fb000
RBP: ffffb3758138fd50 R08: 0000000000001000 R09: ffff98f17cf90000
R10: 0000000000000000 R11: ffffffff8dacad28 R12: 0000000000001000
R13: ffff98f1793a7d80 R14: ffff98f143231708 R15: ffff98f14d7fb018
FS:  00007ec166097800(0000) GS:ffff98f1bbd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffc04ef420 CR3: 000000010ee9a000 CR4: 00000000003506e0
Call Trace:
 temp_show+0x31/0x68
 dev_attr_show+0x1d/0x4f
 sysfs_kf_seq_show+0x92/0x107
 seq_read_iter+0xf5/0x3f2
 vfs_read+0x205/0x379
 __x64_sys_read+0x7c/0xe2
 do_syscall_64+0x43/0x55
 entry_SYSCALL_64_after_hwframe+0x61/0xc6

if a thermal device is removed while accesses to its device attributes
are ongoing.

The problem is exposed by code in iwl_op_mode_mvm_start(), which registers
a thermal zone device only to unregister it shortly afterwards if an
unrelated failure is encountered while accessing the hardware.

Check if the thermal zone device is registered after acquiring the
thermal zone device mutex to ensure this does not happen.

The code was tested by triggering the failure in iwl_op_mode_mvm_start()
on purpose. Without this patch, the kernel crashes reliably. The crash
is no longer observed after applying this and the preceding patches.
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      1c6b3006
    • Guenter Roeck's avatar
      thermal/core: Delete device under thermal device zone lock · 30b2ae07
      Guenter Roeck authored 
      Thermal device attributes may still be opened after unregistering
the thermal zone and deleting the thermal device.

Currently there is no protection against accessing thermal device
operations after unregistering a thermal zone. To enable adding
such protection, protect the device delete operation with the
thermal zone device mutex. This requires splitting the call to
device_unregister() into its components, device_del() and put_device().
Only the first call can be executed under mutex protection, since
put_device() may result in releasing the thermal zone device memory.
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      30b2ae07
    • Guenter Roeck's avatar
      thermal/core: Destroy thermal zone device mutex in release function · d35f29ed
      Guenter Roeck authored 
      Accesses to thermal zones, and with it the thermal zone device mutex,
are still possible after the thermal zone device has been unregistered.
For example, thermal_zone_get_temp() can be called from temp_show()
in thermal_sysfs.c if the sysfs attribute was opened before the thermal
device was unregistered.

Move the call to mutex_destroy from thermal_zone_device_unregister()
to thermal_release() to ensure that it is only destroyed after it is
guaranteed to be no longer accessed.
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      d35f29ed
  3. 28 Oct, 2022 1 commit
  5. 25 Oct, 2022 2 commits
  7. 23 Oct, 2022 9 commits
  9. 22 Oct, 2022 21 commits
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