linux-stable.git/drivers/cpufreq, branch v5.4.201

Revert "cpufreq: Fix possible race in cpufreq online error path"

2022-06-14T16:11:36+00:00

[ Upstream commit 85f0e42bd65d01b351d561efb38e584d4c596553 ]

This reverts commit f346e96267cd76175d6c201b40f770c0116a8a04.

The commit tried to fix a possible real bug but it made it even worse.
The fix was simply buggy as now an error out to out_offline_policy or
out_exit_policy will try to release a semaphore which was never taken in
the first place. This works fine only if we failed late, i.e. via
out_destroy_policy.

Fixes: f346e96267cd ("cpufreq: Fix possible race in cpufreq online error path")
Signed-off-by: Viresh Kumar 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

cpufreq: Fix possible race in cpufreq online error path

2022-06-14T16:11:33+00:00

[ Upstream commit f346e96267cd76175d6c201b40f770c0116a8a04 ]

When cpufreq online fails, the policy->cpus mask is not cleared and
policy->rwsem is released too early, so the driver can be invoked
via the cpuinfo_cur_freq sysfs attribute while its ->offline() or
->exit() callbacks are being run.

Take policy->clk as an example:

static int cpufreq_online(unsigned int cpu)
{
  ...
  // policy->cpus != 0 at this time
  down_write(&policy->rwsem);
  ret = cpufreq_add_dev_interface(policy);
  up_write(&policy->rwsem);

  return 0;

out_destroy_policy:
	for_each_cpu(j, policy->real_cpus)
		remove_cpu_dev_symlink(policy, get_cpu_device(j));
    up_write(&policy->rwsem);
...
out_exit_policy:
  if (cpufreq_driver->exit)
    cpufreq_driver->exit(policy);
      clk_put(policy->clk);
      // policy->clk is a wild pointer
...
                                    ^
                                    |
                            Another process access
                            __cpufreq_get
                              cpufreq_verify_current_freq
                                cpufreq_generic_get
                                  // acces wild pointer of policy->clk;
                                    |
                                    |
out_offline_policy:                 |
  cpufreq_policy_free(policy);      |
    // deleted here, and will wait for no body reference
    cpufreq_policy_put_kobj(policy);
}

Address this by modifying cpufreq_online() to release policy->rwsem
in the error path after the driver callbacks have run and to clear
policy->cpus before releasing the semaphore.

Fixes: 7106e02baed4 ("cpufreq: release policy->rwsem on error")
Signed-off-by: Schspa Shi 
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

cpufreq: fix memory leak in sun50i_cpufreq_nvmem_probe

2022-05-09T07:03:25+00:00

[ Upstream commit 1aa24a8f3b5133dae4bc1e57427e345445f3e902 ]

--------------------------------------------
unreferenced object 0xffff000010742a00 (size 128):
  comm "swapper/0", pid 1, jiffies 4294902015 (age 1187.652s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000b4dfebaa>] __kmalloc+0x338/0x474
    [<00000000d6e716db>] sun50i_cpufreq_nvmem_probe+0xc4/0x36c
    [<000000007d6082a0>] platform_probe+0x98/0x11c
    [<00000000c990f549>] really_probe+0x234/0x5a0
    [<000000002d9fecc6>] __driver_probe_device+0x194/0x224
    [<00000000cf0b94fa>] driver_probe_device+0x64/0x13c
    [<00000000f238e4cf>] __device_attach_driver+0xf8/0x180
    [<000000006720e418>] bus_for_each_drv+0xf8/0x160
    [<00000000df4f14f6>] __device_attach+0x174/0x29c
    [<00000000782002fb>] device_initial_probe+0x20/0x30
    [<00000000c2681b06>] bus_probe_device+0xfc/0x110
    [<00000000964cf3bd>] device_add+0x5f0/0xcd0
    [<000000004b9264e3>] platform_device_add+0x198/0x390
    [<00000000fa82a9d0>] platform_device_register_full+0x178/0x210
    [<000000009a5daf13>] sun50i_cpufreq_init+0xf8/0x168
    [<000000000377cc7c>] do_one_initcall+0xe4/0x570
--------------------------------------------

if sun50i_cpufreq_get_efuse failed, then opp_tables leak.

Fixes: f328584f7bff ("cpufreq: Add sun50i nvmem based CPU scaling driver")
Signed-off-by: Xiaobing Luo 
Reviewed-by: Samuel Holland 
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

cpufreq: Fix initialization of min and max frequency QoS requests

2022-01-27T08:19:44+00:00

[ Upstream commit 521223d8b3ec078f670c7c35a1a04b1b2af07966 ]

The min and max frequency QoS requests in the cpufreq core are
initialized to whatever the current min and max frequency values are
at the init time, but if any of these values change later (for
example, cpuinfo.max_freq is updated by the driver), these initial
request values will be limiting the CPU frequency unnecessarily
unless they are changed by user space via sysfs.

To address this, initialize min_freq_req and max_freq_req to
FREQ_QOS_MIN_DEFAULT_VALUE and FREQ_QOS_MAX_DEFAULT_VALUE,
respectively, so they don't really limit anything until user
space updates them.

Reported-by: Srinivas Pandruvada 
Tested-by: Srinivas Pandruvada 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

cpufreq: Fix get_cpu_device() failure in add_cpu_dev_symlink()

2021-12-08T08:01:11+00:00

commit 2c1b5a84669d2477d8fffe9136e86a2cff591729 upstream.

When I hot added a CPU, I found 'cpufreq' directory was not created
below /sys/devices/system/cpu/cpuX/.

It is because get_cpu_device() failed in add_cpu_dev_symlink().

cpufreq_add_dev() is the .add_dev callback of a CPU subsys interface.
It will be called when the CPU device registered into the system.
The call chain is as follows:

  register_cpu()
  ->device_register()
   ->device_add()
    ->bus_probe_device()
     ->cpufreq_add_dev()

But only after the CPU device has been registered, we can get the
CPU device by get_cpu_device(), otherwise it will return NULL.

Since we already have the CPU device in cpufreq_add_dev(), pass
it to add_cpu_dev_symlink().

I noticed that the 'kobj' of the CPU device has been added into
the system before cpufreq_add_dev().

Fixes: 2f0ba790df51 ("cpufreq: Fix creation of symbolic links to policy directories")
Signed-off-by: Xiongfeng Wang 
Acked-by: Viresh Kumar 
Cc: All applicable 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

cpufreq: schedutil: Destroy mutex before kobject_put() frees the memory

2021-10-06T13:42:30+00:00

[ Upstream commit cdef1196608892b9a46caa5f2b64095a7f0be60c ]

Since commit e5c6b312ce3c ("cpufreq: schedutil: Use kobject release()
method to free sugov_tunables") kobject_put() has kfree()d the
attr_set before gov_attr_set_put() returns.

kobject_put() isn't the last user of attr_set in gov_attr_set_put(),
the subsequent mutex_destroy() triggers a use-after-free:
| BUG: KASAN: use-after-free in mutex_is_locked+0x20/0x60
| Read of size 8 at addr ffff000800ca4250 by task cpuhp/2/20
|
| CPU: 2 PID: 20 Comm: cpuhp/2 Not tainted 5.15.0-rc1 #12369
| Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development
| Platform, BIOS EDK II Jul 30 2018
| Call trace:
|  dump_backtrace+0x0/0x380
|  show_stack+0x1c/0x30
|  dump_stack_lvl+0x8c/0xb8
|  print_address_description.constprop.0+0x74/0x2b8
|  kasan_report+0x1f4/0x210
|  kasan_check_range+0xfc/0x1a4
|  __kasan_check_read+0x38/0x60
|  mutex_is_locked+0x20/0x60
|  mutex_destroy+0x80/0x100
|  gov_attr_set_put+0xfc/0x150
|  sugov_exit+0x78/0x190
|  cpufreq_offline.isra.0+0x2c0/0x660
|  cpuhp_cpufreq_offline+0x14/0x24
|  cpuhp_invoke_callback+0x430/0x6d0
|  cpuhp_thread_fun+0x1b0/0x624
|  smpboot_thread_fn+0x5e0/0xa6c
|  kthread+0x3a0/0x450
|  ret_from_fork+0x10/0x20

Swap the order of the calls.

Fixes: e5c6b312ce3c ("cpufreq: schedutil: Use kobject release() method to free sugov_tunables")
Cc: 4.7+  # 4.7+
Signed-off-by: James Morse 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Sasha Levin

cpufreq: powernv: Fix init_chip_info initialization in numa=off

2021-09-22T10:26:37+00:00

commit f34ee9cb2c5ac5af426fee6fa4591a34d187e696 upstream.

In the numa=off kernel command-line configuration init_chip_info() loops
around the number of chips and attempts to copy the cpumask of that node
which is NULL for all iterations after the first chip.

Hence, store the cpu mask for each chip instead of derving cpumask from
node while populating the "chips" struct array and copy that to the
chips[i].mask

Fixes: 053819e0bf84 ("cpufreq: powernv: Handle throttling due to Pmax capping at chip level")
Cc: stable@vger.kernel.org # v4.3+
Reported-by: Shirisha Ganta 
Signed-off-by: Pratik R. Sampat 
Reviewed-by: Gautham R. Shenoy 
[mpe: Rename goto label to out_free_chip_cpu_mask]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210728120500.87549-2-psampat@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman

cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant

2021-08-26T12:36:16+00:00

[ Upstream commit 484f2b7c61b9ae58cc00c5127bcbcd9177af8dfe ]

The 1.2 GHz variant of the Armada 3720 SOC is unstable with DVFS: when
the SOC boots, the WTMI firmware sets clocks and AVS values that work
correctly with 1.2 GHz CPU frequency, but random crashes occur once
cpufreq driver starts scaling.

We do not know currently what is the reason:
- it may be that the voltage value for L0 for 1.2 GHz variant provided
  by the vendor in the OTP is simply incorrect when scaling is used,
- it may be that some delay is needed somewhere,
- it may be something else.

The most sane solution now seems to be to simply forbid the cpufreq
driver on 1.2 GHz variant.

Signed-off-by: Marek Behún 
Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx")
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin

cpufreq: Make cpufreq_online() call driver->offline() on errors

2021-07-14T14:53:25+00:00

[ Upstream commit 3b7180573c250eb6e2a7eec54ae91f27472332ea ]

In the CPU removal path the ->offline() callback provided by the
driver is always invoked before ->exit(), but in the cpufreq_online()
error path it is not, so ->exit() is expected to somehow know the
context in which it has been called and act accordingly.

That is less than straightforward, so make cpufreq_online() invoke
the driver's ->offline() callback, if present, on errors before
->exit() too.

This only potentially affects intel_pstate.

Fixes: 91a12e91dc39 ("cpufreq: Allow light-weight tear down and bring up of CPUs")
Signed-off-by: Rafael J. Wysocki 
Acked-by: Viresh Kumar 
Signed-off-by: Sasha Levin

cpufreq: armada-37xx: Fix determining base CPU frequency

2021-05-14T07:44:21+00:00

[ Upstream commit 8bad3bf23cbc40abe1d24cec08a114df6facf858 ]

When current CPU load is not L0 then loading armada-37xx-cpufreq.ko driver
fails with following error:

    # modprobe armada-37xx-cpufreq
    [  502.702097] Unsupported CPU frequency 250 MHz

This issue was partially fixed by commit 8db82563451f ("cpufreq:
armada-37xx: fix frequency calculation for opp"), but only for calculating
CPU frequency for opp.

Fix this also for determination of base CPU frequency.

Signed-off-by: Pali Rohár 
Acked-by: Gregory CLEMENT 
Tested-by: Tomasz Maciej Nowak 
Tested-by: Anders Trier Olesen 
Tested-by: Philip Soares 
Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx")
Signed-off-by: Viresh Kumar 
Signed-off-by: Sasha Levin