<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/drivers/acpi/processor_throttling.c, branch v5.13</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>ACPI: utils: Introduce acpi_evaluation_failure_warn()</title>
<updated>2021-03-08T18:10:30+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2021-03-05T18:41:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=4c324548f09fec413b4ee589174dabacfe17d953'/>
<id>4c324548f09fec413b4ee589174dabacfe17d953</id>
<content type='text'>
Quite a few users of ACPI objects want to log a warning message if
the evaluation fails which is a repeating pattern, so introduce a
helper function for that purpose and convert some code where it is
open-coded to using it.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Quite a few users of ACPI objects want to log a warning message if
the evaluation fails which is a repeating pattern, so introduce a
helper function for that purpose and convert some code where it is
open-coded to using it.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: Get rid of ACPICA message printing</title>
<updated>2021-03-08T15:51:19+00:00</updated>
<author>
<name>Rafael J. Wysocki</name>
<email>rafael.j.wysocki@intel.com</email>
</author>
<published>2021-02-22T18:59:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=52af99c3f55ff0afd815eac0271db2e1751af55c'/>
<id>52af99c3f55ff0afd815eac0271db2e1751af55c</id>
<content type='text'>
The ACPI_DEBUG_PRINT() and ACPI_EXCEPTION() macros are used for
message printing in the ACPICA code and they should not be used
elsewhere.  Special configuration (either kernel command line or
sysfs-based) is needed to see the messages printed by them and
the format of those messages is also special and convoluted.

For this reason, replace all of the ACPI_DEBUG_PRINT() and
ACPI_EXCEPTION() instances in the ACPI processor driver with
corresponding dev_*(), acpi_handle_*() and pr_*() calls depending
on the context in which they appear.

Also drop the ACPI_PROCESSOR_COMPONENT definition that is not going
to be necessary any more.

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The ACPI_DEBUG_PRINT() and ACPI_EXCEPTION() macros are used for
message printing in the ACPICA code and they should not be used
elsewhere.  Special configuration (either kernel command line or
sysfs-based) is needed to see the messages printed by them and
the format of those messages is also special and convoluted.

For this reason, replace all of the ACPI_DEBUG_PRINT() and
ACPI_EXCEPTION() instances in the ACPI processor driver with
corresponding dev_*(), acpi_handle_*() and pr_*() calls depending
on the context in which they appear.

Also drop the ACPI_PROCESSOR_COMPONENT definition that is not going
to be necessary any more.

Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Reviewed-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI: processor: Remove the duplicated ACPI_PROCESSOR_CLASS macro</title>
<updated>2020-11-17T17:12:34+00:00</updated>
<author>
<name>Hanjun Guo</name>
<email>guohanjun@huawei.com</email>
</author>
<published>2020-11-13T02:08:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=eb37ba316fdec9c6af36b8b155732568c5b2a2d4'/>
<id>eb37ba316fdec9c6af36b8b155732568c5b2a2d4</id>
<content type='text'>
The ACPI_PROCESSOR_CLASS macro is defined in &lt;acpi/processor.h&gt;,
and ACPI drivers for processor already included &lt;acpi/processor.h&gt;,
so we can remove those duplicated ACPI_PROCESSOR_CLASS macros.

Signed-off-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The ACPI_PROCESSOR_CLASS macro is defined in &lt;acpi/processor.h&gt;,
and ACPI drivers for processor already included &lt;acpi/processor.h&gt;,
so we can remove those duplicated ACPI_PROCESSOR_CLASS macros.

Signed-off-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>x86: ACPI: fix CPU hotplug deadlock</title>
<updated>2020-04-04T14:28:24+00:00</updated>
<author>
<name>Qian Cai</name>
<email>cai@lca.pw</email>
</author>
<published>2020-04-03T14:03:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=696ac2e3bf267f5a2b2ed7d34e64131f2287d0ad'/>
<id>696ac2e3bf267f5a2b2ed7d34e64131f2287d0ad</id>
<content type='text'>
Similar to commit 0266d81e9bf5 ("acpi/processor: Prevent cpu hotplug
deadlock") except this is for acpi_processor_ffh_cstate_probe():

"The problem is that the work is scheduled on the current CPU from the
hotplug thread associated with that CPU.

It's not required to invoke these functions via the workqueue because
the hotplug thread runs on the target CPU already.

Check whether current is a per cpu thread pinned on the target CPU and
invoke the function directly to avoid the workqueue."

 WARNING: possible circular locking dependency detected
 ------------------------------------------------------
 cpuhp/1/15 is trying to acquire lock:
 ffffc90003447a28 ((work_completion)(&amp;wfc.work)){+.+.}-{0:0}, at: __flush_work+0x4c6/0x630

 but task is already holding lock:
 ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -&gt; #1 (cpu_hotplug_lock){++++}-{0:0}:
 cpus_read_lock+0x3e/0xc0
 irq_calc_affinity_vectors+0x5f/0x91
 __pci_enable_msix_range+0x10f/0x9a0
 pci_alloc_irq_vectors_affinity+0x13e/0x1f0
 pci_alloc_irq_vectors_affinity at drivers/pci/msi.c:1208
 pqi_ctrl_init+0x72f/0x1618 [smartpqi]
 pqi_pci_probe.cold.63+0x882/0x892 [smartpqi]
 local_pci_probe+0x7a/0xc0
 work_for_cpu_fn+0x2e/0x50
 process_one_work+0x57e/0xb90
 worker_thread+0x363/0x5b0
 kthread+0x1f4/0x220
 ret_from_fork+0x27/0x50

 -&gt; #0 ((work_completion)(&amp;wfc.work)){+.+.}-{0:0}:
 __lock_acquire+0x2244/0x32a0
 lock_acquire+0x1a2/0x680
 __flush_work+0x4e6/0x630
 work_on_cpu+0x114/0x160
 acpi_processor_ffh_cstate_probe+0x129/0x250
 acpi_processor_evaluate_cst+0x4c8/0x580
 acpi_processor_get_power_info+0x86/0x740
 acpi_processor_hotplug+0xc3/0x140
 acpi_soft_cpu_online+0x102/0x1d0
 cpuhp_invoke_callback+0x197/0x1120
 cpuhp_thread_fun+0x252/0x2f0
 smpboot_thread_fn+0x255/0x440
 kthread+0x1f4/0x220
 ret_from_fork+0x27/0x50

 other info that might help us debug this:

 Chain exists of:
 (work_completion)(&amp;wfc.work) --&gt; cpuhp_state-up --&gt; cpuidle_lock

 Possible unsafe locking scenario:

 CPU0                    CPU1
 ----                    ----
 lock(cpuidle_lock);
                         lock(cpuhp_state-up);
                         lock(cpuidle_lock);
 lock((work_completion)(&amp;wfc.work));

 *** DEADLOCK ***

 3 locks held by cpuhp/1/15:
 #0: ffffffffaf51ab10 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0
 #1: ffffffffaf51ad40 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0
 #2: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20

 Call Trace:
 dump_stack+0xa0/0xea
 print_circular_bug.cold.52+0x147/0x14c
 check_noncircular+0x295/0x2d0
 __lock_acquire+0x2244/0x32a0
 lock_acquire+0x1a2/0x680
 __flush_work+0x4e6/0x630
 work_on_cpu+0x114/0x160
 acpi_processor_ffh_cstate_probe+0x129/0x250
 acpi_processor_evaluate_cst+0x4c8/0x580
 acpi_processor_get_power_info+0x86/0x740
 acpi_processor_hotplug+0xc3/0x140
 acpi_soft_cpu_online+0x102/0x1d0
 cpuhp_invoke_callback+0x197/0x1120
 cpuhp_thread_fun+0x252/0x2f0
 smpboot_thread_fn+0x255/0x440
 kthread+0x1f4/0x220
 ret_from_fork+0x27/0x50

Signed-off-by: Qian Cai &lt;cai@lca.pw&gt;
Tested-by: Borislav Petkov &lt;bp@suse.de&gt;
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Similar to commit 0266d81e9bf5 ("acpi/processor: Prevent cpu hotplug
deadlock") except this is for acpi_processor_ffh_cstate_probe():

"The problem is that the work is scheduled on the current CPU from the
hotplug thread associated with that CPU.

It's not required to invoke these functions via the workqueue because
the hotplug thread runs on the target CPU already.

Check whether current is a per cpu thread pinned on the target CPU and
invoke the function directly to avoid the workqueue."

 WARNING: possible circular locking dependency detected
 ------------------------------------------------------
 cpuhp/1/15 is trying to acquire lock:
 ffffc90003447a28 ((work_completion)(&amp;wfc.work)){+.+.}-{0:0}, at: __flush_work+0x4c6/0x630

 but task is already holding lock:
 ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -&gt; #1 (cpu_hotplug_lock){++++}-{0:0}:
 cpus_read_lock+0x3e/0xc0
 irq_calc_affinity_vectors+0x5f/0x91
 __pci_enable_msix_range+0x10f/0x9a0
 pci_alloc_irq_vectors_affinity+0x13e/0x1f0
 pci_alloc_irq_vectors_affinity at drivers/pci/msi.c:1208
 pqi_ctrl_init+0x72f/0x1618 [smartpqi]
 pqi_pci_probe.cold.63+0x882/0x892 [smartpqi]
 local_pci_probe+0x7a/0xc0
 work_for_cpu_fn+0x2e/0x50
 process_one_work+0x57e/0xb90
 worker_thread+0x363/0x5b0
 kthread+0x1f4/0x220
 ret_from_fork+0x27/0x50

 -&gt; #0 ((work_completion)(&amp;wfc.work)){+.+.}-{0:0}:
 __lock_acquire+0x2244/0x32a0
 lock_acquire+0x1a2/0x680
 __flush_work+0x4e6/0x630
 work_on_cpu+0x114/0x160
 acpi_processor_ffh_cstate_probe+0x129/0x250
 acpi_processor_evaluate_cst+0x4c8/0x580
 acpi_processor_get_power_info+0x86/0x740
 acpi_processor_hotplug+0xc3/0x140
 acpi_soft_cpu_online+0x102/0x1d0
 cpuhp_invoke_callback+0x197/0x1120
 cpuhp_thread_fun+0x252/0x2f0
 smpboot_thread_fn+0x255/0x440
 kthread+0x1f4/0x220
 ret_from_fork+0x27/0x50

 other info that might help us debug this:

 Chain exists of:
 (work_completion)(&amp;wfc.work) --&gt; cpuhp_state-up --&gt; cpuidle_lock

 Possible unsafe locking scenario:

 CPU0                    CPU1
 ----                    ----
 lock(cpuidle_lock);
                         lock(cpuhp_state-up);
                         lock(cpuidle_lock);
 lock((work_completion)(&amp;wfc.work));

 *** DEADLOCK ***

 3 locks held by cpuhp/1/15:
 #0: ffffffffaf51ab10 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0
 #1: ffffffffaf51ad40 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x69/0x2f0
 #2: ffffffffafa1c0e8 (cpuidle_lock){+.+.}-{3:3}, at: cpuidle_pause_and_lock+0x17/0x20

 Call Trace:
 dump_stack+0xa0/0xea
 print_circular_bug.cold.52+0x147/0x14c
 check_noncircular+0x295/0x2d0
 __lock_acquire+0x2244/0x32a0
 lock_acquire+0x1a2/0x680
 __flush_work+0x4e6/0x630
 work_on_cpu+0x114/0x160
 acpi_processor_ffh_cstate_probe+0x129/0x250
 acpi_processor_evaluate_cst+0x4c8/0x580
 acpi_processor_get_power_info+0x86/0x740
 acpi_processor_hotplug+0xc3/0x140
 acpi_soft_cpu_online+0x102/0x1d0
 cpuhp_invoke_callback+0x197/0x1120
 cpuhp_thread_fun+0x252/0x2f0
 smpboot_thread_fn+0x255/0x440
 kthread+0x1f4/0x220
 ret_from_fork+0x27/0x50

Signed-off-by: Qian Cai &lt;cai@lca.pw&gt;
Tested-by: Borislav Petkov &lt;bp@suse.de&gt;
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157</title>
<updated>2019-05-30T18:26:37+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2019-05-27T06:55:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c942fddf8793b2013be8c901b47d0a8dc02bf99f'/>
<id>c942fddf8793b2013be8c901b47d0a8dc02bf99f</id>
<content type='text'>
Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Richard Fontana &lt;rfontana@redhat.com&gt;
Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Based on 3 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] this program is distributed in the hope that
  it will be useful but without any warranty without even the implied
  warranty of merchantability or fitness for a particular purpose see
  the gnu general public license for more details

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] this program is distributed in the hope
  that it will be useful but without any warranty without even the
  implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Reviewed-by: Richard Fontana &lt;rfontana@redhat.com&gt;
Reviewed-by: Kate Stewart &lt;kstewart@linuxfoundation.org&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: kmalloc() -&gt; kmalloc_array()</title>
<updated>2018-06-12T23:19:22+00:00</updated>
<author>
<name>Kees Cook</name>
<email>keescook@chromium.org</email>
</author>
<published>2018-06-12T20:55:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6da2ec56059c3c7a7e5f729e6349e74ace1e5c57'/>
<id>6da2ec56059c3c7a7e5f729e6349e74ace1e5c57</id>
<content type='text'>
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This
patch replaces cases of:

        kmalloc(a * b, gfp)

with:
        kmalloc_array(a * b, gfp)

as well as handling cases of:

        kmalloc(a * b * c, gfp)

with:

        kmalloc(array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        kmalloc_array(array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        kmalloc(4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The tools/ directory was manually excluded, since it has its own
implementation of kmalloc().

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
  kmalloc(
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  kmalloc(
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  kmalloc(
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

- kmalloc
+ kmalloc_array
  (
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  kmalloc(
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  kmalloc(
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
  kmalloc(
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  kmalloc(sizeof(THING) * C2, ...)
|
  kmalloc(sizeof(TYPE) * C2, ...)
|
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(C1 * C2, ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * E2
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	E1 * E2
+	E1, E2
  , ...)
)

Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This
patch replaces cases of:

        kmalloc(a * b, gfp)

with:
        kmalloc_array(a * b, gfp)

as well as handling cases of:

        kmalloc(a * b * c, gfp)

with:

        kmalloc(array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        kmalloc_array(array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        kmalloc(4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The tools/ directory was manually excluded, since it has its own
implementation of kmalloc().

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
  kmalloc(
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  kmalloc(
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  kmalloc(
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  kmalloc(
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

- kmalloc
+ kmalloc_array
  (
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  kmalloc(
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kmalloc(
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  kmalloc(
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  kmalloc(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
  kmalloc(
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kmalloc(
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  kmalloc(
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  kmalloc(sizeof(THING) * C2, ...)
|
  kmalloc(sizeof(TYPE) * C2, ...)
|
  kmalloc(C1 * C2 * C3, ...)
|
  kmalloc(C1 * C2, ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * E2
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- kmalloc
+ kmalloc_array
  (
-	E1 * E2
+	E1, E2
  , ...)
)

Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>acpi/processor: Prevent cpu hotplug deadlock</title>
<updated>2017-05-26T08:10:47+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2017-05-24T08:15:42+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0266d81e9bf5cc1fe6405c0523dfa015fe55aae1'/>
<id>0266d81e9bf5cc1fe6405c0523dfa015fe55aae1</id>
<content type='text'>
With the enhanced CPU hotplug lockdep coverage the following lockdep splat
happens:

======================================================
WARNING: possible circular locking dependency detected
4.12.0-rc2+ #84 Tainted: G        W      
------------------------------------------------------
cpuhp/1/15 is trying to acquire lock:
flush_work+0x39/0x2f0

but task is already holding lock:
cpuhp_thread_fun+0x30/0x160

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-&gt; #2 (cpuhp_state){+.+.+.}:
       lock_acquire+0xb4/0x200
       cpuhp_kick_ap_work+0x72/0x330
       _cpu_down+0x8b/0x100
       do_cpu_down+0x3e/0x60
       cpu_down+0x10/0x20
       cpu_subsys_offline+0x14/0x20
       device_offline+0x88/0xb0
       online_store+0x4c/0xa0
       dev_attr_store+0x18/0x30
       sysfs_kf_write+0x45/0x60
       kernfs_fop_write+0x156/0x1e0
       __vfs_write+0x37/0x160
       vfs_write+0xca/0x1c0
       SyS_write+0x58/0xc0
       entry_SYSCALL_64_fastpath+0x23/0xc2

-&gt; #1 (cpu_hotplug_lock.rw_sem){++++++}:
       lock_acquire+0xb4/0x200
       cpus_read_lock+0x3d/0xb0
       apply_workqueue_attrs+0x17/0x50
       __alloc_workqueue_key+0x1e1/0x530
       scsi_host_alloc+0x373/0x480 [scsi_mod]
       ata_scsi_add_hosts+0xcb/0x130 [libata]
       ata_host_register+0x11a/0x2c0 [libata]
       ata_host_activate+0xf0/0x150 [libata]
       ahci_host_activate+0x13e/0x170 [libahci]
       ahci_init_one+0xa3a/0xd3f [ahci]
       local_pci_probe+0x45/0xa0
       work_for_cpu_fn+0x14/0x20
       process_one_work+0x1f9/0x690
       worker_thread+0x200/0x3d0
       kthread+0x138/0x170
       ret_from_fork+0x31/0x40

-&gt; #0 ((&amp;wfc.work)){+.+.+.}:
       __lock_acquire+0x11e1/0x13e0
       lock_acquire+0xb4/0x200
       flush_work+0x5c/0x2f0
       work_on_cpu+0xa1/0xd0
       acpi_processor_get_throttling+0x3d/0x50
       acpi_processor_reevaluate_tstate+0x2c/0x50
       acpi_soft_cpu_online+0x69/0xd0
       cpuhp_invoke_callback+0xb4/0x8b0
       cpuhp_up_callbacks+0x36/0xc0
       cpuhp_thread_fun+0x14e/0x160
       smpboot_thread_fn+0x1e8/0x300
       kthread+0x138/0x170
       ret_from_fork+0x31/0x40

other info that might help us debug this:

Chain exists of:
  (&amp;wfc.work) --&gt; cpu_hotplug_lock.rw_sem --&gt; cpuhp_state

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(cpuhp_state);
                               lock(cpu_hotplug_lock.rw_sem);
                               lock(cpuhp_state);
  lock((&amp;wfc.work));

 *** DEADLOCK ***

1 lock held by cpuhp/1/15:
cpuhp_thread_fun+0x30/0x160

stack backtrace:
CPU: 1 PID: 15 Comm: cpuhp/1 Tainted: G        W       4.12.0-rc2+ #84
Hardware name: Supermicro SYS-4048B-TR4FT/X10QBi, BIOS 1.1a 07/29/2015
Call Trace:
 dump_stack+0x85/0xc4
 print_circular_bug+0x209/0x217
 __lock_acquire+0x11e1/0x13e0
 lock_acquire+0xb4/0x200
 ? lock_acquire+0xb4/0x200
 ? flush_work+0x39/0x2f0
 ? acpi_processor_start+0x50/0x50
 flush_work+0x5c/0x2f0
 ? flush_work+0x39/0x2f0
 ? acpi_processor_start+0x50/0x50
 ? mark_held_locks+0x6d/0x90
 ? queue_work_on+0x56/0x90
 ? trace_hardirqs_on_caller+0x154/0x1c0
 ? trace_hardirqs_on+0xd/0x10
 ? acpi_processor_start+0x50/0x50
 work_on_cpu+0xa1/0xd0
 ? find_worker_executing_work+0x50/0x50
 ? acpi_processor_power_exit+0x70/0x70
 acpi_processor_get_throttling+0x3d/0x50
 acpi_processor_reevaluate_tstate+0x2c/0x50
 acpi_soft_cpu_online+0x69/0xd0
 cpuhp_invoke_callback+0xb4/0x8b0
 ? lock_acquire+0xb4/0x200
 ? padata_replace+0x120/0x120
 cpuhp_up_callbacks+0x36/0xc0
 cpuhp_thread_fun+0x14e/0x160
 smpboot_thread_fn+0x1e8/0x300
 kthread+0x138/0x170
 ? sort_range+0x30/0x30
 ? kthread_create_on_node+0x70/0x70
 ret_from_fork+0x31/0x40

The problem is that the work is scheduled on the current CPU from the
hotplug thread associated with that CPU.

It's not required to invoke these functions via the workqueue because the
hotplug thread runs on the target CPU already.

Check whether current is a per cpu thread pinned on the target CPU and
invoke the function directly to avoid the workqueue.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Sebastian Siewior &lt;bigeasy@linutronix.de&gt;
Cc: "Rafael J. Wysocki" &lt;rjw@rjwysocki.net&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: linux-acpi@vger.kernel.org
Cc: Len Brown &lt;lenb@kernel.org&gt;
Link: http://lkml.kernel.org/r/20170524081549.620489733@linutronix.de

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
With the enhanced CPU hotplug lockdep coverage the following lockdep splat
happens:

======================================================
WARNING: possible circular locking dependency detected
4.12.0-rc2+ #84 Tainted: G        W      
------------------------------------------------------
cpuhp/1/15 is trying to acquire lock:
flush_work+0x39/0x2f0

but task is already holding lock:
cpuhp_thread_fun+0x30/0x160

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-&gt; #2 (cpuhp_state){+.+.+.}:
       lock_acquire+0xb4/0x200
       cpuhp_kick_ap_work+0x72/0x330
       _cpu_down+0x8b/0x100
       do_cpu_down+0x3e/0x60
       cpu_down+0x10/0x20
       cpu_subsys_offline+0x14/0x20
       device_offline+0x88/0xb0
       online_store+0x4c/0xa0
       dev_attr_store+0x18/0x30
       sysfs_kf_write+0x45/0x60
       kernfs_fop_write+0x156/0x1e0
       __vfs_write+0x37/0x160
       vfs_write+0xca/0x1c0
       SyS_write+0x58/0xc0
       entry_SYSCALL_64_fastpath+0x23/0xc2

-&gt; #1 (cpu_hotplug_lock.rw_sem){++++++}:
       lock_acquire+0xb4/0x200
       cpus_read_lock+0x3d/0xb0
       apply_workqueue_attrs+0x17/0x50
       __alloc_workqueue_key+0x1e1/0x530
       scsi_host_alloc+0x373/0x480 [scsi_mod]
       ata_scsi_add_hosts+0xcb/0x130 [libata]
       ata_host_register+0x11a/0x2c0 [libata]
       ata_host_activate+0xf0/0x150 [libata]
       ahci_host_activate+0x13e/0x170 [libahci]
       ahci_init_one+0xa3a/0xd3f [ahci]
       local_pci_probe+0x45/0xa0
       work_for_cpu_fn+0x14/0x20
       process_one_work+0x1f9/0x690
       worker_thread+0x200/0x3d0
       kthread+0x138/0x170
       ret_from_fork+0x31/0x40

-&gt; #0 ((&amp;wfc.work)){+.+.+.}:
       __lock_acquire+0x11e1/0x13e0
       lock_acquire+0xb4/0x200
       flush_work+0x5c/0x2f0
       work_on_cpu+0xa1/0xd0
       acpi_processor_get_throttling+0x3d/0x50
       acpi_processor_reevaluate_tstate+0x2c/0x50
       acpi_soft_cpu_online+0x69/0xd0
       cpuhp_invoke_callback+0xb4/0x8b0
       cpuhp_up_callbacks+0x36/0xc0
       cpuhp_thread_fun+0x14e/0x160
       smpboot_thread_fn+0x1e8/0x300
       kthread+0x138/0x170
       ret_from_fork+0x31/0x40

other info that might help us debug this:

Chain exists of:
  (&amp;wfc.work) --&gt; cpu_hotplug_lock.rw_sem --&gt; cpuhp_state

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(cpuhp_state);
                               lock(cpu_hotplug_lock.rw_sem);
                               lock(cpuhp_state);
  lock((&amp;wfc.work));

 *** DEADLOCK ***

1 lock held by cpuhp/1/15:
cpuhp_thread_fun+0x30/0x160

stack backtrace:
CPU: 1 PID: 15 Comm: cpuhp/1 Tainted: G        W       4.12.0-rc2+ #84
Hardware name: Supermicro SYS-4048B-TR4FT/X10QBi, BIOS 1.1a 07/29/2015
Call Trace:
 dump_stack+0x85/0xc4
 print_circular_bug+0x209/0x217
 __lock_acquire+0x11e1/0x13e0
 lock_acquire+0xb4/0x200
 ? lock_acquire+0xb4/0x200
 ? flush_work+0x39/0x2f0
 ? acpi_processor_start+0x50/0x50
 flush_work+0x5c/0x2f0
 ? flush_work+0x39/0x2f0
 ? acpi_processor_start+0x50/0x50
 ? mark_held_locks+0x6d/0x90
 ? queue_work_on+0x56/0x90
 ? trace_hardirqs_on_caller+0x154/0x1c0
 ? trace_hardirqs_on+0xd/0x10
 ? acpi_processor_start+0x50/0x50
 work_on_cpu+0xa1/0xd0
 ? find_worker_executing_work+0x50/0x50
 ? acpi_processor_power_exit+0x70/0x70
 acpi_processor_get_throttling+0x3d/0x50
 acpi_processor_reevaluate_tstate+0x2c/0x50
 acpi_soft_cpu_online+0x69/0xd0
 cpuhp_invoke_callback+0xb4/0x8b0
 ? lock_acquire+0xb4/0x200
 ? padata_replace+0x120/0x120
 cpuhp_up_callbacks+0x36/0xc0
 cpuhp_thread_fun+0x14e/0x160
 smpboot_thread_fn+0x1e8/0x300
 kthread+0x138/0x170
 ? sort_range+0x30/0x30
 ? kthread_create_on_node+0x70/0x70
 ret_from_fork+0x31/0x40

The problem is that the work is scheduled on the current CPU from the
hotplug thread associated with that CPU.

It's not required to invoke these functions via the workqueue because the
hotplug thread runs on the target CPU already.

Check whether current is a per cpu thread pinned on the target CPU and
invoke the function directly to avoid the workqueue.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Cc: Paul E. McKenney &lt;paulmck@linux.vnet.ibm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Sebastian Siewior &lt;bigeasy@linutronix.de&gt;
Cc: "Rafael J. Wysocki" &lt;rjw@rjwysocki.net&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Cc: linux-acpi@vger.kernel.org
Cc: Len Brown &lt;lenb@kernel.org&gt;
Link: http://lkml.kernel.org/r/20170524081549.620489733@linutronix.de

</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI/processor: Replace racy task affinity logic</title>
<updated>2017-04-15T10:20:54+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2017-04-12T20:07:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8153f9ac43897f9f4786b30badc134fcc1a4fb11'/>
<id>8153f9ac43897f9f4786b30badc134fcc1a4fb11</id>
<content type='text'>
acpi_processor_get_throttling() requires to invoke the getter function on
the target CPU. This is achieved by temporarily setting the affinity of the
calling user space thread to the requested CPU and reset it to the original
affinity afterwards.

That's racy vs. CPU hotplug and concurrent affinity settings for that
thread resulting in code executing on the wrong CPU and overwriting the
new affinity setting.

acpi_processor_get_throttling() is invoked in two ways:

1) The CPU online callback, which is already running on the target CPU and
   obviously protected against hotplug and not affected by affinity
   settings.

2) The ACPI driver probe function, which is not protected against hotplug
   during modprobe.

Switch it over to work_on_cpu() and protect the probe function against CPU
hotplug.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Cc: "Rafael J. Wysocki" &lt;rjw@rjwysocki.net&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Sebastian Siewior &lt;bigeasy@linutronix.de&gt;
Cc: Lai Jiangshan &lt;jiangshanlai@gmail.com&gt;
Cc: linux-acpi@vger.kernel.org
Cc: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Len Brown &lt;lenb@kernel.org&gt;
Link: http://lkml.kernel.org/r/20170412201042.785920903@linutronix.de
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
acpi_processor_get_throttling() requires to invoke the getter function on
the target CPU. This is achieved by temporarily setting the affinity of the
calling user space thread to the requested CPU and reset it to the original
affinity afterwards.

That's racy vs. CPU hotplug and concurrent affinity settings for that
thread resulting in code executing on the wrong CPU and overwriting the
new affinity setting.

acpi_processor_get_throttling() is invoked in two ways:

1) The CPU online callback, which is already running on the target CPU and
   obviously protected against hotplug and not affected by affinity
   settings.

2) The ACPI driver probe function, which is not protected against hotplug
   during modprobe.

Switch it over to work_on_cpu() and protect the probe function against CPU
hotplug.

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Cc: Fenghua Yu &lt;fenghua.yu@intel.com&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Herbert Xu &lt;herbert@gondor.apana.org.au&gt;
Cc: "Rafael J. Wysocki" &lt;rjw@rjwysocki.net&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Sebastian Siewior &lt;bigeasy@linutronix.de&gt;
Cc: Lai Jiangshan &lt;jiangshanlai@gmail.com&gt;
Cc: linux-acpi@vger.kernel.org
Cc: Viresh Kumar &lt;viresh.kumar@linaro.org&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Tejun Heo &lt;tj@kernel.org&gt;
Cc: "David S. Miller" &lt;davem@davemloft.net&gt;
Cc: Len Brown &lt;lenb@kernel.org&gt;
Link: http://lkml.kernel.org/r/20170412201042.785920903@linutronix.de
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Replace &lt;asm/uaccess.h&gt; with &lt;linux/uaccess.h&gt; globally</title>
<updated>2016-12-24T19:46:01+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2016-12-24T19:46:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7c0f6ba682b9c7632072ffbedf8d328c8f3c42ba'/>
<id>7c0f6ba682b9c7632072ffbedf8d328c8f3c42ba</id>
<content type='text'>
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*&lt;asm/uaccess.h&gt;'
  sed -i -e "s!$PATT!#include &lt;linux/uaccess.h&gt;!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*&lt;asm/uaccess.h&gt;'
  sed -i -e "s!$PATT!#include &lt;linux/uaccess.h&gt;!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ACPI/processor: Convert to hotplug state machine</title>
<updated>2016-09-19T19:44:29+00:00</updated>
<author>
<name>Sebastian Andrzej Siewior</name>
<email>bigeasy@linutronix.de</email>
</author>
<published>2016-09-06T17:04:47+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=64f3bf2f85c5690228200d6b94eb6847049af70d'/>
<id>64f3bf2f85c5690228200d6b94eb6847049af70d</id>
<content type='text'>
Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Acked-by: "Rafael J. Wysocki" &lt;rjw@rjwysocki.net&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: linux-acpi@vger.kernel.org
Cc: rt@linutronix.de
Cc: Len Brown &lt;lenb@kernel.org&gt;
Link: http://lkml.kernel.org/r/20160906170457.32393-12-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Acked-by: "Rafael J. Wysocki" &lt;rjw@rjwysocki.net&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: linux-acpi@vger.kernel.org
Cc: rt@linutronix.de
Cc: Len Brown &lt;lenb@kernel.org&gt;
Link: http://lkml.kernel.org/r/20160906170457.32393-12-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</pre>
</div>
</content>
</entry>
</feed>
