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Jamie Iles 0fada27714 ACPI: debug: don't allow debugging when ACPI is disabled
If ACPI is disabled then loading the acpi_dbg module will result in the
following splat when lock debugging is enabled.

  DEBUG_LOCKS_WARN_ON(lock->magic != lock)
  WARNING: CPU: 0 PID: 1 at kernel/locking/mutex.c:938 __mutex_lock+0xa10/0x1290
  Kernel panic - not syncing: panic_on_warn set ...
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc8+ #103
  Hardware name: linux,dummy-virt (DT)
  Call trace:
   dump_backtrace+0x0/0x4d8
   show_stack+0x34/0x48
   dump_stack+0x174/0x1f8
   panic+0x360/0x7a0
   __warn+0x244/0x2ec
   report_bug+0x240/0x398
   bug_handler+0x50/0xc0
   call_break_hook+0x160/0x1d8
   brk_handler+0x30/0xc0
   do_debug_exception+0x184/0x340
   el1_dbg+0x48/0xb0
   el1_sync_handler+0x170/0x1c8
   el1_sync+0x80/0x100
   __mutex_lock+0xa10/0x1290
   mutex_lock_nested+0x6c/0xc0
   acpi_register_debugger+0x40/0x88
   acpi_aml_init+0xc4/0x114
   do_one_initcall+0x24c/0xb10
   kernel_init_freeable+0x690/0x728
   kernel_init+0x20/0x1e8
   ret_from_fork+0x10/0x18

This is because acpi_debugger.lock has not been initialized as
acpi_debugger_init() is not called when ACPI is disabled.  Fail module
loading to avoid this and any subsequent problems that might arise by
trying to debug AML when ACPI is disabled.

Fixes: 8cfb0cdf07 ("ACPI / debugger: Add IO interface to access debugger functionalities")
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Jamie Iles <jamie@nuviainc.com>
Cc: 4.10+ <stable@vger.kernel.org> # 4.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-10-16 17:58:52 +02:00
Documentation ACPI updates for 5.10-rc1 2020-10-14 11:42:04 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch ACPI updates for 5.10-rc1 2020-10-14 11:42:04 -07:00
block drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
drivers ACPI: debug: don't allow debugging when ACPI is disabled 2020-10-16 17:58:52 +02:00
fs mm, oom_adj: don't loop through tasks in __set_oom_adj when not necessary 2020-10-13 18:38:35 -07:00
include ACPI updates for 5.10-rc1 2020-10-14 11:42:04 -07:00
init printk changes for 5.10 2020-10-13 15:58:10 -07:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel Power management updates for 5.10-rc1 2020-10-14 10:45:41 -07:00
lib mm/page_alloc.c: fix freeing non-compound pages 2020-10-13 18:38:33 -07:00
mm mm/migrate: remove obsolete comment about device public 2020-10-13 18:38:36 -07:00
net io_uring-5.10-2020-10-12 2020-10-13 12:36:21 -07:00
samples mm,kmemleak-test.c: move kmemleak-test.c to samples dir 2020-10-13 18:38:27 -07:00
scripts Merge branch 'akpm' (patches from Andrew) 2020-10-14 09:57:24 -07:00
security selinux/stable-5.10 PR 20201012 2020-10-13 16:29:55 -07:00
sound sound fixes for 5.9-rc7 2020-09-24 09:00:05 -07:00
tools ACPI updates for 5.10-rc1 2020-10-14 11:42:04 -07:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: fix memory leak in kvm_io_bus_unregister_dev() 2020-09-11 13:15:11 -04:00
.clang-format memblock: use separate iterators for memory and reserved regions 2020-10-13 18:38:35 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap As hoped, things calmed down for docs this cycle; fewer changes and almost 2020-10-12 16:21:29 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS ACPI updates for 5.10-rc1 2020-10-14 11:42:04 -07:00
Makefile Revert "kbuild: disable clang's default use of -fmerge-all-constants" 2020-10-13 18:38:26 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.