mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-14 14:42:34 -04:00
0fada27714
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>
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.