e5f516b24c
commit a83c68a3bf7c418c9a46693c63c638852b0c1f4e upstream.
Buggy BIOSes may have invalid FPDT subtables, e.g. on my hardware:
S3PT subtable:
7F20FE30: 53 33 50 54 24 00 00 00-00 00 00 00 00 00 18 01 *S3PT$...........*
7F20FE40: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 *................*
7F20FE50: 00 00 00 00
Here the first record has zero length.
FBPT subtable:
7F20FE50: 46 42 50 54-3C 00 00 00 46 42 50 54 *....FBPT<...FBPT*
7F20FE60: 02 00 30 02 00 00 00 00-00 00 00 00 00 00 00 00 *..0.............*
7F20FE70: 2A A6 BC 6E 0B 00 00 00-1A 44 41 70 0B 00 00 00 **..n.....DAp....*
7F20FE80: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 *................*
And here FBPT table has FBPT signature repeated instead of the first
record.
Current code will be looping indefinitely due to zero length records, so
break out of the loop if record length is zero.
While we are here, add proper handling for fpdt_process_subtable()
failures.
Fixes: d1eb86e59be0 ("ACPI: tables: introduce support for FPDT table")
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
[ rjw: Comment edit, added empty code lines ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.