1bd54d851f
kgdboc_option_setup does not check input argument before passing it to strlen. The argument would be a NULL pointer if "ekgdboc", without its value, is set in command line and thus cause the following panic. PANIC: early exception 0xe3 IP 10:ffffffff8fbbb620 error 0 cr2 0x0 [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18-rc8+ #1 [ 0.000000] RIP: 0010:strlen+0x0/0x20 ... [ 0.000000] Call Trace [ 0.000000] ? kgdboc_option_setup+0x9/0xa0 [ 0.000000] ? kgdboc_early_init+0x6/0x1b [ 0.000000] ? do_early_param+0x4d/0x82 [ 0.000000] ? parse_args+0x212/0x330 [ 0.000000] ? rdinit_setup+0x26/0x26 [ 0.000000] ? parse_early_options+0x20/0x23 [ 0.000000] ? rdinit_setup+0x26/0x26 [ 0.000000] ? parse_early_param+0x2d/0x39 [ 0.000000] ? setup_arch+0x2f7/0xbf4 [ 0.000000] ? start_kernel+0x5e/0x4c2 [ 0.000000] ? load_ucode_bsp+0x113/0x12f [ 0.000000] ? secondary_startup_64+0xa5/0xb0 This patch adds a check to prevent the panic. Cc: stable@vger.kernel.org Cc: jason.wessel@windriver.com Cc: gregkh@linuxfoundation.org Cc: jslaby@suse.com Signed-off-by: He Zhe <zhe.he@windriver.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> 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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.