Kees Cook bdc77507fe um: virt-pci: Avoid GCC non-NULL warning
GCC gets confused about the return value of get_cpu_var() possibly
being NULL, so explicitly test for it before calls to memcpy() and
memset(). Avoids warnings like this:

   arch/um/drivers/virt-pci.c: In function 'um_pci_send_cmd':
   include/linux/fortify-string.h:48:33: warning: argument 1 null where non-null expected [-Wnonnull]
      48 | #define __underlying_memcpy     __builtin_memcpy
         |                                 ^
   include/linux/fortify-string.h:438:9: note: in expansion of macro '__underlying_memcpy'
     438 |         __underlying_##op(p, q, __fortify_size);                        \
         |         ^~~~~~~~~~~~~
   include/linux/fortify-string.h:483:26: note: in expansion of macro '__fortify_memcpy_chk'
     483 | #define memcpy(p, q, s)  __fortify_memcpy_chk(p, q, s,                  \
         |                          ^~~~~~~~~~~~~~~~~~~~
   arch/um/drivers/virt-pci.c:100:9: note: in expansion of macro 'memcpy'
     100 |         memcpy(buf, cmd, cmd_size);
         |         ^~~~~~

While at it, avoid literal "8" and use stored sizeof(buf->data) in
memset() and um_pci_send_cmd().

Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/202211271212.SUZSC9f9-lkp@intel.com
Fixes: ba38961a06 ("um: Enable FORTIFY_SOURCE")
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Xiu Jianfeng <xiujianfeng@huawei.com>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: linux-um@lists.infradead.org
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
2022-12-02 13:04:44 -08:00
2022-09-28 09:02:20 +02:00
2022-09-28 09:02:20 +02:00
2022-09-28 09:02:20 +02:00

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.
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