fec4d42724
intel_dp_check_mst_status() uses a 14-byte array to read the DPRX Event
Status Indicator data, but then passes that buffer at offset 10 off as
an argument to drm_dp_channel_eq_ok().
End result: there are only 4 bytes remaining of the buffer, yet
drm_dp_channel_eq_ok() wants a 6-byte buffer. gcc-11 correctly warns
about this case:
drivers/gpu/drm/i915/display/intel_dp.c: In function ‘intel_dp_check_mst_status’:
drivers/gpu/drm/i915/display/intel_dp.c:3491:22: warning: ‘drm_dp_channel_eq_ok’ reading 6 bytes from a region of size 4 [-Wstringop-overread]
3491 | !drm_dp_channel_eq_ok(&esi[10], intel_dp->lane_count)) {
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/i915/display/intel_dp.c:3491:22: note: referencing argument 1 of type ‘const u8 *’ {aka ‘const unsigned char *’}
In file included from drivers/gpu/drm/i915/display/intel_dp.c:38:
include/drm/drm_dp_helper.h:1466:6: note: in a call to function ‘drm_dp_channel_eq_ok’
1466 | bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],
| ^~~~~~~~~~~~~~~~~~~~
6:14 elapsed
This commit just extends the original array by 2 zero-initialized bytes,
avoiding the warning.
There may be some underlying bug in here that caused this confusion, but
this is at least no worse than the existing situation that could use
random data off the stack.
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dave Airlie <airlied@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.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.