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21f46f5476
The MMIO_REMAP BO is a special 4K IO page that does not have a ttm_tt behind it. However, amdgpu_ttm_tt_pde_flags() was treating it like normal TT/doorbell/preempt memory and unconditionally accessed ttm->caching. For the MMIO_REMAP BO, ttm is NULL, so this leads to a NULL pointer dereference when computing PDE flags. Fix this by checking that ttm is non-NULL before reading ttm->caching. This prevents the crash for MMIO_REMAP and also makes the code more defensive if other BOs ever come through without a ttm_tt. Fixes:fb5a52dbe9("drm/amdgpu: Implement TTM handling for MMIO_REMAP placement") Suggested-by: Jesse Zhang <Jesse.Zhang@amd.com> Suggested-by: Christian König <christian.koenig@amd.com> Cc: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com> Reviewed-by: Jesse Zhang <Jesse.Zhang@amd.com> Tested-by: Jesse Zhang <Jesse.Zhang@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> (cherry picked from commit0db94da5a0)
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 reStructuredText 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.