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George Spelvin authored
igt_mm_config() calls ilog2() on the (pseudo)random 21-bit number s>>12. Once in 2 million seeds, this is zero and ilog2 summons the nasal demons. There was an attempt to handle this case with a max(), but that's too late; ms could already be something bizarre. Given that the low 12 bits of s and ms are always zero, it's a lot simpler just to divide them by 4096, then everything fits into 32 bits, and we can easily generate a random number 1 <= s <= 0x1fffff. Fixes: 14d1b9a6 ("drm/i915: buddy allocator") Signed-off-by:
George Spelvin <lkml@sdf.org> Cc: Matthew Auld <matthew.auld@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: intel-gfx@lists.freedesktop.org Reviewed-by:
Matthew Auld <matthew.auld@intel.com> Signed-off-by:
Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20200325192429.GA8865@SDF.ORGSigned-off-by:
Rodrigo Vivi <rodrigo.vivi@intel.com> (cherry picked from commit 21118e8e) Signed-off-by:
Jani Nikula <jani.nikula@intel.com>
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