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Michael Bommarito
55fb23f8bd
[ Upstream commita82c8a05e8] assoc_array_walk() masks off the bits past shortcut->skip_to_level in the word that contains skip_to_level, gated on round_up(sc_level, ASSOC_ARRAY_KEY_CHUNK_SIZE) > skip_to_level. That guard is wrong in two opposite ways: - When sc_level is word-aligned (every word after the first) round_up() is a no-op, so the guard is sc_level > skip_to_level and never fires for the word that holds skip_to_level. A shortcut that spans more than one word and ends in the middle of its last word leaves that word untrimmed, and its stale high bits leak into the dissimilarity word and can steer the walk down the wrong descendant. - When sc_level is unaligned (the first word) and skip_to_level sits on the next chunk boundary, sc_level + CHUNK would exceed skip_to_level and fire the trim with shift = skip_to_level & CHUNK_MASK == 0, which clears the whole dissimilarity word and makes a differing shortcut compare equal. Use the end of the chunk that contains sc_level instead: skip_to_level < round_down(sc_level, CHUNK) + CHUNK For an aligned sc_level whose word holds skip_to_level this now fires (the first bug); for an unaligned sc_level with skip_to_level on the following boundary it does not, so shift is never 0 when the branch runs and the trim never clears the whole word. Fixes:3cb989501c("Add a generic associative array implementation.") Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com> Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> Tested-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/r/20260719161505.2423935-4-michael.bommarito@gmail.com Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.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.