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Nitin Gote
5634c8cb29
The current iosys_map_clear() implementation reads the potentially
uninitialized 'is_iomem' boolean field to decide which union member
to clear. This causes undefined behavior when called on uninitialized
structures, as 'is_iomem' may contain garbage values like 0xFF.
UBSAN detects this as:
UBSAN: invalid-load in include/linux/iosys-map.h:267
load of value 255 is not a valid value for type '_Bool'
Fix by unconditionally clearing the entire structure with memset(),
eliminating the need to read uninitialized data and ensuring all
fields are set to known good values.
Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14639
Fixes: 01fd30da04 ("dma-buf: Add struct dma-buf-map for storing struct dma_buf.vaddr_ptr")
Signed-off-by: Nitin Gote <nitin.r.gote@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20250718105051.2709487-1-nitin.r.gote@intel.com
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.