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Sebastian Andrzej Siewior
570db4b39f
The per-CPU data section is handled differently than the other sections. The memory allocations requires a special __percpu pointer and then the section is copied into the view of each CPU. Therefore the SHF_ALLOC flag is removed to ensure move_module() skips it. Later, relocations are applied and apply_relocations() skips sections without SHF_ALLOC because they have not been copied. This also skips the per-CPU data section. The missing relocations result in a NULL pointer on x86-64 and very small values on x86-32. This results in a crash because it is not skipped like NULL pointer would and can't be dereferenced. Such an assignment happens during static per-CPU lock initialisation with lockdep enabled. Allow relocation processing for the per-CPU section even if SHF_ALLOC is missing. Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202506041623.e45e4f7d-lkp@intel.com Fixes: 1a6100caae425 ("Don't relocate non-allocated regions in modules.") #v2.6.1-rc3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Petr Pavlu <petr.pavlu@suse.com> Link: https://lore.kernel.org/r/20250610163328.URcsSUC1@linutronix.de Signed-off-by: Daniel Gomez <da.gomez@samsung.com> Message-ID: <20250610163328.URcsSUC1@linutronix.de>
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.