68d27da765
[ Upstream commit de979c83574abf6e78f3fa65b716515c91b2613d ] With CONFIG_PREEMPTION disabled, arch/x86/entry/thunk_$(BITS).o becomes an empty object file. With some old versions of binutils (i.e., 2.35.90.20210113-1ubuntu1) the GNU assembler doesn't generate a symbol table for empty object files and objtool fails with the following error when a valid symbol table cannot be found: arch/x86/entry/thunk_64.o: warning: objtool: missing symbol table To prevent this from happening, build thunk_$(BITS).o only if CONFIG_PREEMPTION is enabled. BugLink: https://bugs.launchpad.net/bugs/1911359 Fixes: 320100a5ffe5 ("x86/entry: Remove the TRACE_IRQS cruft") Signed-off-by: Andrea Righi <andrea.righi@canonical.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/Ys/Ke7EWjcX+ZlXO@arighi-desktop 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.