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.
Sami Tolvanen
authored
With GCOV_PROFILE_ALL, Clang injects __llvm_gcov_* functions to each object file, including the *.mod.o. As we filter out CC_FLAGS_CFI for *.mod.o, the compiler won't generate type hashes for the injected functions, and therefore indirectly calling them during module loading trips indirect call checking. Enabling CFI for *.mod.o isn't sufficient to fix this issue after commit 0c3e806e ("x86/cfi: Add boot time hash randomization"), as *.mod.o aren't processed by objtool, which means any hashes emitted there won't be randomized. Therefore, in addition to disabling CFI for *.mod.o, also disable GCOV, as the object files don't otherwise contain any executable code. Fixes: cf68fffb ("add support for Clang CFI") Reported-by:Joe Fradley <joefradley@google.com> Signed-off-by:
Sami Tolvanen <samitolvanen@google.com> Acked-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by:
Kees Cook <keescook@chromium.org> Reviewed-by:
Nick Desaulniers <ndesaulniers@google.com> Signed-off-by:
Masahiro Yamada <masahiroy@kernel.org>