e6a908c593
[ Upstream commit e68ac0082787f4e8ee6ae5b19076ec7709ce715b ] When the loader indicates an internal error (result of a checked bpf system call), it returns the result in attr.test.retval. However, tests that rely on ASSERT_OK_PTR on NULL (returned from light skeleton) may miss that NULL denotes an error if errno is set to 0. This would result in skel pointer being NULL, while ASSERT_OK_PTR returning 1, leading to a SEGV on dereference of skel, because libbpf_get_error relies on the assumption that errno is always set in case of error for ptr == NULL. In particular, this was observed for the ksyms_module test. When executed using `./test_progs -t ksyms`, prior tests manipulated errno and the test didn't crash when it failed at ksyms_module load, while using `./test_progs -t ksyms_module` crashed due to errno being untouched. Fixes: 67234743736a (libbpf: Generate loader program out of BPF ELF file.) Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210927145941.1383001-11-memxor@gmail.com 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.