bf9bec4cb3
Eduard Zingerman says: ==================== This patch-set modifies BPF verifier to accept programs that read from uninitialized stack locations, but only if executed in privileged mode. This provides significant verification performance gains: 30% to 70% less processed states for big number of test programs. The reason for performance gains comes from treating STACK_MISC and STACK_INVALID as compatible, when cached state is compared to current state in verifier.c:stacksafe(). The change should not affect safety, because any value read from STACK_MISC location has full binary range (e.g. 0x00-0xff for byte-sized reads). Details and measurements are provided in the description for the patch #1. The change was suggested by Andrii Nakryiko, the initial patch was created by Alexei Starovoitov. The discussion could be found at [1]. Changes v1 -> v2 (v1 available at [2]): - Calls to helper functions now convert STACK_INVALID to STACK_MISC (suggested by Andrii); - The test case progs/test_global_func10.c is updated to expect new error message. Before recent commit [3] exact content of error messages was not verified for this test. - Replaced incorrect '//'-style comments in test case asm blocks by '/*...*/'-style comments in order to fix compilation issues; - Changed the tag from "Suggested-By" to "Co-developed-by" for Alexei on patch #1, please let me know if this is appropriate use of the tag. [1] https://lore.kernel.org/bpf/CAADnVQKs2i1iuZ5SUGuJtxWVfGYR9kDgYKhq3rNV+kBLQCu7rA@mail.gmail.com/ [2] https://lore.kernel.org/bpf/20230216183606.2483834-1-eddyz87@gmail.com/ [3] 95ebb376176c ("selftests/bpf: Convert test_global_funcs test to test_loader framework") ==================== Signed-off-by: Alexei Starovoitov <ast@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.