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Daniel T. Lee says: ==================== samples/bpf: make BPF programs more libbpf aware The existing tracing programs have been developed for a considerable period of time and, as a result, do not properly incorporate the features of the current libbpf, such as CO-RE. This is evident in frequent usage of functions like PT_REGS* and the persistence of "hack" methods using underscore-style bpf_probe_read_kernel from the past. These programs are far behind the current level of libbpf and can potentially confuse users. The kernel has undergone significant changes, and some of these changes have broken these programs, but on the other hand, more robust APIs have been developed for increased stableness. To list some of the kernel changes that this patch set is focusing on, - symbol mismatch occurs due to compiler optimization [1] - inline of blk_account_io* breaks BPF kprobe program [2] - new tracepoints for the block_io_start/done are introduced [3] - map lookup probes can't be triggered (bpf_disable_instrumentation)[4] - BPF_KSYSCALL has been introduced to simplify argument fetching [5] - convert to vmlinux.h and use tp argument structure within it - make tracing programs to be more CO-RE centric In this regard, this patch set aims not only to integrate the latest features of libbpf into BPF programs but also to reduce confusion and clarify the BPF programs. This will help with the potential confusion among users and make the programs more intutitive. [1]: https://github.com/iovisor/bcc/issues/1754 [2]: https://github.com/iovisor/bcc/issues/4261 [3]: commit5a80bd075f("block: introduce block_io_start/block_io_done tracepoints") [4]: commit7c4cd051ad("bpf: Fix syscall's stackmap lookup potential deadlock") [5]: commit6f5d467d55("libbpf: improve BPF_KPROBE_SYSCALL macro and rename it to BPF_KSYSCALL") ==================== Link: https://lore.kernel.org/r/20230818090119.477441-1-danieltimlee@gmail.com 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.