summaryrefslogtreecommitdiff
path: root/Documentation/bpf/bpf_devel_QA.rst
AgeCommit message (Collapse)Author
2023-06-29bpf: Replace deprecated -target with --target= for ClangFangrui Song
The -target option has been deprecated since clang 3.4 in 2013. Therefore, use the preferred --target=bpf form instead. This also matches how we use --target= in scripts/Makefile.clang. Signed-off-by: Fangrui Song <maskray@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Quentin Monnet <quentin@isovalent.com> Link: https://github.com/llvm/llvm-project/commit/274b6f0c87a6a1798de0a68135afc7f95def6277 Link: https://lore.kernel.org/bpf/20230624001856.1903733-1-maskray@google.com
2023-04-13Daniel Borkmann says:Jakub Kicinski
==================== pull-request: bpf-next 2023-04-13 We've added 260 non-merge commits during the last 36 day(s) which contain a total of 356 files changed, 21786 insertions(+), 11275 deletions(-). The main changes are: 1) Rework BPF verifier log behavior and implement it as a rotating log by default with the option to retain old-style fixed log behavior, from Andrii Nakryiko. 2) Adds support for using {FOU,GUE} encap with an ipip device operating in collect_md mode and add a set of BPF kfuncs for controlling encap params, from Christian Ehrig. 3) Allow BPF programs to detect at load time whether a particular kfunc exists or not, and also add support for this in light skeleton, from Alexei Starovoitov. 4) Optimize hashmap lookups when key size is multiple of 4, from Anton Protopopov. 5) Enable RCU semantics for task BPF kptrs and allow referenced kptr tasks to be stored in BPF maps, from David Vernet. 6) Add support for stashing local BPF kptr into a map value via bpf_kptr_xchg(). This is useful e.g. for rbtree node creation for new cgroups, from Dave Marchevsky. 7) Fix BTF handling of is_int_ptr to skip modifiers to work around tracing issues where a program cannot be attached, from Feng Zhou. 8) Migrate a big portion of test_verifier unit tests over to test_progs -a verifier_* via inline asm to ease {read,debug}ability, from Eduard Zingerman. 9) Several updates to the instruction-set.rst documentation which is subject to future IETF standardization (https://lwn.net/Articles/926882/), from Dave Thaler. 10) Fix BPF verifier in the __reg_bound_offset's 64->32 tnum sub-register known bits information propagation, from Daniel Borkmann. 11) Add skb bitfield compaction work related to BPF with the overall goal to make more of the sk_buff bits optional, from Jakub Kicinski. 12) BPF selftest cleanups for build id extraction which stand on its own from the upcoming integration work of build id into struct file object, from Jiri Olsa. 13) Add fixes and optimizations for xsk descriptor validation and several selftest improvements for xsk sockets, from Kal Conley. 14) Add BPF links for struct_ops and enable switching implementations of BPF TCP cong-ctls under a given name by replacing backing struct_ops map, from Kui-Feng Lee. 15) Remove a misleading BPF verifier env->bypass_spec_v1 check on variable offset stack read as earlier Spectre checks cover this, from Luis Gerhorst. 16) Fix issues in copy_from_user_nofault() for BPF and other tracers to resemble copy_from_user_nmi() from safety PoV, from Florian Lehner and Alexei Starovoitov. 17) Add --json-summary option to test_progs in order for CI tooling to ease parsing of test results, from Manu Bretelle. 18) Batch of improvements and refactoring to prep for upcoming bpf_local_storage conversion to bpf_mem_cache_{alloc,free} allocator, from Martin KaFai Lau. 19) Improve bpftool's visual program dump which produces the control flow graph in a DOT format by adding C source inline annotations, from Quentin Monnet. 20) Fix attaching fentry/fexit/fmod_ret/lsm to modules by extracting the module name from BTF of the target and searching kallsyms of the correct module, from Viktor Malik. 21) Improve BPF verifier handling of '<const> <cond> <non_const>' to better detect whether in particular jmp32 branches are taken, from Yonghong Song. 22) Allow BPF TCP cong-ctls to write app_limited of struct tcp_sock. A built-in cc or one from a kernel module is already able to write to app_limited, from Yixin Shen. Conflicts: Documentation/bpf/bpf_devel_QA.rst b7abcd9c656b ("bpf, doc: Link to submitting-patches.rst for general patch submission info") 0f10f647f455 ("bpf, docs: Use internal linking for link to netdev subsystem doc") https://lore.kernel.org/all/20230307095812.236eb1be@canb.auug.org.au/ include/net/ip_tunnels.h bc9d003dc48c3 ("ip_tunnel: Preserve pointer const in ip_tunnel_info_opts") ac931d4cdec3d ("ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices") https://lore.kernel.org/all/20230413161235.4093777-1-broonie@kernel.org/ net/bpf/test_run.c e5995bc7e2ba ("bpf, test_run: fix crashes due to XDP frame overwriting/corruption") 294635a8165a ("bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES") https://lore.kernel.org/all/20230320102619.05b80a98@canb.auug.org.au/ ==================== Link: https://lore.kernel.org/r/20230413191525.7295-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-03-17bpf, docs: Use internal linking for link to netdev subsystem docBagas Sanjaya
Commit d56b0c461d19da ("bpf, docs: Fix link to netdev-FAQ target") attempts to fix linking problem to undefined "netdev-FAQ" label introduced in 287f4fa99a5281 ("docs: Update references to netdev-FAQ") by changing internal cross reference to netdev subsystem documentation (Documentation/process/maintainer-netdev.rst) to external one at docs.kernel.org. However, the linking problem is still not resolved, as the generated link points to non-existent netdev-FAQ section of the external doc, which when clicked, will instead going to the top of the doc. Revert back to internal linking by simply mention the doc path while massaging the leading text to the link, since the netdev subsystem doc contains no FAQs but rather general information about the subsystem. Fixes: d56b0c461d19 ("bpf, docs: Fix link to netdev-FAQ target") Fixes: 287f4fa99a52 ("docs: Update references to netdev-FAQ") Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230314074449.23620-1-bagasdotme@gmail.com
2023-03-09Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Documentation/bpf/bpf_devel_QA.rst b7abcd9c656b ("bpf, doc: Link to submitting-patches.rst for general patch submission info") d56b0c461d19 ("bpf, docs: Fix link to netdev-FAQ target") https://lore.kernel.org/all/20230307095812.236eb1be@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-03-06bpf, doc: Link to submitting-patches.rst for general patch submission infoBagas Sanjaya
The link for patch submission information in general refers to index page for "Working with the kernel development community" section of kernel docs, whereas the link should have been Documentation/process/submitting-patches.rst instead. Fix it by replacing the index target with the appropriate doc. Fixes: 542228384888f5 ("bpf, doc: convert bpf_devel_QA.rst to use RST formatting") Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230228074523.11493-3-bagasdotme@gmail.com
2023-03-06bpf, doc: Do not link to docs.kernel.org for kselftest linkBagas Sanjaya
The question on how to run BPF selftests have a reference link to kernel selftest documentation (Documentation/dev-tools/kselftest.rst). However, it uses external link to the documentation at kernel.org/docs (aka docs.kernel.org) instead, which requires Internet access. Fix this and replace the link with internal linking, by using :doc: directive while keeping the anchor text. Fixes: b7a27c3aafa252 ("bpf, doc: howto use/run the BPF selftests") Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230228074523.11493-2-bagasdotme@gmail.com
2023-03-02bpf, docs: Fix link to netdev-FAQ targetDavid Vernet
The BPF devel Q&A documentation page makes frequent reference to the netdev-QA page via the netdev-FAQ rst link. This link is currently broken, as is evidenced by the build output when making BPF docs: ./Documentation/bpf/bpf_devel_QA.rst:150: WARNING: undefined label: 'netdev-faq' ./Documentation/bpf/bpf_devel_QA.rst:206: WARNING: undefined label: 'netdev-faq' ./Documentation/bpf/bpf_devel_QA.rst:231: WARNING: undefined label: 'netdev-faq' ./Documentation/bpf/bpf_devel_QA.rst:396: WARNING: undefined label: 'netdev-faq' ./Documentation/bpf/bpf_devel_QA.rst:412: WARNING: undefined label: 'netdev-faq' Fix the links to point to the actual netdev-faq page. Signed-off-by: David Vernet <void@manifault.com> Link: https://lore.kernel.org/r/20230302183918.54190-1-void@manifault.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2023-02-27bpf, docs: Fix link to BTF docBagas Sanjaya
Ross reported broken link to BTF documentation (Documentation/bpf/btf.rst) in Documentation/bpf/bpf_devel_QA.rst. The link in question is written using external link syntax, with the target refers to BTF doc in reST source (btf.rst), which doesn't exist in resulting HTML output. Fix the link by replacing external link syntax with simply writing out the target doc, which the link will be generated to the correct HTML doc target. Fixes: 6736aa793c2b5f ("selftests/bpf: Add general instructions for test execution") Reported-by: Ross Zwisler <zwisler@google.com> Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Ross Zwisler <zwisler@google.com> Link: https://lore.kernel.org/linux-doc/Y++09LKx25dtR4Ow@google.com/ Link: https://lore.kernel.org/bpf/20230222083530.26136-1-bagasdotme@gmail.com
2022-11-17bpf/docs: Include blank lines between bullet points in bpf_devel_QA.rstDaniel Müller
Commit 26a9b433cf08 ("bpf/docs: Document how to run CI without patch submission") caused a warning to be generated when compiling the documentation: > bpf_devel_QA.rst:55: WARNING: Unexpected indentation. > bpf_devel_QA.rst:56: WARNING: Block quote ends without a blank line This change fixes the problem by inserting the required blank lines. Fixes: 26a9b433cf08 ("bpf/docs: Document how to run CI without patch submission") Reported-by: Akira Yokosawa <akiyks@gmail.com> Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Akira Yokosawa <akiyks@gmail.com> Link: https://lore.kernel.org/bpf/20221116174358.2744613-1-deso@posteo.net
2022-11-15bpf/docs: Document how to run CI without patch submissionDaniel Müller
This change documents the process for running the BPF CI before submitting a patch to the upstream mailing list, similar to what happens if a patch is send to bpf@vger.kernel.org: it builds kernel and selftests and runs the latter on different architecture (but it notably does not cover stylistic checks such as cover letter verification). Running BPF CI this way can help achieve better test coverage ahead of patch submission than merely running locally (say, using tools/testing/selftests/bpf/vmtest.sh), as additional architectures may be covered as well. Signed-off-by: Daniel Müller <deso@posteo.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20221114211501.2068684-1-deso@posteo.net
2022-03-31docs: netdev: move the netdev-FAQ to the process pagesJakub Kicinski
The documentation for the tip tree is really in quite a similar spirit to the netdev-FAQ. Move the netdev-FAQ to the process docs as well. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2021-04-23bpf: Document the pahole release info related to libbpf in bpf_devel_QA.rstTiezhu Yang
pahole starts to use libbpf definitions and APIs since v1.13 after the commit 21507cd3e97b ("pahole: add libbpf as submodule under lib/bpf"). It works well with the git repository because the libbpf submodule will use "git submodule update --init --recursive" to update. Unfortunately, the default github release source code does not contain libbpf submodule source code and this will cause build issues, the tarball from https://git.kernel.org/pub/scm/devel/pahole/pahole.git/ is same with github, you can get the source tarball with corresponding libbpf submodule codes from https://fedorapeople.org/~acme/dwarves This change documents the above issues to give more information so that we can get the tarball from the right place, early discussion is here: https://lore.kernel.org/bpf/2de4aad5-fa9e-1c39-3c92-9bb9229d0966@loongson.cn/ Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Arnaldo Carvalho de Melo <acme@redhat.com> Link: https://lore.kernel.org/bpf/1619141010-12521-1-git-send-email-yangtiezhu@loongson.cn
2021-04-22bpf, doc: Fix some invalid links in bpf_devel_QA.rstTiezhu Yang
There exist some errors "404 Not Found" when I click the link of "MAINTAINERS" [1], "samples/bpf/" [2] and "selftests" [3] in the documentation "HOWTO interact with BPF subsystem" [4]. As Alexei Starovoitov suggested, just remove "MAINTAINERS" and "samples/bpf/" links and use correct link of "selftests". [1] https://www.kernel.org/doc/html/MAINTAINERS [2] https://www.kernel.org/doc/html/samples/bpf/ [3] https://www.kernel.org/doc/html/tools/testing/selftests/bpf/ [4] https://www.kernel.org/doc/html/latest/bpf/bpf_devel_QA.html Fixes: 542228384888 ("bpf, doc: convert bpf_devel_QA.rst to use RST formatting") Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Link: https://lore.kernel.org/bpf/1619062560-30483-1-git-send-email-yangtiezhu@loongson.cn
2021-01-23bpf, docs: Update build procedure for manually compiling LLVM and ClangTiezhu Yang
The current LLVM and Clang build procedure in samples/bpf/README.rst is out of date. See below that the links are not accessible any more. $ git clone http://llvm.org/git/llvm.git Cloning into 'llvm'... fatal: unable to access 'http://llvm.org/git/llvm.git/': Maximum (20) redirects followed $ git clone --depth 1 http://llvm.org/git/clang.git Cloning into 'clang'... fatal: unable to access 'http://llvm.org/git/clang.git/': Maximum (20) redirects followed The LLVM community has adopted new ways to build the compiler. There are different ways to build LLVM and Clang, the Clang Getting Started page [1] has one way. As Yonghong said, it is better to copy the build procedure in Documentation/bpf/bpf_devel_QA.rst to keep consistent. I verified the procedure and it is proved to be feasible, so we should update README.rst to reflect the reality. At the same time, update the related comment in Makefile. Additionally, as Fangrui said, the dir llvm-project/llvm/build/install is not used, BUILD_SHARED_LIBS=OFF is the default option [2], so also change Documentation/bpf/bpf_devel_QA.rst together. At last, we recommend that developers who want the fastest incremental builds use the Ninja build system [1], you can find it in your system's package manager, usually the package is ninja or ninja-build [3], so add ninja to build dependencies suggested by Nathan. [1] https://clang.llvm.org/get_started.html [2] https://www.llvm.org/docs/CMake.html [3] https://github.com/ninja-build/ninja/wiki/Pre-built-Ninja-packages Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Acked-by: Yonghong Song <yhs@fb.com> Cc: Fangrui Song <maskray@google.com> Link: https://lore.kernel.org/bpf/1611279584-26047-1-git-send-email-yangtiezhu@loongson.cn
2020-10-11bpf: Migrate from patchwork.ozlabs.org to patchwork.kernel.org.Alexei Starovoitov
Move the bpf/bpf-next patch processing queue to patchwork.kernel.org. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20201011200149.66537-1-alexei.starovoitov@gmail.com
2020-08-24docs: Correct subject prefix and update LLVM infoJianlin Lv
bpf_devel_QA.rst:152 The subject prefix information is not accurate, it should be 'PATCH bpf-next v2' Also update LLVM version info and add information about ‘-DLLVM_TARGETS_TO_BUILD’ to prompt the developer to build the desired target. Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200821052817.46887-1-Jianlin.Lv@arm.com
2020-07-23docs: bpf/bpf_devel_QA.rst: fix reference to nonexistent documentDaniel W. S. Almeida
Fix the following sphinx warning: bpf_devel_QA.rst:444: WARNING: Unknown target name: "documentation/bpf/btf.rst" No target was defined for 'btf.rst' in the document. Fix it. Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com> Link: https://lore.kernel.org/r/20200718165107.625847-6-dwlsalmeida@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-05-23selftests/bpf: Add general instructions for test executionAlan Maguire
Getting a clean BPF selftests run involves ensuring latest trunk LLVM/clang are used, pahole is recent (>=1.16) and config matches the specified config file as closely as possible. Add to bpf_devel_QA.rst and point tools/testing/selftests/bpf/README.rst to it. Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/1590146674-25485-1-git-send-email-alan.maguire@oracle.com
2020-02-20docs/bpf: Update bpf development Q/A fileYonghong Song
bpf now has its own mailing list bpf@vger.kernel.org. Update the bpf_devel_QA.rst file to reflect this. Also llvm has switch to github with llvm and clang in the same repo https://github.com/llvm/llvm-project.git. Update the QA file with newer build instructions. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200221004354.930952-1-yhs@fb.com
2018-07-26docs: Update references to netdev-FAQTobin C. Harding
File 'Documentation/networking/netdev-FAQ.txt' has been converted to RST format. We should update all links/references to point to the new file. Update references to netdev-FAQ Signed-off-by: Tobin C. Harding <me@tobin.cc> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-14bpf, doc: howto use/run the BPF selftestsJesper Dangaard Brouer
I always forget howto run the BPF selftests. Thus, lets add that info to the QA document. Documentation was based on Cilium's documentation: http://cilium.readthedocs.io/en/latest/bpf/#verifying-the-setup Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-14bpf, doc: convert bpf_devel_QA.rst to use RST formattingJesper Dangaard Brouer
Same story as bpf_design_QA.rst RST format conversion. Again thanks to Quentin Monnet <quentin.monnet@netronome.com> for fixes and patches that have been squashed. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-14bpf, doc: rename txt files to rst filesJesper Dangaard Brouer
This will cause them to get auto rendered, e.g. when viewing them on GitHub. Followup patches will correct the content to be RST compliant. Also adjust README.rst to point to the renamed files. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>