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2022-03-08bpf: Remove redundant slashYuntao Wang1-3/+2
The trailing slash of LIBBPF_SRCS is redundant, remove it. Also inline it as its only used in LIBBPF_INCLUDE. Signed-off-by: Yuntao Wang <ytcoode@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220305161013.361646-1-ytcoode@gmail.com
2022-02-25bpf: Fix issue with bpf preload module taking over stdout/stdin of kernel.Yucong Sun1-0/+7
In cb80ddc67152 ("bpf: Convert bpf_preload.ko to use light skeleton.") BPF preload was switched from user mode process to use in-kernel light skeleton instead. However, in the kernel context, early in the boot sequence, the first available FD can start from 0, instead of normally 3 for user mode process. So FDs 0 and 1 are then used for loaded BPF programs and prevent init process from setting up stdin/stdout/stderr on FD 0, 1, and 2 as expected. Before the fix: ls -lah /proc/1/fd/* lrwx------1 root root 64 Feb 23 17:20 /proc/1/fd/0 -> /dev/null lrwx------ 1 root root 64 Feb 23 17:20 /proc/1/fd/1 -> /dev/null lrwx------ 1 root root 64 Feb 23 17:20 /proc/1/fd/2 -> /dev/console lrwx------ 1 root root 64 Feb 23 17:20 /proc/1/fd/6 -> /dev/console lrwx------ 1 root root 64 Feb 23 17:20 /proc/1/fd/7 -> /dev/console After the fix: ls -lah /proc/1/fd/* lrwx------ 1 root root 64 Feb 24 21:23 /proc/1/fd/0 -> /dev/console lrwx------ 1 root root 64 Feb 24 21:23 /proc/1/fd/1 -> /dev/console lrwx------ 1 root root 64 Feb 24 21:23 /proc/1/fd/2 -> /dev/console Fix by closing prog FDs after initialization. struct bpf_prog's themselves are kept alive through direct kernel references taken with bpf_link_get_from_fd(). Fixes: cb80ddc67152 ("bpf: Convert bpf_preload.ko to use light skeleton.") Signed-off-by: Yucong Sun <fallentree@fb.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220225185923.2535519-1-fallentree@fb.com
2022-02-11bpf: Convert bpf_preload.ko to use light skeleton.Alexei Starovoitov7-218/+58
The main change is a move of the single line #include "iterators.lskel.h" from iterators/iterators.c to bpf_preload_kern.c. Which means that generated light skeleton can be used from user space or user mode driver like iterators.c or from the kernel module or the kernel itself. The direct use of light skeleton from the kernel module simplifies the code, since UMD is no longer necessary. The libbpf.a required user space and UMD. The CO-RE in the kernel and generated "loader bpf program" used by the light skeleton are capable to perform complex loading operations traditionally provided by libbpf. In addition UMD approach was launching UMD process every time bpffs has to be mounted. With light skeleton in the kernel the bpf_preload kernel module loads bpf iterators once and pins them multiple times into different bpffs mounts. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209232001.27490-6-alexei.starovoitov@gmail.com
2022-02-11bpf: Update iterators.lskel.h.Alexei Starovoitov1-72/+69
Light skeleton and skel_internal.h have changed. Update iterators.lskel.h. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209232001.27490-5-alexei.starovoitov@gmail.com
2022-02-02bpf: Drop libbpf, libelf, libz dependency from bpf preload.Alexei Starovoitov1-26/+2
Drop libbpf, libelf, libz dependency from bpf preload. This reduces bpf_preload_umd binary size from 1.7M to 30k unstripped with debug info and from 300k to 19k stripped. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20220131220528.98088-8-alexei.starovoitov@gmail.com
2022-02-02bpf: Open code obj_get_info_by_fd in bpf preload.Alexei Starovoitov1-1/+17
Open code obj_get_info_by_fd in bpf preload. It's the last part of libbpf that preload/iterators were using. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20220131220528.98088-7-alexei.starovoitov@gmail.com
2022-02-02bpf: Convert bpf preload to light skeleton.Alexei Starovoitov4-420/+436
Convert bpffs preload iterators to light skeleton. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20220131220528.98088-6-alexei.starovoitov@gmail.com
2022-02-02bpf: Remove unnecessary setrlimit from bpf preload.Alexei Starovoitov1-2/+0
BPF programs and maps are memcg accounted. setrlimit is obsolete. Remove its use from bpf preload. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20220131220528.98088-5-alexei.starovoitov@gmail.com
2021-10-20bpf/preload: Clean up .gitignore and "clean-files" targetQuentin Monnet2-5/+2
kernel/bpf/preload/Makefile was recently updated to have it install libbpf's headers locally instead of pulling them from tools/lib/bpf. But two items still need to be addressed. First, the local .gitignore file was not adjusted to ignore the files generated in the new kernel/bpf/preload/libbpf output directory. Second, the "clean-files" target is now incorrect. The old artefacts names were not removed from the target, while the new ones were added incorrectly. This is because "clean-files" expects names relative to $(obj), but we passed the absolute path instead. This results in the output and header-destination directories for libbpf (and their contents) not being removed from kernel/bpf/preload on "make clean" from the root of the repository. This commit fixes both issues. Note that $(userprogs) needs not be added to "clean-files", because the cleaning infrastructure already accounts for it. Cleaning the files properly also prevents make from printing the following message, for builds coming after a "make clean": "make[4]: Nothing to be done for 'install_headers'." v2: Simplify the "clean-files" target. Fixes: bf60791741d4 ("bpf: preload: Install libbpf headers when building") Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20211020094647.15564-1-quentin@isovalent.com
2021-10-08bpftool: Add install-bin target to install binary onlyQuentin Monnet1-1/+1
With "make install", bpftool installs its binary and its bash completion file. Usually, this is what we want. But a few components in the kernel repository (namely, BPF iterators and selftests) also install bpftool locally before using it. In such a case, bash completion is not necessary and is just a useless build artifact. Let's add an "install-bin" target to bpftool, to offer a way to install the binary only. Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211007194438.34443-13-quentin@isovalent.com
2021-10-08bpf: iterators: Install libbpf headers when buildingQuentin Monnet1-13/+25
API headers from libbpf should not be accessed directly from the library's source directory. Instead, they should be exported with "make install_headers". Let's make sure that bpf/preload/iterators/Makefile installs the headers properly when building. Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211007194438.34443-8-quentin@isovalent.com
2021-10-08bpf: preload: Install libbpf headers when buildingQuentin Monnet1-5/+20
API headers from libbpf should not be accessed directly from the library's source directory. Instead, they should be exported with "make install_headers". Let's make sure that bpf/preload/Makefile installs the headers properly when building. Note that we declare an additional dependency for iterators/iterators.o: having $(LIBBPF_A) as a dependency to "$(obj)/bpf_preload_umd" is not sufficient, as it makes it required only at the linking step. But we need libbpf to be compiled, and in particular its headers to be exported, before we attempt to compile iterators.o. The issue would not occur before this commit, because libbpf's headers were not exported and were always available under tools/lib/bpf. Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20211007194438.34443-7-quentin@isovalent.com
2021-05-26libbpf: Move BPF_SEQ_PRINTF and BPF_SNPRINTF to bpf_helpers.hFlorent Revest1-1/+0
These macros are convenient wrappers around the bpf_seq_printf and bpf_snprintf helpers. They are currently provided by bpf_tracing.h which targets low level tracing primitives. bpf_helpers.h is a better fit. The __bpf_narg and __bpf_apply are needed in both files and provided twice. __bpf_empty isn't used anywhere and is removed from bpf_tracing.h Reported-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Florent Revest <revest@chromium.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210526164643.2881368-1-revest@chromium.org
2021-03-20bpf: Fix umd memory leak in copy_process()Zqiang1-4/+15
The syzbot reported a memleak as follows: BUG: memory leak unreferenced object 0xffff888101b41d00 (size 120): comm "kworker/u4:0", pid 8, jiffies 4294944270 (age 12.780s) backtrace: [<ffffffff8125dc56>] alloc_pid+0x66/0x560 [<ffffffff81226405>] copy_process+0x1465/0x25e0 [<ffffffff81227943>] kernel_clone+0xf3/0x670 [<ffffffff812281a1>] kernel_thread+0x61/0x80 [<ffffffff81253464>] call_usermodehelper_exec_work [<ffffffff81253464>] call_usermodehelper_exec_work+0xc4/0x120 [<ffffffff812591c9>] process_one_work+0x2c9/0x600 [<ffffffff81259ab9>] worker_thread+0x59/0x5d0 [<ffffffff812611c8>] kthread+0x178/0x1b0 [<ffffffff8100227f>] ret_from_fork+0x1f/0x30 unreferenced object 0xffff888110ef5c00 (size 232): comm "kworker/u4:0", pid 8414, jiffies 4294944270 (age 12.780s) backtrace: [<ffffffff8154a0cf>] kmem_cache_zalloc [<ffffffff8154a0cf>] __alloc_file+0x1f/0xf0 [<ffffffff8154a809>] alloc_empty_file+0x69/0x120 [<ffffffff8154a8f3>] alloc_file+0x33/0x1b0 [<ffffffff8154ab22>] alloc_file_pseudo+0xb2/0x140 [<ffffffff81559218>] create_pipe_files+0x138/0x2e0 [<ffffffff8126c793>] umd_setup+0x33/0x220 [<ffffffff81253574>] call_usermodehelper_exec_async+0xb4/0x1b0 [<ffffffff8100227f>] ret_from_fork+0x1f/0x30 After the UMD process exits, the pipe_to_umh/pipe_from_umh and tgid need to be released. Fixes: d71fa5c9763c ("bpf: Add kernel module with user mode driver that populates bpffs.") Reported-by: syzbot+44908bb56d2bfe56b28e@syzkaller.appspotmail.com Signed-off-by: Zqiang <qiang.zhang@windriver.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20210317030915.2865-1-qiang.zhang@windriver.com
2021-02-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-1/+4
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-01-27bpf, preload: Fix build when $(O) points to a relative pathQuentin Monnet1-1/+4
Building the kernel with CONFIG_BPF_PRELOAD, and by providing a relative path for the output directory, may fail with the following error: $ make O=build bindeb-pkg ... /.../linux/tools/scripts/Makefile.include:5: *** O=build does not exist. Stop. make[7]: *** [/.../linux/kernel/bpf/preload/Makefile:9: kernel/bpf/preload/libbpf.a] Error 2 make[6]: *** [/.../linux/scripts/Makefile.build:500: kernel/bpf/preload] Error 2 make[5]: *** [/.../linux/scripts/Makefile.build:500: kernel/bpf] Error 2 make[4]: *** [/.../linux/Makefile:1799: kernel] Error 2 make[4]: *** Waiting for unfinished jobs.... In the case above, for the "bindeb-pkg" target, the error is produced by the "dummy" check in Makefile.include, called from libbpf's Makefile. This check changes directory to $(PWD) before checking for the existence of $(O). But at this step we have $(PWD) pointing to "/.../linux/build", and $(O) pointing to "build". So the Makefile.include tries in fact to assert the existence of a directory named "/.../linux/build/build", which does not exist. Note that the error does not occur for all make targets and architectures combinations. This was observed on x86 for "bindeb-pkg", or for a regular build for UML [0]. Here are some details. The root Makefile recursively calls itself once, after changing directory to $(O). The content for the variable $(PWD) is preserved across recursive calls to make, so it is unchanged at this step. For "bindeb-pkg", $(PWD) is eventually updated because the target writes a new Makefile (as debian/rules) and calls it indirectly through dpkg-buildpackage. This script does not preserve $(PWD), which is reset to the current working directory when the target in debian/rules is called. Although not investigated, it seems likely that something similar causes UML to change its value for $(PWD). Non-trivial fixes could be to remove the use of $(PWD) from the "dummy" check, or to make sure that $(PWD) and $(O) are preserved or updated to always play well and form a valid $(PWD)/$(O) path across the different targets and architectures. Instead, we take a simpler approach and just update $(O) when calling libbpf's Makefile, so it points to an absolute path which should always resolve for the "dummy" check run (through includes) by that Makefile. David Gow previously posted a slightly different version of this patch as a RFC [0], two months ago or so. [0] https://lore.kernel.org/bpf/20201119085022.3606135-1-davidgow@google.com/t/#u Fixes: d71fa5c9763c ("bpf: Add kernel module with user mode driver that populates bpffs.") Reported-by: David Gow <davidgow@google.com> Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andrii@kernel.org> Cc: Brendan Higgins <brendanhiggins@google.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Link: https://lore.kernel.org/bpf/20210126161320.24561-1-quentin@isovalent.com
2021-01-09bpf: Remove unnecessary <argp.h> include from preload/iteratorsLeah Neukirchen1-1/+1
This program does not use argp (which is a glibcism). Instead include <errno.h> directly, which was pulled in by <argp.h>. Signed-off-by: Leah Neukirchen <leah@vuxu.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20201216100306.30942-1-leah@vuxu.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-11-06bpf: BPF_PRELOAD depends on BPF_SYSCALLRandy Dunlap1-0/+1
Fix build error when BPF_SYSCALL is not set/enabled but BPF_PRELOAD is by making BPF_PRELOAD depend on BPF_SYSCALL. ERROR: modpost: "bpf_preload_ops" [kernel/bpf/preload/bpf_preload.ko] undefined! Reported-by: kernel test robot <lkp@intel.com> Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20201105195109.26232-1-rdunlap@infradead.org
2020-09-29bpf: Move prog->aux->linked_prog and trampoline into bpf_link on attachToke Høiland-Jørgensen2-223/+225
In preparation for allowing multiple attachments of freplace programs, move the references to the target program and trampoline into the bpf_tracing_link structure when that is created. To do this atomically, introduce a new mutex in prog->aux to protect writing to the two pointers to target prog and trampoline, and rename the members to make it clear that they are related. With this change, it is no longer possible to attach the same tracing program multiple times (detaching in-between), since the reference from the tracing program to the target disappears on the first attach. However, since the next patch will let the caller supply an attach target, that will also make it possible to attach to the same place multiple times. Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/160138355059.48470.2503076992210324984.stgit@toke.dk
2020-09-29bpf/preload: Make sure Makefile cleans up after itself, and add .gitignoreToke Høiland-Jørgensen2-0/+6
The Makefile in bpf/preload builds a local copy of libbpf, but does not properly clean up after itself. This can lead to subsequent compilation failures, since the feature detection cache is kept around which can lead subsequent detection to fail. Fix this by properly setting clean-files, and while we're at it, also add a .gitignore for the directory to ignore the build artifacts. Fixes: d71fa5c9763c ("bpf: Add kernel module with user mode driver that populates bpffs.") Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200927193005.8459-1-toke@redhat.com
2020-08-26bpf: Disallow BPF_PRELOAD in allmodconfig buildsAlexei Starovoitov1-0/+3
The CC_CAN_LINK checks that the host compiler can link, but bpf_preload relies on libbpf which in turn needs libelf to be present during linking. allmodconfig runs in odd setups with cross compilers and missing host libraries like libelf. Instead of extending kconfig with every possible library that bpf_preload might need disallow building BPF_PRELOAD in such build-only configurations. Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-08-20bpf: Add kernel module with user mode driver that populates bpffs.Alexei Starovoitov7-0/+267
Add kernel module with user mode driver that populates bpffs with BPF iterators. $ mount bpffs /my/bpffs/ -t bpf $ ls -la /my/bpffs/ total 4 drwxrwxrwt 2 root root 0 Jul 2 00:27 . drwxr-xr-x 19 root root 4096 Jul 2 00:09 .. -rw------- 1 root root 0 Jul 2 00:27 maps.debug -rw------- 1 root root 0 Jul 2 00:27 progs.debug The user mode driver will load BPF Type Formats, create BPF maps, populate BPF maps, load two BPF programs, attach them to BPF iterators, and finally send two bpf_link IDs back to the kernel. The kernel will pin two bpf_links into newly mounted bpffs instance under names "progs.debug" and "maps.debug". These two files become human readable. $ cat /my/bpffs/progs.debug id name attached 11 dump_bpf_map bpf_iter_bpf_map 12 dump_bpf_prog bpf_iter_bpf_prog 27 test_pkt_access 32 test_main test_pkt_access test_pkt_access 33 test_subprog1 test_pkt_access_subprog1 test_pkt_access 34 test_subprog2 test_pkt_access_subprog2 test_pkt_access 35 test_subprog3 test_pkt_access_subprog3 test_pkt_access 36 new_get_skb_len get_skb_len test_pkt_access 37 new_get_skb_ifindex get_skb_ifindex test_pkt_access 38 new_get_constant get_constant test_pkt_access The BPF program dump_bpf_prog() in iterators.bpf.c is printing this data about all BPF programs currently loaded in the system. This information is unstable and will change from kernel to kernel as ".debug" suffix conveys. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200819042759.51280-4-alexei.starovoitov@gmail.com
2020-08-20bpf: Add BPF program and map iterators as built-in BPF programs.Alexei Starovoitov5-0/+587
The program and map iterators work similar to seq_file-s. Once the program is pinned in bpffs it can be read with "cat" tool to print human readable output. In this case about BPF programs and maps. For example: $ cat /sys/fs/bpf/progs.debug id name attached 5 dump_bpf_map bpf_iter_bpf_map 6 dump_bpf_prog bpf_iter_bpf_prog $ cat /sys/fs/bpf/maps.debug id name max_entries 3 iterator.rodata 1 To avoid kernel build dependency on clang 10 separate bpf skeleton generation into manual "make" step and instead check-in generated .skel.h into git. Unlike 'bpftool prog show' in-kernel BTF name is used (when available) to print full name of BPF program instead of 16-byte truncated name. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200819042759.51280-3-alexei.starovoitov@gmail.com
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