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* Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller2020-07-0471-1003/+4078
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Daniel Borkmann says: ==================== pull-request: bpf-next 2020-07-04 The following pull-request contains BPF updates for your *net-next* tree. We've added 73 non-merge commits during the last 17 day(s) which contain a total of 106 files changed, 5233 insertions(+), 1283 deletions(-). The main changes are: 1) bpftool ability to show PIDs of processes having open file descriptors for BPF map/program/link/BTF objects, relying on BPF iterator progs to extract this info efficiently, from Andrii Nakryiko. 2) Addition of BPF iterator progs for dumping TCP and UDP sockets to seq_files, from Yonghong Song. 3) Support access to BPF map fields in struct bpf_map from programs through BTF struct access, from Andrey Ignatov. 4) Add a bpf_get_task_stack() helper to be able to dump /proc/*/stack via seq_file from BPF iterator progs, from Song Liu. 5) Make SO_KEEPALIVE and related options available to bpf_setsockopt() helper, from Dmitry Yakunin. 6) Optimize BPF sk_storage selection of its caching index, from Martin KaFai Lau. 7) Removal of redundant synchronize_rcu()s from BPF map destruction which has been a historic leftover, from Alexei Starovoitov. 8) Several improvements to test_progs to make it easier to create a shell loop that invokes each test individually which is useful for some CIs, from Jesper Dangaard Brouer. 9) Fix bpftool prog dump segfault when compiled without skeleton code on older clang versions, from John Fastabend. 10) Bunch of cleanups and minor improvements, from various others. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
| * selftests/bpf: Fix compilation error of bpf_iter_task_stack.cSong Liu2020-07-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BPF selftests show a compilation error as follows: libbpf: invalid relo for 'entries' in special section 0xfff2; forgot to initialize global var?.. Fix it by initializing 'entries' to zeros. Fixes: c7568114bc56 ("selftests/bpf: Add bpf_iter test with bpf_get_task_stack()") Reported-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200703181719.3747072-1-songliubraving@fb.com
| * bpf: Fix bpftool without skeleton code enabledJohn Fastabend2020-07-031-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix segfault from bpftool by adding emit_obj_refs_plain when skeleton code is disabled. Tested by deleting BUILD_BPF_SKELS in Makefile. We found this doing backports for Cilium when a testing image pulled in latest bpf-next bpftool, but kept using an older clang-7. # ./bpftool prog show Error: bpftool built without PID iterator support 3: cgroup_skb tag 7be49e3934a125ba gpl loaded_at 2020-07-01T08:01:29-0700 uid 0 Segmentation fault Fixes: d53dee3fe013 ("tools/bpftool: Show info for processes holding BPF map/prog/link/btf FDs") Reported-by: Joe Stringer <joe@wand.net.nz> Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/159375071997.14984.17404504293832961401.stgit@john-XPS-13-9370
| * bpf: selftests: Restore netns after each testMartin KaFai Lau2020-07-022-2/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is common for networking tests creating its netns and making its own setting under this new netns (e.g. changing tcp sysctl). If the test forgot to restore to the original netns, it would affect the result of other tests. This patch saves the original netns at the beginning and then restores it after every test. Since the restore "setns()" is not expensive, it does it on all tests without tracking if a test has created a new netns or not. The new restore_netns() could also be done in test__end_subtest() such that each subtest will get an automatic netns reset. However, the individual test would lose flexibility to have total control on netns for its own subtests. In some cases, forcing a test to do unnecessary netns re-configure for each subtest is time consuming. e.g. In my vm, forcing netns re-configure on each subtest in sk_assign.c increased the runtime from 1s to 8s. On top of that, test_progs.c is also doing per-test (instead of per-subtest) cleanup for cgroup. Thus, this patch also does per-test restore_netns(). The only existing per-subtest cleanup is reset_affinity() and no test is depending on this. Thus, it is removed from test__end_subtest() to give a consistent expectation to the individual tests. test_progs.c only ensures any affinity/netns/cgroup change made by an earlier test does not affect the following tests. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200702004858.2103728-1-kafai@fb.com
| * bpf: selftests: A few improvements to network_helpers.cMartin KaFai Lau2020-07-026-86/+110
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch makes a few changes to the network_helpers.c 1) Enforce SO_RCVTIMEO and SO_SNDTIMEO This patch enforces timeout to the network fds through setsockopt SO_RCVTIMEO and SO_SNDTIMEO. It will remove the need for SOCK_NONBLOCK that requires a more demanding timeout logic with epoll/select, e.g. epoll_create, epoll_ctrl, and then epoll_wait for timeout. That removes the need for connect_wait() from the cgroup_skb_sk_lookup.c. The needed change is made in cgroup_skb_sk_lookup.c. 2) start_server(): Add optional addr_str and port to start_server(). That removes the need of the start_server_with_port(). The caller can pass addr_str==NULL and/or port==0. I have a future tcp-hdr-opt test that will pass a non-NULL addr_str and it is in general useful for other future tests. "int timeout_ms" is also added to control the timeout on the "accept(listen_fd)". 3) connect_to_fd(): Fully use the server_fd. The server sock address has already been obtained from getsockname(server_fd). The sockaddr includes the family, so the "int family" arg is redundant. Since the server address is obtained from server_fd, there is little reason not to get the server's socket type from the server_fd also. getsockopt(server_fd) can be used to do that, so "int type" arg is also removed. "int timeout_ms" is added. 4) connect_fd_to_fd(): "int timeout_ms" is added. Some code is also refactored to connect_fd_to_addr() which is shared with connect_to_fd(). 5) Preserve errno: Some callers need to check errno, e.g. cgroup_skb_sk_lookup.c. Make changes to do it more consistently in save_errno_close() and log_err(). Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200702004852.2103003-1-kafai@fb.com
| * selftests/bpf: Test_progs option for listing test namesJesper Dangaard Brouer2020-07-012-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The program test_progs have some very useful ability to specify a list of test name substrings for selecting which tests to run. This patch add the ability to list the selected test names without running them. This is practical for seeing which tests gets selected with given select arguments (which can also contain a exclude list via --name-blacklist). This output can also be used by shell-scripts in a for-loop: for N in $(./test_progs --list -t xdp); do \ ./test_progs -t $N 2>&1 > result_test_${N}.log & \ done ; wait This features can also be used for looking up a test number and returning a testname. If the selection was empty then a shell EXIT_FAILURE is returned. This is useful for scripting. e.g. like this: n=1; while [ $(./test_progs --list -n $n) ] ; do \ ./test_progs -n $n ; n=$(( n+1 )); \ done Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/159363985751.930467.9610992940793316982.stgit@firesoul
| * selftests/bpf: Test_progs option for getting number of testsJesper Dangaard Brouer2020-07-012-0/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It can be practial to get the number of tests that test_progs contain. This could for example be used to create a shell for-loop construct that runs the individual tests. Like: for N in $(seq 1 $(./test_progs -c)); do ./test_progs -n $N 2>&1 > result_test_${N}.log & done ; wait V2: Add the ability to return the count for the selected tests. This is useful for getting a count e.g. after excluding some tests with option -b. The current beakers test script like to report the max test count upfront. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/159363985244.930467.12617117873058936829.stgit@firesoul
| * selftests/bpf: Test_progs indicate to shell on non-actionsJesper Dangaard Brouer2020-07-011-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | When a user selects a non-existing test the summary is printed with indication 0 for all info types, and shell "success" (EXIT_SUCCESS) is indicated. This can be understood by a human end-user, but for shell scripting is it useful to indicate a shell failure (EXIT_FAILURE). Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/159363984736.930467.17956007131403952343.stgit@firesoul
| * tools/bpftool: Turn off -Wnested-externs warningAndrii Nakryiko2020-07-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Turn off -Wnested-externs to avoid annoying warnings in BUILD_BUG_ON macro when compiling bpftool: In file included from /data/users/andriin/linux/tools/include/linux/build_bug.h:5, from /data/users/andriin/linux/tools/include/linux/kernel.h:8, from /data/users/andriin/linux/kernel/bpf/disasm.h:10, from /data/users/andriin/linux/kernel/bpf/disasm.c:8: /data/users/andriin/linux/kernel/bpf/disasm.c: In function ‘__func_get_name’: /data/users/andriin/linux/tools/include/linux/compiler.h:37:38: warning: nested extern declaration of ‘__compiletime_assert_0’ [-Wnested-externs] _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) ^~~~~~~~~~~~~~~~~~~~~ /data/users/andriin/linux/tools/include/linux/compiler.h:16:15: note: in definition of macro ‘__compiletime_assert’ extern void prefix ## suffix(void) __compiletime_error(msg); \ ^~~~~~ /data/users/andriin/linux/tools/include/linux/compiler.h:37:2: note: in expansion of macro ‘_compiletime_assert’ _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) ^~~~~~~~~~~~~~~~~~~ /data/users/andriin/linux/tools/include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’ #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) ^~~~~~~~~~~~~~~~~~ /data/users/andriin/linux/tools/include/linux/build_bug.h:50:2: note: in expansion of macro ‘BUILD_BUG_ON_MSG’ BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) ^~~~~~~~~~~~~~~~ /data/users/andriin/linux/kernel/bpf/disasm.c:20:2: note: in expansion of macro ‘BUILD_BUG_ON’ BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID); ^~~~~~~~~~~~ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200701212816.2072340-1-andriin@fb.com
| * selftests/bpf: Switch test_vmlinux to use hrtimer_range_start_ns.Hao Luo2020-07-011-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The test_vmlinux test uses hrtimer_nanosleep as hook to test tracing programs. But in a kernel built by clang, which performs more aggresive inlining, that function gets inlined into its caller SyS_nanosleep. Therefore, even though fentry and kprobe do hook on the function, they aren't triggered by the call to nanosleep in the test. A possible fix is switching to use a function that is less likely to be inlined, such as hrtimer_range_start_ns. The EXPORT_SYMBOL functions shouldn't be inlined based on the description of [1], therefore safe to use for this test. Also the arguments of this function include the duration of sleep, therefore suitable for test verification. [1] af3b56289be1 time: don't inline EXPORT_SYMBOL functions Tested: In a clang build kernel, before this change, the test fails: test_vmlinux:PASS:skel_open 0 nsec test_vmlinux:PASS:skel_attach 0 nsec test_vmlinux:PASS:tp 0 nsec test_vmlinux:PASS:raw_tp 0 nsec test_vmlinux:PASS:tp_btf 0 nsec test_vmlinux:FAIL:kprobe not called test_vmlinux:FAIL:fentry not called After switching to hrtimer_range_start_ns, the test passes: test_vmlinux:PASS:skel_open 0 nsec test_vmlinux:PASS:skel_attach 0 nsec test_vmlinux:PASS:tp 0 nsec test_vmlinux:PASS:raw_tp 0 nsec test_vmlinux:PASS:tp_btf 0 nsec test_vmlinux:PASS:kprobe 0 nsec test_vmlinux:PASS:fentry 0 nsec Signed-off-by: Hao Luo <haoluo@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200701175315.1161242-1-haoluo@google.com
| * selftests/bpf: Add bpf_iter test with bpf_get_task_stack()Song Liu2020-07-012-0/+54
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The new test is similar to other bpf_iter tests. It dumps all /proc/<pid>/stack to a seq_file. Here is some example output: pid: 2873 num_entries: 3 [<0>] worker_thread+0xc6/0x380 [<0>] kthread+0x135/0x150 [<0>] ret_from_fork+0x22/0x30 pid: 2874 num_entries: 9 [<0>] __bpf_get_stack+0x15e/0x250 [<0>] bpf_prog_22a400774977bb30_dump_task_stack+0x4a/0xb3c [<0>] bpf_iter_run_prog+0x81/0x170 [<0>] __task_seq_show+0x58/0x80 [<0>] bpf_seq_read+0x1c3/0x3b0 [<0>] vfs_read+0x9e/0x170 [<0>] ksys_read+0xa7/0xe0 [<0>] do_syscall_64+0x4c/0xa0 [<0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Note: bpf_iter test as-is doesn't print the contents of the seq_file. To see the example above, it is necessary to add printf() to do_dummy_read. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200630062846.664389-5-songliubraving@fb.com
| * bpf: Introduce helper bpf_get_task_stack()Song Liu2020-07-011-1/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce helper bpf_get_task_stack(), which dumps stack trace of given task. This is different to bpf_get_stack(), which gets stack track of current task. One potential use case of bpf_get_task_stack() is to call it from bpf_iter__task and dump all /proc/<pid>/stack to a seq_file. bpf_get_task_stack() uses stack_trace_save_tsk() instead of get_perf_callchain() for kernel stack. The benefit of this choice is that stack_trace_save_tsk() doesn't require changes in arch/. The downside of using stack_trace_save_tsk() is that stack_trace_save_tsk() dumps the stack trace to unsigned long array. For 32-bit systems, we need to translate it to u64 array. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200630062846.664389-3-songliubraving@fb.com
| * selftests/bpf: Add byte swapping selftestAndrii Nakryiko2020-07-012-0/+90
| | | | | | | | | | | | | | | | | | Add simple selftest validating byte swap built-ins and compile-time macros. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200630152125.3631920-3-andriin@fb.com
| * libbpf: Make bpf_endian co-exist with vmlinux.hAndrii Nakryiko2020-07-011-8/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make bpf_endian.h compatible with vmlinux.h. It is a frequent request from users wanting to use bpf_endian.h in their BPF applications using CO-RE and vmlinux.h. To achieve that, re-implement byte swap macros and drop all the header includes. This way it can be used both with linux header includes, as well as with a vmlinux.h. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200630152125.3631920-2-andriin@fb.com
| * selftests/bpf: Allow substituting custom vmlinux.h for selftests buildAndrii Nakryiko2020-06-301-2/+7
| | | | | | | | | | | | | | | | | | | | | | Similarly to bpftool Makefile, allow to specify custom location of vmlinux.h to be used during the build. This allows simpler testing setups with checked-in pre-generated vmlinux.h. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200630004759.521530-2-andriin@fb.com
| * tools/bpftool: Allow substituting custom vmlinux.h for the buildAndrii Nakryiko2020-06-301-3/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In some build contexts (e.g., Travis CI build for outdated kernel), vmlinux.h, generated from available kernel, doesn't contain all the types necessary for BPF program compilation. For such set up, the most maintainable way to deal with this problem is to keep pre-generated (almost up-to-date) vmlinux.h checked in and use it for compilation purposes. bpftool after that can deal with kernel missing some of the features in runtime with no problems. To that effect, allow to specify path to custom vmlinux.h to bpftool's Makefile with VMLINUX_H variable. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200630004759.521530-1-andriin@fb.com
| * selftests/bpf: Test auto-load disabling logic for BPF programsAndrii Nakryiko2020-06-282-0/+81
| | | | | | | | | | | | | | | | | | Validate that BPF object with broken (in multiple ways) BPF program can still be successfully loaded, if that broken BPF program is disabled. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200625232629.3444003-3-andriin@fb.com
| * libbpf: Support disabling auto-loading BPF programsAndrii Nakryiko2020-06-283-8/+44
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, bpf_object__load() (and by induction skeleton's load), will always attempt to prepare, relocate, and load into kernel every single BPF program found inside the BPF object file. This is often convenient and the right thing to do and what users expect. But there are plenty of cases (especially with BPF development constantly picking up the pace), where BPF application is intended to work with old kernels, with potentially reduced set of features. But on kernels supporting extra features, it would like to take a full advantage of them, by employing extra BPF program. This could be a choice of using fentry/fexit over kprobe/kretprobe, if kernel is recent enough and is built with BTF. Or BPF program might be providing optimized bpf_iter-based solution that user-space might want to use, whenever available. And so on. With libbpf and BPF CO-RE in particular, it's advantageous to not have to maintain two separate BPF object files to achieve this. So to enable such use cases, this patch adds ability to request not auto-loading chosen BPF programs. In such case, libbpf won't attempt to perform relocations (which might fail due to old kernel), won't try to resolve BTF types for BTF-aware (tp_btf/fentry/fexit/etc) program types, because BTF might not be present, and so on. Skeleton will also automatically skip auto-attachment step for such not loaded BPF programs. Overall, this feature allows to simplify development and deployment of real-world BPF applications with complicated compatibility requirements. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200625232629.3444003-2-andriin@fb.com
| * tools, bpftool: Define attach_type_name array only onceTobias Klauser2020-06-252-35/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Define attach_type_name in common.c instead of main.h so it is only defined once. This leads to a slight decrease in the binary size of bpftool. Before: text data bss dec hex filename 399024 11168 1573160 1983352 1e4378 bpftool After: text data bss dec hex filename 398256 10880 1573160 1982296 1e3f58 bpftool Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20200624143154.13145-1-tklauser@distanz.ch
| * tools, bpftool: Define prog_type_name array only onceTobias Klauser2020-06-255-37/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Define prog_type_name in prog.c instead of main.h so it is only defined once. This leads to a slight decrease in the binary size of bpftool. Before: text data bss dec hex filename 401032 11936 1573160 1986128 1e4e50 bpftool After: text data bss dec hex filename 399024 11168 1573160 1983352 1e4378 bpftool Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20200624143124.12914-1-tklauser@distanz.ch
| * selftests/bpf: Add tcp/udp iterator programs to selftestsYonghong Song2020-06-241-0/+68
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Added tcp{4,6} and udp{4,6} bpf programs into test_progs selftest so that they at least can load successfully. $ ./test_progs -n 3 ... #3/7 tcp4:OK #3/8 tcp6:OK #3/9 udp4:OK #3/10 udp6:OK ... #3 bpf_iter:OK Summary: 1/16 PASSED, 0 SKIPPED, 0 FAILED Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230823.3989372-1-yhs@fb.com
| * selftests/bpf: Implement sample udp/udp6 bpf_iter programsYonghong Song2020-06-243-0/+166
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On my VM, I got identical results between /proc/net/udp[6] and the udp{4,6} bpf iterator. For udp6: $ cat /sys/fs/bpf/p1 sl local_address remote_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode ref pointer drops 1405: 000080FE00000000FF7CC4D0D9EFE4FE:0222 00000000000000000000000000000000:0000 07 00000000:00000000 00:00000000 00000000 193 0 19183 2 0000000029eab111 0 $ cat /proc/net/udp6 sl local_address remote_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode ref pointer drops 1405: 000080FE00000000FF7CC4D0D9EFE4FE:0222 00000000000000000000000000000000:0000 07 00000000:00000000 00:00000000 00000000 193 0 19183 2 0000000029eab111 0 For udp4: $ cat /sys/fs/bpf/p4 sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode ref pointer drops 2007: 00000000:1F90 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 72540 2 000000004ede477a 0 $ cat /proc/net/udp sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode ref pointer drops 2007: 00000000:1F90 00000000:0000 07 00000000:00000000 00:00000000 00000000 0 0 72540 2 000000004ede477a 0 Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230822.3989299-1-yhs@fb.com
| * selftests/bpf: Implement sample tcp/tcp6 bpf_iter programsYonghong Song2020-06-243-0/+499
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In my VM, I got identical result compared to /proc/net/{tcp,tcp6}. For tcp6: $ cat /proc/net/tcp6 sl local_address remote_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode 0: 00000000000000000000000000000000:0016 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000001 00000000 0 0 17955 1 000000003eb3102e 100 0 0 10 0 $ cat /sys/fs/bpf/p1 sl local_address remote_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode 0: 00000000000000000000000000000000:0016 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 00000000 0 0 17955 1 000000003eb3102e 100 0 0 10 0 For tcp: $ cat /proc/net/tcp sl local_address rem_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode 0: 00000000:0016 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0 0 2666 1 000000007152e43f 100 0 0 10 0 $ cat /sys/fs/bpf/p2 sl local_address remote_address st tx_queue rx_queue tr tm->when retrnsmt uid timeout inode 1: 00000000:0016 00000000:0000 0A 00000000:00000000 00:00000000 00000000 0 0 2666 1 000000007152e43f 100 0 0 10 0 Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230820.3989165-1-yhs@fb.com
| * selftests/bpf: Add more common macros to bpf_tracing_net.hYonghong Song2020-06-241-0/+35
| | | | | | | | | | | | | | | | | | | | | | These newly added macros will be used in subsequent bpf iterator tcp{4,6} and udp{4,6} programs. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230819.3989050-1-yhs@fb.com
| * selftests/bpf: Refactor some net macros to bpf_tracing_net.hYonghong Song2020-06-243-9/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Refactor bpf_iter_ipv6_route.c and bpf_iter_netlink.c so net macros, originally from various include/linux header files, are moved to a new header file bpf_tracing_net.h. The goal is to improve reuse so networking tracing programs do not need to copy these macros every time they use them. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230817.3988962-1-yhs@fb.com
| * selftests/bpf: Move newer bpf_iter_* type redefining to a new header fileYonghong Song2020-06-249-136/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit b9f4c01f3e0b ("selftest/bpf: Make bpf_iter selftest compilable against old vmlinux.h") and Commit dda18a5c0b75 ("selftests/bpf: Convert bpf_iter_test_kern{3, 4}.c to define own bpf_iter_meta") redefined newly introduced types in bpf programs so the bpf program can still compile properly with old kernels although loading may fail. Since this patch set introduced new types and the same workaround is needed, so let us move the workaround to a separate header file so they do not clutter bpf programs. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230816.3988656-1-yhs@fb.com
| * bpf: Add bpf_skc_to_udp6_sock() helperYonghong Song2020-06-241-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | The helper is used in tracing programs to cast a socket pointer to a udp6_sock pointer. The return value could be NULL if the casting is illegal. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Cc: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/bpf/20200623230815.3988481-1-yhs@fb.com
| * bpf: Add bpf_skc_to_{tcp, tcp_timewait, tcp_request}_sock() helpersYonghong Song2020-06-241-1/+22
| | | | | | | | | | | | | | | | | | | | | | Three more helpers are added to cast a sock_common pointer to an tcp_sock, tcp_timewait_sock or a tcp_request_sock for tracing programs. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230811.3988277-1-yhs@fb.com
| * bpf: Add bpf_skc_to_tcp6_sock() helperYonghong Song2020-06-241-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The helper is used in tracing programs to cast a socket pointer to a tcp6_sock pointer. The return value could be NULL if the casting is illegal. A new helper return type RET_PTR_TO_BTF_ID_OR_NULL is added so the verifier is able to deduce proper return types for the helper. Different from the previous BTF_ID based helpers, the bpf_skc_to_tcp6_sock() argument can be several possible btf_ids. More specifically, all possible socket data structures with sock_common appearing in the first in the memory layout. This patch only added socket types related to tcp and udp. All possible argument btf_id and return value btf_id for helper bpf_skc_to_tcp6_sock() are pre-calculcated and cached. In the future, it is even possible to precompute these btf_id's at kernel build time. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230809.3988195-1-yhs@fb.com
| * bpf: Add SO_KEEPALIVE and related options to bpf_setsockoptDmitry Yakunin2020-06-242-2/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds support of SO_KEEPALIVE flag and TCP related options to bpf_setsockopt() routine. This is helpful if we want to enable or tune TCP keepalive for applications which don't do it in the userspace code. v3: - update kernel-doc in uapi (Nikita Vetoshkin <nekto0n@yandex-team.ru>) v4: - update kernel-doc in tools too (Alexei Starovoitov) - add test to selftests (Alexei Starovoitov) Signed-off-by: Dmitry Yakunin <zeil@yandex-team.ru> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200620153052.9439-3-zeil@yandex-team.ru
| * selftests/bpf: Workaround for get_stack_rawtp test.Alexei Starovoitov2020-06-241-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ./test_progs-no_alu32 -t get_stack_raw_tp fails due to: 52: (85) call bpf_get_stack#67 53: (bf) r8 = r0 54: (bf) r1 = r8 55: (67) r1 <<= 32 56: (c7) r1 s>>= 32 ; if (usize < 0) 57: (c5) if r1 s< 0x0 goto pc+26 R0=inv(id=0,smax_value=800) R1_w=inv(id=0,umax_value=800,var_off=(0x0; 0x3ff)) R6=ctx(id=0,off=0,imm=0) R7=map_value(id=0,off=0,ks=4,vs=1600,imm=0) R8_w=inv(id=0,smax_value=800) R9=inv800 ; ksize = bpf_get_stack(ctx, raw_data + usize, max_len - usize, 0); 58: (1f) r9 -= r8 ; ksize = bpf_get_stack(ctx, raw_data + usize, max_len - usize, 0); 59: (bf) r2 = r7 60: (0f) r2 += r1 regs=1 stack=0 before 52: (85) call bpf_get_stack#67 ; ksize = bpf_get_stack(ctx, raw_data + usize, max_len - usize, 0); 61: (bf) r1 = r6 62: (bf) r3 = r9 63: (b7) r4 = 0 64: (85) call bpf_get_stack#67 R0=inv(id=0,smax_value=800) R1_w=ctx(id=0,off=0,imm=0) R2_w=map_value(id=0,off=0,ks=4,vs=1600,umax_value=800,var_off=(0x0; 0x3ff),s32_max_value=1023,u32_max_value=1023) R3_w=inv(id=0,umax_value=9223372036854776608) R3 unbounded memory access, use 'var &= const' or 'if (var < const)' In the C code: usize = bpf_get_stack(ctx, raw_data, max_len, BPF_F_USER_STACK); if (usize < 0) return 0; ksize = bpf_get_stack(ctx, raw_data + usize, max_len - usize, 0); if (ksize < 0) return 0; We used to have problem with pointer arith in R2. Now it's a problem with two integers in R3. 'if (usize < 0)' is comparing R1 and makes it [0,800], but R8 stays [-inf,800]. Both registers represent the same 'usize' variable. Then R9 -= R8 is doing 800 - [-inf, 800] so the result of "max_len - usize" looks unbounded to the verifier while it's obvious in C code that "max_len - usize" should be [0, 800]. To workaround the problem convert ksize and usize variables from int to long. Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| * libbpf: Prevent loading vmlinux BTF twiceAndrii Nakryiko2020-06-241-11/+22
| | | | | | | | | | | | | | | | | | | | Prevent loading/parsing vmlinux BTF twice in some cases: for CO-RE relocations and for BTF-aware hooks (tp_btf, fentry/fexit, etc). Fixes: a6ed02cac690 ("libbpf: Load btf_vmlinux only once per object.") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200624043805.1794620-1-andriin@fb.com
| * libbpf: Fix spelling mistake "kallasyms" -> "kallsyms"Colin Ian King2020-06-241-1/+1
| | | | | | | | | | | | | | | | | | There is a spelling mistake in a pr_warn message. Fix it. Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200623084207.149253-1-colin.king@canonical.com
| * tools, bpftool: Fix variable shadowing in emit_obj_refs_json()Quentin Monnet2020-06-241-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Building bpftool yields the following complaint: pids.c: In function 'emit_obj_refs_json': pids.c:175:80: warning: declaration of 'json_wtr' shadows a global declaration [-Wshadow] 175 | void emit_obj_refs_json(struct obj_refs_table *table, __u32 id, json_writer_t *json_wtr) | ~~~~~~~~~~~~~~~^~~~~~~~ In file included from pids.c:11: main.h:141:23: note: shadowed declaration is here 141 | extern json_writer_t *json_wtr; | ^~~~~~~~ Let's rename the variable. v2: - Rename the variable instead of calling the global json_wtr directly. Signed-off-by: Quentin Monnet <quentin@isovalent.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200623213600.16643-1-quentin@isovalent.com
| * Merge up to bpf_probe_read_kernel_str() fix into bpf-nextAlexei Starovoitov2020-06-232-1/+2
| |\
| * | tools, bpftool: Correctly evaluate $(BUILD_BPF_SKELS) in MakefileTobias Klauser2020-06-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, if the clang-bpf-co-re feature is not available, the build fails with e.g. CC prog.o prog.c:1462:10: fatal error: profiler.skel.h: No such file or directory 1462 | #include "profiler.skel.h" | ^~~~~~~~~~~~~~~~~ This is due to the fact that the BPFTOOL_WITHOUT_SKELETONS macro is not defined, despite BUILD_BPF_SKELS not being set. Fix this by correctly evaluating $(BUILD_BPF_SKELS) when deciding on whether to add -DBPFTOOL_WITHOUT_SKELETONS to CFLAGS. Fixes: 05aca6da3b5a ("tools/bpftool: Generalize BPF skeleton support and generate vmlinux.h") Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200623103710.10370-1-tklauser@distanz.ch
| * | selftests/bpf: Add variable-length data concat pattern less than testJohn Fastabend2020-06-242-4/+78
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extend original variable-length tests with a case to catch a common existing pattern of testing for < 0 for errors. Note because verifier also tracks upper bounds and we know it can not be greater than MAX_LEN here we can skip upper bound check. In ALU64 enabled compilation converting from long->int return types in probe helpers results in extra instruction pattern, <<= 32, s >>= 32. The trade-off is the non-ALU64 case works. If you really care about every extra insn (XDP case?) then you probably should be using original int type. In addition adding a sext insn to bpf might help the verifier in the general case to avoid these types of tricks. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200623032224.4020118-3-andriin@fb.com
| * | selftests/bpf: Add variable-length data concatenation pattern testAndrii Nakryiko2020-06-242-0/+152
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add selftest that validates variable-length data reading and concatentation with one big shared data array. This is a common pattern in production use for monitoring and tracing applications, that potentially can read a lot of data, but overall read much less. Such pattern allows to determine precisely what amount of data needs to be sent over perfbuf/ringbuf and maximize efficiency. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200623032224.4020118-2-andriin@fb.com
| * | bpf: Switch most helper return values from 32-bit int to 64-bit longAndrii Nakryiko2020-06-241-96/+96
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Switch most of BPF helper definitions from returning int to long. These definitions are coming from comments in BPF UAPI header and are used to generate bpf_helper_defs.h (under libbpf) to be later included and used from BPF programs. In actual in-kernel implementation, all the helpers are defined as returning u64, but due to some historical reasons, most of them are actually defined as returning int in UAPI (usually, to return 0 on success, and negative value on error). This actually causes Clang to quite often generate sub-optimal code, because compiler believes that return value is 32-bit, and in a lot of cases has to be up-converted (usually with a pair of 32-bit bit shifts) to 64-bit values, before they can be used further in BPF code. Besides just "polluting" the code, these 32-bit shifts quite often cause problems for cases in which return value matters. This is especially the case for the family of bpf_probe_read_str() functions. There are few other similar helpers (e.g., bpf_read_branch_records()), in which return value is used by BPF program logic to record variable-length data and process it. For such cases, BPF program logic carefully manages offsets within some array or map to read variable-length data. For such uses, it's crucial for BPF verifier to track possible range of register values to prove that all the accesses happen within given memory bounds. Those extraneous zero-extending bit shifts, inserted by Clang (and quite often interleaved with other code, which makes the issues even more challenging and sometimes requires employing extra per-variable compiler barriers), throws off verifier logic and makes it mark registers as having unknown variable offset. We'll study this pattern a bit later below. Another common pattern is to check return of BPF helper for non-zero state to detect error conditions and attempt alternative actions in such case. Even in this simple and straightforward case, this 32-bit vs BPF's native 64-bit mode quite often leads to sub-optimal and unnecessary extra code. We'll look at this pattern as well. Clang's BPF target supports two modes of code generation: ALU32, in which it is capable of using lower 32-bit parts of registers, and no-ALU32, in which only full 64-bit registers are being used. ALU32 mode somewhat mitigates the above described problems, but not in all cases. This patch switches all the cases in which BPF helpers return 0 or negative error from returning int to returning long. It is shown below that such change in definition leads to equivalent or better code. No-ALU32 mode benefits more, but ALU32 mode doesn't degrade or still gets improved code generation. Another class of cases switched from int to long are bpf_probe_read_str()-like helpers, which encode successful case as non-negative values, while still returning negative value for errors. In all of such cases, correctness is preserved due to two's complement encoding of negative values and the fact that all helpers return values with 32-bit absolute value. Two's complement ensures that for negative values higher 32 bits are all ones and when truncated, leave valid negative 32-bit value with the same value. Non-negative values have upper 32 bits set to zero and similarly preserve value when high 32 bits are truncated. This means that just casting to int/u32 is correct and efficient (and in ALU32 mode doesn't require any extra shifts). To minimize the chances of regressions, two code patterns were investigated, as mentioned above. For both patterns, BPF assembly was analyzed in ALU32/NO-ALU32 compiler modes, both with current 32-bit int return type and new 64-bit long return type. Case 1. Variable-length data reading and concatenation. This is quite ubiquitous pattern in tracing/monitoring applications, reading data like process's environment variables, file path, etc. In such case, many pieces of string-like variable-length data are read into a single big buffer, and at the end of the process, only a part of array containing actual data is sent to user-space for further processing. This case is tested in test_varlen.c selftest (in the next patch). Code flow is roughly as follows: void *payload = &sample->payload; u64 len; len = bpf_probe_read_kernel_str(payload, MAX_SZ1, &source_data1); if (len <= MAX_SZ1) { payload += len; sample->len1 = len; } len = bpf_probe_read_kernel_str(payload, MAX_SZ2, &source_data2); if (len <= MAX_SZ2) { payload += len; sample->len2 = len; } /* and so on */ sample->total_len = payload - &sample->payload; /* send over, e.g., perf buffer */ There could be two variations with slightly different code generated: when len is 64-bit integer and when it is 32-bit integer. Both variations were analysed. BPF assembly instructions between two successive invocations of bpf_probe_read_kernel_str() were used to check code regressions. Results are below, followed by short analysis. Left side is using helpers with int return type, the right one is after the switch to long. ALU32 + INT ALU32 + LONG =========== ============ 64-BIT (13 insns): 64-BIT (10 insns): ------------------------------------ ------------------------------------ 17: call 115 17: call 115 18: if w0 > 256 goto +9 <LBB0_4> 18: if r0 > 256 goto +6 <LBB0_4> 19: w1 = w0 19: r1 = 0 ll 20: r1 <<= 32 21: *(u64 *)(r1 + 0) = r0 21: r1 s>>= 32 22: r6 = 0 ll 22: r2 = 0 ll 24: r6 += r0 24: *(u64 *)(r2 + 0) = r1 00000000000000c8 <LBB0_4>: 25: r6 = 0 ll 25: r1 = r6 27: r6 += r1 26: w2 = 256 00000000000000e0 <LBB0_4>: 27: r3 = 0 ll 28: r1 = r6 29: call 115 29: w2 = 256 30: r3 = 0 ll 32: call 115 32-BIT (11 insns): 32-BIT (12 insns): ------------------------------------ ------------------------------------ 17: call 115 17: call 115 18: if w0 > 256 goto +7 <LBB1_4> 18: if w0 > 256 goto +8 <LBB1_4> 19: r1 = 0 ll 19: r1 = 0 ll 21: *(u32 *)(r1 + 0) = r0 21: *(u32 *)(r1 + 0) = r0 22: w1 = w0 22: r0 <<= 32 23: r6 = 0 ll 23: r0 >>= 32 25: r6 += r1 24: r6 = 0 ll 00000000000000d0 <LBB1_4>: 26: r6 += r0 26: r1 = r6 00000000000000d8 <LBB1_4>: 27: w2 = 256 27: r1 = r6 28: r3 = 0 ll 28: w2 = 256 30: call 115 29: r3 = 0 ll 31: call 115 In ALU32 mode, the variant using 64-bit length variable clearly wins and avoids unnecessary zero-extension bit shifts. In practice, this is even more important and good, because BPF code won't need to do extra checks to "prove" that payload/len are within good bounds. 32-bit len is one instruction longer. Clang decided to do 64-to-32 casting with two bit shifts, instead of equivalent `w1 = w0` assignment. The former uses extra register. The latter might potentially lose some range information, but not for 32-bit value. So in this case, verifier infers that r0 is [0, 256] after check at 18:, and shifting 32 bits left/right keeps that range intact. We should probably look into Clang's logic and see why it chooses bitshifts over sub-register assignments for this. NO-ALU32 + INT NO-ALU32 + LONG ============== =============== 64-BIT (14 insns): 64-BIT (10 insns): ------------------------------------ ------------------------------------ 17: call 115 17: call 115 18: r0 <<= 32 18: if r0 > 256 goto +6 <LBB0_4> 19: r1 = r0 19: r1 = 0 ll 20: r1 >>= 32 21: *(u64 *)(r1 + 0) = r0 21: if r1 > 256 goto +7 <LBB0_4> 22: r6 = 0 ll 22: r0 s>>= 32 24: r6 += r0 23: r1 = 0 ll 00000000000000c8 <LBB0_4>: 25: *(u64 *)(r1 + 0) = r0 25: r1 = r6 26: r6 = 0 ll 26: r2 = 256 28: r6 += r0 27: r3 = 0 ll 00000000000000e8 <LBB0_4>: 29: call 115 29: r1 = r6 30: r2 = 256 31: r3 = 0 ll 33: call 115 32-BIT (13 insns): 32-BIT (13 insns): ------------------------------------ ------------------------------------ 17: call 115 17: call 115 18: r1 = r0 18: r1 = r0 19: r1 <<= 32 19: r1 <<= 32 20: r1 >>= 32 20: r1 >>= 32 21: if r1 > 256 goto +6 <LBB1_4> 21: if r1 > 256 goto +6 <LBB1_4> 22: r2 = 0 ll 22: r2 = 0 ll 24: *(u32 *)(r2 + 0) = r0 24: *(u32 *)(r2 + 0) = r0 25: r6 = 0 ll 25: r6 = 0 ll 27: r6 += r1 27: r6 += r1 00000000000000e0 <LBB1_4>: 00000000000000e0 <LBB1_4>: 28: r1 = r6 28: r1 = r6 29: r2 = 256 29: r2 = 256 30: r3 = 0 ll 30: r3 = 0 ll 32: call 115 32: call 115 In NO-ALU32 mode, for the case of 64-bit len variable, Clang generates much superior code, as expected, eliminating unnecessary bit shifts. For 32-bit len, code is identical. So overall, only ALU-32 32-bit len case is more-or-less equivalent and the difference stems from internal Clang decision, rather than compiler lacking enough information about types. Case 2. Let's look at the simpler case of checking return result of BPF helper for errors. The code is very simple: long bla; if (bpf_probe_read_kenerl(&bla, sizeof(bla), 0)) return 1; else return 0; ALU32 + CHECK (9 insns) ALU32 + CHECK (9 insns) ==================================== ==================================== 0: r1 = r10 0: r1 = r10 1: r1 += -8 1: r1 += -8 2: w2 = 8 2: w2 = 8 3: r3 = 0 3: r3 = 0 4: call 113 4: call 113 5: w1 = w0 5: r1 = r0 6: w0 = 1 6: w0 = 1 7: if w1 != 0 goto +1 <LBB2_2> 7: if r1 != 0 goto +1 <LBB2_2> 8: w0 = 0 8: w0 = 0 0000000000000048 <LBB2_2>: 0000000000000048 <LBB2_2>: 9: exit 9: exit Almost identical code, the only difference is the use of full register assignment (r1 = r0) vs half-registers (w1 = w0) in instruction #5. On 32-bit architectures, new BPF assembly might be slightly less optimal, in theory. But one can argue that's not a big issue, given that use of full registers is still prevalent (e.g., for parameter passing). NO-ALU32 + CHECK (11 insns) NO-ALU32 + CHECK (9 insns) ==================================== ==================================== 0: r1 = r10 0: r1 = r10 1: r1 += -8 1: r1 += -8 2: r2 = 8 2: r2 = 8 3: r3 = 0 3: r3 = 0 4: call 113 4: call 113 5: r1 = r0 5: r1 = r0 6: r1 <<= 32 6: r0 = 1 7: r1 >>= 32 7: if r1 != 0 goto +1 <LBB2_2> 8: r0 = 1 8: r0 = 0 9: if r1 != 0 goto +1 <LBB2_2> 0000000000000048 <LBB2_2>: 10: r0 = 0 9: exit 0000000000000058 <LBB2_2>: 11: exit NO-ALU32 is a clear improvement, getting rid of unnecessary zero-extension bit shifts. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200623032224.4020118-1-andriin@fb.com
| * | tools/bpftool: Add documentation and sample output for process infoAndrii Nakryiko2020-06-224-2/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add statements about bpftool being able to discover process info, holding reference to BPF map, prog, link, or BTF. Show example output as well. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20200619231703.738941-10-andriin@fb.com
| * | tools/bpftool: Show info for processes holding BPF map/prog/link/btf FDsAndrii Nakryiko2020-06-2210-0/+378
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add bpf_iter-based way to find all the processes that hold open FDs against BPF object (map, prog, link, btf). bpftool always attempts to discover this, but will silently give up if kernel doesn't yet support bpf_iter BPF programs. Process name and PID are emitted for each process (task group). Sample output for each of 4 BPF objects: $ sudo ./bpftool prog show 2694: cgroup_device tag 8c42dee26e8cd4c2 gpl loaded_at 2020-06-16T15:34:32-0700 uid 0 xlated 648B jited 409B memlock 4096B pids systemd(1) 2907: cgroup_skb name egress tag 9ad187367cf2b9e8 gpl loaded_at 2020-06-16T18:06:54-0700 uid 0 xlated 48B jited 59B memlock 4096B map_ids 2436 btf_id 1202 pids test_progs(2238417), test_progs(2238445) $ sudo ./bpftool map show 2436: array name test_cgr.bss flags 0x400 key 4B value 8B max_entries 1 memlock 8192B btf_id 1202 pids test_progs(2238417), test_progs(2238445) 2445: array name pid_iter.rodata flags 0x480 key 4B value 4B max_entries 1 memlock 8192B btf_id 1214 frozen pids bpftool(2239612) $ sudo ./bpftool link show 61: cgroup prog 2908 cgroup_id 375301 attach_type egress pids test_progs(2238417), test_progs(2238445) 62: cgroup prog 2908 cgroup_id 375344 attach_type egress pids test_progs(2238417), test_progs(2238445) $ sudo ./bpftool btf show 1202: size 1527B prog_ids 2908,2907 map_ids 2436 pids test_progs(2238417), test_progs(2238445) 1242: size 34684B pids bpftool(2258892) Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20200619231703.738941-9-andriin@fb.com
| * | libbpf: Wrap source argument of BPF_CORE_READ macro in parenthesesAndrii Nakryiko2020-06-221-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Wrap source argument of BPF_CORE_READ family of macros into parentheses to allow uses like this: BPF_CORE_READ((struct cast_struct *)src, a, b, c); Fixes: 7db3822ab991 ("libbpf: Add BPF_CORE_READ/BPF_CORE_READ_INTO helpers") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200619231703.738941-8-andriin@fb.com
| * | tools/bpftool: Generalize BPF skeleton support and generate vmlinux.hAndrii Nakryiko2020-06-227-66/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adapt Makefile to support BPF skeleton generation beyond single profiler.bpf.c case. Also add vmlinux.h generation and switch profiler.bpf.c to use it. clang-bpf-global-var feature is extended and renamed to clang-bpf-co-re to check for support of preserve_access_index attribute, which, together with BTF for global variables, is the minimum requirement for modern BPF programs. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20200619231703.738941-7-andriin@fb.com
| * | tools/bpftool: Minimize bootstrap bpftoolAndrii Nakryiko2020-06-224-32/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Build minimal "bootstrap mode" bpftool to enable skeleton (and, later, vmlinux.h generation), instead of building almost complete, but slightly different (w/o skeletons, etc) bpftool to bootstrap complete bpftool build. Current approach doesn't scale well (engineering-wise) when adding more BPF programs to bpftool and other complicated functionality, as it requires constant adjusting of the code to work in both bootstrapped mode and normal mode. So it's better to build only minimal bpftool version that supports only BPF skeleton code generation and BTF-to-C conversion. Thankfully, this is quite easy to accomplish due to internal modularity of bpftool commands. This will also allow to keep adding new functionality to bpftool in general, without the need to care about bootstrap mode for those new parts of bpftool. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20200619231703.738941-6-andriin@fb.com
| * | tools/bpftool: Move map/prog parsing logic into commonAndrii Nakryiko2020-06-224-308/+310
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move functions that parse map and prog by id/tag/name/etc outside of map.c/prog.c, respectively. These functions are used outside of those files and are generic enough to be in common. This also makes heavy-weight map.c and prog.c more decoupled from the rest of bpftool files and facilitates more lightweight bootstrap bpftool variant. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20200619231703.738941-5-andriin@fb.com
| * | selftests/bpf: Add __ksym extern selftestAndrii Nakryiko2020-06-222-0/+103
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Validate libbpf is able to handle weak and strong kernel symbol externs in BPF code correctly. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/bpf/20200619231703.738941-4-andriin@fb.com
| * | libbpf: Add support for extracting kernel symbol addressesAndrii Nakryiko2020-06-223-6/+144
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for another (in addition to existing Kconfig) special kind of externs in BPF code, kernel symbol externs. Such externs allow BPF code to "know" kernel symbol address and either use it for comparisons with kernel data structures (e.g., struct file's f_op pointer, to distinguish different kinds of file), or, with the help of bpf_probe_user_kernel(), to follow pointers and read data from global variables. Kernel symbol addresses are found through /proc/kallsyms, which should be present in the system. Currently, such kernel symbol variables are typeless: they have to be defined as `extern const void <symbol>` and the only operation you can do (in C code) with them is to take its address. Such extern should reside in a special section '.ksyms'. bpf_helpers.h header provides __ksym macro for this. Strong vs weak semantics stays the same as with Kconfig externs. If symbol is not found in /proc/kallsyms, this will be a failure for strong (non-weak) extern, but will be defaulted to 0 for weak externs. If the same symbol is defined multiple times in /proc/kallsyms, then it will be error if any of the associated addresses differs. In that case, address is ambiguous, so libbpf falls on the side of caution, rather than confusing user with randomly chosen address. In the future, once kernel is extended with variables BTF information, such ksym externs will be supported in a typed version, which will allow BPF program to read variable's contents directly, similarly to how it's done for fentry/fexit input arguments. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/bpf/20200619231703.738941-3-andriin@fb.com
| * | libbpf: Generalize libbpf externs supportAndrii Nakryiko2020-06-221-140/+206
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Switch existing Kconfig externs to be just one of few possible kinds of more generic externs. This refactoring is in preparation for ksymbol extern support, added in the follow up patch. There are no functional changes intended. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Reviewed-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/bpf/20200619231703.738941-2-andriin@fb.com
| * | libbpf: Add a bunch of attribute getters/setters for map definitionsAndrii Nakryiko2020-06-233-10/+134
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a bunch of getter for various aspects of BPF map. Some of these attribute (e.g., key_size, value_size, type, etc) are available right now in struct bpf_map_def, but this patch adds getter allowing to fetch them individually. bpf_map_def approach isn't very scalable, when ABI stability requirements are taken into account. It's much easier to extend libbpf and add support for new features, when each aspect of BPF map has separate getter/setter. Getters follow the common naming convention of not explicitly having "get" in its name: bpf_map__type() returns map type, bpf_map__key_size() returns key_size. Setters, though, explicitly have set in their name: bpf_map__set_type(), bpf_map__set_key_size(). This patch ensures we now have a getter and a setter for the following map attributes: - type; - max_entries; - map_flags; - numa_node; - key_size; - value_size; - ifindex. bpf_map__resize() enforces unnecessary restriction of max_entries > 0. It is unnecessary, because libbpf actually supports zero max_entries for some cases (e.g., for PERF_EVENT_ARRAY map) and treats it specially during map creation time. To allow setting max_entries=0, new bpf_map__set_max_entries() setter is added. bpf_map__resize()'s behavior is preserved for backwards compatibility reasons. Map ifindex getter is added as well. There is a setter already, but no corresponding getter. Fix this assymetry as well. bpf_map__set_ifindex() itself is converted from void function into error-returning one, similar to other setters. The only error returned right now is -EBUSY, if BPF map is already loaded and has corresponding FD. One lacking attribute with no ability to get/set or even specify it declaratively is numa_node. This patch fixes this gap and both adds programmatic getter/setter, as well as adds support for numa_node field in BTF-defined map. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20200621062112.3006313-1-andriin@fb.com
| * | selftests/bpf: Test access to bpf map pointerAndrey Ignatov2020-06-223-0/+780
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add selftests to test access to map pointers from bpf program for all map types except struct_ops (that one would need additional work). verifier test focuses mostly on scenarios that must be rejected. prog_tests test focuses on accessing multiple fields both scalar and a nested struct from bpf program and verifies that those fields have expected values. Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/139a6a17f8016491e39347849b951525335c6eb4.1592600985.git.rdna@fb.com
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