- 18 Mar, 2022 33 commits
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Andrii Nakryiko authored
Delyan Kratunov says: ==================== In the quest for ever more modularity, a new need has arisen - the ability to access data associated with a BPF library from a corresponding userspace library. The catch is that we don't want the userspace library to know about the structure of the final BPF object that the BPF library is linked into. In pursuit of this modularity, this patch series introduces *subskeletons.* Subskeletons are similar in use and design to skeletons with a couple of differences: 1. The generated storage types do not rely on contiguous storage for the library's variables because they may be interspersed randomly throughout the final BPF object's sections. 2. Subskeletons do not own objects and instead require a loaded bpf_object* to be passed at runtime in order to be initialized. By extension, symbols are resolved at runtime by parsing the final object's BTF. 3. Subskeletons allow access to all global variables, programs, and custom maps. They also expose the internal maps *of the final object*. This allows bpf_var_skeleton objects to contain a bpf_map** instead of a section name. Changes since v3: - Re-add key/value type lookup for legacy user maps (fixing btf test) - Minor cleanups (missed sanitize_identifier call, error messages, formatting) Changes since v2: - Reuse SEC_NAME strict mode flag - Init bpf_map->btf_value_type_id on open for internal maps *and* user BTF maps - Test custom section names (.data.foo) and overlapping kconfig externs between the final object and the library - Minor review comments in gen.c & libbpf.c Changes since v1: - Introduced new strict mode knob for single-routine-in-.text compatibility behavior, which disproportionately affects library objects. bpftool works in 1.0 mode so subskeleton generation doesn't have to worry about this now. - Made bpf_map_btf_value_type_id available earlier and used it wherever applicable. - Refactoring in bpftool gen.c per review comments. - Subskels now use typeof() for array and func proto globals to avoid the need for runtime split btf. - Expanded the subskeleton test to include arrays, custom maps, extern maps, weak symbols, and kconfigs. - selftests/bpf/Makefile now generates a subskel.h for every skel.h it would make. For reference, here is a shortened subskeleton header: #ifndef __TEST_SUBSKELETON_LIB_SUBSKEL_H__ #define __TEST_SUBSKELETON_LIB_SUBSKEL_H__ struct test_subskeleton_lib { struct bpf_object *obj; struct bpf_object_subskeleton *subskel; struct { struct bpf_map *map2; struct bpf_map *map1; struct bpf_map *data; struct bpf_map *rodata; struct bpf_map *bss; struct bpf_map *kconfig; } maps; struct { struct bpf_program *lib_perf_handler; } progs; struct test_subskeleton_lib__data { int *var6; int *var2; int *var5; } data; struct test_subskeleton_lib__rodata { int *var1; } rodata; struct test_subskeleton_lib__bss { struct { int var3_1; __s64 var3_2; } *var3; int *libout1; typeof(int[4]) *var4; typeof(int (*)()) *fn_ptr; } bss; struct test_subskeleton_lib__kconfig { _Bool *CONFIG_BPF_SYSCALL; } kconfig; static inline struct test_subskeleton_lib * test_subskeleton_lib__open(const struct bpf_object *src) { struct test_subskeleton_lib *obj; struct bpf_object_subskeleton *s; int err; ... s = (struct bpf_object_subskeleton *)calloc(1, sizeof(*s)); ... s->var_cnt = 9; ... s->vars[0].name = "var6"; s->vars[0].map = &obj->maps.data; s->vars[0].addr = (void**) &obj->data.var6; ... /* maps */ ... /* programs */ s->prog_cnt = 1; ... err = bpf_object__open_subskeleton(s); ... return obj; } #endif /* __TEST_SUBSKELETON_LIB_SUBSKEL_H__ */ ==================== Signed-off-by:Andrii Nakryiko <andrii@kernel.org>
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Delyan Kratunov authored
This patch changes the selftests/bpf Makefile to also generate a subskel.h for every skel.h it would have normally generated. Separately, it also introduces a new subskeleton test which tests library objects, externs, weak symbols, kconfigs, and user maps. Signed-off-by:
Delyan Kratunov <delyank@fb.com> Signed-off-by:
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Delyan Kratunov authored
Subskeletons are headers which require an already loaded program to operate. For example, when a BPF library is linked into a larger BPF object file, the library userspace needs a way to access its own global variables without requiring knowledge about the larger program at build time. As a result, subskeletons require a loaded bpf_object to open(). Further, they find their own symbols in the larger program by walking BTF type data at run time. At this time, programs, maps, and globals are supported through non-owning pointers. Signed-off-by:
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Delyan Kratunov authored
In symmetry with bpf_object__open_skeleton(), bpf_object__open_subskeleton() performs the actual walking and linking of maps, progs, and globals described by bpf_*_skeleton objects. Signed-off-by:
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Delyan Kratunov authored
For internal and user maps, look up the key and value btf types on open() and not load(), so that `bpf_map_btf_value_type_id` is usable in `bpftool gen`. Signed-off-by:
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Delyan Kratunov authored
Currently, libbpf considers a single routine in .text to be a program. This is particularly confusing when it comes to library objects - a single routine meant to be used as an extern will instead be considered a bpf_program. This patch hides this compatibility behavior behind the pre-existing SEC_NAME strict mode flag. Signed-off-by:
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Alexei Starovoitov authored
Jiri Olsa says: ==================== hi, this patchset adds new link type BPF_TRACE_KPROBE_MULTI that attaches kprobe program through fprobe API [1] instroduced by Masami. The fprobe API allows to attach probe on multiple functions at once very fast, because it works on top of ftrace. On the other hand this limits the probe point to the function entry or return. With bpftrace support I see following attach speed: # perf stat --null -r 5 ./src/bpftrace -e 'kprobe:x* { } i:ms:1 { exit(); } ' Attaching 2 probes... Attaching 3342 functions ... 1.4960 +- 0.0285 seconds time elapsed ( +- 1.91% ) v3 changes: - based on latest fprobe post from Masami [2] - add acks - add extra comment to kprobe_multi_link_handler wrt entry ip setup [Masami] - keep swap_words_64 static and swap values directly in bpf_kprobe_multi_cookie_swap [Andrii] - rearrange locking/migrate setup in kprobe_multi_link_prog_run [Andrii] - move uapi fields [Andrii] - add bpf_program__attach_kprobe_multi_opts function [Andrii] - many small test changes [Andrii] - added tests for bpf_program__attach_kprobe_multi_opts - make kallsyms_lookup_name check for empty string [Andrii] v2 changes: - based on latest fprobe changes [1] - renaming the uapi interface to kprobe multi - adding support for sort_r to pass user pointer for swap functions and using that in cookie support to keep just single functions array - moving new link to kernel/trace/bpf_trace.c file - using single fprobe callback function for entry and exit - using kvzalloc, libbpf_ensure_mem functions - adding new k[ret]probe.multi sections instead of using current kprobe - used glob_match from test_progs.c, added '?' matching - move bpf_get_func_ip verifier inline change to seprate change - couple of other minor fixes Also available at: https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git bpf/kprobe_multi thanks, jirka [1] https://lore.kernel.org/bpf/164458044634.586276.3261555265565111183.stgit@devnote2/ [2] https://lore.kernel.org/bpf/164735281449.1084943.12438881786173547153.stgit@devnote2/ ==================== Signed-off-by:Alexei Starovoitov <ast@kernel.org>
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Jiri Olsa authored
Adding bpf_cookie test for programs attached by bpf_program__attach_kprobe_multi_opts API. Signed-off-by:
Jiri Olsa <jolsa@kernel.org> Signed-off-by:
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Jiri Olsa authored
Adding tests for bpf_program__attach_kprobe_multi_opts function, that test attach with pattern, symbols and addrs. Signed-off-by:
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Jiri Olsa authored
Adding bpf_cookie test for programs attached by kprobe_multi links. Signed-off-by:
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Jiri Olsa authored
Adding kprobe_multi attach test that uses new fprobe interface to attach kprobe program to multiple functions. The test is attaching programs to bpf_fentry_test* functions and uses single trampoline program bpf_prog_test_run to trigger bpf_fentry_test* functions. Signed-off-by:
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Jiri Olsa authored
Adding bpf_program__attach_kprobe_multi_opts function for attaching kprobe program to multiple functions. struct bpf_link * bpf_program__attach_kprobe_multi_opts(const struct bpf_program *prog, const char *pattern, const struct bpf_kprobe_multi_opts *opts); User can specify functions to attach with 'pattern' argument that allows wildcards (*?' supported) or provide symbols or addresses directly through opts argument. These 3 options are mutually exclusive. When using symbols or addresses, user can also provide cookie value for each symbol/address that can be retrieved later in bpf program with bpf_get_attach_cookie helper. struct bpf_kprobe_multi_opts { size_t sz; const char **syms; const unsigned long *addrs; const __u64 *cookies; size_t cnt; bool retprobe; size_t :0; }; Symbols, addresses and cookies are provided through opts object (syms/addrs/cookies) as array pointers with specified count (cnt). Each cookie value is paired with provided function address or symbol with the same array index. The program can be also attached as return probe if 'retprobe' is set. For quick usage with NULL opts argument, like: bpf_program__attach_kprobe_multi_opts(prog, "ksys_*", NULL) the 'prog' will be attached as kprobe to 'ksys_*' functions. Also adding new program sections for automatic attachment: kprobe.multi/<symbol_pattern> kretprobe.multi/<symbol_pattern> The symbol_pattern is used as 'pattern' argument in bpf_program__attach_kprobe_multi_opts function. Signed-off-by: -
Jiri Olsa authored
Adding new kprobe_multi struct to bpf_link_create_opts object to pass multiple kprobe data to link_create attr uapi. Signed-off-by:
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Jiri Olsa authored
Move the kallsyms parsing in internal libbpf_kallsyms_parse function, so it can be used from other places. It will be used in following changes. Signed-off-by:
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Jiri Olsa authored
Adding support to call bpf_get_attach_cookie helper from kprobe programs attached with kprobe multi link. The cookie is provided by array of u64 values, where each value is paired with provided function address or symbol with the same array index. When cookie array is provided it's sorted together with addresses (check bpf_kprobe_multi_cookie_swap). This way we can find cookie based on the address in bpf_get_attach_cookie helper. Suggested-by:
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Jiri Olsa authored
Adding support to inline it on x86, because it's single load instruction. Signed-off-by:
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Jiri Olsa authored
Adding support to call bpf_get_func_ip helper from kprobe programs attached by multi kprobe link. Signed-off-by:
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Alexei Starovoitov authored
Masami Hiramatsu says: ==================== Hi, Here is the 12th version of fprobe. This version fixes a possible gcc-11 issue which was reported as kretprobes on arm issue, and also I updated the fprobe document. The previous version (v11) is here[1]; [1] https://lore.kernel.org/all/164701432038.268462.3329725152949938527.stgit@devnote2/T/#u This series introduces the fprobe, the function entry/exit probe with multiple probe point support for x86, arm64 and powerpc64le. This also introduces the rethook for hooking function return as same as the kretprobe does. This abstraction will help us to generalize the fgraph tracer, because we can just switch to it from the rethook in fprobe, depending on the kernel configuration. The patch [1/12] is from Jiri's series[2]. [2] https://lore.kernel.org/all/20220104080943.113249-1-jolsa@kernel.org/T/#u And the patch [9/10] adds the FPROBE_FL_KPROBE_SHARED flag for the case if user wants to share the same code (or share a same resource) on the fprobe and the kprobes. I forcibly updated my kprobes/fprobe branch, you can pull this series from: https://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git kprobes/fprobe Thank you, --- Jiri Olsa (1): ftrace: Add ftrace_set_filter_ips function ==================== Signed-off-by:
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Jiri Olsa authored
Adding new link type BPF_LINK_TYPE_KPROBE_MULTI that attaches kprobe program through fprobe API. The fprobe API allows to attach probe on multiple functions at once very fast, because it works on top of ftrace. On the other hand this limits the probe point to the function entry or return. The kprobe program gets the same pt_regs input ctx as when it's attached through the perf API. Adding new attach type BPF_TRACE_KPROBE_MULTI that allows attachment kprobe to multiple function with new link. User provides array of addresses or symbols with count to attach the kprobe program to. The new link_create uapi interface looks like: struct { __u32 flags; __u32 cnt; __aligned_u64 syms; __aligned_u64 addrs; } kprobe_multi; The flags field allows single BPF_TRACE_KPROBE_MULTI bit to create return multi kprobe. Signed-off-by:Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by:
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Jiri Olsa authored
When kallsyms_lookup_name is called with empty string, it will do futile search for it through all the symbols. Skipping the search for empty string. Signed-off-by:
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Jiri Olsa authored
Adding support to have priv pointer in swap callback function. Following the initial change on cmp callback functions [1] and adding SWAP_WRAPPER macro to identify sort call of sort_r. Signed-off-by:
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Masami Hiramatsu authored
Add a KUnit based selftest for fprobe interface. Signed-off-by:
Steven Rostedt (Google) <rostedt@goodmis.org> Tested-by:
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Masami Hiramatsu authored
Add a documentation of fprobe for the user who needs this interface. Signed-off-by:
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Masami Hiramatsu authored
Introduce FPROBE_FL_KPROBE_SHARED flag for sharing fprobe callback with kprobes safely from the viewpoint of recursion. Since the recursion safety of the fprobe (and ftrace) is a bit different from the kprobes, this may cause an issue if user wants to run the same code from the fprobe and the kprobes. The kprobes has per-cpu 'current_kprobe' variable which protects the kprobe handler from recursion in any case. On the other hand, the fprobe uses only ftrace_test_recursion_trylock(), which will allow interrupt context calls another (or same) fprobe during the fprobe user handler is running. This is not a matter in cases if the common callback shared among the kprobes and the fprobe has its own recursion detection, or it can handle the recursion in the different contexts (normal/interrupt/NMI.) But if it relies on the 'current_kprobe' recursion lock, it has to check kprobe_running() and use kprobe_busy_*() APIs. Fprobe has FPROBE_FL_KPROBE_SHARED flag to do this. If your common callback code will be shared with kprobes, please set FPROBE_FL_KPROBE_SHARED *before* registering the fprobe, like; fprobe.flags = FPROBE_FL_KPROBE_SHARED; register_fprobe(&fprobe, "func*", NULL); This will protect your common callback from the nested call. Signed-off-by:
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Masami Hiramatsu authored
Add a sample program for the fprobe. The sample_fprobe puts a fprobe on kernel_clone() by default. This dump stack and some called address info at the function entry and exit. The sample_fprobe.ko gets 2 parameters. - symbol: you can specify the comma separated symbols or wildcard symbol pattern (in this case you can not use comma) - stackdump: a bool value to enable or disable stack dump in the fprobe handler. Signed-off-by:
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Masami Hiramatsu authored
Add exit_handler to fprobe. fprobe + rethook allows us to hook the kernel function return. The rethook will be enabled only if the fprobe::exit_handler is set. Signed-off-by:
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Masami Hiramatsu authored
Add rethook arm implementation. Most of the code has been copied from kretprobes on arm. Since the arm's ftrace implementation is a bit special, this needs a special care using from fprobe. Signed-off-by:
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Masami Hiramatsu authored
Add rethook powerpc64 implementation. Most of the code has been copied from kretprobes on powerpc64. Signed-off-by:
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Masami Hiramatsu authored
Add rethook arm64 implementation. Most of the code has been copied from kretprobes on arm64. Signed-off-by:
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Masami Hiramatsu authored
Add rethook for x86 implementation. Most of the code has been copied from kretprobes on x86. Signed-off-by:
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Masami Hiramatsu authored
Add a return hook framework which hooks the function return. Most of the logic came from the kretprobe, but this is independent from kretprobe. Note that this is expected to be used with other function entry hooking feature, like ftrace, fprobe, adn kprobes. Eventually this will replace the kretprobe (e.g. kprobe + rethook = kretprobe), but at this moment, this is just an additional hook. Signed-off-by:
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Masami Hiramatsu authored
The fprobe is a wrapper API for ftrace function tracer. Unlike kprobes, this probes only supports the function entry, but this can probe multiple functions by one fprobe. The usage is similar, user will set their callback to fprobe::entry_handler and call register_fprobe*() with probed functions. There are 3 registration interfaces, - register_fprobe() takes filtering patterns of the functin names. - register_fprobe_ips() takes an array of ftrace-location addresses. - register_fprobe_syms() takes an array of function names. The registered fprobes can be unregistered with unregister_fprobe(). e.g. struct fprobe fp = { .entry_handler = user_handler }; const char *targets[] = { "func1", "func2", "func3"}; ... ret = register_fprobe_syms(&fp, targets, ARRAY_SIZE(targets)); ... unregister_fprobe(&fp); Signed-off-by: -
Jiri Olsa authored
Adding ftrace_set_filter_ips function to be able to set filter on multiple ip addresses at once. With the kprobe multi attach interface we have cases where we need to initialize ftrace_ops object with thousands of functions, so having single function diving into ftrace_hash_move_and_update_ops with ftrace_lock is faster. The functions ips are passed as unsigned long array with count. Signed-off-by:
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- 17 Mar, 2022 4 commits
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Kaixi Fan authored
In namespace at_ns0, the IP address of tnl dev is 10.1.1.100 which is the overlay IP, and the ip address of veth0 is 172.16.1.100 which is the vtep IP. When doing 'ping 10.1.1.100' from root namespace, the remote_ip should be 172.16.1.100. Fixes: 933a741e ("selftests/bpf: bpf tunnel test.") Signed-off-by:
Kaixi Fan <fankaixi.li@bytedance.com> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Acked-by:
John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20220313164116.5889-1-fankaixi.li@bytedance.comSigned-off-by:
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Lorenzo Bianconi authored
Allow increasing the MTU over page boundaries on veth devices if the attached xdp program declares to support xdp fragments. Signed-off-by:
Lorenzo Bianconi <lorenzo@kernel.org> Signed-off-by:
Toke Høiland-Jørgensen <toke@redhat.com> Acked-by:
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Lorenzo Bianconi authored
Introduce veth_convert_skb_to_xdp_buff routine in order to convert a non-linear skb into a xdp buffer. If the received skb is cloned or shared, veth_convert_skb_to_xdp_buff will copy it in a new skb composed by order-0 pages for the linear and the fragmented area. Moreover veth_convert_skb_to_xdp_buff guarantees we have enough headroom for xdp. This is a preliminary patch to allow attaching xdp programs with frags support on veth devices. Signed-off-by:
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Lorenzo Bianconi authored
Even if this is a theoretical issue since it is not possible to perform XDP_REDIRECT on a non-linear xdp_frame, veth driver does not account paged area in ndo_xdp_xmit function pointer. Introduce xdp_get_frame_len utility routine to get the xdp_frame full length and account total frame size running XDP_REDIRECT of a non-linear xdp frame into a veth device. Signed-off-by:
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- 16 Mar, 2022 3 commits
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Hou Tao authored
When bpf_jit_harden is toggled between 0 and 2, subprog jit may fail due to inconsistent twice read values of bpf_jit_harden during jit. So add a test to ensure the problem is fixed. Signed-off-by:
Hou Tao <houtao1@huawei.com> Signed-off-by:
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Hou Tao authored
It is the bpf_jit_harden counterpart to commit 60b58afc ("bpf: fix net.core.bpf_jit_enable race"). bpf_jit_harden will be tested twice for each subprog if there are subprogs in bpf program and constant blinding may increase the length of program, so when running "./test_progs -t subprogs" and toggling bpf_jit_harden between 0 and 2, jit_subprogs may fail because constant blinding increases the length of subprog instructions during extra passs. So cache the value of bpf_jit_blinding_enabled() during program allocation, and use the cached value during constant blinding, subprog JITing and args tracking of tail call. Signed-off-by:
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Hou Tao authored
Extra pass for subprog jit may fail (e.g. due to bpf_jit_harden race), but bpf_func is not cleared for the subprog and jit_subprogs will succeed. The running of the bpf program may lead to oops because the memory for the jited subprog image has already been freed. So fall back to interpreter mode by clearing bpf_func/jited/jited_len when extra pass fails. Signed-off-by:
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