kernel/linux.git/tools/lib/bpf/libbpf.c, branch v5.4.7

libbpf: Fix error handling in bpf_map__reuse_fd()

2019-12-31T15:44:33+00:00

[ Upstream commit d1b4574a4b86565325ef2e545eda8dfc9aa07c60 ] bpf_map__reuse_fd() was calling close() in the error path before returning an error value based on errno. However, close can change errno, so that can lead to potentially misleading error messages. Instead, explicitly store errno in the err variable before each goto. Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/157269297769.394725.12634985106772698611.stgit@toke.dk Signed-off-by: Sasha Levin

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2019-08-19T18:54:03+00:00

Merge conflict of mlx5 resolved using instructions in merge commit 9566e650bf7fdf58384bb06df634f7531ca3a97e. Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2019-08-13T23:24:57+00:00

Daniel Borkmann says: ==================== The following pull-request contains BPF updates for your *net-next* tree. There is a small merge conflict in libbpf (Cc Andrii so he's in the loop as well): for (i = 1; i <= btf__get_nr_types(btf); i++) { t = (struct btf_type *)btf__type_by_id(btf, i); if (!has_datasec && btf_is_var(t)) { /* replace VAR with INT */ t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0); <<<<<<< HEAD /* * using size = 1 is the safest choice, 4 will be too * big and cause kernel BTF validation failure if * original variable took less than 4 bytes */ t->size = 1; *(int *)(t+1) = BTF_INT_ENC(0, 0, 8); } else if (!has_datasec && kind == BTF_KIND_DATASEC) { ======= t->size = sizeof(int); *(int *)(t + 1) = BTF_INT_ENC(0, 0, 32); } else if (!has_datasec && btf_is_datasec(t)) { >>>>>>> 72ef80b5ee131e96172f19e74b4f98fa3404efe8 /* replace DATASEC with STRUCT */ Conflict is between the two commits 1d4126c4e119 ("libbpf: sanitize VAR to conservative 1-byte INT") and b03bc6853c0e ("libbpf: convert libbpf code to use new btf helpers"), so we need to pick the sanitation fixup as well as use the new btf_is_datasec() helper and the whitespace cleanup. Looks like the following: [...] if (!has_datasec && btf_is_var(t)) { /* replace VAR with INT */ t->info = BTF_INFO_ENC(BTF_KIND_INT, 0, 0); /* * using size = 1 is the safest choice, 4 will be too * big and cause kernel BTF validation failure if * original variable took less than 4 bytes */ t->size = 1; *(int *)(t + 1) = BTF_INT_ENC(0, 0, 8); } else if (!has_datasec && btf_is_datasec(t)) { /* replace DATASEC with STRUCT */ [...] The main changes are: 1) Addition of core parts of compile once - run everywhere (co-re) effort, that is, relocation of fields offsets in libbpf as well as exposure of kernel's own BTF via sysfs and loading through libbpf, from Andrii. More info on co-re: http://vger.kernel.org/bpfconf2019.html#session-2 and http://vger.kernel.org/lpc-bpf2018.html#session-2 2) Enable passing input flags to the BPF flow dissector to customize parsing and allowing it to stop early similar to the C based one, from Stanislav. 3) Add a BPF helper function that allows generating SYN cookies from XDP and tc BPF, from Petar. 4) Add devmap hash-based map type for more flexibility in device lookup for redirects, from Toke. 5) Improvements to XDP forwarding sample code now utilizing recently enabled devmap lookups, from Jesper. 6) Add support for reporting the effective cgroup progs in bpftool, from Jakub and Takshak. 7) Fix reading kernel config from bpftool via /proc/config.gz, from Peter. 8) Fix AF_XDP umem pages mapping for 32 bit architectures, from Ivan. 9) Follow-up to add two more BPF loop tests for the selftest suite, from Alexei. 10) Add perf event output helper also for other skb-based program types, from Allan. 11) Fix a co-re related compilation error in selftests, from Yonghong. ==================== Signed-off-by: Jakub Kicinski

libbpf: attempt to load kernel BTF from sysfs first

2019-08-13T21:19:42+00:00

Add support for loading kernel BTF from sysfs (/sys/kernel/btf/vmlinux) as a target BTF. Also extend the list of on disk search paths for vmlinux ELF image with entries that perf is searching for. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann

libbpf: implement BPF CO-RE offset relocation algorithm

2019-08-07T21:43:49+00:00

This patch implements the core logic for BPF CO-RE offsets relocations. Every instruction that needs to be relocated has corresponding bpf_offset_reloc as part of BTF.ext. Relocations are performed by trying to match recorded "local" relocation spec against potentially many compatible "target" types, creating corresponding spec. Details of the algorithm are noted in corresponding comments in the code. Signed-off-by: Andrii Nakryiko Acked-by: Song Liu Signed-off-by: Alexei Starovoitov

libbpf: convert libbpf code to use new btf helpers

2019-08-07T21:43:49+00:00

Simplify code by relying on newly added BTF helper functions. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov

libbpf: set BTF FD for prog only when there is supported .BTF.ext data

2019-08-01T20:10:45+00:00

5d01ab7bac46 ("libbpf: fix erroneous multi-closing of BTF FD") introduced backwards-compatibility issue, manifesting itself as -E2BIG error returned on program load due to unknown non-zero btf_fd attribute value for BPF_PROG_LOAD sys_bpf() sub-command. This patch fixes bug by ensuring that we only ever associate BTF FD with program if there is a BTF.ext data that was successfully loaded into kernel, which automatically means kernel supports func_info/line_info and associated BTF FD for progs (checked and ensured also by BTF sanitization code). Fixes: 5d01ab7bac46 ("libbpf: fix erroneous multi-closing of BTF FD") Reported-by: Andrey Ignatov Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov

libbpf : make libbpf_num_possible_cpus function thread safe

2019-08-01T03:35:19+00:00

Having static variable `cpus` in libbpf_num_possible_cpus function without guarding it with mutex makes this function thread-unsafe. If multiple threads accessing this function, in the current form; it leads to incrementing the static variable value `cpus` in the multiple of total available CPUs. Used local stack variable to calculate the number of possible CPUs and then updated the static variable using WRITE_ONCE(). Changes since v1: * added stack variable to calculate cpus * serialized static variable update using WRITE_ONCE() * fixed Fixes tag Fixes: 6446b3155521 ("bpf: add a new API libbpf_num_possible_cpus()") Signed-off-by: Takshak Chahande Acked-by: Andrey Ignatov Reviewed-by: Jakub Kicinski Signed-off-by: Alexei Starovoitov

libbpf: return previous print callback from libbpf_set_print

2019-07-28T05:36:19+00:00

By returning previously set print callback from libbpf_set_print, it's possible to restore it, eventually. This is useful when running many independent test with one default print function, but overriding log verbosity for particular subset of tests. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov

libbpf: fix erroneous multi-closing of BTF FD

2019-07-27T00:23:16+00:00

Libbpf stores associated BTF FD per each instance of bpf_program. When program is unloaded, that FD is closed. This is wrong, because leads to a race and possibly closing of unrelated files, if application simultaneously opens new files while bpf_programs are unloaded. It's also unnecessary, because struct btf "owns" that FD, and btf__free(), called from bpf_object__close() will close it. Thus the fix is to never have per-program BTF FD and fetch it from obj->btf, when necessary. Fixes: 2993e0515bb4 ("tools/bpf: add support to read .BTF.ext sections") Reported-by: Andrey Ignatov Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov