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2026-08-20Merge tag 'bpf-next-7.3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next Pull bpf updates from Daniel Borkmann: "Major changes: - Redesign the verifier error reporting: failures now carry source and instruction annotations along with the causal event history that led to them, making program rejections far easier to debug and repair (Kumar Kartikeya Dwivedi) - Add arena argument support to kfuncs and struct_ops through the new __arena and __arena__nullable suffixes (Tejun Heo, Puranjay Mohan, Kumar Kartikeya Dwivedi, Ihor Solodrai) - Signed BPF program loader rework to accommodate both BPF and security community needs where the kernel runs the signature verification at BPF_PROG_LOAD time before the LSM admission hook (Daniel Borkmann) - Add a set of ksock kfuncs which let BPF LSM and syscall programs create, connect and send on UDP sockets in order to emit telemetry data (Mahe Tardy) - Unify helper and kfunc call argument verification and classify kfunc arguments purely from BTF into a generated bpf_func_proto which is computed once at add-call time (Amery Hung) Other features and fixes: - Enable EXECMEM_ROX_CACHE for BPF allocations on x86 (Mike Rapoport) - Add bidirectional VLAN support to bpf_fib_lookup() through the new BPF_FIB_LOOKUP_VLAN and BPF_FIB_LOOKUP_VLAN_INPUT flags (Avinash Duduskar) - Infer zext_dst from static register liveness analysis to fix 32-bit zero-extension semantics, and remove the artificial limitations on pointer types eligible for spilling (Eduard Zingerman) - Inline the numeric open-coded iterator kfuncs so that bpf_for() loops no longer pay a kfunc call on every iteration (Puranjay Mohan) - Add an arena-based bitmap data structure to libarena along with serial and parallel selftests (Emil Tsalapatis) - Teach resolve_btfids to discover kfuncs from the kernel's BTF ID sets and to emit kfunc BTF decl tags, reducing the kernel build's dependency on pahole features (Ihor Solodrai) - Add BPF_F_ADJ_ROOM_DECAP_* flags to bpf_skb_adjust_room() so that tunnel decapsulation can update the GSO and encapsulation state of the skb (Nick Hudson) - Fix the ring buffer pending_pos walk and the available-data accounting on 32-bit position wrap (Israel Téllez García) - Add memory usage accounting for arena maps and fix an mmap_lock deadlock on arena lock failure (Jiayuan Chen) - Add tracing_multi link info support to the kernel UAPI and bpftool, and refactor the stack map code to run with preemption disabled (Jiri Olsa) - Support BPF_F_EGRESS in bpf_redirect_peer() to emit the skb in the egress direction of the target's peer device (Jordan Rife) - Add a KF_SPINLOCK_SAFE kfunc flag so that providers, in particular modules, can declare kfuncs safe to call under bpf_spin_lock instead of relying on the verifier's hard-coded allowlist (Kaitao Cheng) - Introduce global percpu data for BPF programs with libbpf probing and bpftool skeleton support, and stop exposing uninitialized kernel heap memory when copying per-CPU map values (Leon Hwang) - Add s390 JIT support for load-acquire and store-release instructions (Maxim Khmelevskii) - Fix a CFI mismatch in the task work callback and an arm64 KASAN false positive after bpf_throw() (Mykyta Yatsenko) - Reject writes through untrusted BTF pointers and bound the rdonly/rdwr_buf_size kfunc arguments (Nicholas Dudar) - Invalidate RCU pointers only after the final spin unlock and account for preempt and IRQ disabled regions as overlapping RCU protection (Ning Ding) - Support mixing bpf2bpf calls and tail calls on RV64, add signed operations and 32-bit atomics to the RV32 JIT, and add timed may_goto support (Pu Lehui, Kuan-Wei Chiu, Feng Jiang) - Fix a use-after-free on mm_struct in bpf_find_vma() for foreign tasks and an mmap_lock leak in the irq_work path (Sanghyun Park) - Populate mmap-able BPF array map memory lazily which makes mmap() O(1) instead of proportional to the map size (Song Liu) - Introduce a jit_required flag and reject programs with inlined helpers when no JIT is available, where the interpreter would otherwise jump into an invalid address (Tiezhu Yang) - Fix the x86 JIT per-CPU address resolution into an extended register where the REX prefix dropped the high destination register bit (Vineet Gupta) - Reject MEM_ALLOC BTF accesses past object bounds, arena frees below the arena base, and mixed arena and ordinary atomic paths (Yiyang Chen) - Fix the trampoline handling of 128-bit arguments and of return values larger than 8 bytes (Yonghong Song) - Ensure that any fault prone load is rewritten with exception table handling, and fix the arena load-acquire and atomic fetch handling in the x86, arm64, riscv and s390 JITs (Daniel Borkmann) - Many more fixes and cleanups across the verifier, arena, trampolines, sockmap, cgroup, ring buffer, x86/arm64/riscv/s390 JITs, libbpf, bpftool, resolve_btfids and selftests" * tag 'bpf-next-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (373 commits) selftests/bpf: Add tests for a store on a fault prone qdisc pointer selftests/bpf: Add tests for fault prone loads out of RCU pointers selftests/bpf: Add tests for pointer type merge at a shared load selftests/bpf: Remove duplicate copies of the arena spinlock qnodes selftests/bpf: Retry stat generation in cgroup_iter_memcg selftests/bpf: Test pseudo-function policy diagnostics bpf: Distinguish function references in policy diagnostics bpf: Preserve source attribution without source text selftests/bpf: Test kfunc argument diagnostics bpf: Correct kfunc argument diagnostics bpf: Use canonical stack argument names in diagnostics bpf: Preserve R0 lineage across helper calls selftests/bpf: Exercise negative optlen in cgroup getsockopt hook bpf: Reject negative optlen in cgroup getsockopt hook selftests/bpf: tc_tunnel - validate decap GSO and encapsulation state bpf: Clear decap state on skb_adjust_room shrink path bpf: Allow new DECAP flags and add guard rails bpf: Add BPF_F_ADJ_ROOM_DECAP_* flags for tunnel decapsulation bpf: Refactor masks for ADJ_ROOM flags and encap validation bpf: Name the enum for BPF_FUNC_skb_adjust_room flags ...
2026-08-13libbpf: Probe percpu data featureLeon Hwang
libbpf needs a reliable way to distinguish kernels that can support global percpu data from those that cannot. Add a dedicated feature probe, so libbpf can make capability decisions early and fail predictably when global percpu data is unavailable. Signed-off-by: Leon Hwang <leon.hwang@linux.dev> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20260813152324.97937-5-leon.hwang@linux.dev
2026-07-04libbpf: Detect uprobe syscall with new errorJiri Olsa
In the previous optimized uprobe fix we changed the syscall error used for its detection from ENXIO to EPROTO. Changing related probe_uprobe_syscall detection check. Fixes: 05738da0efa1 ("libbpf: Add uprobe syscall feature detection") Fixes: 554ba38456da ("uprobes/x86: Move optimized uprobe from nop5 to nop10") Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://patch.msgid.link/20260703114917.238144-8-jolsa@kernel.org
2026-05-12libbpf: Add support for extended BPF syscallLeon Hwang
To support the extended BPF syscall introduced in the previous commit, introduce the following internal APIs: * 'sys_bpf_ext()' * 'sys_bpf_ext_fd()' They wrap the raw 'syscall()' interface to support passing extended attributes. * 'probe_sys_bpf_ext()' Check whether current kernel supports the BPF syscall common attributes. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Leon Hwang <leon.hwang@linux.dev> Link: https://lore.kernel.org/r/20260512153157.28382-3-leon.hwang@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-03-26libbpf: Support sanitization of BTF layout for older kernelsAlan Maguire
Add a FEAT_BTF_LAYOUT feature check which checks if the kernel supports BTF layout information. Also sanitize BTF if it contains layout data but the kernel does not support it. The sanitization requires rewriting raw BTF data to update the header and eliminate the layout section (since it lies between the types and strings), so refactor sanitization to do the raw BTF retrieval and creation of updated BTF, returning that new BTF on success. Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20260326145444.2076244-7-alan.maguire@oracle.com
2026-03-03libbpf: Add uprobe syscall feature detectionJiri Olsa
Adding uprobe syscall feature detection that will be used in following changes. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20260224103915.1369690-2-jolsa@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-02-17libbpf: Do not use PROG_TYPE_TRACEPOINT program for feature gatingEmil Tsalapatis
Commit 728ff167910e uses a PROG_TYPE_TRACEPOINT BPF test program to check whether the running kernel supports large LDIMM64 offsets. The feature gate incorrectly assumes that the program will fail at verification time with one of two messages, depending on whether the feature is supported by the running kernel. However, PROG_TYPE_TRACEPOINT programs may fail to load before verification even starts, e.g., if the shell does not have the appropriate capabilities. Use a BPF_PROG_TYPE_SOCKET_FILTER program for the feature gate instead. Also fix two minor issues. First, ensure the log buffer for the test is initialized: Failing program load before verification led to libbpf dumping uninitialized data to stdout. Also, ensure that close() is only called for program_fd in the probe if the program load actually succeeded. The call was currently failing silently with -EBADF most of the time. Fixes: 728ff167910e ("libbpf: Add gating for arena globals relocation feature") Reported-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20260217204345.548648-2-emil@etsalapatis.com
2026-02-13libbpf: Add gating for arena globals relocation featureEmil Tsalapatis
Add feature gating for the arena globals relocation introduced in commit c1f61171d44b. The commit depends on a previous commit in the same patchset that is absent from older kernels (12a1fe6e12db "bpf/verifier: Do not limit maximum direct offset into arena map"). Without this commit, arena globals relocation with arenas >= 512MiB fails to load and breaks libbpf's backwards compatibility. Introduce a libbpf feature to check whether the running kernel allows for full range ldimm64 offset, and only relocate arena globals if it does. Fixes: c1f61171d44b ("libbpf: Move arena globals to the end of the arena") Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20260210184532.255475-1-emil@etsalapatis.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-10-01libbpf: move libbpf_errstr() into libbpf_utils.cAndrii Nakryiko
Get rid of str_err.{c,h} by moving implementation of libbpf_errstr() into libbpf_utils.c and declarations into libbpf_internal.h. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20251001171326.3883055-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com>
2024-11-11libbpf: Stringify errno in log messages in the remaining codeMykyta Yatsenko
Convert numeric error codes into the string representations in log messages in the rest of libbpf source files. Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20241111212919.368971-5-mykyta.yatsenko5@gmail.com
2024-05-31libbpf: don't close(-1) in multi-uprobe feature detectorAndrii Nakryiko
Guard close(link_fd) with extra link_fd >= 0 check to prevent close(-1). Detected by Coverity static analysis. Fixes: 04d939a2ab22 ("libbpf: detect broken PID filtering logic for multi-uprobe") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20240529231212.768828-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-05-25libbpf: detect broken PID filtering logic for multi-uprobeAndrii Nakryiko
Libbpf is automatically (and transparently to user) detecting multi-uprobe support in the kernel, and, if supported, uses multi-uprobes to improve USDT attachment speed. USDTs can be attached system-wide or for the specific process by PID. In the latter case, we rely on correct kernel logic of not triggering USDT for unrelated processes. As such, on older kernels that do support multi-uprobes, but still have broken PID filtering logic, we need to fall back to singular uprobes. Unfortunately, whether user is using PID filtering or not is known at the attachment time, which happens after relevant BPF programs were loaded into the kernel. Also unfortunately, we need to make a call whether to use multi-uprobes or singular uprobe for SEC("usdt") programs during BPF object load time, at which point we have no information about possible PID filtering. The distinction between single and multi-uprobes is small, but important for the kernel. Multi-uprobes get BPF_TRACE_UPROBE_MULTI attach type, and kernel internally substitiute different implementation of some of BPF helpers (e.g., bpf_get_attach_cookie()) depending on whether uprobe is multi or singular. So, multi-uprobes and singular uprobes cannot be intermixed. All the above implies that we have to make an early and conservative call about the use of multi-uprobes. And so this patch modifies libbpf's existing feature detector for multi-uprobe support to also check correct PID filtering. If PID filtering is not yet fixed, we fall back to singular uprobes for USDTs. This extension to feature detection is simple thanks to kernel's -EINVAL addition for pid < 0. Acked-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240521163401.3005045-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-05-15libbpf: fix feature detectors when using token_fdAndrii Nakryiko
Adjust `union bpf_attr` size passed to kernel in two feature-detecting functions to take into account prog_token_fd field. Libbpf is avoiding memset()'ing entire `union bpf_attr` by only using minimal set of bpf_attr's fields. Two places have been missed when wiring BPF token support in libbpf's feature detection logic. Fix them trivially. Fixes: f3dcee938f48 ("libbpf: Wire up token_fd into feature probing logic") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240513180804.403775-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-03-06libbpf: Rewrite btf datasec names starting from '?'Eduard Zingerman
Optional struct_ops maps are defined using question mark at the start of the section name, e.g.: SEC("?.struct_ops") struct test_ops optional_map = { ... }; This commit teaches libbpf to detect if kernel allows '?' prefix in datasec names, and if it doesn't then to rewrite such names by replacing '?' with '_', e.g.: DATASEC ?.struct_ops -> DATASEC _.struct_ops Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240306104529.6453-13-eddyz87@gmail.com
2024-01-29libbpf: integrate __arg_ctx feature detector into kernel_supports()Andrii Nakryiko
Now that feature detection code is in bpf-next tree, integrate __arg_ctx kernel-side support into kernel_supports() framework. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240125205510.3642094-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-01-24libbpf: Wire up token_fd into feature probing logicAndrii Nakryiko
Adjust feature probing callbacks to take into account optional token_fd. In unprivileged contexts, some feature detectors would fail to detect kernel support just because BPF program, BPF map, or BTF object can't be loaded due to privileged nature of those operations. So when BPF object is loaded with BPF token, this token should be used for feature probing. This patch is setting support for this scenario, but we don't yet pass non-zero token FD. This will be added in the next patch. We also switched BPF cookie detector from using kprobe program to tracepoint one, as tracepoint is somewhat less dangerous BPF program type and has higher likelihood of being allowed through BPF token in the future. This change has no effect on detection behavior. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-25-andrii@kernel.org
2024-01-24libbpf: Move feature detection code into its own fileAndrii Nakryiko
It's quite a lot of well isolated code, so it seems like a good candidate to move it out of libbpf.c to reduce its size. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20240124022127.2379740-24-andrii@kernel.org