kernel.git/kernel/bpf/btf.c, branch master

Convert 'alloc_flex' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51Z

This is the exact same thing as the 'alloc_obj()' version, only much smaller because there are a lot fewer users of the *alloc_flex() interface. As with alloc_obj() version, this was done entirely with mindless brute force, using the same script, except using 'flex' in the pattern rather than 'objs*'. Signed-off-by: Linus Torvalds

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51Z

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28Z

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

bpf: Replace snprintf("%s") with strscpy

2026-02-03T02:43:33Z

Replace snprintf("%s") with the faster and more direct strscpy(). Signed-off-by: Thorsten Blum Link: https://lore.kernel.org/r/20260201215247.677121-2-thorsten.blum@linux.dev Signed-off-by: Alexei Starovoitov

bpf: add fsession support

2026-01-25T02:49:35Z

The fsession is something that similar to kprobe session. It allow to attach a single BPF program to both the entry and the exit of the target functions. Introduce the struct bpf_fsession_link, which allows to add the link to both the fentry and fexit progs_hlist of the trampoline. Signed-off-by: Menglong Dong Co-developed-by: Leon Hwang Signed-off-by: Leon Hwang Link: https://lore.kernel.org/r/20260124062008.8657-2-dongml2@chinatelecom.cn Signed-off-by: Alexei Starovoitov

bpf: Refactor btf_kfunc_id_set_contains

2026-01-21T00:15:56Z

btf_kfunc_id_set_contains() is called by fetch_kfunc_meta() in the BPF verifier to get the kfunc flags stored in the .BTF_ids ELF section. If it returns NULL instead of a valid pointer, it's interpreted as an illegal kfunc usage failing the verification. There are two potential reasons for btf_kfunc_id_set_contains() to return NULL: 1. Provided kfunc BTF id is not present in relevant kfunc id sets. 2. The kfunc is not allowed, as determined by the program type specific filter [1]. The filter functions accept a pointer to `struct bpf_prog`, so they might implicitly depend on earlier stages of verification, when bpf_prog members are set. For example, bpf_qdisc_kfunc_filter() in linux/net/sched/bpf_qdisc.c inspects prog->aux->st_ops [2], which is initialized in: check_attach_btf_id() -> check_struct_ops_btf_id() So far this hasn't been an issue, because fetch_kfunc_meta() is the only caller of btf_kfunc_id_set_contains(). However in subsequent patches of this series it is necessary to inspect kfunc flags earlier in BPF verifier, in the add_kfunc_call(). To resolve this, refactor btf_kfunc_id_set_contains() into two interface functions: * btf_kfunc_flags() that simply returns pointer to kfunc_flags without applying the filters * btf_kfunc_is_allowed() that both checks for kfunc_flags existence (which is a requirement for a kfunc to be allowed) and applies the prog filters See [3] for the previous version of this patch. [1] https://lore.kernel.org/all/20230519225157.760788-7-aditi.ghag@isovalent.com/ [2] https://lore.kernel.org/all/20250409214606.2000194-4-ameryhung@gmail.com/ [3] https://lore.kernel.org/bpf/20251029190113.3323406-3-ihor.solodrai@linux.dev/ Reviewed-by: Eduard Zingerman Signed-off-by: Ihor Solodrai Link: https://lore.kernel.org/r/20260120222638.3976562-2-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov

bpf: Skip anonymous types in type lookup for performance

2026-01-14T00:21:36Z

Currently, vmlinux and kernel module BTFs are unconditionally sorted during the build phase, with named types placed at the end. Thus, anonymous types should be skipped when starting the search. In my vmlinux BTF, the number of anonymous types is 61,747, which means the loop count can be reduced by 61,747. Signed-off-by: Donglin Peng Signed-off-by: Andrii Nakryiko Acked-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20260109130003.3313716-9-dolinux.peng@gmail.com

btf: Verify BTF sorting

2026-01-14T00:21:30Z

This patch checks whether the BTF is sorted by name in ascending order. If sorted, binary search will be used when looking up types. Specifically, vmlinux and kernel module BTFs are always sorted during the build phase with anonymous types placed before named types, so we only need to identify the starting ID of named types. Signed-off-by: Donglin Peng Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20260109130003.3313716-8-dolinux.peng@gmail.com

btf: Optimize type lookup with binary search

2026-01-14T00:20:38Z

Improve btf_find_by_name_kind() performance by adding binary search support for sorted types. Falls back to linear search for compatibility. Signed-off-by: Donglin Peng Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20260109130003.3313716-7-dolinux.peng@gmail.com

bpf, btf: Enforce destructor kfunc type with CFI

2026-01-13T02:53:57Z

Ensure that registered destructor kfuncs have the same type as btf_dtor_kfunc_t to avoid a kernel panic on systems with CONFIG_CFI enabled. Signed-off-by: Sami Tolvanen Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20260110082548.113748-10-samitolvanen@google.com Signed-off-by: Alexei Starovoitov