linux.git/tools/lib/bpf/libbpf.c, branch v7.0

libbpf: Delay feature gate check until object prepare time

2026-02-17T22:20:24+00:00

Commit 728ff167910e ("libbpf: Add gating for arena globals relocation feature")
adds a feature gate check that loads a map and BPF program to
test the running kernel supports large direct offsets for LDIMM64
instructions. This check is currently used to calculate arena symbol
offsets during bpf_object__collect_relos, itself called by
bpf_object_open.

However, the program calling bpf_object_open may not have the permissions to
load maps and programs. This is the case with the BPF selftests, where
bpftool is invoked at compilation time during skeleton generation. This
causes errors as the feature gate unexpectedly fails with -EPERM.

Avoid this by moving all the use of the FEAT_LDIMM64_FULL_RANGE_OFF feature gate
to BPF object preparation time instead.

Fixes: 728ff167910e ("libbpf: Add gating for arena globals relocation feature")
Signed-off-by: Emil Tsalapatis 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20260217204345.548648-3-emil@etsalapatis.com

libbpf: Add gating for arena globals relocation feature

2026-02-13T22:14:27+00:00

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 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20260210184532.255475-1-emil@etsalapatis.com
Signed-off-by: Alexei Starovoitov

libbpf: add fsession support

2026-01-25T02:49:36+00:00

Add BPF_TRACE_FSESSION to libbpf.

Signed-off-by: Menglong Dong 
Link: https://lore.kernel.org/r/20260124062008.8657-9-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov

btf: Refactor the code by calling str_is_empty

2026-01-14T00:21:56+00:00

Calling the str_is_empty function to clarify the code and
no functional changes are introduced.

Signed-off-by: Donglin Peng 
Signed-off-by: Andrii Nakryiko 
Acked-by: Eduard Zingerman 
Link: https://lore.kernel.org/bpf/20260109130003.3313716-12-dolinux.peng@gmail.com

libbpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu maps

2026-01-07T04:48:32+00:00

Add libbpf support for the BPF_F_CPU flag for percpu maps by embedding the
cpu info into the high 32 bits of:

1. **flags**: bpf_map_lookup_elem_flags(), bpf_map__lookup_elem(),
   bpf_map_update_elem() and bpf_map__update_elem()
2. **opts->elem_flags**: bpf_map_lookup_batch() and
   bpf_map_update_batch()

And the flag can be BPF_F_ALL_CPUS, but cannot be
'BPF_F_CPU | BPF_F_ALL_CPUS'.

Behavior:

* If the flag is BPF_F_ALL_CPUS, the update is applied across all CPUs.
* If the flag is BPF_F_CPU, it updates value only to the specified CPU.
* If the flag is BPF_F_CPU, lookup value only from the specified CPU.
* lookup does not support BPF_F_ALL_CPUS.

Acked-by: Andrii Nakryiko 
Signed-off-by: Leon Hwang 
Link: https://lore.kernel.org/r/20260107022022.12843-7-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf after 6.19-rc1

2025-12-17T05:29:38+00:00

Cross-merge BPF and other fixes after downstream PR.

Signed-off-by: Alexei Starovoitov

libbpf: Move arena globals to the end of the arena

2025-12-16T18:42:55+00:00

Arena globals are currently placed at the beginning of the arena
by libbpf. This is convenient, but prevents users from reserving
guard pages in the beginning of the arena to identify NULL pointer
dereferences. Adjust the load logic to place the globals at the
end of the arena instead.

Also modify bpftool to set the arena pointer in the program's BPF
skeleton to point to the globals. Users now call bpf_map__initial_value()
to find the beginning of the arena mapping and use the arena pointer
in the skeleton to determine which part of the mapping holds the
arena globals and which part is free.

Suggested-by: Andrii Nakryiko 
Signed-off-by: Emil Tsalapatis 
Signed-off-by: Andrii Nakryiko 
Acked-by: Eduard Zingerman 
Link: https://lore.kernel.org/bpf/20251216173325.98465-5-emil@etsalapatis.com

libbpf: Turn relo_core->sym_off unsigned

2025-12-16T18:42:55+00:00

The symbols' relocation offsets in BPF are stored in an int field,
but cannot actually be negative. When in the next patch libbpf relocates
globals to the end of the arena, it is also possible to have valid
offsets > 2GiB that are used to calculate the final relo offsets.
Avoid accidentally interpreting large offsets as negative by turning
the sym_off field unsigned.

Signed-off-by: Emil Tsalapatis 
Signed-off-by: Andrii Nakryiko 
Acked-by: Eduard Zingerman 
Link: https://lore.kernel.org/bpf/20251216173325.98465-4-emil@etsalapatis.com

libbpf: Fix -Wdiscarded-qualifiers under C23

2025-12-10T07:23:21+00:00

glibc ≥ 2.42 (GCC 15) defaults to -std=gnu23, which promotes
-Wdiscarded-qualifiers to an error.

In C23, strstr() and strchr() return "const char *".

Change variable types to const char * where the pointers are never
modified (res, sym_sfx, next_path).

Suggested-by: Florian Weimer 
Suggested-by: Andrii Nakryiko 
Signed-off-by: Mikhail Gavrilov 
Link: https://lore.kernel.org/r/20251206092825.1471385-1-mikhail.v.gavrilov@gmail.com
Signed-off-by: Alexei Starovoitov

libbpf: Add support for associating BPF program with struct_ops

2025-12-06T00:17:57+00:00

Add low-level wrapper and libbpf API for BPF_PROG_ASSOC_STRUCT_OPS
command in the bpf() syscall.

Signed-off-by: Amery Hung 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20251203233748.668365-4-ameryhung@gmail.com