The offset for the cleanup-label jump is computed before the MOV R7
instruction is emitted, but the JMP lands after it. Account for the
extra insn in the offset calculation (-2 instead of -1). Drop the
redundant self-loop in the else branch; gen->error = -ERANGE already
marks the generation as failed.
Fixes: fb2b0e2901 ("libbpf: Update light skeleton for signing")
Signed-off-by: KP Singh <kpsingh@kernel.org>
Link: https://lore.kernel.org/r/20260522215337.662271-2-kpsingh@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Sashiko found possible double close of btf object fd [1],
which happens when strdup in load_module_btfs fails at which
point the obj->btf_module_cnt is already incremented.
The error path close btf fd and so does later cleanup code in
bpf_object_post_load_cleanup function.
Also libbpf_ensure_mem failure leaves btf object not assigned
and it's leaked.
Replacing the err_out label with break to make the error path
less confusing as suggested by Alan.
Incrementing obj->btf_module_cnt only if there's no failure
and releasing btf object in error path.
Fixes: 91abb4a6d7 ("libbpf: Support attachment of BPF tracing programs to kernel modules")
[1] https://sashiko.dev/#/patchset/20260324081846.2334094-1-jolsa%40kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260416100034.1610852-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow bpf object feat_cache assignment in BPF selftests
to simulate missing features via inclusion of libbpf_internal.h
and use of bpf_object_set_feat_cache() and bpf_object__sanitize_btf() to
test BTF sanitization for cases where missing features are simulated.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/r/20260408165735.843763-2-alan.maguire@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
CO-RE accessor strings are colon-separated indices that describe a path
from a root BTF type to a target field, e.g. "0:1:2" walks through
nested struct members. bpf_core_parse_spec() parses each component with
sscanf("%d"), so negative values like -1 are silently accepted. The
subsequent bounds checks (access_idx >= btf_vlen(t)) only guard the
upper bound and always pass for negative values because C integer
promotion converts the __u16 btf_vlen result to int, making the
comparison (int)(-1) >= (int)(N) false for any positive N.
When -1 reaches btf_member_bit_offset() it gets cast to u32 0xffffffff,
producing an out-of-bounds read far past the members array. A crafted
BPF program with a negative CO-RE accessor on any struct that exists in
vmlinux BTF (e.g. task_struct) crashes the kernel deterministically
during BPF_PROG_LOAD on any system with CONFIG_DEBUG_INFO_BTF=y
(default on major distributions). The bug is reachable with CAP_BPF:
BUG: unable to handle page fault for address: ffffed11818b6626
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
Oops: Oops: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 85 Comm: poc Not tainted 7.0.0-rc6 #18 PREEMPT(full)
RIP: 0010:bpf_core_parse_spec (tools/lib/bpf/relo_core.c:354)
RAX: 00000000ffffffff
Call Trace:
<TASK>
bpf_core_calc_relo_insn (tools/lib/bpf/relo_core.c:1321)
bpf_core_apply (kernel/bpf/btf.c:9507)
check_core_relo (kernel/bpf/verifier.c:19475)
bpf_check (kernel/bpf/verifier.c:26031)
bpf_prog_load (kernel/bpf/syscall.c:3089)
__sys_bpf (kernel/bpf/syscall.c:6228)
</TASK>
CO-RE accessor indices are inherently non-negative (struct member index,
array element index, or enumerator index), so reject them immediately
after parsing.
Fixes: ddc7c30426 ("libbpf: implement BPF CO-RE offset relocation algorithm")
Reported-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Paul Chaignon <paul.chaignon@gmail.com>
Link: https://lore.kernel.org/r/20260404161221.961828-2-bestswngs@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_program__attach_kprobe_opts() documents single-kprobe attach
through func_name, with an optional offset. For the PMU-based path,
func_name = NULL with an absolute address in offset already works as
well, but that is not described in the API.
This commit clarifies this existing non-legacy behavior. For PMU-based
attach, callers can use func_name = NULL with an absolute address in
offset as the raw-address form. For legacy tracefs/debugfs kprobes,
reject this form explicitly.
Signed-off-by: Hoyeon Lee <hoyeon.lee@suse.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20260401143116.185049-3-hoyeon.lee@suse.com
Align bpf_program__clone() with bpf_object_load_prog() by gating
BTF func/line info on FEAT_BTF_FUNC kernel support, and resolve
caller-provided prog_btf_fd before checking obj->btf so that callers
with their own BTF can use clone() even when the object has no BTF
loaded.
While at it, treat func_info and line_info fields as atomic groups
to prevent mismatches between pointer and count from different sources.
Move bpf_program__clone() to libbpf 1.8.
Fixes: 970bd2dced ("libbpf: Introduce bpf_program__clone()")
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260401151640.356419-1-mykyta.yatsenko5@gmail.com
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
Support encoding of BTF layout data via btf__new_empty_opts().
Current supported opts are base_btf and add_layout.
Layout information is maintained in btf.c in the layouts[] array;
when BTF is created with the add_layout option it represents the
current view of supported BTF kinds.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260326145444.2076244-5-alan.maguire@oracle.com
Support reading in layout fixing endian issues on reading;
also support writing layout section to raw BTF object.
There is not yet an API to populate the layout with meaningful
information.
As part of this, we need to consider multiple valid BTF header
sizes; the original or the layout-extended headers.
So to support this, the "struct btf" representation is modified
to contain a "struct btf_header" and we copy the valid
portion from the raw data to it; this means we can always safely
check fields like btf->hdr.layout_len .
Note if parsed-in BTF has extra header information beyond
sizeof(struct btf_header) - if so we make that BTF ineligible
for modification by setting btf->has_hdr_extra .
Ensure that we handle endianness issues for BTF layout section,
though currently only field that needs this (flags) is unused.
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260326145444.2076244-3-alan.maguire@oracle.com
Add bpf_program__clone() API that loads a single BPF program from a
prepared BPF object into the kernel, returning a file descriptor owned
by the caller.
After bpf_object__prepare(), callers can use bpf_program__clone() to
load individual programs with custom bpf_prog_load_opts, instead of
loading all programs at once via bpf_object__load(). Non-zero fields in
opts override the defaults derived from the program and object
internals; passing NULL opts populates everything automatically.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Link: https://lore.kernel.org/r/20260317-veristat_prepare-v4-1-74193d4cc9d9@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Detect exact function names (no wildcards) in
bpf_program__attach_kprobe_multi_opts() and bypass kallsyms parsing,
passing the symbol directly to the kernel via syms[] array. This
benefits all callers, not just kprobe.session.
When the pattern contains no '*' or '?' characters, set syms to point
directly at the pattern string and cnt to 1, skipping the expensive
/proc/kallsyms or available_filter_functions parsing (~150ms per
function).
Error code normalization: the fast path returns ESRCH from kernel's
ftrace_lookup_symbols(), while the slow path returns ENOENT from
userspace kallsyms parsing. Convert ESRCH to ENOENT in the
bpf_link_create error path to maintain API consistency - both paths
now return identical error codes for "symbol not found".
Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@crowdstrike.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260302200837.317907-2-andrey.grodzovsky@crowdstrike.com
btf__add_btf() currently rejects split BTF sources with -ENOTSUP.
This prevents merging types from multiple kernel module BTFs that
are all split against the same vmlinux base.
Extend btf__add_btf() to handle split BTF sources by:
- Replacing the blanket -ENOTSUP with a validation that src and dst
share the same base BTF pointer when both are split, returning
-EOPNOTSUPP on mismatch.
- Computing src_start_id from the source's base to distinguish base
type ID references (which must remain unchanged) from split type
IDs (which must be remapped to new positions in the destination).
- Using src_btf->nr_types instead of btf__type_cnt()-1 for the type
count, which is correct for both split and non-split sources.
- Skipping base string offsets (< start_str_off) during the string
rewrite loop, mirroring the type ID skip pattern. Since src and
dst share the same base BTF, base string offsets are already valid
and need no remapping.
For non-split sources the behavior is identical: src_start_id is 1,
the type_id < 1 guard is never true (VOID is already skipped), and
the remapping formula reduces to the original. start_str_off is 0
so no string offsets are skipped.
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Link: https://lore.kernel.org/bpf/c00216ed48cf7897078d9645679059d5ebf42738.1772657690.git.josef@toxicpanda.com
Adding support to detect nop,nop5 instructions combo for usdt probe
by checking on probe's following nop5 instruction.
When the nop,nop5 combo is detected together with uprobe syscall,
we can place the probe on top of nop5 and get it optimized.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260224103915.1369690-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Netlink requires that the recv buffer used during dumps is at least
min(PAGE_SIZE, 8k) (see the man page). Otherwise the messages will
get truncated. Make sure bpftool follows this requirement, avoid
missing information on systems with large pages.
Acked-by: Quentin Monnet <qmo@kernel.org>
Fixes: 7084566a23 ("tools/bpftool: Remove libbpf_internal.h usage in bpftool")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://lore.kernel.org/r/20260217194150.734701-1-kuba@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Commit 728ff16791 ("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: 728ff16791 ("libbpf: Add gating for arena globals relocation feature")
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260217204345.548648-3-emil@etsalapatis.com
Commit 728ff16791 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: 728ff16791 ("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
Add feature gating for the arena globals relocation introduced in
commit c1f61171d4. The commit depends on a previous commit in the
same patchset that is absent from older kernels
(12a1fe6e12 "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: c1f61171d4 ("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>
