[ Upstream commit 0cc114dc358cf8da2ca23a366e761e89a46ca277 ]
When a module registers a struct_ops, the struct_ops type and its
corresponding map_value type ("bpf_struct_ops_") may reside in different
btf objects, here are four possible case:
+--------+---------------+-------------+---------------------------------+
| |bpf_struct_ops_| xxx_ops | |
+--------+---------------+-------------+---------------------------------+
| case 0 | btf_vmlinux | btf_vmlinux | be used and reg only in vmlinux |
+--------+---------------+-------------+---------------------------------+
| case 1 | btf_vmlinux | mod_btf | INVALID |
+--------+---------------+-------------+---------------------------------+
| case 2 | mod_btf | btf_vmlinux | reg in mod but be used both in |
| | | | vmlinux and mod. |
+--------+---------------+-------------+---------------------------------+
| case 3 | mod_btf | mod_btf | be used and reg only in mod |
+--------+---------------+-------------+---------------------------------+
Currently we figure out the mod_btf by searching with the struct_ops type,
which makes it impossible to figure out the mod_btf when the struct_ops
type is in btf_vmlinux while it's corresponding map_value type is in
mod_btf (case 2).
The fix is to use the corresponding map_value type ("bpf_struct_ops_")
as the lookup anchor instead of the struct_ops type to figure out the
`btf` and `mod_btf` via find_ksym_btf_id(), and then we can locate
the kern_type_id via btf__find_by_name_kind() with the `btf` we just
obtained from find_ksym_btf_id().
With this change the lookup obtains the correct btf and mod_btf for case 2,
preserves correct behavior for other valid cases, and still fails as
expected for the invalid scenario (case 1).
Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support")
Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20250926071751.108293-1-alibuda@linux.alibaba.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 6c6b4146deb12d20f42490d5013f2043df942161 ]
Previously, re-using pinned DEVMAP maps would always fail, because
get_map_info on a DEVMAP always returns flags with BPF_F_RDONLY_PROG set,
but BPF_F_RDONLY_PROG being set on a map during creation is invalid.
Thus, ignore the BPF_F_RDONLY_PROG flag in the flags returned from
get_map_info when checking for compatibility with an existing DEVMAP.
The same problem is handled in a third-party ebpf library:
- https://github.com/cilium/ebpf/issues/925
- https://github.com/cilium/ebpf/pull/930
Fixes: 0cdbb4b09a06 ("devmap: Allow map lookups from eBPF")
Signed-off-by: Yureka Lilian <yuka@yuka.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250814180113.1245565-3-yuka@yuka.dev
Signed-off-by: Sasha Levin <sashal@kernel.org>
Automatically enabling a perf event after attaching a BPF prog to it is not always desirable. Add a new "dont_enable" field to struct bpf_perf_event_opts. While introducing "enable" instead would be nicer in that it would avoid a double negation in the implementation, it would make DECLARE_LIBBPF_OPTS() less efficient. Acked-by: Eduard Zingerman <eddyz87@gmail.com> Suggested-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Thomas Richter <tmricht@linux.ibm.com> Co-developed-by: Thomas Richter <tmricht@linux.ibm.com> Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Link: https://lore.kernel.org/r/20250806162417.19666-2-iii@linux.ibm.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Though mod_len is only read when mod_name != NULL and both are initialized
together, gcc15 produces a warning with -Werror=maybe-uninitialized:
libbpf.c: In function 'find_kernel_btf_id.constprop':
libbpf.c:10100:33: error: 'mod_len' may be used uninitialized [-Werror=maybe-uninitialized]
10100 | if (mod_name && strncmp(mod->name, mod_name, mod_len) != 0)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libbpf.c:10070:21: note: 'mod_len' was declared here
10070 | int ret, i, mod_len;
| ^~~~~~~
Silence the false positive.
Signed-off-by: Achill Gilgenast <fossdd@pwned.life>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250729094611.2065713-1-fossdd@pwned.life
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Fuzzer reported a memory access error in bpf_program__record_reloc() that happens when: - ".addr_space.1" section exists - there is a relocation referencing this section - there are no arena maps defined in BTF. Sanity checks for maps existence are already present in bpf_program__record_reloc(), hence this commit adds another one. [1] https://github.com/libbpf/libbpf/actions/runs/16375110681/job/46272998064 Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250718222059.281526-1-eddyz87@gmail.com
Cross-merge BPF and other fixes after downstream PR. No conflicts. Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When compiling libbpf with some compilers, this warning is triggered:
libbpf.c: In function ‘bpf_object__gen_loader’:
libbpf.c:9209:28: error: ‘calloc’ sizes specified with ‘sizeof’ in the earlier argument and not in the later argument [-Werror=calloc-transposed-args]
9209 | gen = calloc(sizeof(*gen), 1);
| ^
libbpf.c:9209:28: note: earlier argument should specify number of elements, later size of each element
Fix this by inverting the calloc() arguments.
Signed-off-by: Matteo Croce <teknoraver@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20250717200337.49168-1-technoboy85@gmail.com
Initial __arena global variable support implementation in libbpf
contains a bug: it remembers struct bpf_map pointer for arena, which is
used later on to process relocations. Recording this pointer is
problematic because map pointers are not stable during ELF relocation
collection phase, as an array of struct bpf_map's can be reallocated,
invalidating all the pointers. Libbpf is dealing with similar issues by
using a stable internal map index, though for BPF arena map specifically
this approach wasn't used due to an oversight.
The resulting behavior is non-deterministic issue which depends on exact
layout of ELF object file, number of actual maps, etc. We didn't hit
this until very recently, when this bug started triggering crash in BPF
CI when validating one of sched-ext BPF programs.
The fix is rather straightforward: we just follow an established pattern
of remembering map index (just like obj->kconfig_map_idx, for example)
instead of `struct bpf_map *`, and resolving index to a pointer at the
point where map information is necessary.
While at it also add debug-level message for arena-related relocation
resolution information, which we already have for all other kinds of
maps.
Fixes: 2e7ba4f8fd1f ("libbpf: Recognize __arena global variables.")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250718001009.610955-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cross-merge BPF, perf and other fixes after downstream PRs.
It restores BPF CI to green after critical fix
commit bc4394e5e79c ("perf: Fix the throttle error of some clock events")
No conflicts.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The `name` field in `obj->externs` points into the BTF data at initial
open time. However, some functions may invalidate this after opening and
before loading (e.g. `bpf_map__set_value_size`), which results in
pointers into freed memory and undefined behavior.
The simplest solution is to simply `strdup` these strings, similar to
the `essent_name`, and free them at the same time.
In order to test this path, the `global_map_resize` BPF selftest is
modified slightly to ensure the presence of an extern, which causes this
test to fail prior to the fix. Given there isn't an obvious API or error
to test against, I opted to add this to the existing test as an aspect
of the resizing feature rather than duplicate the test.
Fixes: 9d0a23313b1a ("libbpf: Add capability for resizing datasec maps")
Signed-off-by: Adin Scannell <amscanne@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250625050215.2777374-1-amscanne@meta.com