As shown in [1], it is possible to corrupt a BPF ELF file such that
arbitrary BPF instructions are loaded by libbpf. This can be done by
setting a symbol (BPF program) section offset to a large (unsigned)
number such that <section start + symbol offset> overflows and points
before the section data in the memory.
Consider the situation below where:
- prog_start = sec_start + symbol_offset <-- size_t overflow here
- prog_end = prog_start + prog_size
prog_start sec_start prog_end sec_end
| | | |
v v v v
.....................|################################|............
The report in [1] also provides a corrupted BPF ELF which can be used as
a reproducer:
$ readelf -S crash
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
...
[ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040
0000000000000068 0000000000000000 AX 0 0 8
$ readelf -s crash
Symbol table '.symtab' contains 8 entries:
Num: Value Size Type Bind Vis Ndx Name
...
6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp
Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will
point before the actual memory where section 2 is allocated.
This is also reported by AddressSanitizer:
=================================================================
==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490
READ of size 104 at 0x7c7302fe0000 thread T0
#0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76)
#1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856
#2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928
#3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930
#4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067
#5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090
#6 0x000000400c16 in main /poc/poc.c:8
#7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4)
#8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667)
#9 0x000000400b34 in _start (/poc/poc+0x400b34)
0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8)
allocated by thread T0 here:
#0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b)
#1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600)
#2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018)
#3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740
The problem here is that currently, libbpf only checks that the program
end is within the section bounds. There used to be a check
`while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was
removed by commit 6245947c1b3c ("libbpf: Allow gaps in BPF program
sections to support overriden weak functions").
Add a check for detecting the overflow of `sec_off + prog_sz` to
bpf_object__init_prog to fix this issue.
[1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
Fixes: 6245947c1b3c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions")
Reported-by: lmarch2 <2524158037@qq.com>
Signed-off-by: Viktor Malik <vmalik@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md
Link: https://lore.kernel.org/bpf/20250415155014.397603-1-vmalik@redhat.com
Introducing new libbpf API getters for BTF.ext func and line info,
namely:
bpf_program__func_info
bpf_program__func_info_cnt
bpf_program__line_info
bpf_program__line_info_cnt
This change enables scenarios, when user needs to load bpf_program
directly using `bpf_prog_load`, instead of higher-level
`bpf_object__load`. Line and func info are required for checking BTF
info in verifier; verification may fail without these fields if, for
example, program calls `bpf_obj_new`.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250408234417.452565-2-mykyta.yatsenko5@gmail.com
Since memfd_create() is not consistently available across different
bionic libc implementations, using memfd_create() directly can break
some Android builds:
tools/lib/bpf/linker.c:576:7: error: implicit declaration of function 'memfd_create' [-Werror,-Wimplicit-function-declaration]
576 | fd = memfd_create(filename, 0);
| ^
To fix this, relocate and inline the sys_memfd_create() helper so that
it can be used in "linker.c". Similar issues were previously fixed by
commit 9fa5e1a180aa ("libbpf: Call memfd_create() syscall directly").
Fixes: 6d5e5e5d7ce1 ("libbpf: Extend linker API to support in-memory ELF files")
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250330211325.530677-1-cmllamas@google.com
When statically linking symbols can be replaced with those from other
statically linked libraries depending on the link order and the hoped
for "multiple definition" error may not appear. To avoid conflicts it
is good practice to namespace symbols, this change renames errstr to
libbpf_errstr. To avoid churn a #define is used to turn use of
errstr(err) to libbpf_errstr(err).
Fixes: 1633a83bf993 ("libbpf: Introduce errstr() for stringifying errno")
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250320222439.1350187-1-irogers@google.com
Introduce bpf_object__prepare API: additional intermediate preparation
step that performs ELF processing, relocations, prepares final state of
BPF program instructions (accessible with bpf_program__insns()), creates
and (potentially) pins maps, and stops short of loading BPF programs.
We anticipate few use cases for this API, such as:
* Use prepare to initialize bpf_token, without loading freplace
programs, unlocking possibility to lookup BTF of other programs.
* Execute prepare to obtain finalized BPF program instructions without
loading programs, enabling tools like veristat to process one program at
a time, without incurring cost of ELF parsing and processing.
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250303135752.158343-4-mykyta.yatsenko5@gmail.com
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
In `set_kcfg_value_str`, an untrusted string is accessed with the assumption
that it will be at least two characters long due to the presence of checks for
opening and closing quotes. But the check for the closing quote
(value[len - 1] != '"') misses the fact that it could be checking the opening
quote itself in case of an invalid input that consists of just the opening
quote.
This commit adds an explicit check to make sure the string is at least two
characters long.
Signed-off-by: Nandakumar Edamana <nandakumar@nandakumar.co.in>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250221210110.3182084-1-nandakumar@nandakumar.co.in
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Fix theoretical NULL dereference in linker when resolving *extern*
STT_SECTION symbol against not-yet-existing ELF section. Not sure if
it's possible in practice for valid ELF object files (this would require
embedded assembly manipulations, at which point BTF will be missing),
but fix the s/dst_sym/dst_sec/ typo guarding this condition anyways.
Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs")
Fixes: a46349227cd8 ("libbpf: Add linker extern resolution support for functions and global variables")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20250220002821.834400-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Libbpf has a somewhat obscure feature of automatically adjusting the
"size" of LDX/STX/ST instruction (memory store and load instructions),
based on originally recorded access size (u8, u16, u32, or u64) and the
actual size of the field on target kernel. This is meant to facilitate
using BPF CO-RE on 32-bit architectures (pointers are always 64-bit in
BPF, but host kernel's BTF will have it as 32-bit type), as well as
generally supporting safe type changes (unsigned integer type changes
can be transparently "relocated").
One issue that surfaced only now, 5 years after this logic was
implemented, is how this all works when dealing with fields that are
arrays. This isn't all that easy and straightforward to hit (see
selftests that reproduce this condition), but one of sched_ext BPF
programs did hit it with innocent looking loop.
Long story short, libbpf used to calculate entire array size, instead of
making sure to only calculate array's element size. But it's the element
that is loaded by LDX/STX/ST instructions (1, 2, 4, or 8 bytes), so
that's what libbpf should check. This patch adjusts the logic for
arrays and fixed the issue.
Reported-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250207014809.1573841-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Add the following functions to libbpf API:
* btf__add_type_attr()
* btf__add_decl_attr()
These functions allow to add to BTF the type tags and decl tags with
info->kflag set to 1. The kflag indicates that the tag directly
encodes an __attribute__ and not a normal tag.
See Documentation/bpf/btf.rst changes in the subsequent patch for
details on the semantics.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250130201239.1429648-2-ihor.solodrai@linux.dev
Some versions of kernel were stripping out '.llvm.<hash>' suffix from
kerne symbols (produced by Clang LTO compilation) from function names
reported in available_filter_functions, while kallsyms reported full
original name. This confuses libbpf's multi-kprobe logic of finding all
matching kernel functions for specified user glob pattern by joining
available_filter_functions and kallsyms contents, because joining by
full symbol name won't work for symbols containing '.llvm.<hash>' suffix.
This was eventually fixed by [0] in the kernel, but we'd like to not
regress multi-kprobe experience and add a work around for this bug on
libbpf side, stripping kallsym's name if it matches user pattern and
contains '.llvm.' suffix.
[0] fb6a421fb615 ("kallsyms: Match symbols exactly with CONFIG_LTO_CLANG")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20250117003957.179331-1-andrii@kernel.org
When redirecting the split BTF to the vmlinux base BTF, we need to mark
the distilled base struct/union members of split BTF structs/unions in
id_map with BTF_IS_EMBEDDED. This indicates that these types must match
both name and size later. Therefore, we need to traverse the entire
split BTF, which involves traversing type IDs from nr_dist_base_types to
nr_types. However, the current implementation uses an incorrect
traversal end type ID, so let's correct it.
Fixes: 19e00c897d50 ("libbpf: Split BTF relocation")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250115100241.4171581-3-pulehui@huaweicloud.com
Jordan reported an issue in Meta production environment where func
try_to_wake_up() is renamed to try_to_wake_up.llvm.<hash>() by clang
compiler at lto mode. The original 'kprobe/try_to_wake_up' does not
work any more since try_to_wake_up() does not match the actual func
name in /proc/kallsyms.
There are a couple of ways to resolve this issue. For example, in
attach_kprobe(), we could do lookup in /proc/kallsyms so try_to_wake_up()
can be replaced by try_to_wake_up.llvm.<hach>(). Or we can force users
to use bpf_program__attach_kprobe() where they need to lookup
/proc/kallsyms to find out try_to_wake_up.llvm.<hach>(). But these two
approaches requires extra work by either libbpf or user.
Luckily, suggested by Andrii, multi kprobe already supports wildcard ('*')
for symbol matching. In the above example, 'try_to_wake_up*' can match
to try_to_wake_up() or try_to_wake_up.llvm.<hash>() and this allows
bpf prog works for different kernels as some kernels may have
try_to_wake_up() and some others may have try_to_wake_up.llvm.<hash>().
The original intention is to kprobe try_to_wake_up() only, so an optional
field unique_match is added to struct bpf_kprobe_multi_opts. If the
field is set to true, the number of matched functions must be one.
Otherwise, the attachment will fail. In the above case, multi kprobe
with 'try_to_wake_up*' and unique_match preserves user functionality.
Reported-by: Jordan Rome <linux@jordanrome.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250109174023.3368432-1-yonghong.song@linux.dev
Starting from 105ff5339f49 ("mm/memfd: add MFD_NOEXEC_SEAL and
MFD_EXEC") and until 1717449b4417 ("memfd: drop warning for missing
exec-related flags"), the kernel would print a warning if neither
MFD_NOEXEC_SEAL nor MFD_EXEC is set in memfd_create().
If libbpf runs on on a kernel between these two commits (eg. on an
improperly backported system), it'll trigger this warning.
To avoid this warning (and also be more secure), explicitly set
MFD_NOEXEC_SEAL. But since libbpf can be run on potentially very old
kernels, leave a fallback for kernels without MFD_NOEXEC_SEAL support.
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/r/6e62c2421ad7eb1da49cbf16da95aaaa7f94d394.1735594195.git.dxu@dxuuu.xyz
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The new_fd and add_fd functions correspond to the original new and
add_file functions, but accept an FD instead of a file name. This
gives API consumers the option of using anonymous files/memfds to
avoid writing ELFs to disk.
This new API will be useful for performing linking as part of
bpftrace's JIT compilation.
The add_buf function is a convenience wrapper that does the work of
creating a memfd for the caller.
Signed-off-by: Alastair Robertson <ajor@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241211164030.573042-3-ajor@meta.com
Move the filename arguments and file-descriptor handling from
init_output_elf() and linker_load_obj_file() and instead handle them
at the top-level in bpf_linker__new() and bpf_linker__add_file().
This will allow the inner functions to be shared with a new,
non-filename-based, API in the next commit.
Signed-off-by: Alastair Robertson <ajor@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241211164030.573042-2-ajor@meta.com
Libelf functions do not set errno on failure. Instead, it relies on its
internal _elf_errno value, that can be retrieved via elf_errno (or the
corresponding message via elf_errmsg()). From "man libelf":
If a libelf function encounters an error it will set an internal
error code that can be retrieved with elf_errno. Each thread
maintains its own separate error code. The meaning of each error
code can be determined with elf_errmsg, which returns a string
describing the error.
As a consequence, libbpf should not return -errno when a function from
libelf fails, because an empty value will not be interpreted as an error
and won't prevent the program to stop. This is visible in
bpf_linker__add_file(), for example, where we call a succession of
functions that rely on libelf:
err = err ?: linker_load_obj_file(linker, filename, opts, &obj);
err = err ?: linker_append_sec_data(linker, &obj);
err = err ?: linker_append_elf_syms(linker, &obj);
err = err ?: linker_append_elf_relos(linker, &obj);
err = err ?: linker_append_btf(linker, &obj);
err = err ?: linker_append_btf_ext(linker, &obj);
If the object file that we try to process is not, in fact, a correct
object file, linker_load_obj_file() may fail with errno not being set,
and return 0. In this case we attempt to run linker_append_elf_sysms()
and may segfault.
This can happen (and was discovered) with bpftool:
$ bpftool gen object output.o sample_ret0.bpf.c
libbpf: failed to get ELF header for sample_ret0.bpf.c: invalid `Elf' handle
zsh: segmentation fault (core dumped) bpftool gen object output.o sample_ret0.bpf.c
Fix the issue by returning a non-null error code (-EINVAL) when libelf
functions fail.
Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs")
Signed-off-by: Quentin Monnet <qmo@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241205135942.65262-1-qmo@kernel.org
When running `bpftool` on a kernel module installed in `/lib/modules...`,
this error is encountered if the user does not specify `--base-btf` to
point to a valid base BTF (e.g. usually in `/sys/kernel/btf/vmlinux`).
However, looking at the debug output to determine the cause of the error
simply says `Invalid BTF string section`, which does not point to the
actual source of the error. This just improves that debug message to tell
users what happened.
Signed-off-by: Ben Olson <matthew.olson@intel.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/Z0YqzQ5lNz7obQG7@bolson-desk
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
USDT ELF note optionally can record an offset of .stapsdt.base, which is
used to make adjustments to USDT target attach address. Currently,
libbpf will do this address adjustment unconditionally if it finds
.stapsdt.base ELF section in target binary. But there is a corner case
where .stapsdt.base ELF section is present, but specific USDT note
doesn't reference it. In such case, libbpf will basically just add base
address and end up with absolutely incorrect USDT target address.
This adjustment has to be done only if both .stapsdt.sema section is
present and USDT note is recording a reference to it.
Fixes: 74cc6311cec9 ("libbpf: Add USDT notes parsing and resolution logic")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20241121224558.796110-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Adding support to attach program in uprobe session mode
with bpf_program__attach_uprobe_multi function.
Adding session bool to bpf_uprobe_multi_opts struct that allows
to load and attach the bpf program via uprobe session.
the attachment to create uprobe multi session.
Also adding new program loader section that allows:
SEC("uprobe.session/bpf_fentry_test*")
and loads/attaches uprobe program as uprobe session.
Adding sleepable hook (uprobe.session.s) as well.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241108134544.480660-6-jolsa@kernel.org
Adding support to attach BPF program for entry and return probe
of the same function. This is common use case which at the moment
requires to create two uprobe multi links.
Adding new BPF_TRACE_UPROBE_SESSION attach type that instructs
kernel to attach single link program to both entry and exit probe.
It's possible to control execution of the BPF program on return
probe simply by returning zero or non zero from the entry BPF
program execution to execute or not the BPF program on return
probe respectively.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241108134544.480660-4-jolsa@kernel.org
Since BPF skeleton inception libbpf has been doing mmap()'ing of global
data ARRAY maps in bpf_object__load_skeleton() API, which is used by
code generated .skel.h files (i.e., by BPF skeletons only).
This is wrong because if BPF object is loaded through generic
bpf_object__load() API, global data maps won't be re-mmap()'ed after
load step, and memory pointers returned from bpf_map__initial_value()
would be wrong and won't reflect the actual memory shared between BPF
program and user space.
bpf_map__initial_value() return result is rarely used after load, so
this went unnoticed for a really long time, until bpftrace project
attempted to load BPF object through generic bpf_object__load() API and
then used BPF subskeleton instantiated from such bpf_object. It turned
out that .data/.rodata/.bss data updates through such subskeleton was
"blackholed", all because libbpf wouldn't re-mmap() those maps during
bpf_object__load() phase.
Long story short, this step should be done by libbpf regardless of BPF
skeleton usage, right after BPF map is created in the kernel. This patch
moves this functionality into bpf_object__populate_internal_map() to
achieve this. And bpf_object__load_skeleton() is now simple and almost
trivial, only propagating these mmap()'ed pointers into user-supplied
skeleton structs.
We also do trivial adjustments to error reporting inside
bpf_object__populate_internal_map() for consistency with the rest of
libbpf's map-handling code.
Reported-by: Alastair Robertson <ajor@meta.com>
Reported-by: Jonathan Wiepert <jwiepert@meta.com>
Fixes: d66562fba1ce ("libbpf: Add BPF object skeleton support")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20241023043908.3834423-3-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Initialize 'new_off' and 'pad_bits' to 0 and 'pad_type' to NULL in
btf_dump_emit_bit_padding to prevent compiler warnings/errors which are
observed when compiling with 'EXTRA_CFLAGS=-g -Og' options, but do not
happen when compiling with current default options.
For example, when compiling libbpf with
$ make "EXTRA_CFLAGS=-g -Og" -C tools/lib/bpf/ clean all
Clang version 17.0.6 and GCC 13.3.1 fail to compile btf_dump.c due to
following errors:
btf_dump.c: In function ‘btf_dump_emit_bit_padding’:
btf_dump.c:903:42: error: ‘new_off’ may be used uninitialized [-Werror=maybe-uninitialized]
903 | if (new_off > cur_off && new_off <= next_off) {
| ~~~~~~~~^~~~~~~~~~~
btf_dump.c:870:13: note: ‘new_off’ was declared here
870 | int new_off, pad_bits, bits, i;
| ^~~~~~~
btf_dump.c:917:25: error: ‘pad_type’ may be used uninitialized [-Werror=maybe-uninitialized]
917 | btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
918 | in_bitfield ? new_off - cur_off : 0);
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
btf_dump.c:871:21: note: ‘pad_type’ was declared here
871 | const char *pad_type;
| ^~~~~~~~
btf_dump.c:930:20: error: ‘pad_bits’ may be used uninitialized [-Werror=maybe-uninitialized]
930 | if (bits == pad_bits) {
| ^
btf_dump.c:870:22: note: ‘pad_bits’ was declared here
870 | int new_off, pad_bits, bits, i;
| ^~~~~~~~
cc1: all warnings being treated as errors
Signed-off-by: Eder Zulian <ezulian@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20241022172329.3871958-3-ezulian@redhat.com
The hashmap__for_each_entry[_safe] is accessing 'map' as a pointer.
But it does without parentheses so passing a static hash map with an
ampersand (like '&slab_hash') will cause compiler warnings due
to unmatched types as '->' operator has a higher precedence.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241011170021.1490836-1-namhyung@kernel.org
Libbpf pre-1.0 had a legacy logic of allowing singular non-annotated
(i.e., not having explicit SEC() annotation) function to be treated as
sole entry BPF program (unless there were other explicit entry
programs).
This behavior was dropped during libbpf 1.0 transition period (unless
LIBBPF_STRICT_SEC_NAME flag was unset in libbpf_mode). When 1.0 was
released and all the legacy behavior was removed, the bug slipped
through leaving this legacy behavior around.
Fix this for good, as it actually causes very confusing behavior if BPF
object file only has subprograms, but no entry programs.
Fixes: bd054102a8c7 ("libbpf: enforce strict libbpf 1.0 behaviors")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20241010211731.4121837-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
sym_is_subprog() is incorrectly rejecting relocations against *weak*
global subprogs. Fix that by realizing that STB_WEAK is also a global
function.
While it seems like verifier doesn't support taking an address of
non-static subprog right now, it's still best to fix support for it on
libbpf side, otherwise users will get a very confusing error during BPF
skeleton generation or static linking due to misinterpreted relocation:
libbpf: prog 'handle_tp': bad map relo against 'foo' in section '.text'
Error: failed to open BPF object file: Relocation failed
It's clearly not a map relocation, but is treated and reported as such
without this fix.
Fixes: 53eddb5e04ac ("libbpf: Support subprog address relocation")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20241009011554.880168-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Track target endianness in 'struct bpf_gen' and process in-memory data in
native byte-order, but on finalization convert the embedded loader BPF
insns to target endianness.
The light skeleton also includes a target-accessed data blob which is
heterogeneous and thus difficult to convert to target byte-order on
finalization. Add support functions to convert data to target endianness
as it is added to the blob.
Also add additional debug logging for data blob structure details and
skeleton loading.
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/569562e1d5bf1cce80a1f1a3882461ee2da1ffd5.1726475448.git.tony.ambardar@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
