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bb7fa09399
In current implementation, we assume that symbol found in .dynsym section
would have a version suffix and use it to compare with symbol user supplied.
According to the spec ([0]), this assumption is incorrect, the version info
of dynamic symbols are stored in .gnu.version and .gnu.version_d sections
of ELF objects. For example:
$ nm -D /lib/x86_64-linux-gnu/libc.so.6 | grep rwlock_wrlock
000000000009b1a0 T __pthread_rwlock_wrlock@GLIBC_2.2.5
000000000009b1a0 T pthread_rwlock_wrlock@@GLIBC_2.34
000000000009b1a0 T pthread_rwlock_wrlock@GLIBC_2.2.5
$ readelf -W --dyn-syms /lib/x86_64-linux-gnu/libc.so.6 | grep rwlock_wrlock
706: 000000000009b1a0 878 FUNC GLOBAL DEFAULT 15 __pthread_rwlock_wrlock@GLIBC_2.2.5
2568: 000000000009b1a0 878 FUNC GLOBAL DEFAULT 15 pthread_rwlock_wrlock@@GLIBC_2.34
2571: 000000000009b1a0 878 FUNC GLOBAL DEFAULT 15 pthread_rwlock_wrlock@GLIBC_2.2.5
In this case, specify pthread_rwlock_wrlock@@GLIBC_2.34 or
pthread_rwlock_wrlock@GLIBC_2.2.5 in bpf_uprobe_opts::func_name won't work.
Because the qualified name does NOT match `pthread_rwlock_wrlock` (without
version suffix) in .dynsym sections.
This commit implements the symbol versioning for dynsym and allows user to
specify symbol in the following forms:
- func
- func@LIB_VERSION
- func@@LIB_VERSION
In case of symbol conflicts, error out and users should resolve it by
specifying a qualified name.
[0]: https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/symversion.html
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230918024813.237475-3-hengqi.chen@gmail.com
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| .. | ||
| .gitignore | ||
| bpf.c | ||
| bpf.h | ||
| bpf_core_read.h | ||
| bpf_endian.h | ||
| bpf_gen_internal.h | ||
| bpf_helpers.h | ||
| bpf_prog_linfo.c | ||
| bpf_tracing.h | ||
| btf.c | ||
| btf.h | ||
| btf_dump.c | ||
| Build | ||
| elf.c | ||
| gen_loader.c | ||
| hashmap.c | ||
| hashmap.h | ||
| libbpf.c | ||
| libbpf.h | ||
| libbpf.map | ||
| libbpf.pc.template | ||
| libbpf_common.h | ||
| libbpf_errno.c | ||
| libbpf_internal.h | ||
| libbpf_legacy.h | ||
| libbpf_probes.c | ||
| libbpf_version.h | ||
| linker.c | ||
| Makefile | ||
| netlink.c | ||
| nlattr.c | ||
| nlattr.h | ||
| relo_core.c | ||
| relo_core.h | ||
| ringbuf.c | ||
| skel_internal.h | ||
| str_error.c | ||
| str_error.h | ||
| strset.c | ||
| strset.h | ||
| usdt.bpf.h | ||
| usdt.c | ||
| zip.c | ||
| zip.h | ||