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| author | Hengqi Chen <[email protected]> | 2023-09-18 02:48:12 +0000 |
|---|---|---|
| committer | Andrii Nakryiko <[email protected]> | 2023-09-22 21:27:36 +0000 |
| commit | bb7fa09399b937cdc4432ac99f9748f5a7f69389 (patch) | |
| tree | 44751cb909af38fa067acdf790348ebb1aa54952 /tools/lib/bpf/libbpf.c | |
| parent | libbpf: Resolve symbol conflicts at the same offset for uprobe (diff) | |
| download | kernel-bb7fa09399b937cdc4432ac99f9748f5a7f69389.tar.gz kernel-bb7fa09399b937cdc4432ac99f9748f5a7f69389.zip | |
libbpf: Support symbol versioning for uprobe
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 <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Reviewed-by: Alan Maguire <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 3a6108e3238b..b4758e54a815 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -11630,7 +11630,7 @@ static int attach_uprobe(const struct bpf_program *prog, long cookie, struct bpf *link = NULL; - n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[a-zA-Z0-9_.]+%li", + n = sscanf(prog->sec_name, "%m[^/]/%m[^:]:%m[a-zA-Z0-9_.@]+%li", &probe_type, &binary_path, &func_name, &offset); switch (n) { case 1: |