libbpf: Fix uprobe offset calculation #8647
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As reported on libbpf-rs issue([0]), the current implementation may resolve symbol to a wrong offset and thus missing uprobe events. Calculate the symbol offset from program header instead. This is almost the same as the original implementation in commit 433966e ("libbpf: Support function name-based attach uprobes") but with `phdr.p_flags & PF_X` check dropped. This is because we also use this to calculate offset for non-func symbols like in uprobe multi selftest. See the kernel doc ([1]) and spec ([2]) for references. [0]: libbpf/libbpf-rs#1110 [1]: https://www.kernel.org/doc/html/latest/trace/uprobetracer.html [2]: https://refspecs.linuxfoundation.org/elf/ Fixes: fe92833 ("libbpf: Fix uprobe symbol file offset calculation logic") Fixes: 3774705 ("libbpf: Add elf symbol iterator") Reported-by: Guilherme Pascoal <[email protected]> Signed-off-by: Hengqi Chen <[email protected]>
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As reported on libbpf-rs issue(0), the current implementation may resolve symbol to a wrong offset and thus missing uprobe events. Calculate the symbol offset from program header instead. This is almost the same as the original implementation in commit 433966e ("libbpf: Support function name-based attach uprobes") but with
phdr.p_flags & PF_Xcheck dropped. This is because we also use this to calculate offset for non-func symbols like in uprobe multi selftest. See the kernel doc (1) and spec (2) for references.Fixes: fe92833 ("libbpf: Fix uprobe symbol file offset calculation logic")
Fixes: 3774705 ("libbpf: Add elf symbol iterator")
Reported-by: Guilherme Pascoal [email protected]