https://github.com/pcc created https://github.com/llvm/llvm-project/pull/133532
The -z glibc-228-compat flag is intended to be used for binaries utilizing IFUNCs which need to be compatible with glibc versions containing a bug that was fixed in commit b5c45e83753b27dc538dff2d55d4410c385cf3a4 which was released in version 2.29. The bug causes glibc to mprotect the .text section as RW while calling ifunc resolvers in binaries linked with -z notext, leading to a SIGSEGV at startup time. By setting the W flag on the executable section we work around the bug by avoiding the code path that does the mprotect. It is recommended that binaries linked with this flag contain startup code (e.g. in .init_array) that remaps the executable section as non-writable. TODO: - Add tests. - Possibly decide on another mechanism for enabling this besides the -z flag (e.g. examine symbol version data on libc.so.6). _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
