Hi, On Tue, 4 Jun 2024, Song Liu wrote:
> With CONFIG_LTO_CLANG, the compiler may postfix symbols with .llvm.<hash> > to avoid symbol duplication. scripts/kallsyms.c sorted the symbols > without these postfixes. The default symbol lookup also removes these > postfixes before comparing symbols. > > On the other hand, livepatch need to look up symbols with the full names. > However, calling kallsyms_on_each_match_symbol with full name (with the > postfix) cannot find the symbol(s). As a result, we cannot livepatch > kernel functions with .llvm.<hash> postfix or kernel functions that use > relocation information to symbols with .llvm.<hash> postfixes. > > Fix this by calling kallsyms_on_each_match_symbol without the postfix; > and then match the full name (with postfix) in klp_match_callback. > > Signed-off-by: Song Liu <s...@kernel.org> > --- > include/linux/kallsyms.h | 13 +++++++++++++ > kernel/kallsyms.c | 21 ++++++++++++++++----- > kernel/livepatch/core.c | 32 +++++++++++++++++++++++++++++++- > 3 files changed, 60 insertions(+), 6 deletions(-) I do not like much that something which seems to be kallsyms-internal is leaked out. You need to export cleanup_symbol_name() and there is now a lot of code outside. I would feel much more comfortable if it is all hidden from kallsyms users and kept there. Would it be possible? Moreover, isn't there a similar problem for ftrace, kprobes, ebpf,...? Thank you, Miroslav
