On Jul 29, 2024, at 5:54 PM, Song Liu [off-list ref] wrote:

With CONFIG_LTO_CLANG=y, the compiler may add suffix to function names
to avoid duplication. This causes confusion with users of kallsyms.
On one hand, users like livepatch are required to match the symbols
exactly. On the other hand, users like kprobe would like to match to
original function names.

Solve this by splitting kallsyms APIs. Specifically, existing APIs now
should match the symbols exactly. Add two APIs that matches the full
symbol, or only the part without .llvm.suffix. Specifically, the following
two APIs are added:

1. kallsyms_lookup_name_or_prefix()
2. kallsyms_on_each_match_symbol_or_prefix()

These APIs will be used by kprobe.

Also cleanup some code and adjust kallsyms_selftests accordingly.

Signed-off-by: Song Liu <song@kernel.org>

Actually, if we only remove .llvm.<hash> suffix, but keep other .XXX
suffix, the *_without_suffx APIs will have the same issue Yonghong 
tried to fix in commit 33f0467fe06934d5e4ea6e24ce2b9c65ce618e26: 
binary search with symbols - .llvm.<hash> suffix is not correct. 
(Please see the commit log of 33f0467fe06934d5e4ea6e24ce2b9c65ce618e26 
for more details.)

I am updating the code to remove all .XXX suffix. This design will 
not have this issue. 

Thanks,
Song