On Mon, May 18, 2020 at 05:53:28PM -0500, Josh Poimboeuf wrote:
> > I'm now struggling with a clang -fintegrated-as related failure:
> >
> > arch/x86/kernel/ftrace_64.o: warning: objtool: missing symbol for insn at
> > offset 0x16
> > make[4]: *** [/git/arm-soc/scripts/Makefile.build:355:
> > arch/x86/kernel/ftrace_64.o] Error 255
> >
> > Using this as a local workaround, but I'd like to find out if this is a bug
> > in clang or in objtool:
>
> It seems like an objtool bug, though at first glance I don't know where
> exactly. It could be a problem with the rb-tree stuff Peter added
> recently.
>
> That instruction should be part of the __fentry__ function:
>
> 4: 0000000000000000 165 FUNC GLOBAL DEFAULT 3 __fentry__
>
> So find_symbol_containing() should associate it with __fentry__.
Peter, is find_symbol_containing() broken by aliased functions and/or
overlapping symbols?
Symbol table '.symtab' contains 7 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000000000 0 NOTYPE LOCAL DEFAULT 5
__ksym_marker___fentry__
2: 000000000000000e 0 NOTYPE LOCAL DEFAULT 3 fgraph_trace
3: 000000000000000f 0 NOTYPE LOCAL DEFAULT 3 trace
4: 0000000000000000 165 FUNC GLOBAL DEFAULT 3 __fentry__
5: 000000000000000e 0 NOTYPE GLOBAL DEFAULT 3 ftrace_stub
6: 0000000000000000 0 NOTYPE GLOBAL DEFAULT UND ftrace_trace_function
Notice the NOTYPEs are inside the FUNC.
--
Josh
