On Fri, Jan 08, 2021 at 09:39:53PM +0100, Peter Zijlstra wrote: > On Fri, Jan 08, 2021 at 09:32:58AM +0000, Will Deacon wrote: > > Hi Arnd, > > > > On Fri, Jan 08, 2021 at 10:19:56AM +0100, Arnd Bergmann wrote: > > > From: Arnd Bergmann <arnd@xxxxxxxx> > > > > > > With UBSAN enabled and building with clang, there are occasionally > > > warnings like > > > > > > WARNING: modpost: vmlinux.o(.text+0xc533ec): Section mismatch in reference from the function arch_atomic64_or() to the variable .init.data:numa_nodes_parsed > > > The function arch_atomic64_or() references > > > the variable __initdata numa_nodes_parsed. > > > This is often because arch_atomic64_or lacks a __initdata > > > annotation or the annotation of numa_nodes_parsed is wrong. > > > > > > for functions that end up not being inlined as intended but operating > > > on __initdata variables. Mark these as __always_inline, along with > > > the corresponding asm-generic wrappers. > > > > Hmm, I don't fully grok this. Why does it matter if a non '__init' function > > is called with a pointer to some '__initdata'? Or is the reference coming > > from somewhere else? (where?). > > FWIW the x86 atomics are __always_inline in part due to the noinstr > crud, which I imagine resulted in much the same 'fun'. FWIW, I was planning on doing the same here as part of making arm64 noinstr safe, so I reckon we should probably do this regardless of whether it's a complete fix for the section mismatch issue. Mark.
