On 26 March 2015 at 22:40, Andrew Morton <a...@linux-foundation.org> wrote: > On Thu, 26 Mar 2015 21:49:06 +0100 Mathias Krause <mini...@googlemail.com> > wrote: > >> Andrew, what's your opinion on such a patch set? Do you too think it's >> useful? Or do you share Ingo's fear about the additional maintenance >> burden? > > I don't think the burden would be toooo high, although it will mess the > code up a bit. > > The post-build checking for section reference mismatches will help, > although that seems to have got itself turned off (what happened > there?).
Seem to be working fine here. This is make M=lib/, building the test module: CC [M] lib/test_module.o Building modules, stage 2. MODPOST 1 modules LD [M] lib/test_module.ko This is the same module with two pi_info() calls in a non-__init function, therefore generating section mismatches: CC [M] lib/test_module.o Building modules, stage 2. MODPOST 1 modules WARNING: modpost: Found 2 section mismatch(es). To see full details build your kernel with: 'make CONFIG_DEBUG_SECTION_MISMATCH=y' LD [M] lib/test_module.ko > Did anyone look at writing a postprocessor for the .s files? It > doesn't look like it will be too hard from an initial peek. > > Did anyone ask the gcc developers? I'd have thought that a function-wide > > __attribute__((__string_section__(foo)) > > wouldn't be a ton of work to implement. The point is you cannot blindly mark all strings referenced from __init / __exit code to end up in a matching string section because strings in this code might have to live longer when passed to functions keeping a pointer on them. For example, the name passed to class_create() won't be copied. If that one would go into the .init.rodata section automatically, we would have dangling pointers after the .init.* memory got freed. To know if it's safe to automatically put a string into an .init / .exit section one needs to see the whole code. That's why I'm reasoning it needs to be an LTO pass, not a .s post-processor or function wide section attribute. Or, as in my approach, a source level annotation. Thanks, Mathias -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
