On 2016-12-01 04:39, Nicholas Piggin wrote: > On Thu, 01 Dec 2016 02:35:54 +0000 > Ben Hutchings <ben@xxxxxxxxxxxxxxx> wrote: >> As I understand it, genksyms incorporates the definitions of a >> function's parameter and return types - not just their names - and all >> the types they refer to, recursively. So a structure size change >> should change the version of all functions where the function and its >> caller pass that structure between them, however indirectly. It finds >> such indirect ABI breakage for me fairly regularly, though of course I >> don't know that it finds everything. > > It is only the type name. > > Not only that but even if you did extend it further to structure type > arrangement then you still have to deal with other structures followed > via pointers. Or (rarer but not unheard of): > > - changes to structures without changes of the types of their members > - changes to arguments without changes of their type This is already covered by genksyms. Try make V=1 with CONFIG_MODVERSIONS=y and add the -D option to one of the genksyms command. I wanted to paste the expanded signature for register_filesystem() as an example, but vger would probably drop the mail for being too big :). > - changes to semantics of functions > - data structures derived in ways other than exported symbols, e.g., > fixed register for `current` on some archs Right, this is something that genksyms has no idea about. Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
