Messages in this thread Patch in this message | | | Date | Wed, 19 Feb 2020 09:46:46 +0100 | From | Jessica Yu <> | Subject | Re: [PATCH] modpost: return error if module is missing ns imports and MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n |
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+++ Masahiro Yamada [19/02/20 04:27 +0900]: >On Wed, Feb 19, 2020 at 1:06 AM Jessica Yu <jeyu@kernel.org> wrote: >> >> +++ Matthias Maennich [17/02/20 14:56 +0000]: >> >Hi Jessica! >> > >> >On Fri, Feb 14, 2020 at 03:37:09PM +0100, Jessica Yu wrote: >> >>Currently when CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n, modpost only warns >> >>when a module is missing namespace imports. Under this configuration, such a module >> >>cannot be loaded into the kernel anyway, as the module loader would reject it. >> >>We might as well return a build error when a module is missing namespace imports >> >>under CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n, so that the build >> >>warning does not go ignored/unnoticed. >> > >> >I generally agree with the idea of the patch. Thanks for working on >> >this! I also can't remember any reason why I did not write it like this >> >initially. Probably just because I introduced this configuration option >> >quite late in the development process of the initial patches. >> > >> >> >> >>Signed-off-by: Jessica Yu <jeyu@kernel.org> >> >>--- >> >>scripts/Makefile.modpost | 1 + >> >>scripts/mod/modpost.c | 19 +++++++++++++++---- >> >>2 files changed, 16 insertions(+), 4 deletions(-) >> >> >> >>diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost >> >>index b4d3f2d122ac..a53660f910a9 100644 >> >>--- a/scripts/Makefile.modpost >> >>+++ b/scripts/Makefile.modpost >> >>@@ -53,6 +53,7 @@ MODPOST = scripts/mod/modpost \ >> >> $(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \ >> >> $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ >> >> $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ >> >>+ $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS),,-N) \ >> >> $(if $(KBUILD_MODPOST_WARN),-w) >> >> >> >>ifdef MODPOST_VMLINUX >> >>diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c >> >>index 7edfdb2f4497..53e966f7d557 100644 >> >>--- a/scripts/mod/modpost.c >> >>+++ b/scripts/mod/modpost.c >> >>@@ -39,6 +39,8 @@ static int sec_mismatch_count = 0; >> >>static int sec_mismatch_fatal = 0; >> >>/* ignore missing files */ >> >>static int ignore_missing_files; >> >>+/* Return an error when there are missing namespace imports */ >> >>+static int missing_ns_import_error = 0; >> > >> >A more suitable name is maybe missing_ns_import_is_error or follow the >> >naming of the config option: allow_missing_ns_imports (with default = 1). >> > >> >> >> >>enum export { >> >> export_plain, export_unused, export_gpl, >> >>@@ -2216,9 +2218,15 @@ static int check_exports(struct module *mod) >> >> >> >> if (exp->namespace && >> >> !module_imports_namespace(mod, exp->namespace)) { >> >>- warn("module %s uses symbol %s from namespace %s, but does not import it.\n", >> >>- basename, exp->name, exp->namespace); >> >>- add_namespace(&mod->missing_namespaces, exp->namespace); >> >>+ if (missing_ns_import_error) { >> >>+ merror("module %s uses symbol %s from namespace %s, but does not import it.\n", >> >>+ basename, exp->name, exp->namespace); >> > >> >I would like to avoid the code duplication here. The string literal is >> >identical for both cases. >> >> Hm, but one is a call to merror() and the other to warn(). The >> previous if (warn_unresolved) block does the same thing. I am not sure >> how to simplify it to one call without introducing macro magic or >> overcomplicating things. Or were you thinking of something else? > > >I would not say this is a horrible duplication, >but if you avoid repeating the same string, >maybe you could do like this: > >PRINTF log(enum loglevel loglevel, const char *fmt, ...) > > > >BTW, you accidentally changed the indentation of >add_namespace(&mod->missing_namespaces, exp->namespace); > > > >> >>+ err = 1; >> > >> >Also, if we fail here, we might as well help the user to fix it by >> >suggesting to run `make nsdeps` (once per failed modpost run). Speaking >> >of which, `make nsdeps` is currently broken by this patch as it relies >> >on a successful (yet warning-full) build of the modules. So, in case of >> >`make nsdeps`, we probably have to omit the -N flag again when invoking >> >modpost. >> >> Good catch! Since KBUILD_NSDEPS is set when running `make nsdeps`, >> maybe we can do something like: >> >> diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost >> index a53660f910a9..145703ef8d3a 100644 >> --- a/scripts/Makefile.modpost >> +++ b/scripts/Makefile.modpost >> @@ -53,7 +53,7 @@ MODPOST = scripts/mod/modpost \ >> $(if $(KBUILD_EXTMOD),$(addprefix -e ,$(KBUILD_EXTRA_SYMBOLS))) \ >> $(if $(KBUILD_EXTMOD),-o $(modulesymfile)) \ >> $(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E) \ >> - $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS),,-N) \ >> + $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS),,$(if $(KBUILD_NSDEPS),,-N)) \ > > >If you follow Matthias' suggestion >"follow the naming of the config option: allow_missing_ns_imports >(with default = 1)." >the option is inverted, and you can write it more simply: > > > $(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-n) > \
Yeah, that looks much better. Thanks!
Jessica
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