Messages in this thread | | | Date | Wed, 16 Oct 2019 14:37:10 +0100 | From | Matthias Maennich <> | Subject | Re: Module loading problem since 5.3 |
| |
On Wed, Oct 16, 2019 at 12:50:30PM +0000, Luis Chamberlain wrote: >On Mon, Oct 14, 2019 at 03:44:40PM +0100, Matthias Maennich wrote: >> Hi Luis! >> >> On Mon, Oct 14, 2019 at 08:52:35AM +0000, Luis Chamberlain wrote: >> > On Fri, Oct 11, 2019 at 09:26:05PM +0200, Heiner Kallweit wrote: >> > > On 10.10.2019 19:15, Luis Chamberlain wrote: >> > > > >> > > > >> > > > On Thu, Oct 10, 2019, 6:50 PM Heiner Kallweit <hkallweit1@gmail.com <mailto:hkallweit1@gmail.com>> wrote: >> > > > >> > > > MODULE_SOFTDEP("pre: realtek") >> > > > >> > > > Are you aware of any current issues with module loading >> > > > that could cause this problem? >> > > > >> > > > >> > > > Nope. But then again I was not aware of MODULE_SOFTDEP(). I'd encourage an extension to lib/kmod.c or something similar which stress tests this. One way that comes to mind to test this is to allow a new tests case which loads two drives which co depend on each other using this macro. That'll surely blow things up fast. That is, the current kmod tests uses request_module() or get_fs_type(), you'd want a new test case with this added using then two new dummy test drivers with the macro dependency. >> > > > >> > > > If you want to resolve this using a more tested path, you could have request_module() be used as that is currently tested. Perhaps a test patch for that can rule out if it's the macro magic which is the issue. >> > > > >> > > > Luis >> > > >> > > Maybe issue is related to a bug in introduction of symbol namespaces, see here: >> > > https://lkml.org/lkml/2019/10/11/659 >> > >> > Can you have your user with issues either revert 8651ec01daed or apply the fixes >> > mentioned by Matthias to see if that was the issue? >> > >> > Matthias what module did you run into which let you run into the issue >> > with depmod? I ask as I think it would be wise for us to add a test case >> > using lib/test_kmod.c and tools/testing/selftests/kmod/kmod.sh for the >> > regression you detected. >> >> The depmod warning can be reproduced when using a symbol that is built >> into vmlinux and used from a module. E.g. with CONFIG_USB_STORAGE=y and >> CONFIG_USB_UAS=m, the symbol `usb_stor_adjust_quirks` is built in with >> namespace USB_STORAGE and depmod stumbles upon this emitting the >> following warning (e.g. during make modules_install). >> >> depmod: WARNING: [...]/uas.ko needs unknown symbol usb_stor_adjust_quirks >> >> As there is another (less intrusive) way of implementing the namespace >> feature, I posted a patch series [1] on last Thursday that should >> mitigate the issue as the ksymtab entries depmod eventually relies on >> are no longer carrying the namespace in their names. >> >> Cheers, >> Matthias >> >> [1] https://lore.kernel.org/lkml/20191010151443.7399-1-maennich@google.com/ > >Yes but kmalloc() is built-in, and used by *all* drivers compiled as >modules, so why was that an issue?
I believe you meant, "why was that *not* an issue?". In ksymtab, namespaced symbols had the format
__ksymtab_<NAMESPACE>.<symbol>
while symbols without namespace would still use the old format
__ksymtab_<symbol>
These are also the names that are extracted into System.map (using scripts/mksysmap). Depmod is reading the System.map and for symbols used by modules that are in a namespace, it would not find a match as it does not understand the namespace notation. Depmod would still not emit a warning for symbols without namespace as their format did not change.
Cheers, Matthias
> > Luis
| |