Bug#948427: modules.builtin.modinfo not included in signed image packages
Source: linux
Version: 5.2.6-1
Tags: patch
X-Debbugs-CC: Benjamin Poirier <benjamin.poirier@gmail.com>,Michael Jeanson <mjeanson@debian.org>
As reported in originally https://bugs.debian.org/948257#88 with the
recent kmod update an issue with our signed packages was uncovered:
On Wed, Jan 08, 2020 at 01:45:21PM +0100, Salvatore Bonaccorso wrote:
> Hi Benjamin,
>
> On Wed, Jan 08, 2020 at 01:07:20PM +0100, Salvatore Bonaccorso wrote:
> > Hi Benjamin,
> >
> > On Wed, Jan 08, 2020 at 09:24:30AM +0900, Benjamin Poirier wrote:
> > [...]
> > > Looks like the modules are built before lttng-sessiond is started:
> > > Setting up lttng-modules-dkms (2.11.0-2) ...
> > > Loading new lttng-modules-2.11.0 DKMS files...
> > > Building for 5.4.0-2-amd64
> > > Building initial module for 5.4.0-2-amd64
> > > Done.
> > >
> > > lttng-lib-ring-buffer.ko:
> > > Running module version sanity check.
> > > - Original module
> > > - No original module exists within this kernel
> > > - Installation
> > > - Installing to /lib/modules/5.4.0-2-amd64/updates/dkms/
> > >
> > > [...]
> > >
> > > depmod...
> > >
> > > DKMS: install completed.
> > > Setting up linux-headers-5.4.0-2-amd64 (5.4.8-1) ...
> > > /etc/kernel/header_postinst.d/dkms:
> > > dkms: running auto installation service for kernel 5.4.0-2-amd64:.
> > > Setting up sudo (1.8.29-1) ...
> > > Setting up babeltrace (1.5.7-2) ...
> > > Setting up liburcu6:amd64 (0.11.1-2) ...
> > > Setting up linux-headers-amd64 (5.4.8-1) ...
> > > Setting up liblttng-ctl0:amd64 (2.11.0-3) ...
> > > Setting up lttng-tools (2.11.0-3) ...
> > >
> > > Still, it doesn't work.
> > >
> > > > Simply restarting the sessiond should fix this.
> > >
> > > I tried restarting lttng-sessiond or rebooting the machine but it was no
> > > help, lttng-sessiond always reports:
> > > Error: Failed to load kmod library resources
> > > Warning: No kernel tracer available
> > >
> > > A quick look into the code shows that is:
> > > src/bin/lttng-sessiond/modprobe.c
> > > kmod_set_log_fn(*ctx, log_kmod, NULL);
> > > ret = kmod_load_resources(*ctx);
> > > if (ret < 0) {
> > > ERR("Failed to load kmod library resources");
> > > goto error;
> > > }
> > >
> > > I didn't dig into libkmod, but I noticed (using opensnoop.bt) the
> > > following:
> > > 8071 lttng-sessiond 2 0 /lib/modules/5.4.0-2-amd64/modules.dep.bin
> > > 8071 lttng-sessiond 2 0 /lib/modules/5.4.0-2-amd64/modules.alias.bin
> > > 8071 lttng-sessiond 2 0 /lib/modules/5.4.0-2-amd64/modules.symbols.bin
> > > 8071 lttng-sessiond 2 0 /lib/modules/5.4.0-2-amd64/modules.builtin.alias.bin
> > >
> > > On another machine which I haven't yet updated and where lttng still
> > > works, I see:
> > > 193519 lttng-sessiond 2 0 /lib/modules/5.4.0-1-amd64/modules.dep.bin
> > > 193519 lttng-sessiond 2 0 /lib/modules/5.4.0-1-amd64/modules.alias.bin
> > > 193519 lttng-sessiond 2 0 /lib/modules/5.4.0-1-amd64/modules.symbols.bin
> > > 193519 lttng-sessiond 2 0 /lib/modules/5.4.0-1-amd64/modules.builtin.bin
> > >
> > > Not sure if /lib/modules/5.4.0-2-amd64/modules.builtin.alias.bin is
> > > relevant but it's an empty file...
> > >
> > > After downgrading libkmod2 from
> > > Version: 26+20191223-1
> > > to
> > > Version: 26-3
> > > the issue with lttng is no longer apparent:
> > > root@vsid:/tmp# lttng list --kernel
> > > Kernel events:
> > > -------------
> > > asoc_snd_soc_bias_level_start (loglevel: TRACE_EMERG (0)) (type: tracepoint)
> > > asoc_snd_soc_bias_level_done (loglevel: TRACE_EMERG (0)) (type: tracepoint)
> > > asoc_snd_soc_dapm_start (loglevel: TRACE_EMERG (0)) (type: tracepoint)
> > > [...]
> > >
> >
> > Should we track this in a separate bug from #948257?
>
> So here is what I think is part of what is going on (unless there is
> something broken in my analysis):
>
> Since 898490c010b5 ("moduleparam: Save information about built-in
> modules in separate file")[1] which is in 5.2-rc1, there is a new
> modules.builtin.modinfo provided.
>
> [1]: <https://git.kernel.org/linus/898490c010b5d2e499e03b7e815fc214209ac583>
>
> This one is installed in the -unsigned binary packages but not copied
> over into the signing template, so the signed linux image packages do
> not contain it.
>
> Now with kmod/26+20191223-1 we have 60084cf1cb24 ("libkmod: Add parser
> for modules.builtin.modinfo")[2] adding the parser and [3] and [4]
> using that.
>
> [2]: <https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/commit/?id=60084cf1cb24dc3a257976c0d539a4c3ffda5db5>
> [3]: <https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/commit/?id=73eed2aba3cbe18bbda40f18f7bc32e8de1ec81f>
> [4]: <https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/commit/?id=b866b2165ae6cf18fb26b635f4a7ee57c0334731>
Merge request:
https://salsa.debian.org/kernel-team/linux/merge_requests/201
Regards,
Salvatore
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