From fd1c14f1b944db2970e1022ae4693f12807e6b6c Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Thu, 3 Oct 2024 17:25:54 +0200
Subject: [PATCH 1/8] shared: Export is_dir()

Make it possible to use is_dir() helper outside of util.c.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 shared/util.c | 2 +-
 shared/util.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/shared/util.c b/shared/util.c
index 5102879f..1cd7fc81 100644
--- a/shared/util.c
+++ b/shared/util.c
@@ -377,7 +377,7 @@ char *path_make_absolute_cwd(const char *p)
 	return r;
 }
 
-static inline int is_dir(const char *path)
+int is_dir(const char *path)
 {
 	struct stat st;
 
diff --git a/shared/util.h b/shared/util.h
index bcd834e5..3e0ece32 100644
--- a/shared/util.h
+++ b/shared/util.h
@@ -44,6 +44,7 @@ _nonnull_(1) char *freadline_wrapped(FILE *fp, unsigned int *linenum);
 /* path handling functions                                                  */
 /* ************************************************************************ */
 _must_check_ _nonnull_all_ char *path_make_absolute_cwd(const char *p);
+int is_dir(const char *path);
 int mkdir_p(const char *path, int len, mode_t mode);
 int mkdir_parents(const char *path, mode_t mode);
 unsigned long long stat_mstamp(const struct stat *st);

From 5fdaf03a2e338f948edd4dd59f6f3711e87fade1 Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Thu, 3 Oct 2024 15:31:59 +0200
Subject: [PATCH 2/8] libkmod: Introduce fallback module directory

Currently, traditional Linux systems using initramfs are forced to keep two
copies of the modules which may be needed both during early boot and for
normal system operation. This seems to be inevitable for the case when
initramfs is built locally but with the rise of distro shipped UKIs the
question whether it would be possible to avoid the redundancy arises.

To make it possible to reuse modules from initramfs without copying them to
the root filesystem (which may be read-only), the suggested approach is to
preserve them on tmpfs, e.g. in /run/modules/`uname -r` but the challenge
is to make kmod search there. It would certainly be possible to e.g. bind
mount /run/modules/`uname -r` to /lib/modules/`uname -r` but this will make
the destination read-only and traditional tools which are used to install
packages with modules (e.g. rpm) will break. Instead, a 'fallback'
directory approach is suggested: in case main /lib/modules/`uname -r` is
completely missing, kmod tools will check whether /run/modules/`uname -r`
exist and search there.

In theory, it would've been possible to replace this fallback option with a
dedicated config for kmod making modules location dynamic but this seems to
be a more intrusive change and it will also require additional external
actions to switch from 'fallback' to 'main' if/when modules get installed
to the main system.

Note, no merging of /run/modules/`uname -r` and /lib/modules/`uname -r` is
performed. It is expected, that in case /lib/modules/`uname -r` exists, it
is a superset and modules from initramfs are no longer needed.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 Makefile.am       | 1 +
 configure.ac      | 7 ++++++-
 libkmod/libkmod.c | 8 ++++++++
 man/Makefile.am   | 1 +
 meson.build       | 6 ++++++
 meson_options.txt | 6 ++++++
 6 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Makefile.am b/Makefile.am
index 213a1fe6..449dbf5a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -32,6 +32,7 @@ AM_CPPFLAGS = \
 	-DSYSCONFDIR=\""$(sysconfdir)"\" \
 	-DDISTCONFDIR=\""$(distconfdir)"\" \
 	-DMODULE_DIRECTORY=\""$(module_directory)"\" \
+	-DMODULE_FALLBACK_DIRECTORY=\""$(module_fallback_directory)"\" \
 	${zlib_CFLAGS}
 
 AM_CFLAGS = $(OUR_CFLAGS)
diff --git a/configure.ac b/configure.ac
index c204570d..b62882f1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -85,8 +85,13 @@ AC_ARG_WITH([module_directory],
         [], [with_module_directory=/lib/modules])
 AC_SUBST([module_directory], [$with_module_directory])
 
+AC_ARG_WITH([module_fallback_directory],
+        AS_HELP_STRING([--with-module-fallback_directory=DIR], [alternative directory in which to look for kernel modules @<:@default=/run/modules@:>@]),
+        [], [with_module_fallback_directory=/run/modules])
+AC_SUBST([module_fallback_directory], [$with_module_fallback_directory])
+
 # Check all directory arguments for consistency.
-for ac_var in	distconfdir module_directory
+for ac_var in	distconfdir module_directory module_fallback_directory
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
diff --git a/libkmod/libkmod.c b/libkmod/libkmod.c
index d1e5a82c..4ebd4f35 100644
--- a/libkmod/libkmod.c
+++ b/libkmod/libkmod.c
@@ -164,6 +164,7 @@ static int log_priority(const char *priority)
 }
 
 static const char *dirname_default_prefix = MODULE_DIRECTORY;
+static const char *dirname_fallback_prefix = MODULE_FALLBACK_DIRECTORY;
 
 static char *get_kernel_release(const char *dirname)
 {
@@ -179,6 +180,13 @@ static char *get_kernel_release(const char *dirname)
 	if (asprintf(&p, "%s/%s", dirname_default_prefix, u.release) < 0)
 		return NULL;
 
+	/* If main path doesn't exist, try fallback */
+	if (is_dir(p) <= 0) {
+		free(p);
+		if (asprintf(&p, "%s/%s", dirname_fallback_prefix, u.release) < 0)
+			return NULL;
+	}
+
 	return p;
 }
 
diff --git a/man/Makefile.am b/man/Makefile.am
index 6356d878..2f9fa6ee 100644
--- a/man/Makefile.am
+++ b/man/Makefile.am
@@ -18,6 +18,7 @@ define generate_manpage
 	sed -e 's|@SYSCONFDIR@|$(sysconfdir)|g' | \
 	sed -e 's|@DISTCONFDIR@|$(distconfdir)|g' | \
 	sed -e 's|@MODULE_DIRECTORY@|$(module_directory)|g' | \
+	sed -e 's|@MODULE_FALLBACK_DIRECTORY@|$(module_fallback_directory)|g' | \
 	$(SCDOC) > $@
 endef
 
diff --git a/meson.build b/meson.build
index 1c87fe0e..7b199ba8 100644
--- a/meson.build
+++ b/meson.build
@@ -191,6 +191,12 @@ if moduledir == ''
 endif
 cdata.set_quoted('MODULE_DIRECTORY', moduledir)
 
+moduledir = get_option('modulefallbackdir')
+if moduledir == ''
+  moduledir = '/run/modules'
+endif
+cdata.set_quoted('MODULE_FALLBACK_DIRECTORY', moduledir)
+
 _completiondirs = [
   ['bashcompletiondir', 'bash-completion', 'bash-completion/completions', 'shell-completion/bash/@0@'],
   ['fishcompletiondir', 'fish',            'fish/vendor_functions.d',     'shell-completion/fish/@0@.fish'],
diff --git a/meson_options.txt b/meson_options.txt
index 4a25fb0e..9b5e341b 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -12,6 +12,12 @@ option(
   description : 'Directory to look for kernel modules. Default: /lib/modules',
 )
 
+option(
+  'modulefallbackdir',
+  type : 'string',
+  description : 'Alternative directory to look for kernel modules. Default: /run/modules',
+)
+
 option(
   'bashcompletiondir',
   type : 'string',

From bcc38fcda52d4d76fa850b464cf6a45b01fca0a2 Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Fri, 18 Oct 2024 17:42:39 +0200
Subject: [PATCH 3/8] modprobe: support fallback module directory with -d/-S

By default, modprobe relies on libkmod to set up module search
path (kmod_new(NULL, ...)) but in case -d/-S options are used, modprobe
explicitly defines search path using MODULE_DIRECTORY. Add support for
MODULE_FALLBACK_DIRECTORY when the main one is missing.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 tools/modprobe.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/modprobe.c b/tools/modprobe.c
index 26b252c5..f027c01f 100644
--- a/tools/modprobe.c
+++ b/tools/modprobe.c
@@ -983,6 +983,18 @@ static int do_modprobe(int argc, char **orig_argv)
 			err = -1;
 			goto done;
 		}
+
+		if (is_dir(dirname_buf) <= 0) {
+			n = snprintf(dirname_buf, sizeof(dirname_buf),
+				     "%s" MODULE_FALLBACK_DIRECTORY "/%s", root, kversion);
+			if (n >= (int)sizeof(dirname_buf)) {
+				ERR("bad directory %s" MODULE_FALLBACK_DIRECTORY "/%s: path too long\n",
+				    root, kversion);
+				err = -1;
+				goto done;
+			}
+		}
+
 		dirname = dirname_buf;
 	}
 

From 41738f50b35f920189d133f1eac0685f8d29ce07 Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Fri, 18 Oct 2024 17:24:15 +0200
Subject: [PATCH 4/8] testsuite: add modprobe fallback test

Check whether modprobe is able to load modules from /run/modules/`uname -r`
when /lib/modules/`uname -r` is missing.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 Makefile.am                                   |   2 +-
 scripts/setup-rootfs.sh                       |   2 ++
 .../test-modprobe/fallback/proc/modules       |   0
 .../fallback/run/modules/4.4.4/modules.alias  |   1 +
 .../run/modules/4.4.4/modules.alias.bin       | Bin 0 -> 12 bytes
 .../run/modules/4.4.4/modules.builtin.bin     |   0
 .../fallback/run/modules/4.4.4/modules.dep    |   1 +
 .../run/modules/4.4.4/modules.dep.bin         | Bin 0 -> 58 bytes
 .../run/modules/4.4.4/modules.devname         |   1 +
 .../run/modules/4.4.4/modules.softdep         |   1 +
 .../run/modules/4.4.4/modules.symbols         |   1 +
 .../run/modules/4.4.4/modules.symbols.bin     | Bin 0 -> 12 bytes
 testsuite/test-modprobe.c                     |  23 ++++++++++++++++++
 13 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback/proc/modules
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.alias
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.alias.bin
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.builtin.bin
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.dep
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.dep.bin
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.devname
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.softdep
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.symbols
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.symbols.bin

diff --git a/Makefile.am b/Makefile.am
index 449dbf5a..e27f366b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -197,7 +197,7 @@ MODULE_PLAYGROUND = testsuite/module-playground
 BUILD_MODULES = $(AM_V_GEN) $(top_srcdir)/scripts/setup-modules.sh $(top_srcdir) $(top_builddir) $(MODULE_PLAYGROUND)
 ROOTFS = testsuite/rootfs
 ROOTFS_PRISTINE = $(top_srcdir)/testsuite/rootfs-pristine
-CREATE_ROOTFS = $(AM_V_GEN) $(top_srcdir)/scripts/setup-rootfs.sh $(ROOTFS_PRISTINE) $(ROOTFS) $(MODULE_PLAYGROUND) $(top_builddir)/config.h $(sysconfdir) $(module_directory)
+CREATE_ROOTFS = $(AM_V_GEN) $(top_srcdir)/scripts/setup-rootfs.sh $(ROOTFS_PRISTINE) $(ROOTFS) $(MODULE_PLAYGROUND) $(top_builddir)/config.h $(sysconfdir) $(module_directory) $(module_fallback_directory)
 
 build-module-playground:
 	$(BUILD_MODULES)
diff --git a/scripts/setup-rootfs.sh b/scripts/setup-rootfs.sh
index 92c5d2dd..1b6c5a94 100755
--- a/scripts/setup-rootfs.sh
+++ b/scripts/setup-rootfs.sh
@@ -8,6 +8,7 @@ MODULE_PLAYGROUND=$3
 CONFIG_H=$4
 SYSCONFDIR=$5
 MODULE_DIRECTORY=$6
+MODULE_FALLBACK_DIRECTORY=$7
 ANOTHER_MODULE_DIRECTORY=/foobar
 
 # create rootfs from rootfs-pristine
@@ -98,6 +99,7 @@ map=(
     ["test-modprobe/external/lib/modules/external/"]="mod-simple.ko"
     ["test-modprobe/module-from-abspath/home/foo/"]="mod-simple.ko"
     ["test-modprobe/module-from-relpath/home/foo/"]="mod-simple.ko"
+    ["test-modprobe/fallback$MODULE_FALLBACK_DIRECTORY/4.4.4/kernel/"]="mod-simple.ko"
     ["test-depmod/modules-order-compressed$MODULE_DIRECTORY/4.4.4/kernel/drivers/block/cciss.ko"]="mod-fake-cciss.ko"
     ["test-depmod/modules-order-compressed$MODULE_DIRECTORY/4.4.4/kernel/drivers/scsi/hpsa.ko"]="mod-fake-hpsa.ko"
     ["test-depmod/modules-order-compressed$MODULE_DIRECTORY/4.4.4/kernel/drivers/scsi/scsi_mod.ko"]="mod-fake-scsi-mod.ko"
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback/proc/modules b/testsuite/rootfs-pristine/test-modprobe/fallback/proc/modules
new file mode 100644
index 00000000..e69de29b
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.alias b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.alias
new file mode 100644
index 00000000..ba76e181
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.alias
@@ -0,0 +1 @@
+# Aliases extracted from modules themselves.
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.alias.bin b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.alias.bin
new file mode 100644
index 0000000000000000000000000000000000000000..7075435f6268c4d815aec093d61e26647666ba76
GIT binary patch
literal 12
TcmdnM{w17&iGh)Ufq@4A6;A>Z

literal 0
HcmV?d00001

diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.builtin.bin b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.builtin.bin
new file mode 100644
index 00000000..e69de29b
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.dep b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.dep
new file mode 100644
index 00000000..54766537
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.dep
@@ -0,0 +1 @@
+kernel/mod-simple.ko:
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.dep.bin b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.dep.bin
new file mode 100644
index 0000000000000000000000000000000000000000..b09a85432309c43f99500d6cc3473bcb1ef0a80e
GIT binary patch
literal 58
zcmdnM{w17&iGfjpfx#p{CB8T_w;(5#0SFjDM0RRXUTThhZhnd`L`E+=--;nO_W%O}
F4*<8l52gSB

literal 0
HcmV?d00001

diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.devname b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.devname
new file mode 100644
index 00000000..58f6d6d6
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.devname
@@ -0,0 +1 @@
+# Device nodes to trigger on-demand module loading.
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.softdep b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.softdep
new file mode 100644
index 00000000..5554ccca
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.softdep
@@ -0,0 +1 @@
+# Soft dependencies extracted from modules themselves.
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.symbols b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.symbols
new file mode 100644
index 00000000..618c345f
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.symbols
@@ -0,0 +1 @@
+# Aliases for symbols, used by symbol_request().
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.symbols.bin b/testsuite/rootfs-pristine/test-modprobe/fallback/run/modules/4.4.4/modules.symbols.bin
new file mode 100644
index 0000000000000000000000000000000000000000..7075435f6268c4d815aec093d61e26647666ba76
GIT binary patch
literal 12
TcmdnM{w17&iGh)Ufq@4A6;A>Z

literal 0
HcmV?d00001

diff --git a/testsuite/test-modprobe.c b/testsuite/test-modprobe.c
index cbdd9c75..3e5b7ab2 100644
--- a/testsuite/test-modprobe.c
+++ b/testsuite/test-modprobe.c
@@ -484,4 +484,27 @@ DEFINE_TEST(modprobe_module_from_relpath,
 	.modules_loaded = "mod-simple",
 	);
 
+static noreturn int modprobe_fallback(const struct test *t)
+{
+	const char *progname = TOOLS_DIR "/modprobe";
+	const char *const args[] = {
+		progname,
+		"mod-simple",
+		NULL,
+	};
+
+	test_spawn_prog(progname, args);
+	exit(EXIT_FAILURE);
+}
+DEFINE_TEST(modprobe_fallback,
+	.description = "check modprobe able to load module from fallback path",
+	.config = {
+		[TC_UNAME_R] = "4.4.4",
+		[TC_ROOTFS] = TESTSUITE_ROOTFS "test-modprobe/fallback",
+		[TC_INIT_MODULE_RETCODES] = "",
+	},
+	.need_spawn = true,
+	.modules_loaded = "mod-simple",
+	);
+
 TESTSUITE_MAIN();

From 4e9f5794b42c45dc4d9f1d3e502f9e4846d6ad8e Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Mon, 21 Oct 2024 13:52:06 +0200
Subject: [PATCH 5/8] testsuite: add modprobe fallback custom ver test

Check whether modprobe --set-version is able to load modules from
/run/modules/<custom-ver> when /lib/modules/<custom-ver> is missing.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 scripts/setup-rootfs.sh                       |   1 +
 .../fallback-custom/proc/modules              |   0
 .../run/modules/3.3.3/modules.alias           |   1 +
 .../run/modules/3.3.3/modules.alias.bin       | Bin 0 -> 12 bytes
 .../run/modules/3.3.3/modules.builtin.bin     |   0
 .../run/modules/3.3.3/modules.dep             |   1 +
 .../run/modules/3.3.3/modules.dep.bin         | Bin 0 -> 58 bytes
 .../run/modules/3.3.3/modules.devname         |   1 +
 .../run/modules/3.3.3/modules.softdep         |   1 +
 .../run/modules/3.3.3/modules.symbols         |   1 +
 .../run/modules/3.3.3/modules.symbols.bin     | Bin 0 -> 12 bytes
 testsuite/test-modprobe.c                     |  24 ++++++++++++++++++
 12 files changed, 30 insertions(+)
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback-custom/proc/modules
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.alias
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.alias.bin
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.builtin.bin
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.dep
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.dep.bin
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.devname
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.softdep
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.symbols
 create mode 100644 testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.symbols.bin

diff --git a/scripts/setup-rootfs.sh b/scripts/setup-rootfs.sh
index 1b6c5a94..8f473253 100755
--- a/scripts/setup-rootfs.sh
+++ b/scripts/setup-rootfs.sh
@@ -100,6 +100,7 @@ map=(
     ["test-modprobe/module-from-abspath/home/foo/"]="mod-simple.ko"
     ["test-modprobe/module-from-relpath/home/foo/"]="mod-simple.ko"
     ["test-modprobe/fallback$MODULE_FALLBACK_DIRECTORY/4.4.4/kernel/"]="mod-simple.ko"
+    ["test-modprobe/fallback-custom$MODULE_FALLBACK_DIRECTORY/3.3.3/kernel/"]="mod-simple.ko"
     ["test-depmod/modules-order-compressed$MODULE_DIRECTORY/4.4.4/kernel/drivers/block/cciss.ko"]="mod-fake-cciss.ko"
     ["test-depmod/modules-order-compressed$MODULE_DIRECTORY/4.4.4/kernel/drivers/scsi/hpsa.ko"]="mod-fake-hpsa.ko"
     ["test-depmod/modules-order-compressed$MODULE_DIRECTORY/4.4.4/kernel/drivers/scsi/scsi_mod.ko"]="mod-fake-scsi-mod.ko"
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback-custom/proc/modules b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/proc/modules
new file mode 100644
index 00000000..e69de29b
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.alias b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.alias
new file mode 100644
index 00000000..ba76e181
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.alias
@@ -0,0 +1 @@
+# Aliases extracted from modules themselves.
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.alias.bin b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.alias.bin
new file mode 100644
index 0000000000000000000000000000000000000000..7075435f6268c4d815aec093d61e26647666ba76
GIT binary patch
literal 12
TcmdnM{w17&iGh)Ufq@4A6;A>Z

literal 0
HcmV?d00001

diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.builtin.bin b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.builtin.bin
new file mode 100644
index 00000000..e69de29b
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.dep b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.dep
new file mode 100644
index 00000000..54766537
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.dep
@@ -0,0 +1 @@
+kernel/mod-simple.ko:
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.dep.bin b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.dep.bin
new file mode 100644
index 0000000000000000000000000000000000000000..b09a85432309c43f99500d6cc3473bcb1ef0a80e
GIT binary patch
literal 58
zcmdnM{w17&iGfjpfx#p{CB8T_w;(5#0SFjDM0RRXUTThhZhnd`L`E+=--;nO_W%O}
F4*<8l52gSB

literal 0
HcmV?d00001

diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.devname b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.devname
new file mode 100644
index 00000000..58f6d6d6
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.devname
@@ -0,0 +1 @@
+# Device nodes to trigger on-demand module loading.
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.softdep b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.softdep
new file mode 100644
index 00000000..5554ccca
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.softdep
@@ -0,0 +1 @@
+# Soft dependencies extracted from modules themselves.
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.symbols b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.symbols
new file mode 100644
index 00000000..618c345f
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.symbols
@@ -0,0 +1 @@
+# Aliases for symbols, used by symbol_request().
diff --git a/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.symbols.bin b/testsuite/rootfs-pristine/test-modprobe/fallback-custom/run/modules/3.3.3/modules.symbols.bin
new file mode 100644
index 0000000000000000000000000000000000000000..7075435f6268c4d815aec093d61e26647666ba76
GIT binary patch
literal 12
TcmdnM{w17&iGh)Ufq@4A6;A>Z

literal 0
HcmV?d00001

diff --git a/testsuite/test-modprobe.c b/testsuite/test-modprobe.c
index 3e5b7ab2..d36ede9b 100644
--- a/testsuite/test-modprobe.c
+++ b/testsuite/test-modprobe.c
@@ -507,4 +507,28 @@ DEFINE_TEST(modprobe_fallback,
 	.modules_loaded = "mod-simple",
 	);
 
+static noreturn int modprobe_fallback_custom(const struct test *t)
+{
+	const char *progname = TOOLS_DIR "/modprobe";
+	const char *const args[] = {
+		progname,
+		"--set-version",
+		"3.3.3",
+		"mod-simple",
+		NULL,
+	};
+
+	test_spawn_prog(progname, args);
+	exit(EXIT_FAILURE);
+}
+DEFINE_TEST(modprobe_fallback_custom,
+	.description = "check modprobe able to load module from fallback path with --set-version",
+	.config = {
+		[TC_ROOTFS] = TESTSUITE_ROOTFS "test-modprobe/fallback-custom",
+		[TC_INIT_MODULE_RETCODES] = "",
+	},
+	.need_spawn = true,
+	.modules_loaded = "mod-simple",
+	);
+
 TESTSUITE_MAIN();

From d8a60300a3e35c6216605ea6db8efad960ab080f Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Mon, 21 Oct 2024 17:56:41 +0200
Subject: [PATCH 6/8] modinfo: support fallback module directory with -b/-k

By default, modinfo relies on libkmod to set up module search
path (kmod_new(NULL, ...)) but in case -b/-k options are used, modinfo
explicitly defines search path using MODULE_DIRECTORY. Add support for
MODULE_FALLBACK_DIRECTORY when the main one is missing.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 tools/modinfo.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/tools/modinfo.c b/tools/modinfo.c
index f1323c50..cc0fd538 100644
--- a/tools/modinfo.c
+++ b/tools/modinfo.c
@@ -443,6 +443,17 @@ static int do_modinfo(int argc, char *argv[])
 			    root, kversion);
 			return EXIT_FAILURE;
 		}
+
+		if (is_dir(dirname_buf) <= 0) {
+			n = snprintf(dirname_buf, sizeof(dirname_buf),
+				     "%s" MODULE_FALLBACK_DIRECTORY "/%s", root, kversion);
+			if (n >= (int)sizeof(dirname_buf)) {
+				ERR("bad directory %s" MODULE_FALLBACK_DIRECTORY "/%s: path too long\n",
+				    root, kversion);
+				return EXIT_FAILURE;
+			}
+		}
+
 		dirname = dirname_buf;
 	}
 

From 0155e2eb9851996e4af28abf78a1a0c4da05617d Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Mon, 21 Oct 2024 18:03:44 +0200
Subject: [PATCH 7/8] testsuite: add modinfo fallback test

Check whether modinfo is able to find modules in /run/modules/`uname -r`
when /lib/modules/`uname -r` is missing.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 scripts/setup-rootfs.sh                       |   1 +
 .../test-modinfo/correct-fallback.txt         |   1 +
 .../test-modinfo/fallback/proc/modules        |   0
 .../fallback/run/modules/4.4.4/modules.alias  |   1 +
 .../run/modules/4.4.4/modules.alias.bin       | Bin 0 -> 12 bytes
 .../run/modules/4.4.4/modules.builtin.bin     |   0
 .../fallback/run/modules/4.4.4/modules.dep    |   1 +
 .../run/modules/4.4.4/modules.dep.bin         | Bin 0 -> 58 bytes
 .../run/modules/4.4.4/modules.devname         |   1 +
 .../run/modules/4.4.4/modules.softdep         |   1 +
 .../run/modules/4.4.4/modules.symbols         |   1 +
 .../run/modules/4.4.4/modules.symbols.bin     | Bin 0 -> 12 bytes
 testsuite/test-modinfo.c                      |  24 ++++++++++++++++++
 13 files changed, 31 insertions(+)
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/correct-fallback.txt
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback/proc/modules
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.alias
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.alias.bin
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.builtin.bin
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.dep
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.dep.bin
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.devname
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.softdep
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.symbols
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.symbols.bin

diff --git a/scripts/setup-rootfs.sh b/scripts/setup-rootfs.sh
index 8f473253..587f83c1 100755
--- a/scripts/setup-rootfs.sh
+++ b/scripts/setup-rootfs.sh
@@ -114,6 +114,7 @@ map=(
     ["test-modinfo/mod-simple-sha256.ko"]="mod-simple.ko"
     ["test-modinfo/mod-simple-pkcs7.ko"]="mod-simple.ko"
     ["test-modinfo/external/lib/modules/external/mod-simple.ko"]="mod-simple.ko"
+    ["test-modinfo/fallback$MODULE_FALLBACK_DIRECTORY/4.4.4/kernel/"]="mod-simple.ko"
     ["test-weakdep$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-a.ko"]="mod-loop-a.ko"
     ["test-weakdep$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-b.ko"]="mod-loop-b.ko"
     ["test-weakdep$MODULE_DIRECTORY/4.4.4/kernel/mod-simple.ko"]="mod-simple.ko"
diff --git a/testsuite/rootfs-pristine/test-modinfo/correct-fallback.txt b/testsuite/rootfs-pristine/test-modinfo/correct-fallback.txt
new file mode 100644
index 00000000..30d00414
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/correct-fallback.txt
@@ -0,0 +1 @@
+/run/modules/4.4.4/kernel/mod-simple.ko
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback/proc/modules b/testsuite/rootfs-pristine/test-modinfo/fallback/proc/modules
new file mode 100644
index 00000000..e69de29b
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.alias b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.alias
new file mode 100644
index 00000000..ba76e181
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.alias
@@ -0,0 +1 @@
+# Aliases extracted from modules themselves.
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.alias.bin b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.alias.bin
new file mode 100644
index 0000000000000000000000000000000000000000..7075435f6268c4d815aec093d61e26647666ba76
GIT binary patch
literal 12
TcmdnM{w17&iGh)Ufq@4A6;A>Z

literal 0
HcmV?d00001

diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.builtin.bin b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.builtin.bin
new file mode 100644
index 00000000..e69de29b
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.dep b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.dep
new file mode 100644
index 00000000..54766537
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.dep
@@ -0,0 +1 @@
+kernel/mod-simple.ko:
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.dep.bin b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.dep.bin
new file mode 100644
index 0000000000000000000000000000000000000000..b09a85432309c43f99500d6cc3473bcb1ef0a80e
GIT binary patch
literal 58
zcmdnM{w17&iGfjpfx#p{CB8T_w;(5#0SFjDM0RRXUTThhZhnd`L`E+=--;nO_W%O}
F4*<8l52gSB

literal 0
HcmV?d00001

diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.devname b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.devname
new file mode 100644
index 00000000..58f6d6d6
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.devname
@@ -0,0 +1 @@
+# Device nodes to trigger on-demand module loading.
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.softdep b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.softdep
new file mode 100644
index 00000000..5554ccca
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.softdep
@@ -0,0 +1 @@
+# Soft dependencies extracted from modules themselves.
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.symbols b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.symbols
new file mode 100644
index 00000000..618c345f
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.symbols
@@ -0,0 +1 @@
+# Aliases for symbols, used by symbol_request().
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.symbols.bin b/testsuite/rootfs-pristine/test-modinfo/fallback/run/modules/4.4.4/modules.symbols.bin
new file mode 100644
index 0000000000000000000000000000000000000000..7075435f6268c4d815aec093d61e26647666ba76
GIT binary patch
literal 12
TcmdnM{w17&iGh)Ufq@4A6;A>Z

literal 0
HcmV?d00001

diff --git a/testsuite/test-modinfo.c b/testsuite/test-modinfo.c
index a8e8e552..d1c3f59e 100644
--- a/testsuite/test-modinfo.c
+++ b/testsuite/test-modinfo.c
@@ -124,4 +124,28 @@ DEFINE_TEST(test_modinfo_builtin,
 		.out = TESTSUITE_ROOTFS "test-modinfo/correct-builtin.txt",
 	})
 
+static noreturn int test_modinfo_fallback(const struct test *t)
+{
+	const char *const args[] = {
+		// clang-format off
+		progname,
+		"-F", "filename",
+		"mod-simple",
+		NULL,
+		// clang-format on
+	};
+	test_spawn_prog(progname, args);
+	exit(EXIT_FAILURE);
+}
+DEFINE_TEST(test_modinfo_fallback,
+	.description = "check if modinfo finds external module",
+	.config = {
+		[TC_ROOTFS] = TESTSUITE_ROOTFS "test-modinfo/fallback",
+		[TC_UNAME_R] = "4.4.4",
+	},
+	.output = {
+		.out = TESTSUITE_ROOTFS "test-modinfo/correct-fallback.txt",
+	})
+
+
 TESTSUITE_MAIN();

From 6bf065de9f1a5d24fa4aae34958646fa178dfa79 Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Tue, 22 Oct 2024 15:14:39 +0200
Subject: [PATCH 8/8] testsuite: add modinfo fallback custom ver test

Check whether modinfo --set-version is able to find modules in
/run/modules/<custom-ver> when /lib/modules/<custom-ver> is missing.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 scripts/setup-rootfs.sh                       |   1 +
 .../test-modinfo/correct-fallback-custom.txt  |   1 +
 .../test-modinfo/fallback-custom/proc/modules |   0
 .../run/modules/3.3.3/modules.alias           |   1 +
 .../run/modules/3.3.3/modules.alias.bin       | Bin 0 -> 12 bytes
 .../run/modules/3.3.3/modules.builtin.bin     |   0
 .../run/modules/3.3.3/modules.dep             |   1 +
 .../run/modules/3.3.3/modules.dep.bin         | Bin 0 -> 58 bytes
 .../run/modules/3.3.3/modules.devname         |   1 +
 .../run/modules/3.3.3/modules.softdep         |   1 +
 .../run/modules/3.3.3/modules.symbols         |   1 +
 .../run/modules/3.3.3/modules.symbols.bin     | Bin 0 -> 12 bytes
 testsuite/test-modinfo.c                      |  25 ++++++++++++++++++
 13 files changed, 32 insertions(+)
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/correct-fallback-custom.txt
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback-custom/proc/modules
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.alias
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.alias.bin
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.builtin.bin
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.dep
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.dep.bin
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.devname
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.softdep
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.symbols
 create mode 100644 testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.symbols.bin

diff --git a/scripts/setup-rootfs.sh b/scripts/setup-rootfs.sh
index 587f83c1..f6b47fc7 100755
--- a/scripts/setup-rootfs.sh
+++ b/scripts/setup-rootfs.sh
@@ -115,6 +115,7 @@ map=(
     ["test-modinfo/mod-simple-pkcs7.ko"]="mod-simple.ko"
     ["test-modinfo/external/lib/modules/external/mod-simple.ko"]="mod-simple.ko"
     ["test-modinfo/fallback$MODULE_FALLBACK_DIRECTORY/4.4.4/kernel/"]="mod-simple.ko"
+    ["test-modinfo/fallback-custom$MODULE_FALLBACK_DIRECTORY/3.3.3/kernel/"]="mod-simple.ko"
     ["test-weakdep$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-a.ko"]="mod-loop-a.ko"
     ["test-weakdep$MODULE_DIRECTORY/4.4.4/kernel/mod-loop-b.ko"]="mod-loop-b.ko"
     ["test-weakdep$MODULE_DIRECTORY/4.4.4/kernel/mod-simple.ko"]="mod-simple.ko"
diff --git a/testsuite/rootfs-pristine/test-modinfo/correct-fallback-custom.txt b/testsuite/rootfs-pristine/test-modinfo/correct-fallback-custom.txt
new file mode 100644
index 00000000..92d85ff0
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/correct-fallback-custom.txt
@@ -0,0 +1 @@
+/run/modules/3.3.3/kernel/mod-simple.ko
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback-custom/proc/modules b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/proc/modules
new file mode 100644
index 00000000..e69de29b
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.alias b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.alias
new file mode 100644
index 00000000..ba76e181
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.alias
@@ -0,0 +1 @@
+# Aliases extracted from modules themselves.
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.alias.bin b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.alias.bin
new file mode 100644
index 0000000000000000000000000000000000000000..7075435f6268c4d815aec093d61e26647666ba76
GIT binary patch
literal 12
TcmdnM{w17&iGh)Ufq@4A6;A>Z

literal 0
HcmV?d00001

diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.builtin.bin b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.builtin.bin
new file mode 100644
index 00000000..e69de29b
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.dep b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.dep
new file mode 100644
index 00000000..54766537
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.dep
@@ -0,0 +1 @@
+kernel/mod-simple.ko:
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.dep.bin b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.dep.bin
new file mode 100644
index 0000000000000000000000000000000000000000..b09a85432309c43f99500d6cc3473bcb1ef0a80e
GIT binary patch
literal 58
zcmdnM{w17&iGfjpfx#p{CB8T_w;(5#0SFjDM0RRXUTThhZhnd`L`E+=--;nO_W%O}
F4*<8l52gSB

literal 0
HcmV?d00001

diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.devname b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.devname
new file mode 100644
index 00000000..58f6d6d6
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.devname
@@ -0,0 +1 @@
+# Device nodes to trigger on-demand module loading.
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.softdep b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.softdep
new file mode 100644
index 00000000..5554ccca
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.softdep
@@ -0,0 +1 @@
+# Soft dependencies extracted from modules themselves.
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.symbols b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.symbols
new file mode 100644
index 00000000..618c345f
--- /dev/null
+++ b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.symbols
@@ -0,0 +1 @@
+# Aliases for symbols, used by symbol_request().
diff --git a/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.symbols.bin b/testsuite/rootfs-pristine/test-modinfo/fallback-custom/run/modules/3.3.3/modules.symbols.bin
new file mode 100644
index 0000000000000000000000000000000000000000..7075435f6268c4d815aec093d61e26647666ba76
GIT binary patch
literal 12
TcmdnM{w17&iGh)Ufq@4A6;A>Z

literal 0
HcmV?d00001

diff --git a/testsuite/test-modinfo.c b/testsuite/test-modinfo.c
index d1c3f59e..f4c5b4b4 100644
--- a/testsuite/test-modinfo.c
+++ b/testsuite/test-modinfo.c
@@ -147,5 +147,30 @@ DEFINE_TEST(test_modinfo_fallback,
 		.out = TESTSUITE_ROOTFS "test-modinfo/correct-fallback.txt",
 	})
 
+static noreturn int test_modinfo_fallback_custom(const struct test *t)
+{
+	const char *const args[] = {
+		// clang-format off
+		progname,
+		"-F", "filename",
+		"--set-version",
+		"3.3.3",
+		"mod-simple",
+		NULL,
+		// clang-format on
+	};
+	test_spawn_prog(progname, args);
+	exit(EXIT_FAILURE);
+}
+DEFINE_TEST(test_modinfo_fallback_custom,
+	.description = "check if modinfo finds external module",
+	.config = {
+		[TC_ROOTFS] = TESTSUITE_ROOTFS "test-modinfo/fallback-custom",
+		[TC_UNAME_R] = "4.4.4",
+	},
+	.output = {
+		.out = TESTSUITE_ROOTFS "test-modinfo/correct-fallback-custom.txt",
+	})
+
 
 TESTSUITE_MAIN();