Re: [PATCH] module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree

From: Rusty Russell
Date: Tue Oct 25 2011 - 00:23:10 EST


On Mon, 24 Oct 2011 07:57:03 -0700, Randy Dunlap <rdunlap@xxxxxxxxxxxx> wrote:
> On 10/24/11 06:12, Ben Hutchings wrote:
> > Use of the GPL or a compatible licence doesn't necessarily make the code
> > any good. We already consider staging modules to be suspect, and this
> > should also be true for out-of-tree modules which may receive very
> > little review.
> >
> > Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
> > ---
> > Debian has been carrying this for the last few kernel versions. The
> > recent thread '[RFC] virtualbox tainting.' and discussions at KS suggest
> > that this might be more generally useful.
> >
> > Ben.
> >
> > include/linux/kernel.h | 1 +
> > kernel/module.c | 5 +++++
> > kernel/panic.c | 2 ++
> > scripts/mod/modpost.c | 7 +++++++
> > 4 files changed, 15 insertions(+), 0 deletions(-)
>
> Hi,
>
> Please add 'O' to Documentation/oops-tracing.txt.

I did that, and applied the patch. See below.

Thanks,
Rusty.

From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Subject: module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree
Date: Mon, 24 Oct 2011 15:12:28 +0200

Use of the GPL or a compatible licence doesn't necessarily make the code
any good. We already consider staging modules to be suspect, and this
should also be true for out-of-tree modules which may receive very
little review.

Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Reviewed-by: Dave Jones <davej@xxxxxxxxxx>
Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx> (patched oops-tracing.txt)
---
Documentation/oops-tracing.txt | 2 ++
include/linux/kernel.h | 1 +
kernel/module.c | 5 +++++
kernel/panic.c | 2 ++
scripts/mod/modpost.c | 7 +++++++
5 files changed, 17 insertions(+)

diff --git a/Documentation/oops-tracing.txt b/Documentation/oops-tracing.txt
--- a/Documentation/oops-tracing.txt
+++ b/Documentation/oops-tracing.txt
@@ -263,6 +263,8 @@ characters, each representing a particul
12: 'I' if the kernel is working around a severe bug in the platform
firmware (BIOS or similar).

+ 13: 'O' if an externally-built ("out-of-tree") module has been loaded.
+
The primary reason for the 'Tainted: ' string is to tell kernel
debuggers if this is a clean kernel or if anything unusual has
occurred. Tainting is permanent: even if an offending module is
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -369,6 +369,7 @@ extern enum system_states {
#define TAINT_WARN 9
#define TAINT_CRAP 10
#define TAINT_FIRMWARE_WORKAROUND 11
+#define TAINT_OOT_MODULE 12

extern const char hex_asc[];
#define hex_asc_lo(x) hex_asc[((x) & 0x0f)]
diff --git a/kernel/module.c b/kernel/module.c
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2487,6 +2487,9 @@ static int check_modinfo(struct module *
return -ENOEXEC;
}

+ if (!get_modinfo(info, "intree"))
+ add_taint_module(mod, TAINT_OOT_MODULE);
+
if (get_modinfo(info, "staging")) {
add_taint_module(mod, TAINT_CRAP);
printk(KERN_WARNING "%s: module is from the staging directory,"
@@ -3257,6 +3260,8 @@ static char *module_flags(struct module
buf[bx++] = '(';
if (mod->taints & (1 << TAINT_PROPRIETARY_MODULE))
buf[bx++] = 'P';
+ else if (mod->taints & (1 << TAINT_OOT_MODULE))
+ buf[bx++] = 'O';
if (mod->taints & (1 << TAINT_FORCED_MODULE))
buf[bx++] = 'F';
if (mod->taints & (1 << TAINT_CRAP))
diff --git a/kernel/panic.c b/kernel/panic.c
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -177,6 +177,7 @@ static const struct tnt tnts[] = {
{ TAINT_WARN, 'W', ' ' },
{ TAINT_CRAP, 'C', ' ' },
{ TAINT_FIRMWARE_WORKAROUND, 'I', ' ' },
+ { TAINT_OOT_MODULE, 'O', ' ' },
};

/**
@@ -194,6 +195,7 @@ static const struct tnt tnts[] = {
* 'W' - Taint on warning.
* 'C' - modules from drivers/staging are loaded.
* 'I' - Working around severe firmware bug.
+ * 'O' - Out-of-tree module has been loaded.
*
* The string is overwritten by the next call to print_tainted().
*/
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1849,6 +1849,12 @@ static void add_header(struct buffer *b,
buf_printf(b, "};\n");
}

+static void add_intree_flag(struct buffer *b, int is_intree)
+{
+ if (is_intree)
+ buf_printf(b, "\nMODULE_INFO(intree, \"Y\");\n");
+}
+
static void add_staging_flag(struct buffer *b, const char *name)
{
static const char *staging_dir = "drivers/staging";
@@ -2169,6 +2175,7 @@ int main(int argc, char **argv)
buf.pos = 0;

add_header(&buf, mod);
+ add_intree_flag(&buf, !external_module);
add_staging_flag(&buf, mod->name);
err |= add_versions(&buf, mod);
add_depends(&buf, mod, modules);
--
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