[Greg cc'd]
Peter Osterlund wrote:
> On Mon, 5 Nov 2007, Jens Axboe wrote:
>
>> Hi Peter,
>>
>> You don't seem to have a bugzilla account, so could not reassign to you.
>> See http://bugzilla.kernel.org/show_bug.cgi?id=9294
>
> Problem is repeatable on my computer. It dies in __module_get() on this
> line:
>
> BUG_ON(module_refcount(module) == 0);
>
> I think this is because commit 7b595756ec1f49e0049a9e01a1298d53a7faaa15,
> which states: "Note that with this change, userland holding a sysfs node
> does not prevent the backing module from being unloaded."
>
> Unfortunately, I don't know how this sysfs stuff is supposed to work,
> and therefore don't know how to fix the problem.
Does this fix the problem?
--
tejun
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index a8130a4..a5ee213 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -358,10 +358,19 @@ static ssize_t class_pktcdvd_store_add(struct class *c,
const char *buf,
size_t count)
{
unsigned int major, minor;
+
if (sscanf(buf, "%u:%u", &major, &minor) == 2) {
+ /* pkt_setup_dev() expects caller to hold reference to self */
+ if (!try_module_get(THIS_MODULE))
+ return -ENODEV;
+
pkt_setup_dev(MKDEV(major, minor), NULL);
+
+ module_put(THIS_MODULE);
+
return count;
}
+
return -EINVAL;
}
