Christopher Friedt (1):
Corrected missing binary module dependency of hwa-hc on hwa-rc and
consistent probe failure of hwa-hc. The problem: hwa-rc did not
export any symbols, but hwa-hc depended on it. Hwa-hc gets its
uwb_rc through private driver data. If hwa-rc is not loaded prior
to hwa-hc, then that private driver data is NULL. The problem is
fixed manually by loading hwa-rc and then hwa-hc. However, due to
the missing binary module dependency (i.e. "Used by" field in
lsmod), one can rmove the hwa-rc module while the hwa-hc module is
loaded, leaving any pointers to the uwb_rc struct invalid. This
patch is obviously mainly for illustrative purposes, but it does
actually fix both of the aforementioned problems.
drivers/usb/host/hwa-hc.c | 4 ++++
drivers/uwb/hwa-rc.c | 5 +++++
2 files changed, 9 insertions(+), 0 deletions(-)
>From 9c29727e25a7952caf906665ae31a542ced86405 Mon Sep 17 00:00:00 2001
From: Christopher Friedt <chrisfriedt@xxxxxxxxx>
Date: Wed, 25 Aug 2010 13:34:47 +0200
Subject: [PATCH] Corrected missing binary module dependency of hwa-hc on hwa-rc and consistent probe failure of hwa-hc. The problem: hwa-rc did not export any symbols, but hwa-hc depended on it. Hwa-hc gets its uwb_rc through private driver data. If hwa-rc is not loaded prior to hwa-hc, then that private driver data is NULL. The problem is fixed manually by loading hwa-rc and then hwa-hc. However, due to the missing binary module dependency (i.e. "Used by" field in lsmod), one can rmove the hwa-rc module while the hwa-hc module is loaded, leaving any pointers to the uwb_rc struct invalid. This patch is obviously mainly for illustrative purposes, but it does actually fix both of the aforementioned problems.
Cc: chrisfriedt@xxxxxxxxx
Signed-off-by: Christopher Friedt <chrisfriedt@xxxxxxxxx>
---
drivers/usb/host/hwa-hc.c | 4 ++++
drivers/uwb/hwa-rc.c | 5 +++++
2 files changed, 9 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/host/hwa-hc.c b/drivers/usb/host/hwa-hc.c
index 9bfac65..2d61e4d 100644
--- a/drivers/usb/host/hwa-hc.c
+++ b/drivers/usb/host/hwa-hc.c
@@ -837,8 +837,12 @@ static struct usb_driver hwahc_driver = {
.id_table = hwahc_id_table,
};
+/* required to ensure that hwa-rc loads before hwa-hc */
+extern hwarc_dummy_func(void);
+
static int __init hwahc_driver_init(void)
{
+ hwarc_dummy_func();
return usb_register(&hwahc_driver);
}
module_init(hwahc_driver_init);
diff --git a/drivers/uwb/hwa-rc.c b/drivers/uwb/hwa-rc.c
index 2babcd4..43777f0 100644
--- a/drivers/uwb/hwa-rc.c
+++ b/drivers/uwb/hwa-rc.c
@@ -914,6 +914,11 @@ static struct usb_driver hwarc_driver = {
.post_reset = hwarc_post_reset,
};
+/* required to ensure that hwa-rc loads before hwa-hc */
+void hwarc_dummy_func(void) {
+}
+EXPORT_SYMBOL_GPL(hwarc_dummy_func);
+
static int __init hwarc_driver_init(void)
{
return usb_register(&hwarc_driver);
--
1.7.0.4
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