[1/2] wiphy: prevent multiple wiphy registrations

Commit Message

James Prestwood Jan. 17, 2023, 6:03 p.m. UTC

With really badly timed events a wiphy can be registered twice. This
happens when IWD starts and requests a wiphy dump. Immediately after
a NEW_WIPHY event comes in (presumably when the driver loads) which
starts another dump. The NEW_WIPHY event can't simply be ignored
since it could be a hotplug (e.g. USB card) so to fix this we can
instead just prevent it from being registered.

This does mean both dumps will happen but the information will just
be added to the same wiphy object.
---
 src/wiphy.c | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Denis Kenzior Jan. 17, 2023, 7:12 p.m. UTC | #1

Hi James,

On 1/17/23 12:03, James Prestwood wrote:
> With really badly timed events a wiphy can be registered twice. This
> happens when IWD starts and requests a wiphy dump. Immediately after
> a NEW_WIPHY event comes in (presumably when the driver loads) which
> starts another dump. The NEW_WIPHY event can't simply be ignored
> since it could be a hotplug (e.g. USB card) so to fix this we can
> instead just prevent it from being registered.
> 
> This does mean both dumps will happen but the information will just
> be added to the same wiphy object.
> ---
>   src/wiphy.c | 9 +++++++++
>   1 file changed, 9 insertions(+)

Both applied, thanks.

Regards,
-Denis

Patch

diff --git a/src/wiphy.c b/src/wiphy.c
index 9ca651f4..fcdc3ab8 100644
--- a/src/wiphy.c
+++ b/src/wiphy.c
@@ -2324,6 +2324,15 @@  static void wiphy_get_reg_domain(struct wiphy *wiphy)
 
 void wiphy_create_complete(struct wiphy *wiphy)
 {
+	/*
+	 * With really bad timing two wiphy dumps can occur (initial and a
+	 * NEW_WIPHY event) and actually register twice. Ignoring/preventing the
+	 * second dump is problematic since it _could_ be a legitimate event so
+	 * instead just prevent it from registering twice.
+	 */
+	if (wiphy->registered)
+		return;
+
 	wiphy_register(wiphy);
 
 	if (l_memeqzero(wiphy->permanent_addr, 6)) {