Currently, during link deletion, the link ID is first removed from the
valid_links bitmap before performing any clean-up operations. However, some
functions require the link ID to remain in the valid_links bitmap. One
such example is cfg80211_cac_event(). The flow is -
nl80211_remove_link()
cfg80211_remove_link()
ieee80211_del_intf_link()
ieee80211_vif_set_links()
ieee80211_vif_update_links()
ieee80211_link_stop()
cfg80211_cac_event()
cfg80211_cac_event() requires link ID to be present but it is cleared
already in cfg80211_remove_link(). Ultimately, WARN_ON() is hit.
Therefore, clear the link ID from the bitmap only after completing the link
clean-up.
Signed-off-by: Aditya Kumar Singh <quic_adisi@xxxxxxxxxxx>
---
Changes in v2:
- Handled link ID removal properly instead of removing the WARN_ON()
- Renamed subject accordingly.
- Link to v1: https://lore.kernel.org/r/20241113-mlo_dfs_fix-v1-1-e4326736347b@xxxxxxxxxxx
---
net/mac80211/cfg.c | 8 +++++++-
net/wireless/util.c | 3 +--
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 61a824ec33da356a9d2c4c99a5507b340bbf909e..53dc76bde158b8ada4a504c793246b856c52c83a 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -5046,10 +5046,16 @@ static void ieee80211_del_intf_link(struct wiphy *wiphy,
unsigned int link_id)
{
struct ieee80211_sub_if_data *sdata = IEEE80211_WDEV_TO_SUB_IF(wdev);
+ u16 new_links = wdev->valid_links & ~BIT(link_id);
lockdep_assert_wiphy(sdata->local->hw.wiphy);
- ieee80211_vif_set_links(sdata, wdev->valid_links, 0);
+ /* During the link teardown process, certain functions require the
+ * link_id to remain in the valid_links bitmap. Therefore, instead
+ * of removing the link_id from the bitmap, pass a masked value to
+ * simulate as if link_id does not exist anymore.
+ */
+ ieee80211_vif_set_links(sdata, new_links, 0);
}
static int
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 040d62051eb96ea52ba301f0767d2e4e4ba51e0b..65c8e47246b7c3889e9c2faf0c0b508c426ee513 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -2843,10 +2843,9 @@ void cfg80211_remove_link(struct wireless_dev *wdev, unsigned int link_id)
break;
}
- wdev->valid_links &= ~BIT(link_id);
-
rdev_del_intf_link(rdev, wdev, link_id);
+ wdev->valid_links &= ~BIT(link_id);
eth_zero_addr(wdev->links[link_id].addr);
}
---
base-commit: dfc14664794a4706e0c2186a0c082386e6b14c4d
change-id: 20241113-mlo_dfs_fix-1123060109bc
