From da2ca406f45a6e21760243152ed8d2e8e72915c2 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Sat, 8 Aug 2026 10:47:55 -0400 Subject: [PATCH] wifi: mac80211: avoid WARN in set_bitrate_mask when sdata not in driver ieee80211_set_bitrate_mask() checks if the interface is running via ieee80211_sdata_running(), but it does not check if the interface is still present in the driver. When sdata is running but IEEE80211_SDATA_IN_DRIVER is not set, the call reaches drv_set_bitrate_mask() in driver-ops.h which hits wlan1: Failed check-sdata-in-driver check, flags: 0x0 WARNING: net/mac80211/driver-ops.h:884 at drv_set_bitrate_mask Syzkaller triggers this via wext SIOCSIWRATE ioctl. The Call Trace shows wext_ioctl_dispatch() in wext-core.c dispatching the ioctl, calling ioctl_standard_call() for SIOCSIWRATE, which calls cfg80211_wext_siwrate() in wext-compat.c. That builds a bitrate mask and calls rdev_set_bitrate_mask() which ends up in ieee80211_set_bitrate_mask() in cfg.c. The interface is marked running via SDATA_STATE_RUNNING but flags is 0, so check_sdata_in_driver() fails. When the interface is being torn down, or when wext ioctl is issued during interface bringup before drv_add_interface() sets IN_DRIVER, the running check passes while IN_DRIVER is clear. Check IEEE80211_SDATA_IN_DRIVER in ieee80211_set_bitrate_mask() before calling the driver, returning -ENETDOWN. This avoids the WARN_ONCE in driver-ops.h and matches other cfg.c operations that bail early when not in driver. This change should be safe because wiphy mutex is held in cfg80211_wext_siwrate() via guard(wiphy), and IN_DRIVER is set/cleared under RTNL and wiphy paths in drv_add_interface() and drv_remove_interface() in driver-ops.c, so the check is race-free against driver add/remove. Returning -ENETDOWN is the same error other not-running paths use and does not introduce new locking. Reported-by: syzbot+af177aa139efdd13a9da@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=af177aa139efdd13a9da Link: https://lore.kernel.org/all/6a75205c.59b6c763.2bba34.00c3.GAE@google.com/ Fixes: 554a43d5e77e ("mac80211: check sdata_running on ieee80211_set_bitrate_mask") Cc: stable@vger.kernel.org Assisted-by: Hermes:muse-spark-1.2 syzkaller Signed-off-by: Rik van Riel Link: https://patch.msgid.link/20260808104755.319c686e@fangorn Reported-by: syzbot+dcaca020ca8377e7ced0@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=dcaca020ca8377e7ced0 [also add second syzbot report] Signed-off-by: Johannes Berg --- net/mac80211/cfg.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index 23f4f9ec86d0..1f074799f85f 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -4113,6 +4113,9 @@ static int ieee80211_set_bitrate_mask(struct wiphy *wiphy, if (!ieee80211_sdata_running(sdata)) return -ENETDOWN; + if (!(sdata->flags & IEEE80211_SDATA_IN_DRIVER)) + return -ENETDOWN; + /* * If active validate the setting and reject it if it doesn't leave * at least one basic rate usable, since we really have to be able