diff options
| author | Johannes Berg <johannes.berg@intel.com> | 2026-09-04 16:57:12 +0200 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2026-09-09 14:51:28 +0200 |
| commit | 3f28551d0241254a75626d868041c6340285088b (patch) | |
| tree | a9db215ad13bad1bc9a9e8d3bda54515be88604a /net/mac80211 | |
| parent | ac7472a24bd433b81c06582835dd1d5547c10da9 (diff) | |
wifi: mac80211: reset state when starting AP fails
ieee80211_start_ap() can set enable_beacon (and beacon_int) and fail
later, leaving it set forever. Scanning can then attempt to restore
beaconing on such an interface, leading to:
Oops: divide error: 0000 [#1] SMP KASAN NOPTI
RIP: 0010:mac80211_hwsim_link_info_changed+0xca7/0xf00
Call Trace:
drv_link_info_changed+0x413/0x860 net/mac80211/driver-ops.c:495
ieee80211_link_info_change_notify+0x24b/0x3c0 net/mac80211/main.c:427
ieee80211_offchannel_return+0x381/0x580 net/mac80211/offchannel.c:160
__ieee80211_scan_completed+0x993/0xe30 net/mac80211/scan.c:519
ieee80211_scan_work+0x472/0x2010 net/mac80211/scan.c:1193
cfg80211_wiphy_work+0x2b7/0x550 net/wireless/core.c:538
in hwsim. Also, cfg80211 then allows changing the interface type,
and the off-channel path getgs confused about beaconing as well,
leading to another warning:
WARNING: net/mac80211/driver-ops.c:468 at drv_link_info_changed+0x583/0x880
ieee80211_link_info_change_notify+0x24b/0x3c0 net/mac80211/main.c:427
ieee80211_offchannel_stop_vifs+0x328/0x5c0 net/mac80211/offchannel.c:122
ieee80211_start_sw_scan net/mac80211/scan.c:583 [inline]
__ieee80211_start_scan+0xfb6/0x1af0 net/mac80211/scan.c:882
Reset the state on failures to always have it correct.
Assisted-by: LLM
Fixes: d6a83228823f ("mac80211: track enable_beacon explicitly")
Reported-by: syzbot+ca7a2759caaa6cd4e3db@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=ca7a2759caaa6cd4e3db
Reported-by: syzbot+c4686c3eb8b64032618f@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c4686c3eb8b64032618f
Link: https://patch.msgid.link/20260904165722.9629429a5221.I7f599412bfe12a09d41ea4901be9ad165d07d133@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211')
| -rw-r--r-- | net/mac80211/cfg.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index 2b13c057312e..2d5a0abe35db 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -1929,6 +1929,9 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev, return 0; error: + link_conf->enable_beacon = false; + link_conf->beacon_int = prev_beacon_int; + sdata->vif.cfg.ssid_len = 0; ieee80211_link_release_channel(link); return err; |