From: 傅继晗 Date: Wed, 3 Jun 2026 19:28:54 +0000 (-0700) Subject: wifi: mac80211: fix monitor mode frame capture for real chanctx drivers X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=d832f6b83d48b27b98ffeda973d83c0d0409fccf;p=thirdparty%2Flinux.git wifi: mac80211: fix monitor mode frame capture for real chanctx drivers Commit d594cc6f2c58 ("wifi: mac80211: restore non-chanctx injection behaviour") restored the monitor injection fallback for drivers using chanctx emulation but explicitly deferred drivers that transitioned to real chanctx ops. mt76 falls in that category and still drops every injected frame when monitor coexists with another interface. When the monitor has no chanctx of its own, fall back to the only chanctx in flight if there is exactly one. Refuse if multiple are present: picking arbitrarily would inject on an unrelated channel. Emulated and real chanctx drivers both flow through this fallback, since emulation always presents zero or one chanctx in local->chanctx_list. Reran the airgeddon evil-twin flow (hostapd AP + coexisting monitor VIF on the same phy + aireplay-ng deauth from the monitor) on mt7921e PCIe and mt7921u USB across 2.4 GHz and 5 GHz, and on a Kali VM with MT7921U passthrough as the closest match to the original reporter's setup. None reproduced the hang seen against the earlier attempt at this fix (<20251216111909.25076-2-johannes@sipsolutions.net>) or against v1 on lore in March. Cc: # causes some older drivers to crash Reported-by: Oscar Alfonso Diaz Closes: https://github.com/morrownr/USB-WiFi/issues/682 Tested-by: Devin Wittmayer Fixes: 0a44dfc07074 ("wifi: mac80211: simplify non-chanctx drivers") Signed-off-by: 傅继晗 Signed-off-by: Devin Wittmayer Link: https://patch.msgid.link/5c2760bd9bc34616bf7892848872522254dd1ce5.1780513445.git.lucid_duck@justthetip.ca Signed-off-by: Johannes Berg --- diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 933c86ca21c3..cf336e92c072 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -2407,10 +2407,20 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb, rcu_dereference(tmp_sdata->vif.bss_conf.chanctx_conf); } + if (!chanctx_conf) { + struct ieee80211_chanctx *ctx; + bool first = true; + + list_for_each_entry_rcu(ctx, &local->chanctx_list, list) { + if (!first) + goto fail_rcu; + chanctx_conf = &ctx->conf; + first = false; + } + } + if (chanctx_conf) chandef = &chanctx_conf->def; - else if (local->emulate_chanctx) - chandef = &local->hw.conf.chandef; else goto fail_rcu;