From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 25BBE44C93; Sun, 1 Sep 2024 16:59:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725209957; cv=none; b=lS/lkY0IPIYoFSoCc8mjla/yNB5v1hSMUjbVyZ2PQ8CKJv4roocDs9z1oPL71GFobn7RbclFqmHnL2jTRNO+c8SVkQfqCMUEzUW0qk+xIlYazcNIWanIXDtmzXYBFZi96KJ1Dfg9lbCay0W2Lz3fl2stkTXA74etiQ9YwMwYmsA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725209957; c=relaxed/simple; bh=XQYxFLuai91vNy+43f7keGRDyK+QL8GvTKj4s5jI8oQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BL/uP/APryDdGF/uwQ715xCPcX2vkKZbRT9XP63TANUZ4mfG1LLfRj+vUI32FwkN5t2yDo1i4rCqzn+XA5iZeO49limw0Ykm7J0Dh02tFtdzMZx2+zqCNKlsRLIovqdWTPVMkoyUffokWqw1dF/cADrwF9U3/WzpH3+jyjRNq9Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1qCdU08R; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1qCdU08R" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87B03C4CEC3; Sun, 1 Sep 2024 16:59:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1725209957; bh=XQYxFLuai91vNy+43f7keGRDyK+QL8GvTKj4s5jI8oQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1qCdU08RiXUa14w6loKvSSmvCotvp54nJztSrOnSIfCcNZE8j4vNsAfnqxG8mpGhy fKpcquxmMDX/7vDVfrIDPH1fdfKH0MfTWksPFZqdNd98VVWXCWg7ac8yAOkYNERLQL JWLuOEDKLIo4W93cd5+A6RL7A8O6vhlxeU9Pac34= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Johannes Berg , Sasha Levin Subject: [PATCH 5.15 045/215] wifi: mac80211: fix BA session teardown race Date: Sun, 1 Sep 2024 18:15:57 +0200 Message-ID: <20240901160825.052765002@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240901160823.230213148@linuxfoundation.org> References: <20240901160823.230213148@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johannes Berg [ Upstream commit 05f136220d17839eb7c155f015ace9152f603225 ] As previously reported by Alexander, whose commit 69403bad97aa ("wifi: mac80211: sdata can be NULL during AMPDU start") I'm reverting as part of this commit, there's a race between station destruction and aggregation setup, where the aggregation setup can happen while the station is being removed and queue the work after ieee80211_sta_tear_down_BA_sessions() has already run in __sta_info_destroy_part1(), and thus the worker will run with a now freed station. In his case, this manifested in a NULL sdata pointer, but really there's no guarantee whatsoever. The real issue seems to be that it's possible at all to have a situation where this occurs - we want to stop the BA sessions when doing _part1, but we cannot be sure, and WLAN_STA_BLOCK_BA isn't necessarily effective since we don't know that the setup isn't concurrently running and already got past the check. Simply call ieee80211_sta_tear_down_BA_sessions() again in the second part of station destruction, since at that point really nothing else can hold a reference to the station any more. Also revert the sdata checks since those are just misleading at this point. Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/mac80211/agg-tx.c | 6 +----- net/mac80211/driver-ops.c | 3 --- net/mac80211/sta_info.c | 14 ++++++++++++++ 3 files changed, 15 insertions(+), 8 deletions(-) diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c index a4d3fa14f76b7..1deb3d874a4b9 100644 --- a/net/mac80211/agg-tx.c +++ b/net/mac80211/agg-tx.c @@ -491,7 +491,7 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid) { struct tid_ampdu_tx *tid_tx; struct ieee80211_local *local = sta->local; - struct ieee80211_sub_if_data *sdata; + struct ieee80211_sub_if_data *sdata = sta->sdata; struct ieee80211_ampdu_params params = { .sta = &sta->sta, .action = IEEE80211_AMPDU_TX_START, @@ -521,7 +521,6 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid) */ synchronize_net(); - sdata = sta->sdata; params.ssn = sta->tid_seq[tid] >> 4; ret = drv_ampdu_action(local, sdata, ¶ms); tid_tx->ssn = params.ssn; @@ -535,9 +534,6 @@ void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid) */ set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state); } else if (ret) { - if (!sdata) - return; - ht_dbg(sdata, "BA request denied - HW unavailable for %pM tid %d\n", sta->sta.addr, tid); diff --git a/net/mac80211/driver-ops.c b/net/mac80211/driver-ops.c index 120bd9cdf7dfa..48322e45e7ddb 100644 --- a/net/mac80211/driver-ops.c +++ b/net/mac80211/driver-ops.c @@ -331,9 +331,6 @@ int drv_ampdu_action(struct ieee80211_local *local, might_sleep(); - if (!sdata) - return -EIO; - sdata = get_bss_sdata(sdata); if (!check_sdata_in_driver(sdata)) return -EIO; diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index 6d2b42cb3ad58..d1460b870ed5a 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -1060,6 +1060,20 @@ static void __sta_info_destroy_part2(struct sta_info *sta) * after _part1 and before _part2! */ + /* + * There's a potential race in _part1 where we set WLAN_STA_BLOCK_BA + * but someone might have just gotten past a check, and not yet into + * queuing the work/creating the data/etc. + * + * Do another round of destruction so that the worker is certainly + * canceled before we later free the station. + * + * Since this is after synchronize_rcu()/synchronize_net() we're now + * certain that nobody can actually hold a reference to the STA and + * be calling e.g. ieee80211_start_tx_ba_session(). + */ + ieee80211_sta_tear_down_BA_sessions(sta, AGG_STOP_DESTROY_STA); + might_sleep(); lockdep_assert_held(&local->sta_mtx); -- 2.43.0