From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 0996A3B3BE1; Wed, 30 Sep 2026 18:12:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791932; cv=none; b=KPvYrt1Nix+jv1m8VDIZHZwEoA/d/2l1S3j8gYQQcE75Q5BQCfYT+iaU51XaN3CbWfF5Fs9IRXjjpH3Y0Pp+PbpOFOBADuOVcGpsFvTKsbWLtuIWuFj66xXjXRpO+1sEdyn6SDOA53YC/heKi92+HfMbmL5WUywvP/qed/2oAjU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791932; c=relaxed/simple; bh=uG87h6TUY5RcyjsgG3EUfh4a3xKkjm/EHNumsjgUXdg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Yo6suWWeeegXTihpCo3FWl6z0zHdSESijwntdAJFkjug/idHSUyBPN8F0xq0MWcjAU240iNSXbVF/OXENRaAHiyNFFGBdl1zyGijCIwu+5Y1R7H6h/rW73i4zERFltkiowtrV9QGiz/bwXk+jT/zrHcTx+33ZE1rBtnnlX4BTkE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hXWK2yG2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hXWK2yG2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 648911F000FF; Wed, 30 Sep 2026 18:12:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790791930; bh=fVF+i+KAxwKeYeja4YLtKDwXMqcwNlq/JPKs1oK583o=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hXWK2yG2YQY/YCe7rTdjUBTBJsjFZ/mWiCQbC685bM5JeMNQsvJR+AQiTrTtXt/P4 jF4XSpLgLV9vRNEZviuwBpPW82HTQhMWB1SrfW85AhSN6VySIZXMOQCOLaCCwZiTkB habOkOiJhi4C7ia2sdazmpcaGDAigsoz6V6bNQOs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+b59873f5699e941717ca@syzkaller.appspotmail.com, Johannes Berg , Sasha Levin Subject: [PATCH 5.15 477/752] wifi: mac80211: dont RCU-dereference the mesh CSA settings we just set Date: Wed, 30 Sep 2026 17:25:47 +0200 Message-ID: <20260930152408.594193604@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@linuxfoundation.org> User-Agent: quilt/0.69 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 b481e64e4498e2c053d5954f546ee02338f6ab63 ] In the error path of ieee80211_mesh_csa_beacon() the settings that were just assigned are read back with rcu_dereference(), which lockdep then complains about. There's no need to read the pointer at all, tmp_csa_settings still is the right value anyway. Assisted-by: LLM Fixes: b8456a14e9d2 ("{nl,cfg,mac}80211: implement mesh channel switch userspace API") Reported-by: syzbot+b59873f5699e941717ca@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b59873f5699e941717ca Link: https://patch.msgid.link/20260908122838.201719-17-johannes@sipsolutions.net Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/mac80211/mesh.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c index 167b0625b1a17..b6f2bb6c49663 100644 --- a/net/mac80211/mesh.c +++ b/net/mac80211/mesh.c @@ -1419,7 +1419,6 @@ int ieee80211_mesh_csa_beacon(struct ieee80211_sub_if_data *sdata, ret = ieee80211_mesh_rebuild_beacon(sdata); if (ret) { - tmp_csa_settings = rcu_dereference(ifmsh->csa); RCU_INIT_POINTER(ifmsh->csa, NULL); kfree_rcu(tmp_csa_settings, rcu_head); return ret; -- 2.53.0