From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f42.google.com (mail-wm1-f42.google.com [209.85.128.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9F1873E1209 for ; Thu, 9 Jul 2026 22:19:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783635546; cv=none; b=kxf9hYNLe9SanuEVHommLbsHZNFLfz9sLt0mZk4n8r914qmBuZdZqjpTmKSSczQnlRU1tIqf9gzIGeVJbRVamLr6oVFlChJexuIMHr2vSx4PMPYXAaGvspjQJtZUU2giM4rKalrkNN5A1r5jBJSep6YcG9WE7F/49HsAUGU9EFM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783635546; c=relaxed/simple; bh=Z8Zh1AJp/esp9tFm2eyTQefg9Fl7D1o7AgqFROZ1ab8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=dj0G5BZcvlJznzAx5Z5xKAdeRziSV7kS6uEH2W/hjyIOLXAF5FbgWGPttRrwjMxDwLCT69AXrgEPt1k2XJ7h0dUrSEu0PKy2gVbBoqL4DaM3rM9drkrFBZp71LwGdfDeRma+JmwDAWG0Y6XBVL8R36yIEdcJlgCCKK0HedbUbSs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=cc1B51YO; arc=none smtp.client-ip=209.85.128.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="cc1B51YO" Received: by mail-wm1-f42.google.com with SMTP id 5b1f17b1804b1-493b1710405so1197365e9.2 for ; Thu, 09 Jul 2026 15:19:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1783635543; x=1784240343; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=BqQgw4jCCe/BvKpqMgYyZ70b1id8WmzXWyq/OSrYdlk=; b=cc1B51YOtA/6A1kmzmBig9+12v9yAztZhxpH3H685lT903ZqlkL2wm+Z+wm8vttkNz lKgMwnobY/phweGr4fHRs3TCP7u/azwuLQKW9j6RVCIAdpb/B+4KCLFGi7eYUWwyheeZ kCJvPXXEXeKY1dNFWGsgriCdwpRga/x143RZZyYpSE8TtbNnTHsfir8emVgSpy0itoRj rTUOM3248rbSnl1CdISiqEGI5QPVkI6886LwIDY6pBeBfmelDt3wl/g7Hn8gAITPi8E5 Evy5a50r9+WdNzdetE6fAp/LgF08xbgfvu/RL+uaZOXXc1GKv4CP53bNqr+psE/IvXDZ JsHw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783635543; x=1784240343; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=BqQgw4jCCe/BvKpqMgYyZ70b1id8WmzXWyq/OSrYdlk=; b=J6+vVW/QuAfbN3yNvzZJ7sqhhP+wBQZrnV42OOQ6/ZtHdXgqsYjqgKiFtVEF/6SABI O9JB3FOYrG/0B/zy9b4vQiyr8IqpT/BAvft5JVrhESjiAQw61/o/uAwRib2aJZNkT0X7 gXk/Q1sFvhCYNsnZ8sxCYFF7AU0KA4rESm8n5U7NFNF8vd/eAKknpks3NajV8mn09pJs Uck3vl9eX7d4TKZYeBMU8STc3mash1Kn37f80aNv49ufDdosZ4qtSb1kvav9oEroq74j S0+4AuG+NBegoSYqphZjhStUYMIlInQPccmRqY+/A2RpQqUQVK2hwPK7+Y/lFOSEVbzz apIA== X-Forwarded-Encrypted: i=1; AHgh+RrTYR10rAAwKd3SrkP7kfwz05FLVDEVMfhtQj9zJJf+2yVRI2tOU7Wg3Xm0QvtMBQYRNTyO7WA=@vger.kernel.org X-Gm-Message-State: AOJu0YxgEKsEv8XD4uAUC8fg+n8ziQeu40+4iVwYxXUeyrJf2BrYCgwX 6olpe+JP3zVmW0VkcViK5hhrZXWF7/rQ0zZgzc3V95OD83OR4U3s350s X-Gm-Gg: AfdE7cl4liIq1T7SmcJV50nAERy8jbUFoj4OFpJfbJ+fws4zbPwk5V0dZ4FopT+1cgp DIuHWgzUz8783aLExofFnB9pp9Swavtm8yDHiaSvQkMcFPlOqZ4nJA1+hXXP22cZ9xe5E/+PSHE GmNrIAiiVliZ1Ng4xitBh05y9c9KcyA0isF0mFX2dXd/wzPLshBYgOf9bO7+T4iQtIX+SAI4lxp Y7GpFGpL4zArBdYQX2eOotTwEc7zk7a1/LZJfGJSfaf0jvc2zIlmy6stp+tEI7/5Iq16WnS1TRX RqanVQS2L0UZjTivTHLGMlvwZwnYbRCm4XNf3K+BCookkqd2/l796QY6+V3FDLn+Npbz4pxFzHb Ah2ztS9JR+wgAzMbPkc0Cbx4nbXL35VY1i75mZdYuHxvIxo0zPhRUVRwlnRum1/SMB/chgV2PJ/ iKVO10lgoCYVw/51EdaK1F+UHSckOeSvPwMv2oJ/8uF1amc+9XiC4Qif6L1OKnlhQFE9xXnNib X-Received: by 2002:a05:600c:6211:b0:493:dcad:84da with SMTP id 5b1f17b1804b1-493e683c3b2mr83501675e9.1.1783635542767; Thu, 09 Jul 2026 15:19:02 -0700 (PDT) Received: from dohko.chello.ie (188-141-5-72.dynamic.upc.ie. [188.141.5.72]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-493eb6e8844sm102269415e9.10.2026.07.09.15.19.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jul 2026 15:19:01 -0700 (PDT) From: David Carlier To: alex.aring@gmail.com Cc: stable@vger.kernel.org, syzbot+60332fd095f8bb2946ad@syzkaller.appspotmail.com, David Carlier , Stefan Schmidt , Miquel Raynal , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-wpan@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] ieee802154: hwsim: serialize pib updates to fix double-free Date: Thu, 9 Jul 2026 23:18:58 +0100 Message-ID: <20260709221858.158063-1-devnexen@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit hwsim_update_pib() does an unserialized read-swap-free of phy->pib: pib_old = rtnl_dereference(phy->pib); ... rcu_assign_pointer(phy->pib, pib); kfree_rcu(pib_old, rcu); It assumes the RTNL is held, but ->set_channel is not always called under it: the mac802154 scan worker changes channels via drv_set_channel() without the RTNL. Such an update can race an RTNL-held one on the same phy; both read the same pib_old and both kfree_rcu() it, double-freeing the object. With SLUB percpu sheaves batching kfree_rcu(), this surfaces as a KASAN invalid-free in rcu_free_sheaf(). struct hwsim_phy has no lock for pib. Add one and make the swap atomic with rcu_replace_pointer() under it, dropping the misleading rtnl_dereference(). Reported-by: syzbot+60332fd095f8bb2946ad@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=60332fd095f8bb2946ad Fixes: f25da51fdc38 ("ieee802154: hwsim: add replacement for fakelb") Signed-off-by: David Carlier Cc: --- drivers/net/ieee802154/mac802154_hwsim.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/net/ieee802154/mac802154_hwsim.c b/drivers/net/ieee802154/mac802154_hwsim.c index 6daa0f198b9f..a9bd1555d2dc 100644 --- a/drivers/net/ieee802154/mac802154_hwsim.c +++ b/drivers/net/ieee802154/mac802154_hwsim.c @@ -72,6 +72,8 @@ struct hwsim_phy { struct ieee802154_hw *hw; u32 idx; + /* Serializes phy->pib_updates. */ + spinlock_t pib_lock; struct hwsim_pib __rcu *pib; bool suspended; @@ -102,8 +104,6 @@ static int hwsim_update_pib(struct ieee802154_hw *hw, u8 page, u8 channel, if (!pib) return -ENOMEM; - pib_old = rtnl_dereference(phy->pib); - pib->page = page; pib->channel = channel; pib->filt.short_addr = filt->short_addr; @@ -112,7 +112,10 @@ static int hwsim_update_pib(struct ieee802154_hw *hw, u8 page, u8 channel, pib->filt.pan_coord = filt->pan_coord; pib->filt_level = filt_level; - rcu_assign_pointer(phy->pib, pib); + spin_lock_bh(&phy->pib_lock); + pib_old = rcu_replace_pointer(phy->pib, pib, + lockdep_is_held(&phy->pib_lock)); + spin_unlock_bh(&phy->pib_lock); kfree_rcu(pib_old, rcu); return 0; } @@ -952,6 +955,7 @@ static int hwsim_add_one(struct genl_info *info, struct device *dev, goto err_pib; } + spin_lock_init(&phy->pib_lock); pib->channel = 13; pib->filt.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST); pib->filt.pan_id = cpu_to_le16(IEEE802154_PANID_BROADCAST); -- 2.53.0