From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pz2-f0.google.com (mail-pz2-f0.google.com [74.125.228.0]) (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 E25CF331EB5 for ; Tue, 14 Jul 2026 07:28:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.228.0 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784014088; cv=none; b=BlXKw8ti7nm/GOd/8MKn4hLjhVXcjxvRAr3v+kRPu9r+EFCT9Lv0nbsILW6G5NjhGUJesxdDm6goD5uOUMlaH4A93oSokS7igXWntpvgS7TCshmtM1HUov2M/Fp+bR1e5rwqMHR7oww3nSonyiPnyRURVpLgPSL+5ZTFfF1dK5U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784014088; c=relaxed/simple; bh=VV6RH/yKbbXGqbCZVlFLWMvC2IkSZjVrbZxP+GH89A0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=B5zBfRkY49T2ut2gIpSQmu3Y3wgvvmUMyXfojVnH3Ks0nT8J5FfVlstBGdoWiM7LpGzThoNQXUMi8Pv8mtZqoJaQEiPwephojU+4zO315hyBUm7UNALz7xhzoEg4ggVo1HfjCwQrdywPdbWcRscV6g17PW3cybm7u7kSl1U2bss= 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=MrQKtzVE; arc=none smtp.client-ip=74.125.228.0 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="MrQKtzVE" Received: by mail-pz2-f0.google.com with SMTP id 41be03b00d2f7-c96739a46acso2409540a12.1 for ; Tue, 14 Jul 2026 00:28:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1784014086; x=1784618886; 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=UL4JsWWFy5+1VcD51BCzcQnL+AOhOLYxnY1WLoSce4c=; b=MrQKtzVEK6cC864IUWe3vPOz+tNabRozEn2LOjqLNDT7Mv/1qS6ZzvJN0jatk/6BYD 0aXrWJV2LEUGzI9NhlgvcOd5p4zhDf4cgjbeeI0FWswQnA2/2zKSrCCtP9b3ndmXNqM3 t4WIyKTou7pBYd+W3WEh+5r9L/B5SwdaHZSODinrUXFSe30b5p5D+nuNkCpZ8YtFaK7K yu0y6V3EjupH6oWVGXEOHWbW65pOw8C2Qcne+Vt1YF05S/glcnzK1dXXqVUKI92LL772 UHPwNy5lO92nmraNgsz7wgHEZjCpICyJmlCJcmsCgLSrcm3gW5rphIFAySpSY1cFQ2BO BLqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784014086; x=1784618886; 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=UL4JsWWFy5+1VcD51BCzcQnL+AOhOLYxnY1WLoSce4c=; b=Yasal6UvE23RZk+UkwJrLzqHEgLWp72RyEuyTSkc62tLeOKefBXWUEqj9NtFsFfrZz ng5thOaB9ZeMUP857WDSz87RgP9FSsU/oomMU3UekxytuY0F9boAglzLK0wnK89hD5cZ Z6/blb2DzalhMbiHbsmAMqVwzEGZEcKpjdmmK4q7OJz8FKZd78oyT+oXHmXcj0vc5Zfy 6MpUnCmjQJfA7XZhPOpEl22VF2ee1f9ZRsbvPKkEqgIc/BLrmCuIn/rVzzfUr+4mmYIl TkjwnjqizTq1jc7D/7xXNpSoUoG59LJfiUiAezwBd4sEwGqbzuTiEQ0D+RA6Ky5zwYyb SoYw== X-Gm-Message-State: AOJu0YxTAOBho2m0zMfhUNHEKHWv1ZUKXvgH5QGuHHbHhyOPjxTDQXh7 CRvinYN5GoOYphADAuR22et/ZWHGBhFFDfJPVHEv0Up6z2IXD4pW0VmY1xVK+ZCuUOw3x6cI X-Gm-Gg: AfdE7cmSOtI9f6CZqmy313NzgkfNwlkSNSgKGDCPV72jgXCj9ewTlzuq1maV2M29JEW kwIZ7R2XJDr5mF4ahh/KDtliRA5QAIldNwLyTryhKYW0xqky2pW//7KstpcTLj+K67tFJCBgacW fSxBeVcdADEt1gW1kBT3wGyTEmhCO7XbUt4x5TT2Dws6b0cuFtKk8AfDpE7IFZCrHzr82KLCXZl YJJXQ6Bax7bqz6zLa8Ed1jSHPv+Qh/ZZ9gpj/M1kb4/UdTIreqe2Qp3t/8TVh+RMOh/JB++IhQZ 89Cf/wtCgoe/HnNnTRwqndHPDpzGMjTJUDz1t5aIF4YxDd+4LjPJtZCq5DXIzSRZJSrZq1+BBwf BBS8JPTAart7FfPe9V+esZ1sR5VrAZI+AfIn+d8V89IAD8WG/wlI411gIbmf3/JP39Au1x9XVp9 RJbFHyIUcrXkCN4/dGDbXg5JTPWj2yZD8XmQ== X-Received: by 2002:a05:6a00:1943:b0:841:58b0:82bb with SMTP id d2e1a72fcca58-84a5576ce8cmr1383065b3a.9.1784014086315; Tue, 14 Jul 2026 00:28:06 -0700 (PDT) Received: from J4f-Laptop.localdomain ([2409:8a55:94d0:4771:cc5f:41a5:d797:4728]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-84a4f80de8esm975471b3a.56.2026.07.14.00.28.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jul 2026 00:28:05 -0700 (PDT) From: Shihuang Liu To: netdev@vger.kernel.org Cc: ap420073@gmail.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, linux-kernel@vger.kernel.org, Shihuang Liu , stable@vger.kernel.org Subject: [PATCH] amt: fix use-after-free in AMT delayed works Date: Tue, 14 Jul 2026 15:27:05 +0800 Message-ID: <20260714072705.129262-1-shlomojune6@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When an AMT device is removed, pending delayed works can still access the freed amt_dev structure, which may result in kernel crashes or memory corruption. amt_dev_stop() cancels req_wq and discovery_wq with cancel_delayed_work_sync(), but these works can be scheduled again from event_wq after the cancellation. This allows delayed works to access the freed amt_dev structure after the netdev has been released. The following is a simple race scenario: CPU0 CPU1 amt_dev_stop() cancel_delayed_work_sync() amt_event_work() mod_delayed_work(req_wq) free netdev req_wq accesses freed amt_dev Use disable_delayed_work_sync() in amt_dev_stop() to prevent req_wq and discovery_wq from being queued again and wait for running work items to complete. The delayed works are disabled after initialization in amt_newlink() and enabled only when the device is successfully opened. This keeps the delayed work lifecycle synchronized with the lifetime of the AMT device. Fixes: cbc21dc1cfe9 ("amt: add data plane of amt interface") Cc: stable@vger.kernel.org Signed-off-by: Shihuang Liu --- drivers/net/amt.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/net/amt.c b/drivers/net/amt.c index 951dd10e192b..7eb871b9b7e1 100644 --- a/drivers/net/amt.c +++ b/drivers/net/amt.c @@ -2995,9 +2995,15 @@ static int amt_dev_open(struct net_device *dev) amt->event_idx = 0; amt->nr_events = 0; + enable_delayed_work(&amt->discovery_wq); + enable_delayed_work(&amt->req_wq); + err = amt_socket_create(amt); - if (err) + if (err) { + disable_delayed_work(&amt->req_wq); + disable_delayed_work(&amt->discovery_wq); return err; + } amt->req_cnt = 0; amt->remote_ip = 0; @@ -3023,8 +3029,8 @@ static int amt_dev_stop(struct net_device *dev) struct sock *sk; int i; - cancel_delayed_work_sync(&amt->req_wq); - cancel_delayed_work_sync(&amt->discovery_wq); + disable_delayed_work_sync(&amt->req_wq); + disable_delayed_work_sync(&amt->discovery_wq); cancel_delayed_work_sync(&amt->secret_wq); /* shutdown */ @@ -3278,6 +3284,8 @@ static int amt_newlink(struct net_device *dev, INIT_DELAYED_WORK(&amt->req_wq, amt_req_work); INIT_DELAYED_WORK(&amt->secret_wq, amt_secret_work); INIT_WORK(&amt->event_wq, amt_event_work); + disable_delayed_work(&amt->req_wq); + disable_delayed_work(&amt->discovery_wq); INIT_LIST_HEAD(&amt->tunnel_list); return 0; err: -- 2.43.0