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 2B9BC37AA7D; Thu, 20 Aug 2026 17:40:38 +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=1787247639; cv=none; b=Gsg1mgVhWXJ5zNR+MQ3Z0xDUnIlAVEdZTKEA4La77pCmzkzvIykGL1L6s3iPtIpLxLBfQ6rIdOOlOnkskDTd/W2woa0FuvrZ7rJqVmz1y1FbAoMfa5XNL6M8K4BlxRa/b5KRB/Anlv7qN1WgIFWYF01SVuNXJKEhvikGMqt/lIg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787247639; c=relaxed/simple; bh=WaXwcuq4zJ4wd6j67Z0dzBo1K9Ulw23oGYKhkxaWNNo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uCSGkt6S7JJ0F3U62urbZKh5hZ92aDB9zMuGBNDOXVyPJLaUlT+LL+HIFpauq7U0qKgrnScKjweG42A37H1TZXHv4wqBe71nsSHPF7tm/CSBpTZz/KD7WG5kk0aeWmNUrGSOC5u33z5BDuE+5jvEdolIz1P/ZURIMMnKhFJoriE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=P51Zdu7c; 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="P51Zdu7c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 861CB1F000E9; Thu, 20 Aug 2026 17:40:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787247638; bh=cNmnkBuKJJp+GNSmSrwI5eP1j1xz8zQ8U3QmW72rKJ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=P51Zdu7choWYCnlDxZ579srO3oMuLzzqjwM45P4FgFMuLR0AcOXKLRHev3S891sVA umewndCcHprUz9Kk51ITUe/Xmz06tGy4Qi+tp3BpHCSne2aXjPjAMhH7aw1dROxA64 XtHmWi0j0e++V61cOXIwsr8sE60jIyeYCM5etZ10= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Chengfeng Ye , Simon Horman , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 114/166] net: pktgen: fix proc entry use-after-free Date: Thu, 20 Aug 2026 16:56:13 +0200 Message-ID: <20260820145214.593777818@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820145211.194104353@linuxfoundation.org> References: <20260820145211.194104353@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chengfeng Ye [ Upstream commit 817ff6efdb7f484ea547218e11e17d8e43daa3b4 ] pktgen_change_name() replaces pkt_dev->entry while holding t->if_lock. pktgen_remove_device() removes the same entry before _rem_dev_from_if_list() takes that lock. This allows the following interleaving: CPU 0 (NETDEV_CHANGENAME) CPU 1 (kpktgend) if_lock(t) proc_remove(pkt_dev->entry) proc_remove(pkt_dev->entry) pkt_dev->entry = proc_create_data(...) if_unlock(t) The kthread can pass the stale proc_dir_entry to proc_remove() after the rename path has freed it. A reproducer with a widened race window reports: BUG: KASAN: slab-use-after-free in proc_remove+0x78/0x80 Read of size 8 at addr ffff8881478fea70 by task kpktgend_0/67 Call Trace: proc_remove+0x78/0x80 pktgen_remove_device.isra.0+0x11c/0x4c0 pktgen_thread_worker+0x1214/0x6bc0 kthread+0x2c6/0x3b0 Allocated by task 95: __proc_create+0x204/0x790 proc_create_data+0x72/0xe0 pktgen_thread_write+0xd61/0x1510 Freed by task 28: kmem_cache_free+0xcb/0x3d0 proc_free_inode+0x5b/0x80 rcu_core+0x50a/0x1850 The buggy address belongs to the object at ffff8881478fea00 which belongs to the cache proc_dir_entry of size 192 Move proc_remove() into the if_lock-protected list removal helper. Keep it before list_del_rcu() to preserve the ordering required by add_device(). The rename path must then finish replacing the entry before removal, or it observes that the device is no longer on the list. Fixes: 39df232f1a9b ("[PKTGEN]: fix device name handling") Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye Reviewed-by: Simon Horman Link: https://patch.msgid.link/20260719145740.2888967-1-nicoyip.dev@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/core/pktgen.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -3886,6 +3886,7 @@ static void _rem_dev_from_if_list(struct struct pktgen_dev *p; if_lock(t); + proc_remove(pkt_dev->entry); list_for_each_safe(q, n, &t->if_list) { p = list_entry(q, struct pktgen_dev, list); if (p == pkt_dev) @@ -3915,9 +3916,6 @@ static int pktgen_remove_device(struct p * list to determine if interface already exist, avoid race * with proc_create_data() */ - proc_remove(pkt_dev->entry); - - /* And update the thread if_list */ _rem_dev_from_if_list(t, pkt_dev); #ifdef CONFIG_XFRM