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 90B3E43079F for ; Tue, 11 Aug 2026 11:55:07 +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=1786449308; cv=none; b=SNz40d8WJSir4qOpsnX9PHZYzA1E84hdhvjKpMxLuz1dMaFNW/w4Hf/o8PRiRRcFdoH8i0hjvKiOqGl2eSTPKvRR1yB6kh9V8T4QvJKvdP4MEImS8fPZNLRf4Fr8IyibZS/rlZd09AU0b8OYNh+HzfB4ad9pZxnDeKDdYhNRJfo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786449308; c=relaxed/simple; bh=gYFfdjiMhlYQPHnKaM0c818WpskuLo0ZZ0w95JsPt60=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TXuIi+j6q1P+xjJqcNM5k2EaWKBUFz3U6d26dRcS0TDm1KR7DNzRvonzspnGdLthXK4E8W5XINo5JoIzvQAyEk8hVRxbhgclomnSnqfvqgkrluwww5Z2xjwk1G0+hu1i9/Rx8esrehMvvrIvMhakLQhJB0Tka5EXa1Sw15JohSA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kItTa7UV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kItTa7UV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD3341F00A3E; Tue, 11 Aug 2026 11:55:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786449307; bh=2zL5Da/Kzs3a1l5+yUMDjRcNvCB8GiuryZy9b/+7Ehs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kItTa7UVnhZv6l9ZLC8li90LYwNGUHm4OfrBLjht+wOhkuW5dgaNbFDXYmzSaVATT 3psnaW5cgoiyt6Q2fjRLkppwYOc659DXchbPwwVEyYr3jUZltUHsGcXycIOg3fPVlF n9Qd7fNA/Ube3pj77xKzShSFv3Ax/j5xQOtAZyWgNk10M4+mzPlOgWCZckO6s1vCbM VBXCxxcjJVWVXlfxeunk04JdqXnYmQY8Ivi8A1JALAleozYp/OyhAEVHebzAyT3E4x 9DMgbyFgvjr64adNDaEUCKFmoKjMzFtayUL9sgcQ5Ou0jS/NlVInDykRho/6ACuqdg kJPgQixHrZMeA== From: Sasha Levin To: stable@vger.kernel.org Cc: Chengfeng Ye , Simon Horman , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12.y 2/2] net: pktgen: fix proc entry use-after-free Date: Tue, 11 Aug 2026 07:55:04 -0400 Message-ID: <20260811115504.2333010-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260811115504.2333010-1-sashal@kernel.org> References: <2026080501-backup-vest-eab3@gregkh> <20260811115504.2333010-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 --- net/core/pktgen.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/net/core/pktgen.c b/net/core/pktgen.c index 6c576d11af29f..118036dc16fa5 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c @@ -3934,6 +3934,7 @@ static void _rem_dev_from_if_list(struct pktgen_thread *t, 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) @@ -3963,9 +3964,6 @@ static int pktgen_remove_device(struct pktgen_thread *t, * 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 -- 2.53.0