From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dy1-f199.google.com (mail-dy1-f199.google.com [74.125.82.199]) (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 AC7354C9DF6 for ; Mon, 12 Oct 2026 17:43:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791826996; cv=none; b=JAyBTYL9KgxlNpYfo1tR746WeQDlfvzqamA9RksxgSxOYLy3Cg6V5bvB9rzlj6E/YFqRytnY1ZUYpu3mlkxOKQvWPbnXxpXyNg5Ug7lNd35x7Yk82SEgDbbLn4cVnra3dWfr4tySrPgUT96Wn49LXnXM9eDhyVKYUm1mNbmWgj8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791826996; c=relaxed/simple; bh=6gGUo5bfHG056Upj0Wv3RVCBcYSHTIx2FpNy0nwC6/4=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=SFCcRijFEtVefReb0t8Lk0k8djYIuayxQ2sNcKPU9sqT04x1PVsg0rJxLPrbbij+Hv3+xqtfKOnjXB5SF3qFyVjdsR7Wdj6jJLO5SPClkLX8NQzgUkG/DtoS2QVROsmNQPGLonbDDbK7bWglJjF4O3nGIfkhnv8osNt0cJJOay0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--almasrymina.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=CWIzH4aw; arc=none smtp.client-ip=74.125.82.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--almasrymina.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="CWIzH4aw" Received: by mail-dy1-f199.google.com with SMTP id 5a478bee46e88-35ac5255f1dso4185925eec.0 for ; Mon, 12 Oct 2026 10:43:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1791826992; x=1792431792; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=0d9kx5oWqQ1CybegjOdsNGS+P/geGKBslG4tLGyxeVI=; b=CWIzH4awYFaa2mmvUonfwfCckiw70n84q+KwhfRscqujCHcAEjCGHCHKHRpt8RZ13O WdxAjrSFAWx5FUErFchNOgsom6yWfo14PsZQYXSST5yFKEbRfSUL2thpiYuVhuLGFRdQ XBBiDMkXfBfJUbku8XAZlw9emTWylmxpbpnwhVzrU8DZ7n0vIgt/7vUxM/e4RoYKSEzU ZFbfyGfrO8J7hBFAau+mIa8jfKn1zYI2xnqV+lpuNzv41+t9gzQOWQ1WnaeUmZKq+igf D9xkYkKcJcLK0j7RkTf1YWL7Xhga0ABmZ/nbidJuCU0nO8msbrWLYxohZcBtbt9DjmFC 0TgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791826992; x=1792431792; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=0d9kx5oWqQ1CybegjOdsNGS+P/geGKBslG4tLGyxeVI=; b=D9rnR6wpHEUneMxnAf4M10zNmaePg7MO0P/AxKODaPV+qT95FETU6AsxEh8JsWXhEa o5oNoBVl2OqC4+nKmCeCXno19DnaxW+3682Sf3NmSDAFiGFE9cWGUoNR9Q+qNI+johi6 DfN6wZ9YTfUn+UGGzOO2JFdiu5hAO5F+qxRegMCHhNo1fFDfs9F3MGLVBzzVBlXfQLiv R6IOlBhbanoGj2zsLIlGqboEd5vA0w0hSo9+5xKhkBgYER+X0VqWQaidiui1Pm/6gaqX rRuEG0ZKRLtoBf0nSBnjfO0R7ilEuFT8WVpSmVgAbqUqbehT1AA5ilCMT5MUx8sdCbMr LOOw== X-Forwarded-Encrypted: i=1; AKwUvBwXFMxP3JTX26F2Qj+1g5Y38LgPe+6XFXVcAUH/SbiIdfJX2dXxwcFvdlW/Wz3KwF/M7jV++DM=@vger.kernel.org X-Gm-Message-State: AFq9FYLelNZPd4EqxHmV9TWe3UUnpyybsFbdx6k3JGk4GulctIgccn75 +iqSEIbe3eOmC7Zhi16aYedkHSsus0SstGaq0SS8f7yyqD0A0fKdxImnpiQnYdaJCfbuTt7GHXv wYw2izz8F/HF0jTEG7UM6v+pz+g== X-Received: from dycnn12.prod.google.com ([2002:a05:7301:140c:b0:359:72f9:2aab]) (user=almasrymina job=prod-delivery.src-stubby-dispatcher) by 2002:a05:693c:810e:b0:359:861:7cbd with SMTP id 5a478bee46e88-35908617e44mr9474976eec.10.1791826988403; Mon, 12 Oct 2026 10:43:08 -0700 (PDT) Date: Mon, 12 Oct 2026 17:43:00 +0000 In-Reply-To: <20261012174300.2338784-1-almasrymina@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20261012174300.2338784-1-almasrymina@google.com> X-Mailer: git-send-email 2.56.0.385.gd3acb90ef8-goog Message-ID: <20261012174300.2338784-5-almasrymina@google.com> Subject: [PATCH net v2 4/4] selftests: net: add devmem RX and TX netdev unregister tests From: Mina Almasry To: Jakub Kicinski , David Wei , Pavel Begunkov , Mina Almasry , Taehee Yoo , Stanislav Fomichev , Paolo Abeni , Kaiyuan Zhang , Bobby Eshleman , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: Andrew Lunn , "David S. Miller" , Eric Dumazet , Simon Horman , Shuah Khan , Sumit Semwal , "=?UTF-8?q?Christian=20K=C3=B6nig?=" , Nikolay Aleksandrov , Daniel Borkmann , Tariq Toukan , Kaifeng Wang Content-Type: text/plain; charset="UTF-8" Add devmem_bind_rx_unregister_check and devmem_bind_tx_unregister_check to nl_netdev.py to verify that unregistering a netdevsim device while a netlink socket holds an active RX or TX devmem binding synchronously detaches the dma_buf attachment and cleanly closes the netlink socket without use-after-free or page faults. Cc: Tariq Toukan Cc: Kaifeng Wang Signed-off-by: Mina Almasry --- tools/testing/selftests/net/nl_netdev.py | 108 ++++++++++++++++++++++- 1 file changed, 105 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/net/nl_netdev.py b/tools/testing/selftests/net/nl_netdev.py index ceb44c8e1fec5..bad230ee9dcd2 100755 --- a/tools/testing/selftests/net/nl_netdev.py +++ b/tools/testing/selftests/net/nl_netdev.py @@ -6,10 +6,14 @@ Tests for the netdev netlink family. """ import errno +import fcntl +import mmap +import os +import struct from os import system -from lib.py import ksft_run, ksft_exit +from lib.py import ksft_run, ksft_exit, KsftSkipEx from lib.py import ksft_eq, ksft_ge, ksft_ne, ksft_raises, ksft_busy_wait -from lib.py import NetdevFamily, NetdevSimDev, NlError, defer, ip +from lib.py import EthtoolFamily, NetdevFamily, NetdevSimDev, NlError, defer, ip def empty_check(nf) -> None: @@ -366,6 +370,102 @@ def page_pool_stats_ifindex_check(nf) -> None: ksft_eq(cm.exception.nl_msg.extack['bad-attr'], '.info.id') +def _create_udmabuf(num_pages=64) -> int: + """Create a sealed memfd-backed udmabuf fd for devmem tests.""" + if not os.path.exists("/dev/udmabuf"): + raise KsftSkipEx("/dev/udmabuf is not available") + + size = num_pages * mmap.PAGESIZE + memfd = os.memfd_create("devmem-ksft", os.MFD_ALLOW_SEALING) + os.ftruncate(memfd, size) + fcntl.fcntl(memfd, 1033, 0x0002) # F_ADD_SEALS, F_SEAL_SHRINK + devfd = os.open("/dev/udmabuf", os.O_RDWR) + req = bytearray(struct.pack("IIQQ", memfd, 0, 0, size)) + dmabuf_fd = fcntl.ioctl(devfd, 0x40187542, req) # UDMABUF_CREATE + os.close(devfd) + os.close(memfd) + return dmabuf_fd + + +def _dmabuf_attached_devs(): + """Return attached device names from debugfs dma_buf/bufinfo if available.""" + path = "/sys/kernel/debug/dma_buf/bufinfo" + if not os.path.exists(path): + return None + with open(path, "r", encoding="utf-8") as f: + text = f.read() + attached = [] + in_attached = False + for line in text.splitlines(): + if line.strip() == "Attached Devices:": + in_attached = True + continue + if in_attached: + if line.startswith("\t") and line.strip(): + attached.append(line.strip()) + else: + in_attached = False + return attached + + +def devmem_bind_rx_unregister_check(_nf) -> None: + """Verify RX devmem bindings detach dma_buf synchronously on netdev unregister.""" + dmabuf_fd = _create_udmabuf() + nf_priv = NetdevFamily() + ef = EthtoolFamily() + nsimdev = NetdevSimDev(queue_count=2) + nsim = nsimdev.nsims[0] + + ip(f"link set dev {nsim.ifname} up") + ef.rings_set({"header": {"dev-index": nsim.ifindex}, + "tcp-data-split": "enabled"}) + nf_priv.bind_rx({ + "ifindex": nsim.ifindex, + "fd": dmabuf_fd, + "queues": [{"id": 1, "type": "rx"}], + }) + + attached = _dmabuf_attached_devs() + if attached is not None: + ksft_ge(len(attached), 1) + + nsimdev.remove() + + attached = _dmabuf_attached_devs() + if attached is not None: + ksft_eq(len(attached), 0) + + del nf_priv + os.close(dmabuf_fd) + + +def devmem_bind_tx_unregister_check(_nf) -> None: + """Verify TX devmem bindings detach cleanly on netdev unregister without UAF.""" + dmabuf_fd = _create_udmabuf() + nf_priv = NetdevFamily() + nsimdev = NetdevSimDev(queue_count=2) + nsim = nsimdev.nsims[0] + + ip(f"link set dev {nsim.ifname} up") + nf_priv.bind_tx({ + "ifindex": nsim.ifindex, + "fd": dmabuf_fd, + }) + + attached = _dmabuf_attached_devs() + if attached is not None: + ksft_ge(len(attached), 1) + + nsimdev.remove() + + attached = _dmabuf_attached_devs() + if attached is not None: + ksft_eq(len(attached), 0) + + del nf_priv + os.close(dmabuf_fd) + + def main() -> None: """ Ksft boiler plate main """ nf = NetdevFamily() @@ -379,7 +479,9 @@ def main() -> None: page_pool_check, page_pool_dump_ifindex, page_pool_ifindex_leak_check, - page_pool_stats_ifindex_check + page_pool_stats_ifindex_check, + devmem_bind_rx_unregister_check, + devmem_bind_tx_unregister_check ], args=(nf, )) ksft_exit() -- 2.56.0.385.gd3acb90ef8-goog