From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dy1-f200.google.com (mail-dy1-f200.google.com [74.125.82.200]) (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 024703BE141 for ; Sat, 10 Oct 2026 02:55:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791600937; cv=none; b=pOChDclRgaXP7EXpqhAtug/RZ2WJUYebB3CdobwXsMjh1eXSLcvNXkUtakwkBVIQAnlhnK0XNR/2XaaMfO8kPZlg+YErnYUPqF0adJUtrVoptm7Er9sgm2me7HBMVCxPYXCeVftZDNQrXTjgRYTPZFpBC4/VW1RHPtEheMvA5X8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791600937; c=relaxed/simple; bh=2y6NI7EUqJ+hcZcVtV22rapOiLANuA8VNaJVLpW5Bgk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=E4sYDz7R03xbvTibb0eZl8nbZTC35XuwUdQnIkacG42Lx8jO9deKsjUUpifpTsDaxyW5YOucG6EC5fqWyqd8/PazyygWPd/k/C9oax6YajYZJdztIKRrUYGVOC6CXOCyFaP1BVewBJ0Cwl3wlir0BLtyD4eEZDxU1RlD08ovW0U= 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=qzK2lcl1; arc=none smtp.client-ip=74.125.82.200 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="qzK2lcl1" Received: by mail-dy1-f200.google.com with SMTP id 5a478bee46e88-3552883bd19so1325194eec.1 for ; Fri, 09 Oct 2026 19:55:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1791600935; x=1792205735; 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=BuyDELz7hhEuCW2YvtmlqnI82KO/2H6a0eJ5B6jjRa4=; b=qzK2lcl1bbvky3IyseZC+/uz3dS0wvMDdyDw5T3U+KXuMp+ImAWoDrZOhTCg8tN9UU al+WQyBcak5WIoIOgXY9IcA/MU+rAcuAJoNtKKB+G2jUJpeHBx6OEgrPLUTBqE95Xv9x QmtZNrmDelZu9zr4j0eviBgXVhzGI7ZDqFq7L69mHZg9//x11MRw+wwmZuhEworuCkQX TXlLKQF125fQRaRAYK4VHNv6tCFLvsODr/z7hSUmbSDTS+LdyY/b9Ks2ETGSFTYTVt/E Mpa3+pIF3UYI2aRsaC08iFivhgTuixsrX33wZ4z3XjeHBVO2JFTZt+q4A79r34MFuOg5 BTIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1791600935; x=1792205735; 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=BuyDELz7hhEuCW2YvtmlqnI82KO/2H6a0eJ5B6jjRa4=; b=lDgd4iH8jd+evU3gxCEgALF7yn8WuFGkKm6s27QiQKqmcryfKht6N+oCHRm28agY9K 2nsNeF8uUc7awKOkyuZ+1k4vgCIIzwk951WjAQLMs8oA/+GQmwMkg+1GtstPBdOahU1K sI2eerjgKBd/mZk0DvnHJUtYc2OKBm+JU1DoqhBrKT6lKF3ej8PPldShWba+ZS4aMaW/ PZKZ3L3kJjnVr5m/HeNxROPmjj853F7DbhQoJ010RYbVzuVJZmEqYB768MivUvdm0Dmr jlUkHs0px5liygVbCBzAx+iQVkVLvmndRKAeBUGizYmyMbZx4RgK4FhTqUISfi3hb4Bt aKDw== X-Forwarded-Encrypted: i=1; AKwUvBz/ugSZd/VzPUyyFoAlwcYq1wyeFIPioVm1C8Fg7VovzWGe32b/A/TUguBERLR9LHWasdPHPLY=@vger.kernel.org X-Gm-Message-State: AFq9FYI5mvlwHGuXIz2nSHMPsTRrWLxnhJzI9RL5TH8rx5kiITEK5+PY nSh5k7HcJE3acBo1ru4yzx/d6oag7RLasM9NutqUjHPc2UVbgbVHvPBIaaUiEG5cMuKyTUT0UTz VIBQ39bLQJfjH/sO1WReczecYaA== X-Received: from dyaz17-n2.prod.google.com ([2002:a05:693c:6391:20b0:34b:4d35:2884]) (user=almasrymina job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7301:78ca:b0:351:750d:dd3b with SMTP id 5a478bee46e88-3537dde75a7mr5327189eec.4.1791600934160; Fri, 09 Oct 2026 19:55:34 -0700 (PDT) Date: Sat, 10 Oct 2026 02:55:13 +0000 In-Reply-To: <20261010025532.839559-1-almasrymina@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20261010025532.839559-1-almasrymina@google.com> X-Mailer: git-send-email 2.56.0.385.gd3acb90ef8-goog Message-ID: <20261010025532.839559-2-almasrymina@google.com> Subject: [PATCH net v1 1/4] net: devmem: unmap dma_buf synchronously on queue uninstall From: Mina Almasry To: Jakub Kicinski , Mina Almasry , David Wei , Pavel Begunkov , 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?=" , Daniel Borkmann , Nikolay Aleksandrov , Tariq Toukan , Kaifeng Wang Content-Type: text/plain; charset="UTF-8" When a bound net_device is unregistered while userspace still holds a netlink or TCP socket reference on a devmem binding, mp_dmabuf_devmem_uninstall() clears binding->dev to NULL so netdev_nl_sock_priv_destroy() will not touch the unregistered net_device, but leaves the dma_buf attachment mapped until __net_devmem_dmabuf_binding_free() runs later on socket close. Because dma_buf_attach() does not take a reference on dma_dev, device removal frees dma_dev while the attachment is still mapped. Closing the netlink socket afterwards triggers a slab use-after-free in dma_unmap_sg_attrs(): BUG: KASAN: slab-use-after-free in dma_unmap_sg_attrs+0x76/0x2b0 Read of size 8 at addr ffff88810fae64b0 by task kworker/3:1/53 Workqueue: events __net_devmem_dmabuf_binding_free Call Trace: dma_unmap_sg_attrs+0x76/0x2b0 unmap_udmabuf+0x8e/0x100 dma_buf_unmap_attachment+0x145/0x330 dma_buf_unmap_attachment_unlocked+0x96/0x130 __net_devmem_dmabuf_binding_free+0x156/0x2e0 Freed by task 9: kfree+0x1b8/0x550 nsim_bus_dev_release+0xe/0x60 device_release+0xcf/0x250 Add net_devmem_dmabuf_binding_unmap() serialized under binding->lock and null out binding->sgt and binding->attachment after unmapping so unmapping is idempotent across queue uninstall and deferred binding destruction. Call it synchronously when the last bound RX queue is uninstalled in mp_dmabuf_devmem_uninstall(). Fixes: f8350a4358fc ("net: page_pool: add a mp hook to unregister_netdevice*") Fixes: 0afc44d8cdf6 ("net: devmem: fix kernel panic when netlink socket close after module unload") Cc: Taehee Yoo Cc: Stanislav Fomichev Cc: Tariq Toukan Cc: Kaifeng Wang Signed-off-by: Mina Almasry --- net/core/devmem.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/net/core/devmem.c b/net/core/devmem.c index f4d60654ce7fd..5e4070b82df44 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -58,6 +58,21 @@ static void net_devmem_dmabuf_binding_release(struct percpu_ref *ref) schedule_work(&binding->unbind_w); } +static void +net_devmem_dmabuf_binding_unmap(struct net_devmem_dmabuf_binding *binding) +{ + lockdep_assert_held(&binding->lock); + + if (!binding->sgt) + return; + + dma_buf_unmap_attachment_unlocked(binding->attachment, binding->sgt, + binding->direction); + dma_buf_detach(binding->dmabuf, binding->attachment); + binding->sgt = NULL; + binding->attachment = NULL; +} + void __net_devmem_dmabuf_binding_free(struct work_struct *wq) { struct net_devmem_dmabuf_binding *binding = container_of(wq, typeof(*binding), unbind_w); @@ -74,9 +89,10 @@ void __net_devmem_dmabuf_binding_free(struct work_struct *wq) size, avail)) gen_pool_destroy(binding->chunk_pool); - dma_buf_unmap_attachment_unlocked(binding->attachment, binding->sgt, - binding->direction); - dma_buf_detach(binding->dmabuf, binding->attachment); + mutex_lock(&binding->lock); + net_devmem_dmabuf_binding_unmap(binding); + mutex_unlock(&binding->lock); + dma_buf_put(binding->dmabuf); xa_destroy(&binding->bound_rxqs); percpu_ref_exit(&binding->ref); @@ -535,6 +551,7 @@ static void mp_dmabuf_devmem_uninstall(void *mp_priv, mutex_lock(&binding->lock); ASSERT_EXCLUSIVE_WRITER(binding->dev); WRITE_ONCE(binding->dev, NULL); + net_devmem_dmabuf_binding_unmap(binding); mutex_unlock(&binding->lock); } break; -- 2.56.0.385.gd3acb90ef8-goog