From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794061873; b=1k4ZuNyZ1dIm0cBD9j0YGRnmD5eM76rYCGCvAoQaVw/vLiesUXODARm3zICLdkG/EBEg zdqpOz4qhwhg+/KOMT/1QbszlAQjeiCTfebVV7IGNqEpX9VajXYkabi+bQD6OB88HXtlm AwRUiXYOEjV7R1B54zh8zdEKmD4Q/vScqXqv5ReMwperw683LfHmbyhxN1XOf7WMJeGUT gM60WKip4W0WO96mmMKgiocFiZZwCIPGvu0oNIRe8H+6ZcSnGybPaUFejO5yiwfvObWVr DeJSd4FRGCNskJ0BsRKrSdGnIwY7+857L2+izEcMpMDyG5QFPZpHgwMel+kFcRu3JAg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794061873; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=o3TDiQ1fntGFgtZeFoAnf75bzKvFZCydbsFgdTjeV6U=; b=I5/g7JQVtj0eAqiiw+dtFwEwCv/50+m5PX2OvSILrc1Bjp3O1nVj/V6iRzPnlw+GqZ60 NM8SfhH6aTG87G94L6RSR2aMXgrc25WYK+v/+mX7H1hL8SHkiaM8UFC/SCpFqP87Ihrqn 3GXAHjErTa9oZtWe4o7bqjDQiGIkw5TOV0XmV4/E9iMDnQ421zbGKS5awZC8OEqjkUMwi Qjc5HwXYq8VwO1IKnwXCqmifqlWyRt5YjuyiKze652UEgtZfZVnDncdBHLBMmCI3LcB6b 2JBFdzmAwTFiKNMcj0OgGIHfQSRagCDiWNuDbMbd4DW1yKzeZ31MeiVSLsUWyaRRJ4Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=rNU1NeKv; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2C7F0606A32D; Sat, 7 Nov 2026 14:31:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=rNU1NeKv Received: by smtp.kernel.org (Postfix) with ESMTPSA id 836291F0089F; Sat, 7 Nov 2026 14:31:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794061872; bh=o3TDiQ1fntGFgtZeFoAnf75bzKvFZCydbsFgdTjeV6U=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=rNU1NeKvKWCZvQPKMs8jTx3B9zdGI68PuKUQfAR+AuUNj1vO60bUvQcadCFBovYbt 9iEDYmxoL8awahIc5VOFMLqX4l05l36jgs0K3qfTtVpEDmFphZJepbu4L0nG8BS8hw 6M6O5p9gt0SJzb4AWgUCPHFjQ0xjj5gNv2c6uxsI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yuhao Jiang , Zhenhao Wan , Lyude Paul , Sasha Levin Subject: [PATCH 6.12 0887/1536] drm/nouveau/svm: drain fault handler before freeing svmm Date: Sat, 7 Nov 2026 08:48:23 -0500 Message-ID: <20261107135022.536603652@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134957.653319350@linuxfoundation.org> References: <20261107134957.653319350@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhenhao Wan [ Upstream commit b46ddaf0823405f81e681eb26ec98508f3eb9a07 ] The SVM fault handler nouveau_svm_fault() looks up each fault's nouveau_svmm under svm->mutex, caches it in the fault array, then drops svm->mutex and dereferences the svmm across blocking faults (mmu_interval_notifier_insert(), hmm_range_fault()). nouveau_svmm is not refcounted. On DRM file close nouveau_svmm_fini() -> mmu_notifier_put() frees it asynchronously via call_srcu() without waiting for the handler, and mmget_not_zero() pins the mm, not the svmm. flush_work() on the fault buffer otherwise runs only at device removal and suspend, never on close, so a fault handled concurrently with a close can dereference a freed svmm. The instance is already unlinked by nouveau_svmm_part() earlier in the same close, so no new fault can resolve to it. Drain the handler in nouveau_svmm_fini() before the free, guarding the flush with a NULL check on drm->svm: on device teardown nouveau_svm_fini() runs first and frees drm->svm (NULL) after blocking the notify and flushing the buffer, so the handler is already drained; on per-client close drm->svm is alive and the flush runs. Fixes: eeaf06ac1a55 ("drm/nouveau/svm: initial support for shared virtual memory") Reported-by: Yuhao Jiang Assisted-by: Claude:claude-opus-5 Cc: stable@vger.kernel.org Signed-off-by: Zhenhao Wan Reviewed-by: Lyude Paul Signed-off-by: Lyude Paul Link: https://patch.msgid.link/20260814-nouveau-svm-svmm-uaf-v2-1-8e6590519f07@gmail.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/nouveau/nouveau_svm.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c index 8ea98f06d39af..18ec4db06b962 100644 --- a/drivers/gpu/drm/nouveau/nouveau_svm.c +++ b/drivers/gpu/drm/nouveau/nouveau_svm.c @@ -304,6 +304,19 @@ nouveau_svmm_fini(struct nouveau_svmm **psvmm) { struct nouveau_svmm *svmm = *psvmm; if (svmm) { + struct nouveau_svm *svm = svmm->vmm->cli->drm->svm; + + /* The fault handler caches svmm pointers under svm->mutex and + * dereferences them after dropping it, across blocking faults. + * The instance is already unlinked (nouveau_svmm_part), so drain + * the handler before the free to release any in-flight reference. + * + * On device teardown nouveau_svm_fini() ran first and freed + * drm->svm (NULL) after draining the buffer; nothing to flush. + */ + if (svm) + flush_work(&svm->buffer[0].work); + mutex_lock(&svmm->mutex); svmm->vmm = NULL; mutex_unlock(&svmm->mutex); -- 2.53.0