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=1794280816; b=dXimQrmd6u8w1cEn5sIUnUhvUomrGrRU+O5fd27W7oF3sE72DuMv3q+jhVV3nsyG4h7g b1k2UOuA5Y855MiRLo5q0WN7D0LCnhmkkX49zeBRMwZWF4QYQ0LRWxUMrUq/xoD+QUJIM vJ7Y7iXLBOCpSsVablytiKNfprf4KyW/wZtvY9L+pU44KGE3oItyJIJfAVPGFaERL/cUa sFfX0xHewD/MsyFIn8yqXptuhO2kLME9dOvWXC3cX02kj4Sn/aWSXrTc6NmgHWm/UUepU dkYdBTCZ07/JQgtn1XUrxzz7F4LDldtU5ojp4WbFiIego+3yaOKnXFj3onocM5DkXuw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794280816; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=EQWiNIPgp0Y3iWcclCHTXLZX0urPoSdIN9jt7HQUM44=; b=BWPEScp4XF4qPK1f6PtlG5B0C7JR883MdpRYXrYrW8h5yEtgD88J7Kn8jLjMR6y6z63o mln6CkYI1cbgoqh5s9YSi1pOR4IuuFSphH3FOnQ/oILNu2fqTjIEmmWPQ3IjzBbIivdIA EiweTXsJPRICj0FhJAnKxfljRfaWESIkaXD6Oa5ZCXUsOK+GR0Lhb8Rf49ZyMXUMC1rTo 8hr84qLKlcCwvNCEjE5dK6NJN0pUuW82cl/W6eYO+2KtUEqgUXrk/TOLd2R/ojR8mA8TC SlXDklJZYoT3FfzcQjbDr9R+wPEDvKf5fDpByh/Eb5K65dyNP9P5WDpY8AB2Vgz1dfQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Nude62pb; 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 C4C9A606A334 for ; Tue, 10 Nov 2026 03:20:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Nude62pb Received: by smtp.kernel.org (Postfix) with ESMTPSA id A9F5B1F008A3; Tue, 10 Nov 2026 03:20:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794280815; bh=EQWiNIPgp0Y3iWcclCHTXLZX0urPoSdIN9jt7HQUM44=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Nude62pbXaIWGbmMjeCUwLCC1zdR2bbw93V7DWLPGtmxvsn/hjUieRRYNQdoLu3Fp v24wm4zKouiLQvFwjjGRa5EbQ7u1uHcRWqVq6aw/8ypKDP9SFXgQIXiwy/4brsGEkZ gzrjVd68RmnzMEhSFcCNlSg4Wa/XA2VTU5EXAoqVpiG3YtK0GeK21U1ciOO1D6sWBK a+6FxXHtH5Ftyy/RaIu1bh5bVfm6lOxMjhf7irwR78FMQK4knST8KbQrdklLXB2893 g6OjKx1ynGXfMyP3DXEotJPiOLDCnOyfmZQLMZ8ykkPzrojFn9IUU14sbUayJBaw5g 5rcnyeZIsFsYg== From: Sasha Levin To: stable@vger.kernel.org Cc: Zhenhao Wan , Yuhao Jiang , Lyude Paul , Sasha Levin Subject: [PATCH 5.10.y] drm/nouveau/svm: drain fault handler before freeing svmm Date: Mon, 9 Nov 2026 22:20:13 -0500 Message-ID: <20261110031959.50827-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261107061408-failed-5.10-b46ddaf08234@kernel.org> References: <20261107061408-failed-5.10-b46ddaf08234@kernel.org> 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 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 f67700c028c75..a723c72049df0 100644 --- a/drivers/gpu/drm/nouveau/nouveau_svm.c +++ b/drivers/gpu/drm/nouveau/nouveau_svm.c @@ -302,6 +302,19 @@ 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].notify.work); + mutex_lock(&svmm->mutex); svmm->vmm = NULL; mutex_unlock(&svmm->mutex); -- 2.53.0