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 493BD53B332; Wed, 23 Sep 2026 14:52:53 +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=1790175175; cv=none; b=cnbZSbWVt2L4t10HHbpMXkHac+iFLoaTZJZ9bLHAjmUsXN0iF7zGVkOKZ/ExeXIgsZLDV0sQtFARkD1yqcV0OUUZNCULDwJ7qj8/WY6A74ZlYWJzzyluoAt29PPyrB2cEbHY8Vz3gPnm5p5u3HKGwsGn3jWiZFmVYWrHIt/M8iQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790175175; c=relaxed/simple; bh=xil9GfY0wQGpe++ofXNSpWt+ECYM6eW4+gHpQ6xOU7M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kGBDpOL2HSJkzs71fwRYWxj/YxZ1U12jQab0ldZ9/8vAs4s+2H5xbEn6Vz7kw8NQTntwBPehBnbuS44a5drlRizOIzXOv7LHQn9/IWmI8t1bxZTcqsqbr4if0MLt/B2/iWh7uxMHJA5hMPDEQo37qR1lT7ERdVzyVFzk9Qveu44= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dhOwWxve; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="dhOwWxve" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36EA41F00893; Wed, 23 Sep 2026 14:52:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790175172; bh=bKAiN7oyfzlI46DvbgNkqyhRw9Z79mXO3N97ohmQKq8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dhOwWxves6xQaycMmaSEc8jswE7pJL4jCMZWA84NjkbvACfDybnv3vTuoC/fLCtsY yxFJH25gRTGc/jjs7tpA7/dzKXXxnjl6Bv7VKSUANXJVq2TR17vixiOhnN31qhDxQA VPCeFSMTuXYPca97ac5dzTcSpqEcn6o8aUlUf5s4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Jonghyuk Kim(MalHyuk)" , Rob Clark Subject: [PATCH 6.18 343/398] drm/msm: RCU-free the scheduler-containing ring and VM objects Date: Wed, 23 Sep 2026 16:06:57 +0200 Message-ID: <20260923140652.320954680@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260923140643.441954610@linuxfoundation.org> References: <20260923140643.441954610@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jonghyuk Kim(MalHyuk) commit 01c8d1f385f788f1bbbbb7687c4386d614281218 upstream. Both struct msm_ringbuffer and struct msm_gem_vm embed a struct drm_gpu_scheduler. msm_ringbuffer_destroy() and the VM free callback msm_gem_vm_free() call drm_sched_fini() on the embedded scheduler and then free the containing object with plain kfree(). drm_sched_fence_get_timeline_name() returns fence->sched->name, and the scheduler fence keeps a .release callback so it is not ops-detached on signalling. A finished fence exported to userspace (the submit out-fence, or a VM_BIND fence, via sync_file / drm_syncobj) keeps pointing at the embedded scheduler after the ring/VM is freed, so a later get_timeline_name() -- reachable unprivileged through SYNC_IOC_FILE_INFO -- dereferences freed slab memory (KASAN slab-use-after-free read). Per the dma-fence lifetime contract the exporter must keep the data backing a signalled fence alive for an RCU grace period. Free the scheduler-containing objects with kfree_rcu() instead of kfree(). Fixes: 1d8a5ca436ee ("drm/msm: Conversion to drm scheduler") Fixes: 92395af63a99 ("drm/msm: Add VM_BIND submitqueue") Cc: stable@vger.kernel.org Signed-off-by: Jonghyuk Kim(MalHyuk) Patchwork: https://patchwork.freedesktop.org/patch/750234/ Message-ID: <20260902012720.880783-1-malhyuk97@gmail.com> Signed-off-by: Rob Clark Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/msm/msm_gem.h | 3 +++ drivers/gpu/drm/msm/msm_gem_vma.c | 2 +- drivers/gpu/drm/msm/msm_ringbuffer.c | 2 +- drivers/gpu/drm/msm/msm_ringbuffer.h | 1 + 4 files changed, 6 insertions(+), 2 deletions(-) --- a/drivers/gpu/drm/msm/msm_gem.h +++ b/drivers/gpu/drm/msm/msm_gem.h @@ -68,6 +68,9 @@ struct msm_gem_vm { /** @base: Inherit from drm_gpuvm. */ struct drm_gpuvm base; + /** @rcu: RCU-delayed free so an exported sched fence->sched stays valid. */ + struct rcu_head rcu; + /** * @sched: Scheduler used for asynchronous VM_BIND request. * --- a/drivers/gpu/drm/msm/msm_gem_vma.c +++ b/drivers/gpu/drm/msm/msm_gem_vma.c @@ -166,7 +166,7 @@ msm_gem_vm_free(struct drm_gpuvm *gpuvm) dma_fence_put(vm->last_fence); put_pid(vm->pid); kfree(vm->log); - kfree(vm); + kfree_rcu(vm, rcu); } /** --- a/drivers/gpu/drm/msm/msm_ringbuffer.c +++ b/drivers/gpu/drm/msm/msm_ringbuffer.c @@ -140,5 +140,5 @@ void msm_ringbuffer_destroy(struct msm_r msm_gem_kernel_put(ring->bo, ring->gpu->vm); - kfree(ring); + kfree_rcu(ring, rcu); } --- a/drivers/gpu/drm/msm/msm_ringbuffer.h +++ b/drivers/gpu/drm/msm/msm_ringbuffer.h @@ -53,6 +53,7 @@ struct msm_ringbuffer { /* * The job scheduler for this ring. */ + struct rcu_head rcu; struct drm_gpu_scheduler sched; bool sched_initialized;