lkml.org 
[lkml]   [2024]   [Jan]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
SubjectRE: [BUG] BUG: kernel NULL pointer dereference at ttm_device_init+0xb4
Date
[AMD Official Use Only - General]

-----Original Message-----
From: Steven Rostedt <rostedt@goodmis.org>
Sent: Monday, January 22, 2024 6:19 PM
To: LKML <linux-kernel@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>; Bhardwaj, Rajneesh <Rajneesh.Bhardwaj@amd.com>; Kuehling, Felix <Felix.Kuehling@amd.com>; Koenig, Christian <Christian.Koenig@amd.com>; dri-devel@lists.freedesktop.org
Subject: Re: [BUG] BUG: kernel NULL pointer dereference at ttm_device_init+0xb4

On Mon, 22 Jan 2024 18:15:47 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> > ttm_pool_init(&bdev->pool, dev, dev_to_node(dev), use_dma_alloc, use_dma32); <<<------- BUG!
> >
> > Specifically, it appears that dev is NULL and dev_to_node() doesn't
> > like having a NULL pointer passed to it.
> >
>
> Yeah, that qxl_ttm_init() has:
>
> /* No others user of address space so set it to 0 */
> r = ttm_device_init(&qdev->mman.bdev, &qxl_bo_driver, NULL,
> qdev->ddev.anon_inode->i_mapping,
> qdev->ddev.vma_offset_manager,
> false, false);
>
> Where that NULL is "dev"!
>
> Thus that will never work here.

Perhaps this is the real fix?

I think the fix might be already applied to drm misc. Please see, https://lkml.iu.edu/hypermail/linux/kernel/2401.1/06778.html


-- Steve

diff --git a/drivers/gpu/drm/ttm/ttm_device.c b/drivers/gpu/drm/ttm/ttm_device.c
index f5187b384ae9..bc217b4d6b04 100644
--- a/drivers/gpu/drm/ttm/ttm_device.c
+++ b/drivers/gpu/drm/ttm/ttm_device.c
@@ -215,7 +215,8 @@ int ttm_device_init(struct ttm_device *bdev, const struct ttm_device_funcs *func

ttm_sys_man_init(bdev);

- ttm_pool_init(&bdev->pool, dev, dev_to_node(dev), use_dma_alloc, use_dma32);
+ ttm_pool_init(&bdev->pool, dev, dev ? dev_to_node(dev) : NUMA_NO_NODE,
+ use_dma_alloc, use_dma32);

bdev->vma_manager = vma_manager;
spin_lock_init(&bdev->lru_lock);
\
 
 \ /
  Last update: 2024-05-27 14:29    [from the cache]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and my Meterkast|Read the blog