Re: [PATCH 5.12 237/242] drm/ast: Remove reference to struct drm_device.pdev

From: Thomas Zimmermann
Date: Mon Jul 19 2021 - 10:35:33 EST


hi

Am 19.07.21 um 13:23 schrieb Greg Kroah-Hartman:
On Mon, Jul 19, 2021 at 05:57:30PM +0800, Xiaotian Feng wrote:
On Fri, Jul 16, 2021 at 5:13 AM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:

From: Thomas Zimmermann <tzimmermann@xxxxxxx>

commit 0ecb51824e838372e01330752503ddf9c0430ef7 upstream.

Using struct drm_device.pdev is deprecated. Upcast with to_pci_dev()
from struct drm_device.dev to get the PCI device structure.

v9:
* fix remaining pdev references

Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
Fixes: ba4e0339a6a3 ("drm/ast: Fixed CVE for DP501")
Cc: KuoHsiang Chou <kuohsiang_chou@xxxxxxxxxxxxxx>
Cc: kernel test robot <lkp@xxxxxxxxx>
Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Dave Airlie <airlied@xxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Link: https://patchwork.freedesktop.org/patch/msgid/20210429105101.25667-2-tzimmermann@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/ast/ast_main.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -411,7 +411,6 @@ struct ast_private *ast_device_create(co
return ast;
dev = &ast->base;

- dev->pdev = pdev;
pci_set_drvdata(pdev, dev);

ast->regs = pcim_iomap(pdev, 1, 0);
@@ -453,8 +452,8 @@ struct ast_private *ast_device_create(co

/* map reserved buffer */
ast->dp501_fw_buf = NULL;
- if (dev->vram_mm->vram_size < pci_resource_len(dev->pdev, 0)) {
- ast->dp501_fw_buf = pci_iomap_range(dev->pdev, 0, dev->vram_mm->vram_size, 0);
+ if (dev->vram_mm->vram_size < pci_resource_len(pdev, 0)) {
+ ast->dp501_fw_buf = pci_iomap_range(pdev, 0, dev->vram_mm->vram_size, 0);
if (!ast->dp501_fw_buf)
drm_info(dev, "failed to map reserved buffer!\n");
}


Hi Greg,

This backport is incomplete for 5.10 kernel, kernel is panicked
on RIP: ast_device_create+0x7d. When I look into the crash code, I
found

struct ast_private *ast_device_create(struct drm_driver *drv,
struct pci_dev *pdev,
unsigned long flags)
{
.......
dev->pdev = pdev; // This is removed
pci_set_drvdata(pdev, dev);

ast->regs = pcim_iomap(pdev, 1, 0);
if (!ast->regs)
return ERR_PTR(-EIO);

/*
* If we don't have IO space at all, use MMIO now and
* assume the chip has MMIO enabled by default (rev 0x20
* and higher).
*/
if (!(pci_resource_flags(dev->pdev, 2) & IORESOURCE_IO)) { //
dev->pdev is in used here.
drm_info(dev, "platform has no IO space, trying MMIO\n");
ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
}

That's because commit 46fb883c3d0d8a823ef995ddb1f9b0817dea6882
is not backported to 5.10 kernel.

So what should I do here? Backport that commit (was was not called
out), or just revert this?

Best drop all these 'remove pdev' patches from stable. They are no bugfixes.

Best regards
Thomas


thanks,

greg k-h


--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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