Re: [5.12 regression] ttm->pages NULL dereference with radeon driver

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi guys,

adding a few people who ran into the problem as well and opened a kernel bug.

Am 07.05.21 um 17:11 schrieb Christian König:
Hi Takashi,

Am 07.05.21 um 17:08 schrieb Takashi Iwai:
Hi,

we've received a regression report showing NULL dereference Oops with
radeon driver on 5.12 kernel:
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.opensuse.org%2Fshow_bug.cgi%3Fid%3D1185516&data=04%7C01%7Cchristian.koenig%40amd.com%7C64447e9e97604aaf117008d9116a742a%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637559971181187178%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=1LJMLxuuMjkfgnIt%2B5Z5n19ri%2BMTLMQvEEB%2F%2Fd6SVkg%3D&reserved=0

It turned out that the recent TTM cleanup / refactoring via commit
0575ff3d33cd ("drm/radeon: stop using pages with
drm_prime_sg_to_page_addr_arrays v2") is the culprit.  On 5.12 kernel,
ttm->pages is no longer allocated / set up, while the radeon driver
still has a few places assuming the valid ttm->pages, and for the
reporter (running the modesettig driver), radeon_gart_bind() hits the
problem.

A hackish patch below was confirmed to work, at least, but obviously
we need a proper fix.

Could you take a look at it?

If that's all then that looks trivial to me.

Going to provide a patch on Monday.

Sorry, was a busy start into the week. I've just send a patch which should address the issue to you and the mailing list.

Please test since I can't reproduce the problem locally.

Thanks,
Christian.


Thanks for the notice,
Christian.



thanks,

Takashi

--- a/drivers/gpu/drm/radeon/radeon_gart.c
+++ b/drivers/gpu/drm/radeon/radeon_gart.c
@@ -253,7 +253,7 @@ void radeon_gart_unbind(struct radeon_de
      t = offset / RADEON_GPU_PAGE_SIZE;
      p = t / (PAGE_SIZE / RADEON_GPU_PAGE_SIZE);
      for (i = 0; i < pages; i++, p++) {
-        if (rdev->gart.pages[p]) {
+        if (1 /*rdev->gart.pages[p]*/) {
              rdev->gart.pages[p] = NULL;
              for (j = 0; j < (PAGE_SIZE / RADEON_GPU_PAGE_SIZE); j++, t++) {
                  rdev->gart.pages_entry[t] = rdev->dummy_page.entry;
@@ -301,7 +301,7 @@ int radeon_gart_bind(struct radeon_devic
      p = t / (PAGE_SIZE / RADEON_GPU_PAGE_SIZE);
        for (i = 0; i < pages; i++, p++) {
-        rdev->gart.pages[p] = pagelist[i];
+        /* rdev->gart.pages[p] = pagelist[i]; */
          page_base = dma_addr[i];
          for (j = 0; j < (PAGE_SIZE / RADEON_GPU_PAGE_SIZE); j++, t++) {
              page_entry = radeon_gart_get_page_entry(page_base, flags);
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -360,6 +360,8 @@ static int radeon_ttm_tt_pin_userptr(str
        if (current->mm != gtt->usermm)
          return -EPERM;
+    if (!ttm->pages)
+        return -EPERM;
        if (gtt->userflags & RADEON_GEM_USERPTR_ANONONLY) {
          /* check that we only pin down anonymous memory
_______________________________________________
amd-gfx mailing list
amd-gfx@xxxxxxxxxxxxxxxxxxxxx
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&amp;data=04%7C01%7Cchristian.koenig%40amd.com%7C64447e9e97604aaf117008d9116a742a%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637559971181187178%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=RdzGp1FLxBKE%2ByPclrUBfQomRU0pQT%2F78Ewcj%2FBZ73g%3D&amp;reserved=0


_______________________________________________
amd-gfx mailing list
amd-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/amd-gfx




[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux