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* [PATCH] drm/xe/vm: don't ignore error when in_kthread
@ 2024-02-02 17:14 Matthew Auld
  2024-02-02 17:51 ` ✓ CI.Patch_applied: success for " Patchwork
                   ` (7 more replies)
  0 siblings, 8 replies; 11+ messages in thread
From: Matthew Auld @ 2024-02-02 17:14 UTC (permalink / raw)
  To: intel-xe; +Cc: Thomas Hellström, Matthew Brost

If GUP fails and we are in_kthread, we can have pinned = 0 and ret = 0.
If that happens we call sg_alloc_append_table_from_pages() with n_pages
= 0, which is not well behaved and can trigger:

kernel BUG at include/linux/scatterlist.h:115!

depending on if the pages array happens to be zeroed or not. Even if we
don't hit that it crashes later when trying to dma_map the returned
table.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/xe/xe_vm.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index 9c1c68a2fff7..63aeb3aead04 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -114,11 +114,8 @@ int xe_vma_userptr_pin_pages(struct xe_userptr_vma *uvma)
 					  num_pages - pinned,
 					  read_only ? 0 : FOLL_WRITE,
 					  &pages[pinned]);
-		if (ret < 0) {
-			if (in_kthread)
-				ret = 0;
+		if (ret < 0)
 			break;
-		}
 
 		pinned += ret;
 		ret = 0;
-- 
2.43.0


^ permalink raw reply related	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2024-02-08  9:22 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2024-02-02 17:14 [PATCH] drm/xe/vm: don't ignore error when in_kthread Matthew Auld
2024-02-02 17:51 ` ✓ CI.Patch_applied: success for " Patchwork
2024-02-02 17:51 ` ✓ CI.checkpatch: " Patchwork
2024-02-02 17:52 ` ✓ CI.KUnit: " Patchwork
2024-02-02 17:59 ` ✓ CI.Build: " Patchwork
2024-02-02 17:59 ` ✓ CI.Hooks: " Patchwork
2024-02-02 18:01 ` ✓ CI.checksparse: " Patchwork
2024-02-02 18:24 ` ✓ CI.BAT: " Patchwork
2024-02-05 18:41 ` [PATCH] " Matthew Brost
2024-02-06 10:55   ` Matthew Auld
2024-02-08  9:22   ` Thomas Hellström

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