Commit 9e3fc1d6 authored by Matthew Auld's avatar Matthew Auld Committed by Thomas Hellström
Browse files

drm/xe/vm: don't ignore error when in_kthread 



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.

Fixes: dd08ebf6 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Signed-off-by: default avatarMatthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: default avatarMatthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240202171435.427630-2-matthew.auld@intel.com


(cherry picked from commit 8087199c)
Signed-off-by: default avatarThomas Hellström <thomas.hellstrom@linux.intel.com>
parent 95c058c8

drivers/gpu/drm/xe/xe_vm.c

+1 −4
Original line number Diff line number Diff line
@@ -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;