From: Venkata Ramana Nayana venkata.ramana.nayana@intel.com
commit 78b2eb8a1f10f366681acad8d21c974c1f66791a upstream.
As we use a shmemfs file to hold the context state, when not in use it may be swapped out, such as across suspend. Since we wrote into the shmemfs without marking the pages as dirty, the contents may be dropped instead of being written back to swap. On re-using the shmemfs file, such as creating a new context after resume, the contents of that file were likely garbage and so the new context could then hang the GPU.
Simply mark the page as being written when copying into the shmemfs file, and it the new contents will be retained across swapout.
Fixes: be1cb55a07bf ("drm/i915/gt: Keep a no-frills swappable copy of the default context state") Cc: Sudeep Dutt sudeep.dutt@intel.com Cc: Matthew Auld matthew.auld@intel.com Cc: Tvrtko Ursulin tvrtko.ursulin@intel.com Cc: Ramalingam C ramalingam.c@intel.com Signed-off-by: CQ Tang cq.tang@intel.com Signed-off-by: Venkata Ramana Nayana venkata.ramana.nayana@intel.com Reviewed-by: Chris Wilson chris@chris-wilson.co.uk Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: stable@vger.kernel.org # v5.8+ Link: https://patchwork.freedesktop.org/patch/msgid/20201127120718.454037-161-matt... (cherry picked from commit a9d71f76ccfd309f3bd5f7c9b60e91a4decae792) Signed-off-by: Rodrigo Vivi rodrigo.vivi@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/i915/gt/shmem_utils.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/i915/gt/shmem_utils.c +++ b/drivers/gpu/drm/i915/gt/shmem_utils.c @@ -143,10 +143,13 @@ static int __shmem_rw(struct file *file, return PTR_ERR(page);
vaddr = kmap(page); - if (write) + if (write) { memcpy(vaddr + offset_in_page(off), ptr, this); - else + set_page_dirty(page); + } else { memcpy(ptr, vaddr + offset_in_page(off), this); + } + mark_page_accessed(page); kunmap(page); put_page(page);