Hi,
Static analysis with Coverity in linux-next has detected an issue in
drivers/gpu/drm/ttm/ttm_bo.c with the follow commit:
commit a1f091f8ef2b680a5184db065527612247cb4cae
Author: Christian K?nig <christian.koenig at amd.com>
Date: Tue Oct 6 17:26:42 2020 +0200
drm/ttm: switch to per device LRU lock
Instead of having a global lock for potentially less contention.
The analysis is as follows:
617 int ttm_mem_evict_first(struct ttm_device *bdev,
618 struct ttm_resource_manager *man,
619 const struct ttm_place *place,
620 struct ttm_operation_ctx *ctx,
621 struct ww_acquire_ctx *ticket)
622 {
1. assign_zero: Assigning: bo = NULL.
623 struct ttm_buffer_object *bo = NULL, *busy_bo = NULL;
624 bool locked = false;
625 unsigned i;
626 int ret;
627
Explicit null dereferenced (FORWARD_NULL)2. var_deref_op:
Dereferencing null pointer bo.
628 spin_lock(&bo->bdev->lru_lock);
629 for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) {
The spin_lock on bo is dereferencing a null bo pointer.
Colin
Thanks! Just a copy&paste issue. Patch to fix this is on the mailing list. Christian. Am 25.03.21 um 16:00 schrieb Colin Ian King:> Hi, > > Static analysis with Coverity in linux-next has detected an issue in > drivers/gpu/drm/ttm/ttm_bo.c with the follow commit: > > commit a1f091f8ef2b680a5184db065527612247cb4cae > Author: Christian K?nig <christian.koenig at amd.com> > Date: Tue Oct 6 17:26:42 2020 +0200 > > drm/ttm: switch to per device LRU lock > > Instead of having a global lock for potentially less contention. > > > The analysis is as follows: > > 617 int ttm_mem_evict_first(struct ttm_device *bdev, > 618 struct ttm_resource_manager *man, > 619 const struct ttm_place *place, > 620 struct ttm_operation_ctx *ctx, > 621 struct ww_acquire_ctx *ticket) > 622 { > 1. assign_zero: Assigning: bo = NULL. > > 623 struct ttm_buffer_object *bo = NULL, *busy_bo = NULL; > 624 bool locked = false; > 625 unsigned i; > 626 int ret; > 627 > > Explicit null dereferenced (FORWARD_NULL)2. var_deref_op: > Dereferencing null pointer bo. > > 628 spin_lock(&bo->bdev->lru_lock); > 629 for (i = 0; i < TTM_MAX_BO_PRIORITY; ++i) { > > The spin_lock on bo is dereferencing a null bo pointer. > > Colin