diff options
author | Nicolai Hähnle <nicolai.haehnle@amd.com> | 2017-02-14 09:37:12 +0100 |
---|---|---|
committer | Alex Deucher <alexander.deucher@amd.com> | 2017-03-29 23:53:05 -0400 |
commit | c2c139cf435b18939204800fa72c53a7207bdd68 (patch) | |
tree | 08b8a88fd40b7ceb4e3c82c7c74eeeb0f5ea3f29 /drivers/gpu/drm/ttm | |
parent | 5ebbac4b5c9159130046bf7c56b7f4c71ca7d1b7 (diff) | |
download | linux-c2c139cf435b18939204800fa72c53a7207bdd68.tar.bz2 |
drm/ttm: never add BO that failed to validate to the LRU list
Fixes a potential race condition in amdgpu that looks as follows:
Task 1: attempt ttm_bo_init, but ttm_bo_validate fails
Task 1: add BO to global list anyway
Task 2: grabs hold of the BO, waits on its reservation lock
Task 1: releases its reference of the BO; never gives up the
reservation lock
The patch "drm/amdgpu: fix a potential deadlock in
amdgpu_bo_create_restricted()" attempts to fix that by releasing
the reservation lock in amdgpu code; unfortunately, it introduces
a use-after-free when this race _doesn't_ happen.
This patch should fix the race properly by never adding the BO
to the global list in the first place.
Cc: zhoucm1 <david1.zhou@amd.com>
Signed-off-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Tested-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu/drm/ttm')
-rw-r--r-- | drivers/gpu/drm/ttm/ttm_bo.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c index dca2e809a970..9a6dea976f02 100644 --- a/drivers/gpu/drm/ttm/ttm_bo.c +++ b/drivers/gpu/drm/ttm/ttm_bo.c @@ -1188,18 +1188,20 @@ int ttm_bo_init(struct ttm_bo_device *bdev, if (likely(!ret)) ret = ttm_bo_validate(bo, placement, interruptible, false); - if (!resv) { + if (!resv) ttm_bo_unreserve(bo); - } else if (!(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) { + if (unlikely(ret)) { + ttm_bo_unref(&bo); + return ret; + } + + if (resv && !(bo->mem.placement & TTM_PL_FLAG_NO_EVICT)) { spin_lock(&bo->glob->lru_lock); ttm_bo_add_to_lru(bo); spin_unlock(&bo->glob->lru_lock); } - if (unlikely(ret)) - ttm_bo_unref(&bo); - return ret; } EXPORT_SYMBOL(ttm_bo_init); |