Module: Mesa Branch: staging/23.3 Commit: 10a47cde73f366603720251f3a6755366ab0e3db URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=10a47cde73f366603720251f3a6755366ab0e3db
Author: Rob Clark <[email protected]> Date: Mon Dec 4 09:06:59 2023 -0800 freedreno/drm: Fix zombie BO import harder Fixes: 6ac133c646dd ("freedreno/drm: Fix race in zombie import") Signed-off-by: Rob Clark <[email protected]> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26506> (cherry picked from commit f2e3285d8e2b72e7408845afa5402ce48c4e93a8) --- .pick_status.json | 2 +- src/freedreno/drm/freedreno_bo.c | 9 +++++++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/.pick_status.json b/.pick_status.json index 9452d8c40f2..73ed382a24b 100644 --- a/.pick_status.json +++ b/.pick_status.json @@ -404,7 +404,7 @@ "description": "freedreno/drm: Fix zombie BO import harder", "nominated": true, "nomination_type": 1, - "resolution": 0, + "resolution": 1, "main_sha": null, "because_sha": "6ac133c646dd4f6f9d8f644b24da6aeae95c1ce3", "notes": null diff --git a/src/freedreno/drm/freedreno_bo.c b/src/freedreno/drm/freedreno_bo.c index 3c8ed16a59f..7f4b57a6e56 100644 --- a/src/freedreno/drm/freedreno_bo.c +++ b/src/freedreno/drm/freedreno_bo.c @@ -64,6 +64,15 @@ lookup_bo(struct hash_table *tbl, uint32_t key) * checking for refcnt==0 (ie. 1 after p_atomic_inc_return). */ if (p_atomic_inc_return(&bo->refcnt) == 1) { + /* Restore the zombified reference count, so if another thread + * that ends up calling lookup_bo() gets the table_lock before + * the thread deleting the bo does, it doesn't mistakenly see + * that the BO is live. + * + * We are holding the table_lock here so we can't be racing + * with another caller of lookup_bo() + */ + p_atomic_dec(&bo->refcnt); return &zombie; }
