6.12-stable review patch. If anyone has any objections, please let me know.
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From: Yishai Hadas yishaih@nvidia.com
[ Upstream commit cc668a11e6ac8adb0e016711080d3f314722cc91 ]
This patch addresses a potential race condition for a DMABUF MR that can result in a CQE with an error on the UMR QP.
During the __mlx5_ib_dereg_mr() flow, the following sequence of calls occurs: mlx5_revoke_mr() mlx5r_umr_revoke_mr() mlx5r_umr_post_send_wait() At this point, the lkey is freed from the hardware's perspective.
However, concurrently, mlx5_ib_dmabuf_invalidate_cb() might be triggered by another task attempting to invalidate the MR having that freed lkey.
Since the lkey has already been freed, this can lead to a CQE error, causing the UMR QP to enter an error state.
To resolve this race condition, the dma_resv_lock() which was hold as part of the mlx5_ib_dmabuf_invalidate_cb() is now also acquired as part of the mlx5_revoke_mr() scope.
Upon a successful revoke, we set umem_dmabuf->private which points to that MR to NULL, preventing any further invalidation attempts on its lkey.
Fixes: e6fb246ccafb ("RDMA/mlx5: Consolidate MR destruction to mlx5_ib_dereg_mr()") Signed-off-by: Yishai Hadas yishaih@nvidia.com Reviewed-by: Artemy Kovalyov artemyko@mnvidia.com Link: https://patch.msgid.link/70617067abbfaa0c816a2544c922e7f4346def58.1738587016... Signed-off-by: Leon Romanovsky leon@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/hw/mlx5/mr.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c index bb02b6adbf2c2..0a3cbb14e1839 100644 --- a/drivers/infiniband/hw/mlx5/mr.c +++ b/drivers/infiniband/hw/mlx5/mr.c @@ -1550,7 +1550,7 @@ static void mlx5_ib_dmabuf_invalidate_cb(struct dma_buf_attachment *attach)
dma_resv_assert_held(umem_dmabuf->attach->dmabuf->resv);
- if (!umem_dmabuf->sgt) + if (!umem_dmabuf->sgt || !mr) return;
mlx5r_umr_update_mr_pas(mr, MLX5_IB_UPD_XLT_ZAP); @@ -2022,11 +2022,16 @@ static int mlx5_revoke_mr(struct mlx5_ib_mr *mr) struct mlx5_ib_dev *dev = to_mdev(mr->ibmr.device); struct mlx5_cache_ent *ent = mr->mmkey.cache_ent; bool is_odp = is_odp_mr(mr); + bool is_odp_dma_buf = is_dmabuf_mr(mr) && + !to_ib_umem_dmabuf(mr->umem)->pinned; int ret = 0;
if (is_odp) mutex_lock(&to_ib_umem_odp(mr->umem)->umem_mutex);
+ if (is_odp_dma_buf) + dma_resv_lock(to_ib_umem_dmabuf(mr->umem)->attach->dmabuf->resv, NULL); + if (mr->mmkey.cacheable && !mlx5r_umr_revoke_mr(mr) && !cache_ent_find_and_store(dev, mr)) { ent = mr->mmkey.cache_ent; /* upon storing to a clean temp entry - schedule its cleanup */ @@ -2054,6 +2059,12 @@ static int mlx5_revoke_mr(struct mlx5_ib_mr *mr) mutex_unlock(&to_ib_umem_odp(mr->umem)->umem_mutex); }
+ if (is_odp_dma_buf) { + if (!ret) + to_ib_umem_dmabuf(mr->umem)->private = NULL; + dma_resv_unlock(to_ib_umem_dmabuf(mr->umem)->attach->dmabuf->resv); + } + return ret; }