From: Jason Gunthorpe <jgg@nvidia.com> mainline inclusion from mainline-v7.1-rc3 commit c9341307ea16b9395c2e4c9c94d8499d91fe31d0 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15458 CVE: CVE-2026-46181 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Sashiko points out the radix_tree itself is RCU safe, but nothing ever frees the mlx4_srq struct with RCU, and it isn't even accessed within the RCU critical section. It also will crash if an event is delivered before the srq object is finished initializing. Use the spinlock since it isn't easy to make RCU work, use refcount_inc_not_zero() to protect against partially initialized objects, and order the refcount_set() to be after the srq is fully initialized. Cc: stable@vger.kernel.org Fixes: 30353bfc43a1 ("net/mlx4_core: Use RCU to perform radix tree lookup for SRQ") Link: https://sashiko.dev/#/patchset/0-v2-1c49eeb88c48%2B91-rdma_udata_rep_jgg%40n... Link: https://patch.msgid.link/r/12-v1-41f3135e5565+9d2-rdma_ai_fixes1_jgg@nvidia.... Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Cai Xinchen <caixinchen1@huawei.com> --- drivers/net/ethernet/mellanox/mlx4/srq.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/srq.c b/drivers/net/ethernet/mellanox/mlx4/srq.c index dd890f5d7b72..8711689120f3 100644 --- a/drivers/net/ethernet/mellanox/mlx4/srq.c +++ b/drivers/net/ethernet/mellanox/mlx4/srq.c @@ -44,13 +44,14 @@ void mlx4_srq_event(struct mlx4_dev *dev, u32 srqn, int event_type) { struct mlx4_srq_table *srq_table = &mlx4_priv(dev)->srq_table; struct mlx4_srq *srq; + unsigned long flags; - rcu_read_lock(); + spin_lock_irqsave(&srq_table->lock, flags); srq = radix_tree_lookup(&srq_table->tree, srqn & (dev->caps.num_srqs - 1)); - rcu_read_unlock(); - if (srq) - refcount_inc(&srq->refcount); - else { + if (!srq || !refcount_inc_not_zero(&srq->refcount)) + srq = NULL; + spin_unlock_irqrestore(&srq_table->lock, flags); + if (!srq) { mlx4_warn(dev, "Async event for bogus SRQ %08x\n", srqn); return; } @@ -203,8 +204,8 @@ int mlx4_srq_alloc(struct mlx4_dev *dev, u32 pdn, u32 cqn, u16 xrcd, if (err) goto err_radix; - refcount_set(&srq->refcount, 1); init_completion(&srq->free); + refcount_set_release(&srq->refcount, 1); return 0; -- 2.34.1