6.12-stable review patch. If anyone has any objections, please let me know.
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From: Yishai Hadas yishaih@nvidia.com
commit abb604a1a9c87255c7a6f3b784410a9707baf467 upstream.
This patch addresses a race condition for an ODP 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_invalidate_range() might be triggered by another task attempting to invalidate a range for the same freed lkey.
This task will: - Acquire the umem_odp->umem_mutex lock. - Call mlx5r_umr_update_xlt() on the UMR QP. - Since the lkey has already been freed, this can lead to a CQE error, causing the UMR QP to enter an error state [1].
To resolve this race condition, the umem_odp->umem_mutex lock is now also acquired as part of the mlx5_revoke_mr() scope. Upon successful revoke, we set umem_odp->private which points to that MR to NULL, preventing any further invalidation attempts on its lkey.
[1] From dmesg:
infiniband rocep8s0f0: dump_cqe:277:(pid 0): WC error: 6, Message: memory bind operation error cqe_dump: 00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 cqe_dump: 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 cqe_dump: 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 cqe_dump: 00000030: 00 00 00 00 08 00 78 06 25 00 11 b9 00 0e dd d2
WARNING: CPU: 15 PID: 1506 at drivers/infiniband/hw/mlx5/umr.c:394 mlx5r_umr_post_send_wait+0x15a/0x2b0 [mlx5_ib] Modules linked in: ip6table_mangle ip6table_natip6table_filter ip6_tables iptable_mangle xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi rdma_cm iw_cm ib_umad ib_ipoib ib_cm mlx5_ib ib_uverbs ib_core fuse mlx5_core CPU: 15 UID: 0 PID: 1506 Comm: ibv_rc_pingpong Not tainted 6.12.0-rc7+ #1626 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:mlx5r_umr_post_send_wait+0x15a/0x2b0 [mlx5_ib] [..] Call Trace: <TASK> mlx5r_umr_update_xlt+0x23c/0x3e0 [mlx5_ib] mlx5_ib_invalidate_range+0x2e1/0x330 [mlx5_ib] __mmu_notifier_invalidate_range_start+0x1e1/0x240 zap_page_range_single+0xf1/0x1a0 madvise_vma_behavior+0x677/0x6e0 do_madvise+0x1a2/0x4b0 __x64_sys_madvise+0x25/0x30 do_syscall_64+0x6b/0x140 entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fixes: e6fb246ccafb ("RDMA/mlx5: Consolidate MR destruction to mlx5_ib_dereg_mr()") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/r/68a1e007c25b2b8fe5d625f238cc3b63e5341f77.17372902... Signed-off-by: Yishai Hadas yishaih@nvidia.com Reviewed-by: Artemy Kovalyov artemyko@nvidia.com Signed-off-by: Leon Romanovsky leonro@nvidia.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/infiniband/hw/mlx5/mr.c | 17 +++++++++++++++-- drivers/infiniband/hw/mlx5/odp.c | 2 ++ 2 files changed, 17 insertions(+), 2 deletions(-)
--- a/drivers/infiniband/hw/mlx5/mr.c +++ b/drivers/infiniband/hw/mlx5/mr.c @@ -2021,6 +2021,11 @@ static int mlx5_revoke_mr(struct mlx5_ib { 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); + int ret = 0; + + if (is_odp) + mutex_lock(&to_ib_umem_odp(mr->umem)->umem_mutex);
if (mr->mmkey.cacheable && !mlx5r_umr_revoke_mr(mr) && !cache_ent_find_and_store(dev, mr)) { ent = mr->mmkey.cache_ent; @@ -2032,7 +2037,7 @@ static int mlx5_revoke_mr(struct mlx5_ib ent->tmp_cleanup_scheduled = true; } spin_unlock_irq(&ent->mkeys_queue.lock); - return 0; + goto out; }
if (ent) { @@ -2041,7 +2046,15 @@ static int mlx5_revoke_mr(struct mlx5_ib mr->mmkey.cache_ent = NULL; spin_unlock_irq(&ent->mkeys_queue.lock); } - return destroy_mkey(dev, mr); + ret = destroy_mkey(dev, mr); +out: + if (is_odp) { + if (!ret) + to_ib_umem_odp(mr->umem)->private = NULL; + mutex_unlock(&to_ib_umem_odp(mr->umem)->umem_mutex); + } + + return ret; }
static int __mlx5_ib_dereg_mr(struct ib_mr *ibmr) --- a/drivers/infiniband/hw/mlx5/odp.c +++ b/drivers/infiniband/hw/mlx5/odp.c @@ -282,6 +282,8 @@ static bool mlx5_ib_invalidate_range(str if (!umem_odp->npages) goto out; mr = umem_odp->private; + if (!mr) + goto out;
start = max_t(u64, ib_umem_start(umem_odp), range->start); end = min_t(u64, ib_umem_end(umem_odp), range->end);