RDMA/mlx5: Handle DCT QP logic separately from low level QP interface

Previously when destroying a DCT, if the firmware function for the
destruction failed, the common resource would have been destroyed
either way, since it was destroyed before the firmware object.
Which leads to kernel warning "refcount_t: underflow" which indicates
possible use-after-free.
Which is triggered when we try to destroy the common resource for the
second time and execute refcount_dec_and_test(&common->refcount).

So, let's fix the destruction order by factoring out the DCT QP logic
to be in separate XArray database.

refcount_t: underflow; use-after-free.
WARNING: CPU: 8 PID: 1002 at lib/refcount.c:28 refcount_warn_saturate+0xd8/0xe0
Modules linked in: xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm mlx5_ib ib_uverbs ib_core overlay mlx5_core fuse
CPU: 8 PID: 1002 Comm: python3 Not tainted 5.16.0-rc5+ #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
RIP: 0010:refcount_warn_saturate+0xd8/0xe0
Code: ff 48 c7 c7 18 f5 23 82 c6 05 60 70 ff 00 01 e8 d0 0a 45 00 0f 0b c3 48 c7 c7 c0 f4 23 82 c6 05 4c 70 ff 00 01 e8 ba 0a 45 00 <0f> 0b c3 0f 1f 44 00 00 8b 07 3d 00 00 00 c0 74 12 83 f8 01 74 13
RSP: 0018:ffff8881221d3aa8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff8881313e8d40 RCX: ffff88852cc1b5c8
RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff88852cc1b5c0
RBP: ffff888100f70000 R08: ffff88853ffd1ba8 R09: 0000000000000003
R10: 00000000fffff000 R11: 3fffffffffffffff R12: 0000000000000246
R13: ffff888100f71fa0 R14: ffff8881221d3c68 R15: 0000000000000020
FS:  00007efebbb13740(0000) GS:ffff88852cc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005611aac29f80 CR3: 00000001313de004 CR4: 0000000000370ea0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 destroy_resource_common+0x6e/0x95 [mlx5_ib]
 mlx5_core_destroy_rq_tracked+0x38/0xbe [mlx5_ib]
 mlx5_ib_destroy_wq+0x22/0x80 [mlx5_ib]
 ib_destroy_wq_user+0x1f/0x40 [ib_core]
 uverbs_free_wq+0x19/0x40 [ib_uverbs]
 destroy_hw_idr_uobject+0x18/0x50 [ib_uverbs]
 uverbs_destroy_uobject+0x2f/0x190 [ib_uverbs]
 uobj_destroy+0x3c/0x80 [ib_uverbs]
 ib_uverbs_cmd_verbs+0x3e4/0xb80 [ib_uverbs]
 ? uverbs_free_wq+0x40/0x40 [ib_uverbs]
 ? ip_list_rcv+0xf7/0x120
 ? netif_receive_skb_list_internal+0x1b6/0x2d0
 ? task_tick_fair+0xbf/0x450
 ? __handle_mm_fault+0x11fc/0x1450
 ib_uverbs_ioctl+0xa4/0x110 [ib_uverbs]
 __x64_sys_ioctl+0x3e4/0x8e0
 ? handle_mm_fault+0xb9/0x210
 do_syscall_64+0x3d/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7efebc0be17b
Code: 0f 1e fa 48 8b 05 1d ad 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ed ac 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffe71813e78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffe71813fb8 RCX: 00007efebc0be17b
RDX: 00007ffe71813fa0 RSI: 00000000c0181b01 RDI: 0000000000000005
RBP: 00007ffe71813f80 R08: 00005611aae96020 R09: 000000000000004f
R10: 00007efebbf9ffa0 R11: 0000000000000246 R12: 00007ffe71813f80
R13: 00007ffe71813f4c R14: 00005611aae2eca0 R15: 00007efeae6c89d0
 </TASK>

Signed-off-by: Patrisious Haddad <phaddad@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/4470888466c8a898edc9833286967529cc5f3c0d.1685953497.git.leon@kernel.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>

diff --git a/drivers/infiniband/hw/mlx5/qp.h b/drivers/infiniband/hw/mlx5/qp.h
index f5130873dd52457f7549526dbbb046c9a9ccd339..b6ee7c3ee1ca1b1a96ce4994cfaaf7d000828727 100644 (file)
--- a/drivers/infiniband/hw/mlx5/qp.h
+++ b/drivers/infiniband/hw/mlx5/qp.h
@@ -10,6 +10,7 @@ struct mlx5_ib_dev;
 
 struct mlx5_qp_table {
        struct notifier_block nb;
+       struct xarray dct_xa;
 
        /* protect radix tree
         */

diff --git a/drivers/infiniband/hw/mlx5/qpc.c b/drivers/infiniband/hw/mlx5/qpc.c
index bae0334d6e7f18bc1b0a746379f053961bd88520..3a2f755d4985e4864477fadd5b12fe9feb27d855 100644 (file)
--- a/drivers/infiniband/hw/mlx5/qpc.c
+++ b/drivers/infiniband/hw/mlx5/qpc.c
@@ -88,23 +88,35 @@ static bool is_event_type_allowed(int rsc_type, int event_type)
        }
 }
 
+static int dct_event_notifier(struct mlx5_ib_dev *dev, struct mlx5_eqe *eqe)
+{
+       struct mlx5_core_dct *dct;
+       unsigned long flags;
+       u32 qpn;
+
+       qpn = be32_to_cpu(eqe->data.dct.dctn) & 0xFFFFFF;
+       xa_lock_irqsave(&dev->qp_table.dct_xa, flags);
+       dct = xa_load(&dev->qp_table.dct_xa, qpn);
+       if (dct)
+               complete(&dct->drained);
+       xa_unlock_irqrestore(&dev->qp_table.dct_xa, flags);
+       return NOTIFY_OK;
+}
+
 static int rsc_event_notifier(struct notifier_block *nb,
                              unsigned long type, void *data)
 {
+       struct mlx5_ib_dev *dev =
+               container_of(nb, struct mlx5_ib_dev, qp_table.nb);
        struct mlx5_core_rsc_common *common;
-       struct mlx5_qp_table *table;
-       struct mlx5_core_dct *dct;
+       struct mlx5_eqe *eqe = data;
        u8 event_type = (u8)type;
        struct mlx5_core_qp *qp;
-       struct mlx5_eqe *eqe;
        u32 rsn;
 
        switch (event_type) {
        case MLX5_EVENT_TYPE_DCT_DRAINED:
-               eqe = data;
-               rsn = be32_to_cpu(eqe->data.dct.dctn) & 0xffffff;
-               rsn |= (MLX5_RES_DCT << MLX5_USER_INDEX_LEN);
-               break;
+               return dct_event_notifier(dev, eqe);
        case MLX5_EVENT_TYPE_PATH_MIG:
        case MLX5_EVENT_TYPE_COMM_EST:
        case MLX5_EVENT_TYPE_SQ_DRAINED:
@@ -113,7 +125,6 @@ static int rsc_event_notifier(struct notifier_block *nb,
        case MLX5_EVENT_TYPE_PATH_MIG_FAILED:
        case MLX5_EVENT_TYPE_WQ_INVAL_REQ_ERROR:
        case MLX5_EVENT_TYPE_WQ_ACCESS_ERROR:
-               eqe = data;
                rsn = be32_to_cpu(eqe->data.qp_srq.qp_srq_n) & 0xffffff;
                rsn |= (eqe->data.qp_srq.type << MLX5_USER_INDEX_LEN);
                break;
@@ -121,8 +132,7 @@ static int rsc_event_notifier(struct notifier_block *nb,
                return NOTIFY_DONE;
        }
 
-       table = container_of(nb, struct mlx5_qp_table, nb);
-       common = mlx5_get_rsc(table, rsn);
+       common = mlx5_get_rsc(&dev->qp_table, rsn);
        if (!common)
                return NOTIFY_OK;
 
@@ -137,11 +147,6 @@ static int rsc_event_notifier(struct notifier_block *nb,
                qp->event(qp, event_type);
                /* Need to put resource in event handler */
                return NOTIFY_OK;
-       case MLX5_RES_DCT:
-               dct = (struct mlx5_core_dct *)common;
-               if (event_type == MLX5_EVENT_TYPE_DCT_DRAINED)
-                       complete(&dct->drained);
-               break;
        default:
                break;
        }
@@ -188,28 +193,15 @@ static void destroy_resource_common(struct mlx5_ib_dev *dev,
 }
 
 static int _mlx5_core_destroy_dct(struct mlx5_ib_dev *dev,
-                                 struct mlx5_core_dct *dct, bool need_cleanup)
+                                 struct mlx5_core_dct *dct)
 {
        u32 in[MLX5_ST_SZ_DW(destroy_dct_in)] = {};
        struct mlx5_core_qp *qp = &dct->mqp;
-       int err;
 
-       err = mlx5_core_drain_dct(dev, dct);
-       if (err) {
-               if (dev->mdev->state == MLX5_DEVICE_STATE_INTERNAL_ERROR)
-                       goto destroy;
-
-               return err;
-       }
-       wait_for_completion(&dct->drained);
-destroy:
-       if (need_cleanup)
-               destroy_resource_common(dev, &dct->mqp);
        MLX5_SET(destroy_dct_in, in, opcode, MLX5_CMD_OP_DESTROY_DCT);
        MLX5_SET(destroy_dct_in, in, dctn, qp->qpn);
        MLX5_SET(destroy_dct_in, in, uid, qp->uid);
-       err = mlx5_cmd_exec_in(dev->mdev, destroy_dct, in);
-       return err;
+       return mlx5_cmd_exec_in(dev->mdev, destroy_dct, in);
 }
 
 int mlx5_core_create_dct(struct mlx5_ib_dev *dev, struct mlx5_core_dct *dct,
@@ -227,13 +219,13 @@ int mlx5_core_create_dct(struct mlx5_ib_dev *dev, struct mlx5_core_dct *dct,
 
        qp->qpn = MLX5_GET(create_dct_out, out, dctn);
        qp->uid = MLX5_GET(create_dct_in, in, uid);
-       err = create_resource_common(dev, qp, MLX5_RES_DCT);
+       err = xa_err(xa_store_irq(&dev->qp_table.dct_xa, qp->qpn, dct, GFP_KERNEL));
        if (err)
                goto err_cmd;
 
        return 0;
 err_cmd:
-       _mlx5_core_destroy_dct(dev, dct, false);
+       _mlx5_core_destroy_dct(dev, dct);
        return err;
 }
 
@@ -284,7 +276,31 @@ static int mlx5_core_drain_dct(struct mlx5_ib_dev *dev,
 int mlx5_core_destroy_dct(struct mlx5_ib_dev *dev,
                          struct mlx5_core_dct *dct)
 {
-       return _mlx5_core_destroy_dct(dev, dct, true);
+       struct mlx5_qp_table *table = &dev->qp_table;
+       struct mlx5_core_dct *tmp;
+       int err;
+
+       err = mlx5_core_drain_dct(dev, dct);
+       if (err) {
+               if (dev->mdev->state == MLX5_DEVICE_STATE_INTERNAL_ERROR)
+                       goto destroy;
+
+               return err;
+       }
+       wait_for_completion(&dct->drained);
+
+destroy:
+       tmp = xa_cmpxchg_irq(&table->dct_xa, dct->mqp.qpn, dct, XA_ZERO_ENTRY, GFP_KERNEL);
+       if (WARN_ON(tmp != dct))
+               return xa_err(tmp) ?: -EINVAL;
+
+       err = _mlx5_core_destroy_dct(dev, dct);
+       if (err) {
+               xa_cmpxchg_irq(&table->dct_xa, dct->mqp.qpn, XA_ZERO_ENTRY, dct, 0);
+               return err;
+       }
+       xa_erase_irq(&table->dct_xa, dct->mqp.qpn);
+       return 0;
 }
 
 int mlx5_core_destroy_qp(struct mlx5_ib_dev *dev, struct mlx5_core_qp *qp)
@@ -488,6 +504,7 @@ int mlx5_init_qp_table(struct mlx5_ib_dev *dev)
 
        spin_lock_init(&table->lock);
        INIT_RADIX_TREE(&table->tree, GFP_ATOMIC);
+       xa_init(&table->dct_xa);
        mlx5_qp_debugfs_init(dev->mdev);
 
        table->nb.notifier_call = rsc_event_notifier;

diff --git a/include/linux/mlx5/driver.h b/include/linux/mlx5/driver.h
index e3b616388b18f0819f85a62755d6b0b40274516a..e67c603d507bb3e5f8947f62a737e76514663dee 100644 (file)
--- a/include/linux/mlx5/driver.h
+++ b/include/linux/mlx5/driver.h
@@ -382,7 +382,6 @@ enum mlx5_res_type {
        MLX5_RES_SRQ    = 3,
        MLX5_RES_XSRQ   = 4,
        MLX5_RES_XRQ    = 5,
-       MLX5_RES_DCT    = MLX5_EVENT_QUEUE_TYPE_DCT,
 };
 
 struct mlx5_core_rsc_common {