RDMA/cm: Fix IRQ restore in ib_send_cm_sidr_rep

ib_send_cm_sidr_rep() {
	spin_lock_irqsave()
        cm_send_sidr_rep_locked() {
                ...
        	spin_lock_irq()
                ....
                spin_unlock_irq() <--- this will enable interrupts
        }
        spin_unlock_irqrestore()
}

spin_unlock_irqrestore() expects interrupts to be disabled but the
internal spin_unlock_irq() will always enable hard interrupts.

Fix this by replacing the internal spin_{lock,unlock}_irq() with
irqsave/restore variants.

It fixes the following kernel trace:

 raw_local_irq_restore() called with IRQs enabled
 WARNING: CPU: 2 PID: 20001 at kernel/locking/irqflag-debug.c:10 warn_bogus_irq_restore+0x1d/0x20

 Call Trace:
  _raw_spin_unlock_irqrestore+0x4e/0x50
  ib_send_cm_sidr_rep+0x3a/0x50 [ib_cm]
  cma_send_sidr_rep+0xa1/0x160 [rdma_cm]
  rdma_accept+0x25e/0x350 [rdma_cm]
  ucma_accept+0x132/0x1cc [rdma_ucm]
  ucma_write+0xbf/0x140 [rdma_ucm]
  vfs_write+0xc1/0x340
  ksys_write+0xb3/0xe0
  do_syscall_64+0x2d/0x40
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 87c4c774cbef ("RDMA/cm: Protect access to remote_sidr_table")
Link: https://lore.kernel.org/r/20210301081844.445823-1-leon@kernel.org
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index be996dba040ccf8f56effc3685e01db1fba86444..3d194bb608405de1f8f925395311d13c46b9ba17 100644 (file)
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -3651,6 +3651,7 @@ static int cm_send_sidr_rep_locked(struct cm_id_private *cm_id_priv,
                                   struct ib_cm_sidr_rep_param *param)
 {
        struct ib_mad_send_buf *msg;
+       unsigned long flags;
        int ret;
 
        lockdep_assert_held(&cm_id_priv->lock);
@@ -3676,12 +3677,12 @@ static int cm_send_sidr_rep_locked(struct cm_id_private *cm_id_priv,
                return ret;
        }
        cm_id_priv->id.state = IB_CM_IDLE;
-       spin_lock_irq(&cm.lock);
+       spin_lock_irqsave(&cm.lock, flags);
        if (!RB_EMPTY_NODE(&cm_id_priv->sidr_id_node)) {
                rb_erase(&cm_id_priv->sidr_id_node, &cm.remote_sidr_table);
                RB_CLEAR_NODE(&cm_id_priv->sidr_id_node);
        }
-       spin_unlock_irq(&cm.lock);
+       spin_unlock_irqrestore(&cm.lock, flags);
        return 0;
 }