From 4d809f69695d4e7d1378b3a072fa9aef23123018 Mon Sep 17 00:00:00 2001 From: Niels Dossche Date: Mon, 28 Feb 2022 17:53:30 +0100 Subject: [PATCH] IB/rdmavt: add lock to call to rvt_error_qp to prevent a race condition The documentation of the function rvt_error_qp says both r_lock and s_lock need to be held when calling that function. It also asserts using lockdep that both of those locks are held. However, the commit I referenced in Fixes accidentally makes the call to rvt_error_qp in rvt_ruc_loopback no longer covered by r_lock. This results in the lockdep assertion failing and also possibly in a race condition. Fixes: d757c60eca9b ("IB/rdmavt: Fix concurrency panics in QP post_send and modify to error") Link: https://lore.kernel.org/r/20220228165330.41546-1-dossche.niels@gmail.com Signed-off-by: Niels Dossche Acked-by: Dennis Dalessandro Signed-off-by: Jason Gunthorpe --- drivers/infiniband/sw/rdmavt/qp.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/sw/rdmavt/qp.c b/drivers/infiniband/sw/rdmavt/qp.c index ae50b56e8913..8ef112f883a7 100644 --- a/drivers/infiniband/sw/rdmavt/qp.c +++ b/drivers/infiniband/sw/rdmavt/qp.c @@ -3190,7 +3190,11 @@ void rvt_ruc_loopback(struct rvt_qp *sqp) spin_lock_irqsave(&sqp->s_lock, flags); rvt_send_complete(sqp, wqe, send_status); if (sqp->ibqp.qp_type == IB_QPT_RC) { - int lastwqe = rvt_error_qp(sqp, IB_WC_WR_FLUSH_ERR); + int lastwqe; + + spin_lock(&sqp->r_lock); + lastwqe = rvt_error_qp(sqp, IB_WC_WR_FLUSH_ERR); + spin_unlock(&sqp->r_lock); sqp->s_flags &= ~RVT_S_BUSY; spin_unlock_irqrestore(&sqp->s_lock, flags);