From 82ea790afe2726f0bb01a09e234be31bb6c7749b Mon Sep 17 00:00:00 2001 From: Steve Wise Date: Fri, 31 Aug 2018 07:15:56 -0700 Subject: iw_cxgb4: only allow 1 flush on user qps commit 308aa2b8f7b7db3332a7d41099fd37851fb793b2 upstream. Once the qp has been flushed, it cannot be flushed again. The user qp flush logic wasn't enforcing it however. The bug can cause touch-after-free crashes like: Unable to handle kernel paging request for data at address 0x000001ec Faulting instruction address: 0xc008000016069100 Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [c008000016069100] flush_qp+0x80/0x480 [iw_cxgb4] LR [c00800001606cd6c] c4iw_modify_qp+0x71c/0x11d0 [iw_cxgb4] Call Trace: [c00800001606cd6c] c4iw_modify_qp+0x71c/0x11d0 [iw_cxgb4] [c00800001606e868] c4iw_ib_modify_qp+0x118/0x200 [iw_cxgb4] [c0080000119eae80] ib_security_modify_qp+0xd0/0x3d0 [ib_core] [c0080000119c4e24] ib_modify_qp+0xc4/0x2c0 [ib_core] [c008000011df0284] iwcm_modify_qp_err+0x44/0x70 [iw_cm] [c008000011df0fec] destroy_cm_id+0xcc/0x370 [iw_cm] [c008000011ed4358] rdma_destroy_id+0x3c8/0x520 [rdma_cm] [c0080000134b0540] ucma_close+0x90/0x1b0 [rdma_ucm] [c000000000444da4] __fput+0xe4/0x2f0 So fix flush_qp() to only flush the wq once. Cc: stable@vger.kernel.org Signed-off-by: Steve Wise Signed-off-by: Jason Gunthorpe Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/hw/cxgb4/qp.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/infiniband') diff --git a/drivers/infiniband/hw/cxgb4/qp.c b/drivers/infiniband/hw/cxgb4/qp.c index 53aa7515f542..04206c600098 100644 --- a/drivers/infiniband/hw/cxgb4/qp.c +++ b/drivers/infiniband/hw/cxgb4/qp.c @@ -1183,6 +1183,12 @@ static void flush_qp(struct c4iw_qp *qhp) t4_set_wq_in_error(&qhp->wq); if (qhp->ibqp.uobject) { + + /* for user qps, qhp->wq.flushed is protected by qhp->mutex */ + if (qhp->wq.flushed) + return; + + qhp->wq.flushed = 1; t4_set_cq_in_error(&rchp->cq); spin_lock_irqsave(&rchp->comp_handler_lock, flag); (*rchp->ibcq.comp_handler)(&rchp->ibcq, rchp->ibcq.cq_context); -- cgit v1.2.3