linux-kernel - [PATCH 4.14 044/138] nvme_fcloop: fix abort race condition

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Date:   Wed, 11 Apr 2018 00:23:54 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, James Smart <james.smart@...adcom.com>,
        Christoph Hellwig <hch@....de>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.14 044/138] nvme_fcloop: fix abort race condition

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Smart <jsmart2021@...il.com>


[ Upstream commit 278e096063f1914fccfc77a617be9fc8dbb31b0e ]

A test case revealed a race condition of an i/o completing on a thread
parallel to the delete_association generating the aborts for the
outstanding ios on the controller.  The i/o completion was freeing the
target fcloop context, thus the abort task referenced the just-freed
memory.

Correct by clearing the target/initiator cross pointers in the io
completion and abort tasks before calling the callbacks. On aborts
that detect already finished io's, ensure the complete context is
called.

Signed-off-by: James Smart <james.smart@...adcom.com>
Signed-off-by: Christoph Hellwig <hch@....de>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/nvme/target/fcloop.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/drivers/nvme/target/fcloop.c
+++ b/drivers/nvme/target/fcloop.c
@@ -374,6 +374,7 @@ fcloop_tgt_fcprqst_done_work(struct work
 
 	spin_lock(&tfcp_req->reqlock);
 	fcpreq = tfcp_req->fcpreq;
+	tfcp_req->fcpreq = NULL;
 	spin_unlock(&tfcp_req->reqlock);
 
 	if (tport->remoteport && fcpreq) {
@@ -615,11 +616,7 @@ fcloop_fcp_abort(struct nvme_fc_local_po
 
 	if (!tfcp_req)
 		/* abort has already been called */
-		return;
-
-	if (rport->targetport)
-		nvmet_fc_rcv_fcp_abort(rport->targetport,
-					&tfcp_req->tgt_fcp_req);
+		goto finish;
 
 	/* break initiator/target relationship for io */
 	spin_lock(&tfcp_req->reqlock);
@@ -627,6 +624,11 @@ fcloop_fcp_abort(struct nvme_fc_local_po
 	tfcp_req->fcpreq = NULL;
 	spin_unlock(&tfcp_req->reqlock);
 
+	if (rport->targetport)
+		nvmet_fc_rcv_fcp_abort(rport->targetport,
+					&tfcp_req->tgt_fcp_req);
+
+finish:
 	/* post the aborted io completion */
 	fcpreq->status = -ECANCELED;
 	schedule_work(&inireq->iniwork);