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Commit 4c2a2d01 authored by Quinn Tran's avatar Quinn Tran Committed by Martin K. Petersen
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scsi: qla2xxx: Fix NVME cmd and LS cmd timeout race condition 



This patch uses kref to protect access between fcp_abort path and nvme
command and LS command completion path.  Stack trace below shows the abort
path is accessing stale memory (nvme_private->sp).

When command kref reaches 0, nvme_private & srb resource will be
disconnected from each other.  Any subsequence nvme abort request will not
be able to reference the original srb.

[ 5631.003998] BUG: unable to handle kernel paging request at 00000010000005d8
[ 5631.004016] IP: [<ffffffffc087df92>] qla_nvme_abort_work+0x22/0x100 [qla2xxx]
[ 5631.004086] Workqueue: events qla_nvme_abort_work [qla2xxx]
[ 5631.004097] RIP: 0010:[<ffffffffc087df92>]  [<ffffffffc087df92>] qla_nvme_abort_work+0x22/0x100 [qla2xxx]
[ 5631.004109] Call Trace:
[ 5631.004115]  [<ffffffffaa4b8174>] ? pwq_dec_nr_in_flight+0x64/0xb0
[ 5631.004117]  [<ffffffffaa4b9d4f>] process_one_work+0x17f/0x440
[ 5631.004120]  [<ffffffffaa4bade6>] worker_thread+0x126/0x3c0

Signed-off-by: default avatarQuinn Tran <qutran@marvell.com>
Signed-off-by: default avatarHimanshu Madhani <hmadhani@marvell.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 2eb9238a

drivers/scsi/qla2xxx/qla_def.h

+3 −0
Original line number Diff line number Diff line
@@ -532,6 +532,8 @@ typedef struct srb { 
	uint8_t cmd_type;

	uint8_t pad[3];

	atomic_t ref_count;

	struct kref cmd_kref;	/* need to migrate ref_count over to this */

	void *priv;

	wait_queue_head_t nvme_ls_waitq;

	struct fc_port *fcport;

	struct scsi_qla_host *vha;
@@ -554,6 +556,7 @@ typedef struct srb { 
	} u;

	void (*done)(void *, int);

	void (*free)(void *);

	void (*put_fn)(struct kref *kref);

} srb_t;



#define GET_CMD_SP(sp) (sp->u.scmd.cmd)

drivers/scsi/qla2xxx/qla_nvme.c

+113 −50
Original line number Diff line number Diff line
@@ -123,53 +123,91 @@ static int qla_nvme_alloc_queue(struct nvme_fc_local_port *lport, 
	return 0;

}



static void qla_nvme_sp_ls_done(void *ptr, int res)

static void qla_nvme_release_fcp_cmd_kref(struct kref *kref)

{

	srb_t *sp = ptr;

	struct srb *sp = container_of(kref, struct srb, cmd_kref);

	struct nvme_private *priv = (struct nvme_private *)sp->priv;

	struct nvmefc_fcp_req *fd;

	struct srb_iocb *nvme;

	unsigned long flags;



	if (!priv)

		goto out;



	nvme = &sp->u.iocb_cmd;

	fd = nvme->u.nvme.desc;



	spin_lock_irqsave(&priv->cmd_lock, flags);

	priv->sp = NULL;

	sp->priv = NULL;

	if (priv->comp_status == QLA_SUCCESS) {

		fd->rcv_rsplen = nvme->u.nvme.rsp_pyld_len;

	} else {

		fd->rcv_rsplen = 0;

		fd->transferred_length = 0;

	}

	fd->status = 0;

	spin_unlock_irqrestore(&priv->cmd_lock, flags);



	fd->done(fd);

out:

	qla2xxx_rel_qpair_sp(sp->qpair, sp);

}



static void qla_nvme_release_ls_cmd_kref(struct kref *kref)

{

	struct srb *sp = container_of(kref, struct srb, cmd_kref);

	struct nvme_private *priv = (struct nvme_private *)sp->priv;

	struct nvmefc_ls_req *fd;

	unsigned long flags;



	if (!priv)

		goto out;



	spin_lock_irqsave(&priv->cmd_lock, flags);

	priv->sp = NULL;

	sp->priv = NULL;

	spin_unlock_irqrestore(&priv->cmd_lock, flags);



	fd = priv->fd;

	fd->done(fd, priv->comp_status);

out:

	qla2x00_rel_sp(sp);

}



static void qla_nvme_ls_complete(struct work_struct *work)

{

	struct nvme_private *priv =

		container_of(work, struct nvme_private, ls_work);



	kref_put(&priv->sp->cmd_kref, qla_nvme_release_ls_cmd_kref);

}



static void qla_nvme_sp_ls_done(void *ptr, int res)

{

	srb_t *sp = ptr;

	struct nvme_private *priv;



	if (WARN_ON_ONCE(atomic_read(&sp->ref_count) == 0))

	if (WARN_ON_ONCE(kref_read(&sp->cmd_kref) == 0))

		return;



	atomic_dec(&sp->ref_count);



	if (res)

		res = -EINVAL;



	nvme = &sp->u.iocb_cmd;

	fd = nvme->u.nvme.desc;

	priv = fd->private;

	priv = (struct nvme_private *)sp->priv;

	priv->comp_status = res;

	INIT_WORK(&priv->ls_work, qla_nvme_ls_complete);

	schedule_work(&priv->ls_work);

	/* work schedule doesn't need the sp */

	qla2x00_rel_sp(sp);

}



/* it assumed that QPair lock is held. */

static void qla_nvme_sp_done(void *ptr, int res)

{

	srb_t *sp = ptr;

	struct srb_iocb *nvme;

	struct nvmefc_fcp_req *fd;

	struct nvme_private *priv = (struct nvme_private *)sp->priv;



	nvme = &sp->u.iocb_cmd;

	fd = nvme->u.nvme.desc;



	if (WARN_ON_ONCE(atomic_read(&sp->ref_count) == 0))

		return;



	atomic_dec(&sp->ref_count);



	if (res == QLA_SUCCESS) {

		fd->rcv_rsplen = nvme->u.nvme.rsp_pyld_len;

	} else {

		fd->rcv_rsplen = 0;

		fd->transferred_length = 0;

	}

	fd->status = 0;

	fd->done(fd);

	qla2xxx_rel_qpair_sp(sp->qpair, sp);

	priv->comp_status = res;

	kref_put(&sp->cmd_kref, qla_nvme_release_fcp_cmd_kref);



	return;

}
@@ -188,45 +226,51 @@ static void qla_nvme_abort_work(struct work_struct *work) 
	       __func__, sp, sp->handle, fcport, fcport->deleted);



	if (!ha->flags.fw_started && (fcport && fcport->deleted))

		return;

		goto out;



	if (ha->flags.host_shutting_down) {

		ql_log(ql_log_info, sp->fcport->vha, 0xffff,

		    "%s Calling done on sp: %p, type: 0x%x, sp->ref_count: 0x%x\n",

		    __func__, sp, sp->type, atomic_read(&sp->ref_count));

		sp->done(sp, 0);

		return;

		goto out;

	}



	if (WARN_ON_ONCE(atomic_read(&sp->ref_count) == 0))

		return;



	rval = ha->isp_ops->abort_command(sp);



	ql_dbg(ql_dbg_io, fcport->vha, 0x212b,

	    "%s: %s command for sp=%p, handle=%x on fcport=%p rval=%x\n",

	    __func__, (rval != QLA_SUCCESS) ? "Failed to abort" : "Aborted",

	    sp, sp->handle, fcport, rval);



out:

	/* kref_get was done before work was schedule. */

	kref_put(&sp->cmd_kref, sp->put_fn);

}



static void qla_nvme_ls_abort(struct nvme_fc_local_port *lport,

    struct nvme_fc_remote_port *rport, struct nvmefc_ls_req *fd)

{

	struct nvme_private *priv = fd->private;

	unsigned long flags;



	INIT_WORK(&priv->abort_work, qla_nvme_abort_work);

	schedule_work(&priv->abort_work);

	spin_lock_irqsave(&priv->cmd_lock, flags);

	if (!priv->sp) {

		spin_unlock_irqrestore(&priv->cmd_lock, flags);

		return;

	}



static void qla_nvme_ls_complete(struct work_struct *work)

{

	struct nvme_private *priv =

	    container_of(work, struct nvme_private, ls_work);

	struct nvmefc_ls_req *fd = priv->fd;

	if (!kref_get_unless_zero(&priv->sp->cmd_kref)) {

		spin_unlock_irqrestore(&priv->cmd_lock, flags);

		return;

	}

	spin_unlock_irqrestore(&priv->cmd_lock, flags);



	fd->done(fd, priv->comp_status);

	INIT_WORK(&priv->abort_work, qla_nvme_abort_work);

	schedule_work(&priv->abort_work);

}





static int qla_nvme_ls_req(struct nvme_fc_local_port *lport,

    struct nvme_fc_remote_port *rport, struct nvmefc_ls_req *fd)

{
@@ -257,11 +301,13 @@ static int qla_nvme_ls_req(struct nvme_fc_local_port *lport, 
	sp->type = SRB_NVME_LS;

	sp->name = "nvme_ls";

	sp->done = qla_nvme_sp_ls_done;

	atomic_set(&sp->ref_count, 1);

	nvme = &sp->u.iocb_cmd;

	sp->put_fn = qla_nvme_release_ls_cmd_kref;

	sp->priv = (void *)priv;

	priv->sp = sp;

	kref_init(&sp->cmd_kref);

	spin_lock_init(&priv->cmd_lock);

	nvme = &sp->u.iocb_cmd;

	priv->fd = fd;

	INIT_WORK(&priv->ls_work, qla_nvme_ls_complete);

	nvme->u.nvme.desc = fd;

	nvme->u.nvme.dir = 0;

	nvme->u.nvme.dl = 0;
@@ -278,9 +324,10 @@ static int qla_nvme_ls_req(struct nvme_fc_local_port *lport, 
	if (rval != QLA_SUCCESS) {

		ql_log(ql_log_warn, vha, 0x700e,

		    "qla2x00_start_sp failed = %d\n", rval);

		atomic_dec(&sp->ref_count);

		wake_up(&sp->nvme_ls_waitq);

		sp->free(sp);

		sp->priv = NULL;

		priv->sp = NULL;

		qla2x00_rel_sp(sp);

		return rval;

	}
@@ -292,6 +339,18 @@ static void qla_nvme_fcp_abort(struct nvme_fc_local_port *lport, 
    struct nvmefc_fcp_req *fd)

{

	struct nvme_private *priv = fd->private;

	unsigned long flags;



	spin_lock_irqsave(&priv->cmd_lock, flags);

	if (!priv->sp) {

		spin_unlock_irqrestore(&priv->cmd_lock, flags);

		return;

	}

	if (!kref_get_unless_zero(&priv->sp->cmd_kref)) {

		spin_unlock_irqrestore(&priv->cmd_lock, flags);

		return;

	}

	spin_unlock_irqrestore(&priv->cmd_lock, flags);



	INIT_WORK(&priv->abort_work, qla_nvme_abort_work);

	schedule_work(&priv->abort_work);
@@ -515,12 +574,15 @@ static int qla_nvme_post_cmd(struct nvme_fc_local_port *lport, 
	if (!sp)

		return -EBUSY;



	atomic_set(&sp->ref_count, 1);

	init_waitqueue_head(&sp->nvme_ls_waitq);

	kref_init(&sp->cmd_kref);

	spin_lock_init(&priv->cmd_lock);

	sp->priv = (void *)priv;

	priv->sp = sp;

	sp->type = SRB_NVME_CMD;

	sp->name = "nvme_cmd";

	sp->done = qla_nvme_sp_done;

	sp->put_fn = qla_nvme_release_fcp_cmd_kref;

	sp->qpair = qpair;

	sp->vha = vha;

	nvme = &sp->u.iocb_cmd;
@@ -530,9 +592,10 @@ static int qla_nvme_post_cmd(struct nvme_fc_local_port *lport, 
	if (rval != QLA_SUCCESS) {

		ql_log(ql_log_warn, vha, 0x212d,

		    "qla2x00_start_nvme_mq failed = %d\n", rval);

		atomic_dec(&sp->ref_count);

		wake_up(&sp->nvme_ls_waitq);

		sp->free(sp);

		sp->priv = NULL;

		priv->sp = NULL;

		qla2xxx_rel_qpair_sp(sp->qpair, sp);

	}



	return rval;

drivers/scsi/qla2xxx/qla_nvme.h

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ struct nvme_private { 
	struct work_struct ls_work;

	struct work_struct abort_work;

	int comp_status;

	spinlock_t cmd_lock;

};



struct qla_nvme_rport {