On Thu, 2015-10-15 at 21:25 +0300, Dan Carpenter wrote: > > The patch 0b9252a34858: "iommu/vt-d: Implement page request handling" > from Oct 8, 2015, leads to the following Smatch complaint: > > drivers/iommu/intel-svm.c:452 prq_event_thread() > error: we previously assumed 'svm' could be null (see line 412)
Thanks. I'm going to fix it thus:
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 817be76..b7e923a 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -510,7 +510,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)
pr_err("%s: Page request for invalid PASID %d:
%08llx %08llx\n",
iommu->name, req->pasid, ((unsigned long
long *)req)[0],
((unsigned long long *)req)[1]);
- goto bad_req;
+ goto no_pasid;
}
}
@@ -552,7 +552,11 @@ static irqreturn_t prq_event_thread(int irq, void *d)
(req->wr_req << 1) | (req->exe_req);
sdev->ops->fault_cb(sdev->dev, req->pasid, req->addr,
req->private, rwxp, result);
}
-
+ /* We get here in the error case where the PASID lookup failed,
+ and these can be NULL. Do not use them below this point! */
+ sdev = NULL;
+ svm = NULL;
+ no_pasid:
if (req->lpig) {
/* Page Group Response */
resp.low = QI_PGRP_PASID(req->pasid) |
@@ -562,7 +566,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)
resp.high = QI_PGRP_IDX(req->prg_index) |
QI_PGRP_PRIV(req->private) |
QI_PGRP_RESP_CODE(result);
- qi_submit_sync(&resp, svm->iommu);
+ qi_submit_sync(&resp, iommu);
} else if (req->srr) {
/* Page Stream Response */
resp.low = QI_PSTRM_IDX(req->prg_index) |
@@ -571,7 +575,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)
resp.high = QI_PSTRM_ADDR(address) |
QI_PSTRM_DEVFN(req->devfn) |
QI_PSTRM_RESP_CODE(result);
- qi_submit_sync(&resp, svm->iommu);
+ qi_submit_sync(&resp, iommu);
}
head = (head + sizeof(*req)) & PRQ_RING_MASK;
--
David Woodhouse Open Source Technology Centre
[email protected] Intel Corporation
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