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* [PATCH] PCI: mvebu: Fix uninitialized variable in mvebu_get_tgt_attr()
@ 2014-08-08 15:34 Geert Uytterhoeven
  2014-09-05 17:41 ` Bjorn Helgaas
  0 siblings, 1 reply; 9+ messages in thread
From: Geert Uytterhoeven @ 2014-08-08 15:34 UTC (permalink / raw)
  To: Thomas Petazzoni, Jason Cooper, Bjorn Helgaas
  Cc: linux-pci, linux-arm-kernel, linux-kernel, Geert Uytterhoeven

drivers/pci/host/pci-mvebu.c: In function 'mvebu_get_tgt_attr':
drivers/pci/host/pci-mvebu.c:887:39: warning: 'rtype' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (slot == PCI_SLOT(devfn) && type == rtype) {
                                       ^

If there's ever gonna be a configuration space or 64-bit memory space
entry in DT, rtype will be uninitialized, and the wrong entry may be
returned.

Initialize rtype to 0 (which is an unused IORESOURCE_* type) to fix this.

Introduced in commit 11be65472a427dcf7a11ab6e3e3628f1c6768b5b ("PCI:
mvebu: Adapt to the new device tree layout").

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
Alternatively, should the "else if (DT_FLAGS_TO_TYPE(flags) ==
DT_TYPE_MEM32)" just be changed to "else", assuming there can never be
other entries than for I/O or 32-bit memory space?
---
 drivers/pci/host/pci-mvebu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
index ce23e0f076b6..9515f0d13fd4 100644
--- a/drivers/pci/host/pci-mvebu.c
+++ b/drivers/pci/host/pci-mvebu.c
@@ -877,7 +877,7 @@ static int mvebu_get_tgt_attr(struct device_node *np, int devfn,
 		u32 flags = of_read_number(range, 1);
 		u32 slot = of_read_number(range + 1, 1);
 		u64 cpuaddr = of_read_number(range + na, pna);
-		unsigned long rtype;
+		unsigned long rtype = 0;
 
 		if (DT_FLAGS_TO_TYPE(flags) == DT_TYPE_IO)
 			rtype = IORESOURCE_IO;
-- 
1.9.1


^ permalink raw reply	[flat|nested] 9+ messages in thread
* [PATCH] PCI: mvebu: Fix uninitialized variable in mvebu_get_tgt_attr()
@ 2014-09-17 15:58 Thomas Petazzoni
  2014-09-22 20:43 ` Bjorn Helgaas
  0 siblings, 1 reply; 9+ messages in thread
From: Thomas Petazzoni @ 2014-09-17 15:58 UTC (permalink / raw)
  To: Bjorn Helgaas, linux-pci
  Cc: Jason Cooper, Andrew Lunn, Sebastian Hesselbarth,
	Gregory Clement, linux-arm-kernel, Geert Uytterhoeven,
	Thomas Petazzoni

Geert Uytterhoeven reported a warning when building pci-mvebu:

drivers/pci/host/pci-mvebu.c: In function 'mvebu_get_tgt_attr':
drivers/pci/host/pci-mvebu.c:887:39: warning: 'rtype' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if (slot == PCI_SLOT(devfn) && type == rtype) {
                                       ^

And indeed, the code of mvebu_get_tgt_attr() may lead to the usage of
rtype when being uninitialized, even though it would only happen if we
had entries other than I/O space and 32 bits memory space.

This commit fixes that by simply skipping the current DT range being
considered, if it doesn't match the resource type we're looking for.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
This patch is a different solution than the one proposed by Geert. It
(hopefully) matches the discussion we had with Bjorn and Arnd.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 drivers/pci/host/pci-mvebu.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
index a8c6f1a..b1315e1 100644
--- a/drivers/pci/host/pci-mvebu.c
+++ b/drivers/pci/host/pci-mvebu.c
@@ -873,7 +873,7 @@ static int mvebu_get_tgt_attr(struct device_node *np, int devfn,
 	rangesz = pna + na + ns;
 	nranges = rlen / sizeof(__be32) / rangesz;
 
-	for (i = 0; i < nranges; i++) {
+	for (i = 0; i < nranges; i++, range += rangesz) {
 		u32 flags = of_read_number(range, 1);
 		u32 slot = of_read_number(range + 1, 1);
 		u64 cpuaddr = of_read_number(range + na, pna);
@@ -883,14 +883,14 @@ static int mvebu_get_tgt_attr(struct device_node *np, int devfn,
 			rtype = IORESOURCE_IO;
 		else if (DT_FLAGS_TO_TYPE(flags) == DT_TYPE_MEM32)
 			rtype = IORESOURCE_MEM;
+		else
+			continue;
 
 		if (slot == PCI_SLOT(devfn) && type == rtype) {
 			*tgt = DT_CPUADDR_TO_TARGET(cpuaddr);
 			*attr = DT_CPUADDR_TO_ATTR(cpuaddr);
 			return 0;
 		}
-
-		range += rangesz;
 	}
 
 	return -ENOENT;
-- 
2.0.0


^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2014-09-22 20:43 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-08-08 15:34 [PATCH] PCI: mvebu: Fix uninitialized variable in mvebu_get_tgt_attr() Geert Uytterhoeven
2014-09-05 17:41 ` Bjorn Helgaas
2014-09-05 17:51   ` Arnd Bergmann
2014-09-05 18:20   ` Thomas Petazzoni
2014-09-05 18:34     ` Arnd Bergmann
2014-09-05 19:00       ` Bjorn Helgaas
2014-09-16 23:17         ` Bjorn Helgaas
2014-09-17 15:58 Thomas Petazzoni
2014-09-22 20:43 ` Bjorn Helgaas

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