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SubjectRe: [PATCH] PCI: mvebu: Fix uninitialized variable in mvebu_get_tgt_attr()
On Fri, Aug 08, 2014 at 05:34:05PM +0200, Geert Uytterhoeven wrote:
> 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
>

This fix looks right to me. I added a stable tag as follows. Thomas
and/or Jason, and you ack this?


commit f96f4040d0d01b6eeacda212cf7db105d06a55ba
Author: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Fri Aug 8 17:34:05 2014 +0200

PCI: mvebu: Fix uninitialized "rtype" in mvebu_get_tgt_attr()

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 a DT entry other than DT_TYPE_IO or DT_TYPE_MEM32,
e.g., a configuration space or 64-bit memory space entry, rtype will
be uninitialized, and the wrong entry may be returned.

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

Fixes: 11be65472a42 ("PCI: mvebu: Adapt to the new device tree layout")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org # v3.12+

diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
index a8c6f1a92e0f..081579c0971e 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;

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