Re: [PATCH v2] ahci: qoriq: fixed using uninitialized variable warnings
From: Fengguang Wu
Date: Thu Sep 10 2015 - 23:31:14 EST
Hi Tejun, Yuantian,
On Thu, Sep 10, 2015 at 10:22:14AM -0400, Tejun Heo wrote:
> (cc'ing Fengguang, hi!)
>
> Fengguang, this is about kbuild test robot warning titled
> "drivers/ata/ahci_qoriq.c:70:6: warning: 'px_cmd' may be used
> uninitialized in this function". Yuantian can't reproduce the warning
> and I'm wondering whether the below patch would make the warning go
> away. Which gcc was the build bot using?
It's gcc-4.5.1-or32-1.0rc1. The reproduce steps are:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
git checkout ecfb4598512a7c3e21df2941db58c10461583bb9
# this command will auto download/install openrisc cross compiler
make.cross ARCH=openrisc allyesconfig
make.cross ARCH=openrisc drivers/ata/ahci_qoriq.o
> Would it be possible to
> verify that the following patch makes the warning go away?
With the patch applied, the warnings are still there:
wfg@inn ~/linux/obj-compiletest% make ARCH=openrisc drivers/ata/ahci_qoriq.o
/usr/bin/make -C source O=/home/wfg/linux/obj-compiletest ARCH=openrisc CROSS_COMPILE=/usr/local/gcc-4.5.1-nolibc/or32-linux/bin/or32-linux- -j32 ARCH=openrisc drivers/
ata/ahci_qoriq.o make: Entering directory '/c/wfg/linux'
make[1]: Entering directory '/c/wfg/linux/obj-compiletest'
CHK include/config/kernel.release
GEN ./Makefile
CHK include/generated/uapi/linux/version.h
UPD include/config/kernel.release
Using .. as source for kernel
CHK include/generated/utsrelease.h
UPD include/generated/utsrelease.h
CHK include/generated/timeconst.h
CHK include/generated/bounds.h
CHK include/generated/asm-offsets.h
CALL ../scripts/checksyscalls.sh
<stdin>:1298:2: warning: #warning syscall userfaultfd not implemented
CC drivers/ata/ahci_qoriq.o
../drivers/ata/ahci_qoriq.c: In function 'ahci_qoriq_hardreset':
../drivers/ata/ahci_qoriq.c:70:6: warning: 'px_cmd' may be used uninitialized in this function
../drivers/ata/ahci_qoriq.c:70:14: warning: 'px_is' may be used uninitialized in this function
make[1]: Leaving directory '/c/wfg/linux/obj-compiletest'
make: Leaving directory '/c/wfg/linux'
Thanks,
Fengguang
> On Thu, Sep 10, 2015 at 03:13:32PM +0800, Yuantian.Tang@xxxxxxxxxxxxx wrote:
> > From: Tang Yuantian <Yuantian.Tang@xxxxxxxxxxxxx>
> >
> > kbuild test robot reports the warnings:
> > drivers/ata/ahci_qoriq.c: In function 'ahci_qoriq_hardreset':
> > >> include/asm-generic/io.h:163:2: warning: 'px_is' may be used
> > >> uninitialized in this function [-Wuninitialized]
> > drivers/ata/ahci_qoriq.c:70:14: note: 'px_is' was declared here
> > >> include/asm-generic/io.h:163:2: warning: 'px_cmd' may be used
> > >> uninitialized in this function [-Wuninitialized]
> > drivers/ata/ahci_qoriq.c:70:6: note: 'px_cmd' was declared here
> >
> > This patch fixed it by making type as a local variable.
> >
> > Signed-off-by: Tang Yuantian <Yuantian.Tang@xxxxxxxxxxxxx>
> > ---
> > v2:
> > - try another way to fix the warnings
> > - remove clean up code
> >
> > drivers/ata/ahci_qoriq.c | 13 ++++++-------
> > 1 file changed, 6 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/ata/ahci_qoriq.c b/drivers/ata/ahci_qoriq.c
> > index e5e4988..0d06e76 100644
> > --- a/drivers/ata/ahci_qoriq.c
> > +++ b/drivers/ata/ahci_qoriq.c
> > @@ -48,9 +48,9 @@ enum ahci_qoriq_type {
> > AHCI_LS2085A,
> > };
> >
> > +enum ahci_qoriq_type type;
> > struct ahci_qoriq_priv {
> > struct ccsr_ahci *reg_base;
> > - enum ahci_qoriq_type type;
> > void __iomem *ecc_addr;
> > };
> >
> > @@ -71,7 +71,6 @@ static int ahci_qoriq_hardreset(struct ata_link *link, unsigned int *class,
> > struct ata_port *ap = link->ap;
> > struct ahci_port_priv *pp = ap->private_data;
> > struct ahci_host_priv *hpriv = ap->host->private_data;
> > - struct ahci_qoriq_priv *qoriq_priv = hpriv->plat_data;
> > u8 *d2h_fis = pp->rx_fis + RX_FIS_D2H_REG;
> > struct ata_taskfile tf;
> > bool online;
> > @@ -92,7 +91,7 @@ static int ahci_qoriq_hardreset(struct ata_link *link, unsigned int *class,
> > * After the sequence is complete, software should restore the
> > * PxCMD and PxIS with the stored values.
> > */
> > - if (qoriq_priv->type == AHCI_LS1021A) {
> > + if (type == AHCI_LS1021A) {
> > px_cmd = readl(port_mmio + PORT_CMD);
> > px_is = readl(port_mmio + PORT_IRQ_STAT);
> > }
> > @@ -106,7 +105,7 @@ static int ahci_qoriq_hardreset(struct ata_link *link, unsigned int *class,
> > ahci_check_ready);
> >
> > /* restore the PxCMD and PxIS on ls1021 */
> > - if (qoriq_priv->type == AHCI_LS1021A) {
> > + if (type == AHCI_LS1021A) {
> > px_val = readl(port_mmio + PORT_CMD);
> > if (px_val != px_cmd)
> > writel(px_cmd, port_mmio + PORT_CMD);
> > @@ -146,7 +145,7 @@ static int ahci_qoriq_phy_init(struct ahci_host_priv *hpriv)
> > struct ahci_qoriq_priv *qpriv = hpriv->plat_data;
> > void __iomem *reg_base = hpriv->mmio;
> >
> > - switch (qpriv->type) {
> > + switch (type) {
> > case AHCI_LS1021A:
> > writel(SATA_ECC_DISABLE, qpriv->ecc_addr);
> > writel(AHCI_PORT_PHY_1_CFG, reg_base + PORT_PHY1);
> > @@ -188,9 +187,9 @@ static int ahci_qoriq_probe(struct platform_device *pdev)
> > if (!qoriq_priv)
> > return -ENOMEM;
> >
> > - qoriq_priv->type = (enum ahci_qoriq_type)of_id->data;
> > + type = (enum ahci_qoriq_type)of_id->data;
> >
> > - if (qoriq_priv->type == AHCI_LS1021A) {
> > + if (type == AHCI_LS1021A) {
> > res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> > "sata-ecc");
> > qoriq_priv->ecc_addr = devm_ioremap_resource(dev, res);
> > --
> > 2.1.0.27.g96db324
> >
>
> --
> tejun
> --
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