usb: renesas_usbhs: avoid uninitialized variable use

PATCH New Arnd Bergmann 3 participants 3 messages May 22, 2015 – May 25, 2015

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Arnd Bergmann

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2015-05-22 11:06 UTC #0 lore raw

PATCH 1/1 usb: renesas_usbhs: avoid uninitialized variable use

After the renesas_usbhs driver is enabled in ARM multi_v7_defconfig, we now get a new warning:

renesas_usbhs/mod.c: In function 'usbhs_interrupt':
renesas_usbhs/mod.c:246:7: warning: 'intenb1' may be used uninitialized in this function [-Wmaybe-uninitialized]

gcc correctly points to a problem here, for the case that the device is in host mode, we use the intenb1 variable without having assigned it first. The state->intsts1 has a similar problem, but gcc cannot know that.

This avoids the problem by initializing both sides of the comparison to zero when we don't read them from the respective registers.

Signed-off-by Arnd Bergmann <[email protected]>

Fixes 88a25e02f3 ("usb: renesas_usbhs: Add access control for INTSTS1 and INTENB1 register")

drivers/usb/renesas_usbhs/mod.c +2 -0

index e5ce6e6d4f51..d4be5d594896 100644
@@ -223,6 +223,8 @@ static int usbhs_status_get_each_irq(struct usbhs_priv *priv,
 	if (usbhs_mod_is_host(priv)) {
 		state->intsts1 = usbhs_read(priv, INTSTS1);
 		intenb1 = usbhs_read(priv, INTENB1);
+	} else {
+		state->intsts1 = intenb1 = 0;
 	}
 
 	/* mask */

Yoshihiro Shimoda

2015-05-22 11:33 UTC #1 lore raw

PATCH 1/1 usb: renesas_usbhs: avoid uninitialized variable use

Hi Arnd,

Quoted 13 lines

Sent: Friday, May 22, 2015 8:07 PM
After the renesas_usbhs driver is enabled in ARM multi_v7_defconfig, we now get a new warning:
renesas_usbhs/mod.c: In function 'usbhs_interrupt':
renesas_usbhs/mod.c:246:7: warning: 'intenb1' may be used uninitialized in this function [-Wmaybe-uninitialized]
gcc correctly points to a problem here, for the case that the device is in host mode, we use the intenb1 variable without having assigned it first. The state->intsts1 has a similar problem, but gcc cannot know that.

Quoted 6 lines

This avoids the problem by initializing both sides of the comparison to zero when we don't read them from the respective registers.
Signed-off-by Arnd Bergmann <[email protected]>
Fixes 88a25e02f3 ("usb: renesas_usbhs: Add access control for INTSTS1 and INTENB1 register")

Thank you very much for the patch!

Acked-by Yoshihiro Shimoda <[email protected]>

(I'm not sure why a toolchain I used (Linaro GCC 2014.11) doesn't show this warning...)

Best regards,
Yoshihiro Shimoda

Quoted 18 lines

drivers/usb/renesas_usbhs/mod.c +2 -1
index e5ce6e6d4f51..d4be5d594896 100644
@@ -223,6 +223,8 @@ static int usbhs_status_get_each_irq(struct usbhs_priv *priv,
 	if (usbhs_mod_is_host(priv)) {
 		state->intsts1 = usbhs_read(priv, INTSTS1);
 		intenb1 = usbhs_read(priv, INTENB1);
+	} else {
+		state->intsts1 = intenb1 = 0;
 	}
 
 	/* mask */
 
--
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Simon Horman

2015-05-25 00:53 UTC #2 lore raw

PATCH 1/1 usb: renesas_usbhs: avoid uninitialized variable use

Quoted 22 lines · Yoshihiro Shimoda

Hi Arnd,
Quoted 13 lines
Sent: Friday, May 22, 2015 8:07 PM
After the renesas_usbhs driver is enabled in ARM multi_v7_defconfig, we now get a new warning:
renesas_usbhs/mod.c: In function 'usbhs_interrupt':
renesas_usbhs/mod.c:246:7: warning: 'intenb1' may be used uninitialized in this function [-Wmaybe-uninitialized]
gcc correctly points to a problem here, for the case that the device is in host mode, we use the intenb1 variable without having assigned it first. The state->intsts1 has a similar problem, but gcc cannot know that.
Quoted 6 lines
This avoids the problem by initializing both sides of the comparison to zero when we don't read them from the respective registers.
Signed-off-by Arnd Bergmann <[email protected]>
Fixes 88a25e02f3 ("usb: renesas_usbhs: Add access control for INTSTS1 and INTENB1 register")

Quoted 8 lines

Thank you very much for the patch!
Acked-by Yoshihiro Shimoda <[email protected]>
(I'm not sure why a toolchain I used (Linaro GCC 2014.11) doesn't show this warning...)
Best regards,
Yoshihiro Shimoda

Reviewed-by Simon Horman <[email protected]>

Quoted 20 lines

Quoted 19 lines
drivers/usb/renesas_usbhs/mod.c +2 -1
index e5ce6e6d4f51..d4be5d594896 100644
@@ -223,6 +223,8 @@ static int usbhs_status_get_each_irq(struct usbhs_priv *priv,
 	if (usbhs_mod_is_host(priv)) {
 		state->intsts1 = usbhs_read(priv, INTSTS1);
 		intenb1 = usbhs_read(priv, INTENB1);
+	} else {
+		state->intsts1 = intenb1 = 0;
 	}
 
 	/* mask */
 
--
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