* [PATCH v2] MIPS: ath79: Avoid using unitialized 'reg' variable
@ 2013-08-21 10:47 ` Markos Chandras
0 siblings, 0 replies; 8+ messages in thread
From: Markos Chandras @ 2013-08-21 10:47 UTC (permalink / raw)
To: linux-mips; +Cc: Markos Chandras
Fixes the following build error:
arch/mips/include/asm/mach-ath79/ath79.h:139:20: error: 'reg' may be used
uninitialized in this function [-Werror=maybe-uninitialized]
arch/mips/ath79/common.c:62:6: note: 'reg' was declared here
In file included from arch/mips/ath79/common.c:20:0:
arch/mips/ath79/common.c: In function 'ath79_device_reset_clear':
arch/mips/include/asm/mach-ath79/ath79.h:139:20:
error: 'reg' may be used uninitialized in this function
[-Werror=maybe-uninitialized]
arch/mips/ath79/common.c:90:6: note: 'reg' was declared here
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
---
Changes since v1:
http://www.linux-mips.org/archives/linux-mips/2013-08/msg00126.html
- Remove BUG(). panic() is enough.
http://www.linux-mips.org/archives/linux-mips/2013-08/msg00133.html
- Change panic() message to be more accurate.
http://www.linux-mips.org/archives/linux-mips/2013-08/msg00164.html
---
arch/mips/ath79/common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/mips/ath79/common.c b/arch/mips/ath79/common.c
index eb3966c..6d7a9d4 100644
--- a/arch/mips/ath79/common.c
+++ b/arch/mips/ath79/common.c
@@ -75,7 +75,7 @@ void ath79_device_reset_set(u32 mask)
else if (soc_is_qca955x())
reg = QCA955X_RESET_REG_RESET_MODULE;
else
- BUG();
+ panic("Reset register not defined for this SOC");
spin_lock_irqsave(&ath79_device_reset_lock, flags);
t = ath79_reset_rr(reg);
@@ -103,7 +103,7 @@ void ath79_device_reset_clear(u32 mask)
else if (soc_is_qca955x())
reg = QCA955X_RESET_REG_RESET_MODULE;
else
- BUG();
+ panic("Reset register not defined for this SOC");
spin_lock_irqsave(&ath79_device_reset_lock, flags);
t = ath79_reset_rr(reg);
--
1.8.3.2
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH v2] MIPS: ath79: Avoid using unitialized 'reg' variable
@ 2013-08-21 10:47 ` Markos Chandras
0 siblings, 0 replies; 8+ messages in thread
From: Markos Chandras @ 2013-08-21 10:47 UTC (permalink / raw)
To: linux-mips; +Cc: Markos Chandras
Fixes the following build error:
arch/mips/include/asm/mach-ath79/ath79.h:139:20: error: 'reg' may be used
uninitialized in this function [-Werror=maybe-uninitialized]
arch/mips/ath79/common.c:62:6: note: 'reg' was declared here
In file included from arch/mips/ath79/common.c:20:0:
arch/mips/ath79/common.c: In function 'ath79_device_reset_clear':
arch/mips/include/asm/mach-ath79/ath79.h:139:20:
error: 'reg' may be used uninitialized in this function
[-Werror=maybe-uninitialized]
arch/mips/ath79/common.c:90:6: note: 'reg' was declared here
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
---
Changes since v1:
http://www.linux-mips.org/archives/linux-mips/2013-08/msg00126.html
- Remove BUG(). panic() is enough.
http://www.linux-mips.org/archives/linux-mips/2013-08/msg00133.html
- Change panic() message to be more accurate.
http://www.linux-mips.org/archives/linux-mips/2013-08/msg00164.html
---
arch/mips/ath79/common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/mips/ath79/common.c b/arch/mips/ath79/common.c
index eb3966c..6d7a9d4 100644
--- a/arch/mips/ath79/common.c
+++ b/arch/mips/ath79/common.c
@@ -75,7 +75,7 @@ void ath79_device_reset_set(u32 mask)
else if (soc_is_qca955x())
reg = QCA955X_RESET_REG_RESET_MODULE;
else
- BUG();
+ panic("Reset register not defined for this SOC");
spin_lock_irqsave(&ath79_device_reset_lock, flags);
t = ath79_reset_rr(reg);
@@ -103,7 +103,7 @@ void ath79_device_reset_clear(u32 mask)
else if (soc_is_qca955x())
reg = QCA955X_RESET_REG_RESET_MODULE;
else
- BUG();
+ panic("Reset register not defined for this SOC");
spin_lock_irqsave(&ath79_device_reset_lock, flags);
t = ath79_reset_rr(reg);
--
1.8.3.2
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH v2] MIPS: ath79: Avoid using unitialized 'reg' variable
2013-08-21 10:47 ` Markos Chandras
(?)
@ 2013-08-21 16:40 ` Gabor Juhos
-1 siblings, 0 replies; 8+ messages in thread
From: Gabor Juhos @ 2013-08-21 16:40 UTC (permalink / raw)
To: Markos Chandras; +Cc: linux-mips
2013.08.21. 12:47 keltezéssel, Markos Chandras írta:
> Fixes the following build error:
> arch/mips/include/asm/mach-ath79/ath79.h:139:20: error: 'reg' may be used
> uninitialized in this function [-Werror=maybe-uninitialized]
> arch/mips/ath79/common.c:62:6: note: 'reg' was declared here
> In file included from arch/mips/ath79/common.c:20:0:
> arch/mips/ath79/common.c: In function 'ath79_device_reset_clear':
> arch/mips/include/asm/mach-ath79/ath79.h:139:20:
> error: 'reg' may be used uninitialized in this function
> [-Werror=maybe-uninitialized]
> arch/mips/ath79/common.c:90:6: note: 'reg' was declared here
>
> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Acked-by: Gabor Juhos <juhosg@openwrt.org>
Thanks!
-Gabor
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2] MIPS: ath79: Avoid using unitialized 'reg' variable
2013-08-21 10:47 ` Markos Chandras
(?)
(?)
@ 2013-09-03 13:38 ` Ralf Baechle
2013-09-03 14:03 ` Markos Chandras
-1 siblings, 1 reply; 8+ messages in thread
From: Ralf Baechle @ 2013-09-03 13:38 UTC (permalink / raw)
To: Markos Chandras; +Cc: linux-mips
On Wed, Aug 21, 2013 at 11:47:22AM +0100, Markos Chandras wrote:
> Fixes the following build error:
> arch/mips/include/asm/mach-ath79/ath79.h:139:20: error: 'reg' may be used
> uninitialized in this function [-Werror=maybe-uninitialized]
> arch/mips/ath79/common.c:62:6: note: 'reg' was declared here
> In file included from arch/mips/ath79/common.c:20:0:
> arch/mips/ath79/common.c: In function 'ath79_device_reset_clear':
> arch/mips/include/asm/mach-ath79/ath79.h:139:20:
> error: 'reg' may be used uninitialized in this function
> [-Werror=maybe-uninitialized]
> arch/mips/ath79/common.c:90:6: note: 'reg' was declared here
>
> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
> ---
> Changes since v1:
> http://www.linux-mips.org/archives/linux-mips/2013-08/msg00126.html
> - Remove BUG(). panic() is enough.
> http://www.linux-mips.org/archives/linux-mips/2013-08/msg00133.html
> - Change panic() message to be more accurate.
> http://www.linux-mips.org/archives/linux-mips/2013-08/msg00164.html
> ---
> arch/mips/ath79/common.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/mips/ath79/common.c b/arch/mips/ath79/common.c
> index eb3966c..6d7a9d4 100644
> --- a/arch/mips/ath79/common.c
> +++ b/arch/mips/ath79/common.c
> @@ -75,7 +75,7 @@ void ath79_device_reset_set(u32 mask)
> else if (soc_is_qca955x())
> reg = QCA955X_RESET_REG_RESET_MODULE;
> else
> - BUG();
> + panic("Reset register not defined for this SOC");
>
> spin_lock_irqsave(&ath79_device_reset_lock, flags);
> t = ath79_reset_rr(reg);
> @@ -103,7 +103,7 @@ void ath79_device_reset_clear(u32 mask)
> else if (soc_is_qca955x())
> reg = QCA955X_RESET_REG_RESET_MODULE;
> else
> - BUG();
> + panic("Reset register not defined for this SOC");
>
> spin_lock_irqsave(&ath79_device_reset_lock, flags);
> t = ath79_reset_rr(reg);
Looks more like the implementation of BUG() is wrong and gcc doesn't
notice that BUG() won't return.
Was this triggered by CONFIG_BUG=n?
Ralf
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH v2] MIPS: ath79: Avoid using unitialized 'reg' variable
@ 2013-09-03 14:03 ` Markos Chandras
0 siblings, 0 replies; 8+ messages in thread
From: Markos Chandras @ 2013-09-03 14:03 UTC (permalink / raw)
To: Ralf Baechle; +Cc: linux-mips
On 09/03/13 14:38, Ralf Baechle wrote:
> On Wed, Aug 21, 2013 at 11:47:22AM +0100, Markos Chandras wrote:
>
>> Fixes the following build error:
>> arch/mips/include/asm/mach-ath79/ath79.h:139:20: error: 'reg' may be used
>> uninitialized in this function [-Werror=maybe-uninitialized]
>> arch/mips/ath79/common.c:62:6: note: 'reg' was declared here
>> In file included from arch/mips/ath79/common.c:20:0:
>> arch/mips/ath79/common.c: In function 'ath79_device_reset_clear':
>> arch/mips/include/asm/mach-ath79/ath79.h:139:20:
>> error: 'reg' may be used uninitialized in this function
>> [-Werror=maybe-uninitialized]
>> arch/mips/ath79/common.c:90:6: note: 'reg' was declared here
>>
>> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
>> ---
>> Changes since v1:
>> http://www.linux-mips.org/archives/linux-mips/2013-08/msg00126.html
>> - Remove BUG(). panic() is enough.
>> http://www.linux-mips.org/archives/linux-mips/2013-08/msg00133.html
>> - Change panic() message to be more accurate.
>> http://www.linux-mips.org/archives/linux-mips/2013-08/msg00164.html
>> ---
>> arch/mips/ath79/common.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/mips/ath79/common.c b/arch/mips/ath79/common.c
>> index eb3966c..6d7a9d4 100644
>> --- a/arch/mips/ath79/common.c
>> +++ b/arch/mips/ath79/common.c
>> @@ -75,7 +75,7 @@ void ath79_device_reset_set(u32 mask)
>> else if (soc_is_qca955x())
>> reg = QCA955X_RESET_REG_RESET_MODULE;
>> else
>> - BUG();
>> + panic("Reset register not defined for this SOC");
>>
>> spin_lock_irqsave(&ath79_device_reset_lock, flags);
>> t = ath79_reset_rr(reg);
>> @@ -103,7 +103,7 @@ void ath79_device_reset_clear(u32 mask)
>> else if (soc_is_qca955x())
>> reg = QCA955X_RESET_REG_RESET_MODULE;
>> else
>> - BUG();
>> + panic("Reset register not defined for this SOC");
>>
>> spin_lock_irqsave(&ath79_device_reset_lock, flags);
>> t = ath79_reset_rr(reg);
>
> Looks more like the implementation of BUG() is wrong and gcc doesn't
> notice that BUG() won't return.
>
> Was this triggered by CONFIG_BUG=n?
>
> Ralf
>
Hi Ralf,
Yes it was triggered by CONFIG_BUG=n
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH v2] MIPS: ath79: Avoid using unitialized 'reg' variable
@ 2013-09-03 14:03 ` Markos Chandras
0 siblings, 0 replies; 8+ messages in thread
From: Markos Chandras @ 2013-09-03 14:03 UTC (permalink / raw)
To: Ralf Baechle; +Cc: linux-mips
On 09/03/13 14:38, Ralf Baechle wrote:
> On Wed, Aug 21, 2013 at 11:47:22AM +0100, Markos Chandras wrote:
>
>> Fixes the following build error:
>> arch/mips/include/asm/mach-ath79/ath79.h:139:20: error: 'reg' may be used
>> uninitialized in this function [-Werror=maybe-uninitialized]
>> arch/mips/ath79/common.c:62:6: note: 'reg' was declared here
>> In file included from arch/mips/ath79/common.c:20:0:
>> arch/mips/ath79/common.c: In function 'ath79_device_reset_clear':
>> arch/mips/include/asm/mach-ath79/ath79.h:139:20:
>> error: 'reg' may be used uninitialized in this function
>> [-Werror=maybe-uninitialized]
>> arch/mips/ath79/common.c:90:6: note: 'reg' was declared here
>>
>> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
>> ---
>> Changes since v1:
>> http://www.linux-mips.org/archives/linux-mips/2013-08/msg00126.html
>> - Remove BUG(). panic() is enough.
>> http://www.linux-mips.org/archives/linux-mips/2013-08/msg00133.html
>> - Change panic() message to be more accurate.
>> http://www.linux-mips.org/archives/linux-mips/2013-08/msg00164.html
>> ---
>> arch/mips/ath79/common.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/mips/ath79/common.c b/arch/mips/ath79/common.c
>> index eb3966c..6d7a9d4 100644
>> --- a/arch/mips/ath79/common.c
>> +++ b/arch/mips/ath79/common.c
>> @@ -75,7 +75,7 @@ void ath79_device_reset_set(u32 mask)
>> else if (soc_is_qca955x())
>> reg = QCA955X_RESET_REG_RESET_MODULE;
>> else
>> - BUG();
>> + panic("Reset register not defined for this SOC");
>>
>> spin_lock_irqsave(&ath79_device_reset_lock, flags);
>> t = ath79_reset_rr(reg);
>> @@ -103,7 +103,7 @@ void ath79_device_reset_clear(u32 mask)
>> else if (soc_is_qca955x())
>> reg = QCA955X_RESET_REG_RESET_MODULE;
>> else
>> - BUG();
>> + panic("Reset register not defined for this SOC");
>>
>> spin_lock_irqsave(&ath79_device_reset_lock, flags);
>> t = ath79_reset_rr(reg);
>
> Looks more like the implementation of BUG() is wrong and gcc doesn't
> notice that BUG() won't return.
>
> Was this triggered by CONFIG_BUG=n?
>
> Ralf
>
Hi Ralf,
Yes it was triggered by CONFIG_BUG=n
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH v2] MIPS: ath79: Avoid using unitialized 'reg' variable
2013-09-03 14:03 ` Markos Chandras
(?)
@ 2013-09-18 13:45 ` Ralf Baechle
2013-09-18 13:51 ` Ralf Baechle
-1 siblings, 1 reply; 8+ messages in thread
From: Ralf Baechle @ 2013-09-18 13:45 UTC (permalink / raw)
To: linux-kernel, Arnd Bergmann, David Howells, Markos Chandras; +Cc: linux-mips
On Tue, Sep 03, 2013 at 03:03:39PM +0100, Markos Chandras wrote:
> >Was this triggered by CONFIG_BUG=n?
> >
> > Ralf
> >
>
> Hi Ralf,
>
> Yes it was triggered by CONFIG_BUG=n
So here's a small test case to demonstrate the issue:
/*
* Definition of BUG taken from asm-generic/bug.h for the CONFIG_BUG=n case
*/
#define BUG() do {} while(0)
int foo(int arg)
{
int res;
if (arg == 1)
res = 23;
else if (arg -= 2)
res = 42;
else
BUG();
return res;
}
[ralf@h7 linux-mips]$ gcc -O2 -Wall -c bug.c
bug.c: In function ‘foo’:
bug.c:17:2: warning: ‘res’ may be used uninitialized in this function [-Wmaybe-uninitialized]
return res;
^
It's fairly obvious to see what's happening here - GCC doesn't know that
the else case can not be reached, thus razorsharply concludes that res
may be used uninitialized.
I think the definition of BUG should be changed to something like
#define BUG() unreachable()
This has the disadvantage of of expanding into a while (1) loop for older
compilers - but that's only for older compilers, relativly minor in
bloat and last I checked BUG() wasn't performance critical ;-)
Ralf
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
include/asm-generic/bug.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 7d10f96..6f78771 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -108,7 +108,7 @@ extern void warn_slowpath_null(const char *file, const int line);
#else /* !CONFIG_BUG */
#ifndef HAVE_ARCH_BUG
-#define BUG() do {} while(0)
+#define BUG() unreachable()
#endif
#ifndef HAVE_ARCH_BUG_ON
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH v2] MIPS: ath79: Avoid using unitialized 'reg' variable
2013-09-18 13:45 ` Ralf Baechle
@ 2013-09-18 13:51 ` Ralf Baechle
0 siblings, 0 replies; 8+ messages in thread
From: Ralf Baechle @ 2013-09-18 13:51 UTC (permalink / raw)
To: linux-kernel, Arnd Bergmann, David Howells, Markos Chandras; +Cc: linux-mips
On Wed, Sep 18, 2013 at 03:45:33PM +0200, Ralf Baechle wrote:
> So here's a small test case to demonstrate the issue:
>
> /*
> * Definition of BUG taken from asm-generic/bug.h for the CONFIG_BUG=n case
> */
> #define BUG() do {} while(0)
>
> int foo(int arg)
> {
> int res;
>
> if (arg == 1)
> res = 23;
> else if (arg -= 2)
I fatfingered the testcase while editing the email. this line of course
is "else if (arg == 2)"
Ralf
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2013-09-18 13:52 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-08-21 10:47 [PATCH v2] MIPS: ath79: Avoid using unitialized 'reg' variable Markos Chandras
2013-08-21 10:47 ` Markos Chandras
2013-08-21 16:40 ` Gabor Juhos
2013-09-03 13:38 ` Ralf Baechle
2013-09-03 14:03 ` Markos Chandras
2013-09-03 14:03 ` Markos Chandras
2013-09-18 13:45 ` Ralf Baechle
2013-09-18 13:51 ` Ralf Baechle
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