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Groups > linux.kernel > #1541671 > unrolled thread

linux-next: build warning after merge of the drivers-x86 tree

Started byStephen Rothwell <sfr@canb.auug.org.au>
First post2016-12-14 04:10 +0100
Last post2016-12-15 05:10 +0100
Articles 5 — 2 participants

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  linux-next: build warning after merge of the drivers-x86 tree Stephen Rothwell <sfr@canb.auug.org.au> - 2016-12-14 04:10 +0100
    Re: linux-next: build warning after merge of the drivers-x86 tree Darren Hart <dvhart@infradead.org> - 2016-12-14 23:30 +0100
      Re: linux-next: build warning after merge of the drivers-x86 tree Darren Hart <dvhart@infradead.org> - 2016-12-15 00:00 +0100
        Re: linux-next: build warning after merge of the drivers-x86 tree Stephen Rothwell <sfr@canb.auug.org.au> - 2016-12-15 01:10 +0100
          Re: linux-next: build warning after merge of the drivers-x86 tree Darren Hart <dvhart@infradead.org> - 2016-12-15 05:10 +0100

#1541671 — linux-next: build warning after merge of the drivers-x86 tree

FromStephen Rothwell <sfr@canb.auug.org.au>
Date2016-12-14 04:10 +0100
Subjectlinux-next: build warning after merge of the drivers-x86 tree
Message-ID<sO877-14y-17@gated-at.bofh.it>
Hi Darren,

After merging the drivers-x86 tree, today's linux-next build (x86_64
allmodconfig) produced this warning:

In file included from include/linux/kernel.h:13:0,
                 from drivers/platform/x86/thinkpad_acpi.c:52:
drivers/platform/x86/thinkpad_acpi.c: In function 'hotkey_init':
include/linux/printk.h:299:2: warning: 'type' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
  ^
drivers/platform/x86/thinkpad_acpi.c:3147:8: note: 'type' was declared here
  char *type;
        ^
In file included from include/linux/kernel.h:13:0,
                 from drivers/platform/x86/thinkpad_acpi.c:52:
include/linux/printk.h:299:2: warning: 'in_tablet_mode' may be used uninitialized in this function [-Wmaybe-uninitialized]
  printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
  ^
drivers/platform/x86/thinkpad_acpi.c:3146:6: note: 'in_tablet_mode' was declared here
  int in_tablet_mode, res;
      ^

Introduced by commit

  b31800283868 ("platform/x86: thinkpad_acpi: Move tablet detection into separate function")

I can't tell if this is a false positive or not.

-- 
Cheers,
Stephen Rothwell

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#1542261

FromDarren Hart <dvhart@infradead.org>
Date2016-12-14 23:30 +0100
Message-ID<sOqdI-5Va-27@gated-at.bofh.it>
In reply to#1541671
On Wed, Dec 14, 2016 at 01:50:44PM +1100, Stephen Rothwell wrote:
> Hi Darren,
> 
> After merging the drivers-x86 tree, today's linux-next build (x86_64
> allmodconfig) produced this warning:
> 
> In file included from include/linux/kernel.h:13:0,
>                  from drivers/platform/x86/thinkpad_acpi.c:52:
> drivers/platform/x86/thinkpad_acpi.c: In function 'hotkey_init':
> include/linux/printk.h:299:2: warning: 'type' may be used uninitialized in this function [-Wmaybe-uninitialized]
>   printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
>   ^
> drivers/platform/x86/thinkpad_acpi.c:3147:8: note: 'type' was declared here
>   char *type;
>         ^
> In file included from include/linux/kernel.h:13:0,
>                  from drivers/platform/x86/thinkpad_acpi.c:52:
> include/linux/printk.h:299:2: warning: 'in_tablet_mode' may be used uninitialized in this function [-Wmaybe-uninitialized]
>   printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
>   ^
> drivers/platform/x86/thinkpad_acpi.c:3146:6: note: 'in_tablet_mode' was declared here
>   int in_tablet_mode, res;
>       ^
> 
> Introduced by commit
> 
>   b31800283868 ("platform/x86: thinkpad_acpi: Move tablet detection into separate function")
> 
> I can't tell if this is a false positive or not.

That's an uninitialized local variable. Not sure how I missed that. I'll
fix it up today. Thank you for the report.

-- 
Darren Hart
Intel Open Source Technology Center

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#1542314

FromDarren Hart <dvhart@infradead.org>
Date2016-12-15 00:00 +0100
Message-ID<sOqGK-6gP-17@gated-at.bofh.it>
In reply to#1542261
On Wed, Dec 14, 2016 at 02:21:38PM -0800, Darren Hart wrote:
> On Wed, Dec 14, 2016 at 01:50:44PM +1100, Stephen Rothwell wrote:
> > Hi Darren,
> > 
> > After merging the drivers-x86 tree, today's linux-next build (x86_64
> > allmodconfig) produced this warning:
> > 
> > In file included from include/linux/kernel.h:13:0,
> >                  from drivers/platform/x86/thinkpad_acpi.c:52:
> > drivers/platform/x86/thinkpad_acpi.c: In function 'hotkey_init':
> > include/linux/printk.h:299:2: warning: 'type' may be used uninitialized in this function [-Wmaybe-uninitialized]
> >   printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> >   ^
> > drivers/platform/x86/thinkpad_acpi.c:3147:8: note: 'type' was declared here
> >   char *type;
> >         ^
> > In file included from include/linux/kernel.h:13:0,
> >                  from drivers/platform/x86/thinkpad_acpi.c:52:
> > include/linux/printk.h:299:2: warning: 'in_tablet_mode' may be used uninitialized in this function [-Wmaybe-uninitialized]
> >   printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> >   ^
> > drivers/platform/x86/thinkpad_acpi.c:3146:6: note: 'in_tablet_mode' was declared here
> >   int in_tablet_mode, res;
> >       ^
> > 
> > Introduced by commit
> > 
> >   b31800283868 ("platform/x86: thinkpad_acpi: Move tablet detection into separate function")
> > 
> > I can't tell if this is a false positive or not.
> 
> That's an uninitialized local variable. Not sure how I missed that. I'll
> fix it up today. Thank you for the report.

OK, no, it's a false positive because tp_features.hotkey_tablet is assigned in
both places where in_tablet_mode is assigned, and if the former is 0 (global
scope), the function returns without calling pr_info.

Lyude, Henrique, please confirm.

Regardless, I'll add a patch to init in_tablet_mode to 0 so it is explicit - but
will not rebase as it isn't technically an error.

-- 
Darren Hart
Intel Open Source Technology Center

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#1542377

FromStephen Rothwell <sfr@canb.auug.org.au>
Date2016-12-15 01:10 +0100
Message-ID<sOrMu-78L-47@gated-at.bofh.it>
In reply to#1542314
Hi Darren,

On Wed, 14 Dec 2016 14:59:14 -0800 Darren Hart <dvhart@infradead.org> wrote:
>
> On Wed, Dec 14, 2016 at 02:21:38PM -0800, Darren Hart wrote:
> > On Wed, Dec 14, 2016 at 01:50:44PM +1100, Stephen Rothwell wrote:  
> > > 
> > > After merging the drivers-x86 tree, today's linux-next build (x86_64
> > > allmodconfig) produced this warning:
> > > 
> > > In file included from include/linux/kernel.h:13:0,
> > >                  from drivers/platform/x86/thinkpad_acpi.c:52:
> > > drivers/platform/x86/thinkpad_acpi.c: In function 'hotkey_init':
> > > include/linux/printk.h:299:2: warning: 'type' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > >   printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> > >   ^
> > > drivers/platform/x86/thinkpad_acpi.c:3147:8: note: 'type' was declared here
> > >   char *type;
> > >         ^
> > > In file included from include/linux/kernel.h:13:0,
> > >                  from drivers/platform/x86/thinkpad_acpi.c:52:
> > > include/linux/printk.h:299:2: warning: 'in_tablet_mode' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > >   printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> > >   ^
> > > drivers/platform/x86/thinkpad_acpi.c:3146:6: note: 'in_tablet_mode' was declared here
> > >   int in_tablet_mode, res;
> > >       ^
> > > 
> > > Introduced by commit
> > > 
> > >   b31800283868 ("platform/x86: thinkpad_acpi: Move tablet detection into separate function")
> > > 
> > > I can't tell if this is a false positive or not.  
> > 
> > That's an uninitialized local variable. Not sure how I missed that. I'll
> > fix it up today. Thank you for the report.  
> 
> OK, no, it's a false positive because tp_features.hotkey_tablet is assigned in
> both places where in_tablet_mode is assigned, and if the former is 0 (global
> scope), the function returns without calling pr_info.

How about "type".

> Lyude, Henrique, please confirm.
> 
> Regardless, I'll add a patch to init in_tablet_mode to 0 so it is explicit - but
> will not rebase as it isn't technically an error.

No problem, it is only a warning after all.

-- 
Cheers,
Stephen Rothwell

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#1542467

FromDarren Hart <dvhart@infradead.org>
Date2016-12-15 05:10 +0100
Message-ID<sOvwK-121-7@gated-at.bofh.it>
In reply to#1542377
On Thu, Dec 15, 2016 at 11:02:19AM +1100, Stephen Rothwell wrote:
> Hi Darren,
> 
> On Wed, 14 Dec 2016 14:59:14 -0800 Darren Hart <dvhart@infradead.org> wrote:
> >
> > On Wed, Dec 14, 2016 at 02:21:38PM -0800, Darren Hart wrote:
> > > On Wed, Dec 14, 2016 at 01:50:44PM +1100, Stephen Rothwell wrote:  
> > > > 
> > > > After merging the drivers-x86 tree, today's linux-next build (x86_64
> > > > allmodconfig) produced this warning:
> > > > 
> > > > In file included from include/linux/kernel.h:13:0,
> > > >                  from drivers/platform/x86/thinkpad_acpi.c:52:
> > > > drivers/platform/x86/thinkpad_acpi.c: In function 'hotkey_init':
> > > > include/linux/printk.h:299:2: warning: 'type' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > > >   printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> > > >   ^
> > > > drivers/platform/x86/thinkpad_acpi.c:3147:8: note: 'type' was declared here
> > > >   char *type;
> > > >         ^
> > > > In file included from include/linux/kernel.h:13:0,
> > > >                  from drivers/platform/x86/thinkpad_acpi.c:52:
> > > > include/linux/printk.h:299:2: warning: 'in_tablet_mode' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > > >   printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
> > > >   ^
> > > > drivers/platform/x86/thinkpad_acpi.c:3146:6: note: 'in_tablet_mode' was declared here
> > > >   int in_tablet_mode, res;
> > > >       ^
> > > > 
> > > > Introduced by commit
> > > > 
> > > >   b31800283868 ("platform/x86: thinkpad_acpi: Move tablet detection into separate function")
> > > > 
> > > > I can't tell if this is a false positive or not.  
> > > 
> > > That's an uninitialized local variable. Not sure how I missed that. I'll
> > > fix it up today. Thank you for the report.  
> > 
> > OK, no, it's a false positive because tp_features.hotkey_tablet is assigned in
> > both places where in_tablet_mode is assigned, and if the former is 0 (global
> > scope), the function returns without calling pr_info.
> 
> How about "type".

Ooops, indeed. Same exact issue. I'll update the patch.

-- 
Darren Hart
Intel Open Source Technology Center

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