sparse 0.2 - incomprehensible context warnings

sparse 0.2 - incomprehensible context warnings

[Ulrich Kunitz]

Hi,

I have tried sparse 0.2 for the zd1211rw WLAN driver, which I
happen to contribute too.

I get numerous context imbalance warnings, that I don't
understand. This is on an SMP (x86-64) build of a vanilla 2.6.19.
I get the same warning on an SMP build of PPC32.

A simple example is:

/home/kunitz/zd1211/rw/zd_usb.c:1167:13: warning: context imbalance in 'disable_read_regs_int' - wrong count at exit

zd_usb.c
1167 static void disable_read_regs_int(struct zd_usb *usb)
1168 {
1169         struct zd_usb_interrupt *intr = &usb->intr;
1170
1171         spin_lock_irq(&intr->lock);
1172         intr->read_regs_enabled = 0;
1173         spin_unlock_irq(&intr->lock);
1174 }

Please set me on CC of the answer I'm not a regular reader of this
list.

You will find the driver source in the kernel itself. I tested it
however against my latest git tree, which is available from

git-clone http://deine-taler.de/zd1211/zd1211.git

-- 
Uli Kunitz

Re: sparse 0.2 - incomprehensible context warnings

[Christopher Li]

It has been a while. I find out why during this happen during
I debugging my other interrupt checker.

_spin_unlock_irq() is a macro which will expand to __raw_spin_unlock(),
which inline into a function. But _spin_lock_irq is an external function
which does not inline.

So sparse only sees the unlock, it can't see the locking.

Chris

On Tue, Dec 05, 2006 at 11:07:10PM +0100, Ulrich Kunitz wrote:
> Hi,
> 
> I have tried sparse 0.2 for the zd1211rw WLAN driver, which I
> happen to contribute too.
> 
> I get numerous context imbalance warnings, that I don't
> understand. This is on an SMP (x86-64) build of a vanilla 2.6.19.
> I get the same warning on an SMP build of PPC32.
> 
> A simple example is:
> 
> /home/kunitz/zd1211/rw/zd_usb.c:1167:13: warning: context imbalance in 'disable_read_regs_int' - wrong count at exit
> 
> zd_usb.c
> 1167 static void disable_read_regs_int(struct zd_usb *usb)
> 1168 {
> 1169         struct zd_usb_interrupt *intr = &usb->intr;
> 1170
> 1171         spin_lock_irq(&intr->lock);
> 1172         intr->read_regs_enabled = 0;
> 1173         spin_unlock_irq(&intr->lock);
> 1174 }
> 
> Please set me on CC of the answer I'm not a regular reader of this
> list.
> 
> You will find the driver source in the kernel itself. I tested it
> however against my latest git tree, which is available from
> 
> git-clone http://deine-taler.de/zd1211/zd1211.git
> 
> -- 
> Uli Kunitz
> -
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