Spin Lock

OSR_Community_User · February 14, 2005, 4:43am

Hello,

Is there any problem with this code:

{
KIRQL irql1, irql2;

…

KeAcquireSpinLock( &gSomeLock1, &irql1 );

…

KeAcquireSpinLock( &gSomeLock2, &irql2 );

…

KeReleaseSpinLock( &gSomeLock2, irql2 );

…

KeReleaseSpinLock( &gSomeLock1, irql1 );

…
}

My computer freezes. It must be something with my driver I think. The problem is that I cannot trace this because of the freeze. I keep the debug info in a log file but only the stuff thats == PASSIVE_LEVEL.
Have no idea how to trace it.

Thank you,
Andrei CIUBOTARU

Pawan_Khatri · February 14, 2005, 4:53am

Make sure you maintain the same order for acquring locks at all places
in your driver.
Thanks,
Pawan

On Mon, 14 Feb 2005 01:48:13 -0800 (PST), Ciubotaru Ovidiu Andrei
wrote:
> Hello,
>
> Is there any problem with this code:
>
> {
> KIRQL irql1, irql2;
>
> …
>
> KeAcquireSpinLock( &gSomeLock1, &irql1 );
>
> …
>
> KeAcquireSpinLock( &gSomeLock2, &irql2 );
>
> …
>
> KeReleaseSpinLock( &gSomeLock2, irql2 );
>
> …
>
> KeReleaseSpinLock( &gSomeLock1, irql1 );
>
> …
> }
>
> My computer freezes. It must be something with my driver I think. The problem is that I cannot trace this because of the freeze. I keep the debug info in a log file but only the stuff thats == PASSIVE_LEVEL.
> Have no idea how to trace it.
>
> Thank you,
> Andrei CIUBOTARU
>
> —
> Questions? First check the Kernel Driver FAQ at http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as: xxxxx@gmail.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
>

OSR_Community_User · February 14, 2005, 5:04am

Ciubotaru Ovidiu Andrei wrote:

Hello,

Is there any problem with this code:

{
KIRQL irql1, irql2;

…

KeAcquireSpinLock( &gSomeLock1, &irql1 );

…

KeAcquireSpinLock( &gSomeLock2, &irql2 );

…

KeReleaseSpinLock( &gSomeLock2, irql2 );

…

KeReleaseSpinLock( &gSomeLock1, irql1 );

…
}

You should also check if you acquire a spin lock recursively. (I.e. you
acquire the lock in a function and you call the function while holding
the same lock in another).

My computer freezes. It must be something with my driver I think. The problem is that I cannot trace this because of the freeze. I keep the debug info in a log file but only the stuff thats == PASSIVE_LEVEL.
Have no idea how to trace it.

Check out the *KdPrint *macro.

Thank you,
Andrei CIUBOTARU

Questions? First check the Kernel Driver FAQ at http://www.osronline.com/article.cfm?id=256

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Mark_Roddy · February 14, 2005, 6:57am

Debug the deadlock with a debugger. One of the nice things about a spinlock
deadlock is that the offending threads are present in memory with a stack
that pretty much indicts their lock acquisition order screw-up.

=====================
Mark Roddy
Windows .NET/XP/2000 Consulting
Hollis Technology Solutions 603-321-1032
www.hollistech.com

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Pawan Khatri
Sent: Monday, February 14, 2005 4:53 AM
To: Windows System Software Devs Interest List
Subject: Re: [ntdev] Spin Lock

Make sure you maintain the same order for acquring locks at
all places in your driver.
Thanks,
Pawan

On Mon, 14 Feb 2005 01:48:13 -0800 (PST), Ciubotaru Ovidiu
Andrei wrote:
> > Hello,
> >
> > Is there any problem with this code:
> >
> > {
> > KIRQL irql1, irql2;
> >
> > …
> >
> > KeAcquireSpinLock( &gSomeLock1, &irql1 );
> >
> > …
> >
> > KeAcquireSpinLock( &gSomeLock2, &irql2 );
> >
> > …
> >
> > KeReleaseSpinLock( &gSomeLock2, irql2 );
> >
> > …
> >
> > KeReleaseSpinLock( &gSomeLock1, irql1 );
> >
> > …
> > }
> >
> > My computer freezes. It must be something with my driver I
> think. The problem is that I cannot trace this because of the
> freeze. I keep the debug info in a log file but only the
> stuff thats == PASSIVE_LEVEL.
> > Have no idea how to trace it.
> >
> > Thank you,
> > Andrei CIUBOTARU
> >
> > —
> > Questions? First check the Kernel Driver FAQ at
> > http://www.osronline.com/article.cfm?id=256
> >
> > You are currently subscribed to ntdev as: xxxxx@gmail.com To
> > unsubscribe send a blank email to xxxxx@lists.osr.com
> >
>
> —
> Questions? First check the Kernel Driver FAQ at
> http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as:
> xxxxx@hollistech.com To unsubscribe send a blank email to
> xxxxx@lists.osr.com
>

Girish_Kulkarni · February 14, 2005, 8:31am

You can run your driver with Verifer, and it will crash the system if it
detects a deadlock. It will also point to the offending threads that caused
the deadlock.

-g

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Mark Roddy
Sent: Monday, February 14, 2005 5:27 PM
To: Windows System Software Devs Interest List
Subject: RE: [ntdev] Spin Lock

Debug the deadlock with a debugger. One of the nice things about a spinlock
deadlock is that the offending threads are present in memory with a stack
that pretty much indicts their lock acquisition order screw-up.

=====================
Mark Roddy
Windows .NET/XP/2000 Consulting
Hollis Technology Solutions 603-321-1032 www.hollistech.com

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Pawan Khatri
Sent: Monday, February 14, 2005 4:53 AM
To: Windows System Software Devs Interest List
Subject: Re: [ntdev] Spin Lock

Make sure you maintain the same order for acquring locks at all places
in your driver.
Thanks,
Pawan

On Mon, 14 Feb 2005 01:48:13 -0800 (PST), Ciubotaru Ovidiu Andrei
wrote:
> > Hello,
> >
> > Is there any problem with this code:
> >
> > {
> > KIRQL irql1, irql2;
> >
> > …
> >
> > KeAcquireSpinLock( &gSomeLock1, &irql1 );
> >
> > …
> >
> > KeAcquireSpinLock( &gSomeLock2, &irql2 );
> >
> > …
> >
> > KeReleaseSpinLock( &gSomeLock2, irql2 );
> >
> > …
> >
> > KeReleaseSpinLock( &gSomeLock1, irql1 );
> >
> > …
> > }
> >
> > My computer freezes. It must be something with my driver I
> think. The problem is that I cannot trace this because of the freeze.
> I keep the debug info in a log file but only the stuff thats ==
> PASSIVE_LEVEL.
> > Have no idea how to trace it.
> >
> > Thank you,
> > Andrei CIUBOTARU
> >
> > —
> > Questions? First check the Kernel Driver FAQ at
> > http://www.osronline.com/article.cfm?id=256
> >
> > You are currently subscribed to ntdev as: xxxxx@gmail.com To
> > unsubscribe send a blank email to xxxxx@lists.osr.com
> >
>
> —
> Questions? First check the Kernel Driver FAQ at
> http://www.osronline.com/article.cfm?id=256
>
> You are currently subscribed to ntdev as:
> xxxxx@hollistech.com To unsubscribe send a blank email to
> xxxxx@lists.osr.com
>

—
Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@cisco.com To unsubscribe
send a blank email to xxxxx@lists.osr.com

OSR_Community_User · February 14, 2005, 11:51am

There is nothing wrong with the code, but I have a couple of suggestions

if you suspect a deadlock, enable deadlock detection with driver
verifier against your driver
if you know that you are already holding another spinlock or you are
already at DISPATCH_LEVEL, you can use
KeAcquireSpinLockAtDpcLevel/KeReleaseSpinLockAtDpcLevel. These 2
functions are bit more performant than their normal acquire/release
spinlock siblings because there is no IRQL check or raise.

d

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Ciubotaru Ovidiu
Andrei
Sent: Monday, February 14, 2005 1:36 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Spin Lock