Problem on a kernel driver(SuSE, SMP)

From: Libershteyn, Vladimir (vladimir.libershteyn@hp.com)
Date: Wed Sep 04 2002 - 11:54:15 EST

Hi, All,

I'm looking for a help on a kernel module programming issue.

We have a hardware device I have a driver written for.
It works without any problem on any of Red Hat, SMP machine or not. The same driver does work with
SuSE 7.x non-SMP, but has a problem with SMP machines.

Here is a problem:

For synchronization I use semaphores. Semaphores initializes with init_MUTEX_LOCKED function
which basically set the atomic value of a count to 0.
In a routine that looking for a data I use a function down_interruptible(&sem) which should
check the count value to be 0 and if it so the thread goes to slip until the ISR will set the
semaphore count back to initial value with a command up(&sem);

What happens with my driver, when it comes to the command down_interruptible(...) the whole
system just hangs. I could not find any restrictions on using this mechanism, but just for the testing
I switched from using semaphores to wait queues. The result is exactly the same.

What am I doing wrong? The kernel I'm running is 2.4.7-64G... and the OS is SuSE7.x Enterprise
Again, It works fine on any Red Hat OS

Regards,
Vladimir Libershteyn
Hewlett-Packard
tel. 408-285-5270
fax. 408-285-2044

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