VTune on FC 6 - insmod errors

[keshavan]

Hi,
I was attempting to get the VTune driver running on Fedora Core 6 on P4-HT (i686; kernel: 2.6.18-1.2849.fc6). I was able to successfully compile the driver. When I tried to install the module, I got the following error:
# insmod vtune_drv-x32-2.6.18-1.2849.fc6smp.ko
insmod: error inserting 'vtune_drv-x32-2.6.18-1.2849.fc6smp.ko': -1 Unknown symbol in module
The dmesg indicates that unknown symbol is "tasklist_lock".
vtune_drv: Unknown symbol tasklist_lock

Can you please help me with this?

Thanks and Regards
Keshavan

[keshavan]

I have some more updates with regard to the errors seen on FC6 (kernel: 2.6.18). The support for tasklist_lock has been removed from the 2.6.18 kernel. Also a solution has been proposed for libafs in the link below. http://www.mail-archive.com/openafs-info@openafs.org/msg22061.html

It is proposed that read_lock and read_unlock be replaced with rcu_read_lock() and rcu_read_unlock(). However I did not find an alternative call for read_trylock() which is being used in vtune.c (function: get_tgid_trylock). This function uses TGID_TRY and TGID_RELEASE macros (defined in vtprotos.h). I was considering replacing this with rcu_read_lock and rcu_read_unlock, since I dont know an alternative technique. However the comments in the code indicate:
// Since we want the interrupt handler to avoid possible deadlock
// due to a spin on the tasklist_lock, we will use the read_trylock()
// call when it is available, but when it isn't we'll use the more
// heavy handed write_trylock() which is available on all the kernels
// we support...

I modified the driver, compiled it and loaded it. There does not seem to be any errors so far. Since I am not a kernel programmer and have no familiarity with Linux kernel, this needs some more investigation from the more knowledgable ones. Can someone give me some guidance on this?

Many Thanks,

Regards
--Keshavan

[aokunev]

Hi Keshavan

This is a know issue. It will be addressed in the 8.0.3 product update which is expected soon. Please upgrade your version once it's released.

Regards, Andrei

[Karthik_Kumar_Viswan]

Hi,

You could replace all references to read_lock(&tasklist) by rcu_read_lock and similiarly for read_unlock.

Now try_lock tries to get a lock before 10,000 spins or retire; If you think a lock can be acquires within lesser spins, you CAN use a rcu_read_lock in place. (and the release part is a rcu_read_unlock)

I don't think this is what was required, though.

[David_A_Intel1]

Note: Fedora Core* 6 is not supported by any available releases. Please watch http://www.intel.com/software/products/vtunefor updates.

[brady1]

I wonder does anyone have a timeline on that?

Regards
Mike Brady

[philbinj]

Hi, i'm running FC5 with a new 2.6.20 kernel - has anyone managed to compile the vkl code by replacing read_try_lock with the rcu versions? If so, could someone send the patch?

Thanks,
Shash

[keshavan]

Hi,

I have modified the code and compiled it for 2.6.18 kernel. I can send you the modified source code. I dont know how to create a patch for the same. Let me know if you want it.

Regards

Keshavan