I have a customer who set up permissions on the driver 600. Obviously this is wrong since a non-root user in the vtune group will not have permissions.
I advised to insmod with permission 660 to restrict use to those in the vtune group. Fine. Now their question is - does the group perms NEED WRITE permission? Shouldn't the perms be 640 - in other words, why does a user need write permission?
If you use default permission, that is "666", but at least you need to use "660" for non-root user, otherwise - the driver has no write permission to create file
# ./insmod-sep3 -p 640
Checking for PMU arbitration service (PAX) ... detected.
PAX service is accessible to all users.
Executing: insmod ./sep3_15-x32_64-2.6.32-71.el6.x86_64smp.ko
Creating /dev/sep3_15 base devices with major number 247 ... done.
Creating /dev/sep3_15 percpu devices with major number 246 ... done.
Setting group ownership of devices to group "vtune" ... done.
Setting file permissions on devices to "640" ... done.
The sep3_15 driver has been successfully loaded.
Checking for vtsspp driver ... not detected.
Executing: insmod ./vtsspp/vtsspp-x32_64-2.6.32-71.el6.x86_64smp.ko gid=511 mode=0640
The vtsspp driver has been successfully loaded.
# su peter
$ amplxe-cl -c advanced-hotspots -r /tmp/r003ah -d 5
amplxe: Collection started. To stop the collection, either press CTRL-C or enter from another console window: amplxe-cl -r /tmp/r003ah -command stop.
amplxe: Warning: To enable hardware event-base
Problem accessing the sampling driver. The driver may need to be (re)installed with appropriate group/file permissions
amplxe: Error: Error: Cannot create output file -- The file directory does not exist, or the directory is not writable
ERROR: Options error
amplxe: Collection failed.
amplxe: Internal Error