Bug 1257938

Summary: devname not known for vfs_read/write probes on ppc64
Product: Red Hat Enterprise Linux 7 Reporter: Tereza Cerna <tcerna>
Component: systemtapAssignee: Frank Ch. Eigler <fche>
Status: CLOSED WONTFIX QA Contact: qe-baseos-tools-bugs
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 7.2CC: jeder, jistone, jscotka, jskarvad, lberk, mcermak, mjw
Target Milestone: rc   
Target Release: ---   
Hardware: ppc64   
OS: Unspecified   
Whiteboard:
Fixed In Version: Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2018-11-29 14:49:55 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1065459, 1173076, 1785287    
Bug Blocks: 1295396, 1305230    
Attachments:
Description Flags
Reproducer none

Comment 2 Jaroslav Škarvada 2016-07-15 11:35:37 UTC 
This seems like kernel/systemtap. It seems to work OK on other architectures. I think the vfs.write probe should also work on ppc64, reassigning to systemtap. Please reassign if it is kernel.

The code causing the problem:
https://git.fedorahosted.org/cgit/tuned.git/tree/systemtap/diskdevstat

usage:
# diskdevstat 1 10 0
Comment 3 Jaroslav Škarvada 2016-07-15 12:07:54 UTC 
It seems vfs.read/write probes doesn't know devname on ppc64. Attaching stripped down reproducer.
Comment 4 Jaroslav Škarvada 2016-07-15 12:09:07 UTC 
Created attachment 1180124 [details]
Reproducer
Comment 10 Frank Ch. Eigler 2016-12-08 01:33:33 UTC 
This apparent debuginfo problem can only clumsily be worked around with tapset-level workarounds like the .statement probe.  We don't have facilities to reliably avoid having to hard-code line numbers like that.
Comment 11 Frank Ch. Eigler 2018-11-29 14:49:48 UTC 
I propose CANTFIX closing this because of the fragility of the situation.  Should users encounter this problem, we can talk them through .statement() probes that can work on their particular kernel/architecture.
Comment 12 Red Hat Bugzilla Rules Engine 2018-11-29 14:49:55 UTC 
Development Management has reviewed and declined this request. You may appeal this decision by reopening this request.