ubuntu guest with 10G n/w and Texan iSCSI crashes during FIO
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| linux (Ubuntu) |
Fix Released
|
Medium
|
Taco Screen team | ||
| Vivid |
Fix Released
|
Undecided
|
Unassigned | ||
| Wily |
Fix Released
|
Undecided
|
Unassigned | ||
| Xenial |
Fix Released
|
Medium
|
Taco Screen team | ||
Bug Description
Issues were found in iSCSI tests with hardware remote targets. Specifically, kernel crash happens due to dereferencing a null pointer (sc->device->lun at libiscsi.c:369, with sc==NULL). During the crash, lots of messages regarding lists invalid accesses are showed in kernel log.
The commit 659743b02c41 ("[SCSI] libiscsi: Reduce locking contention in fast path") appears to be the cause.
Reverting the commit solve the issue, at least until we can discuss and
find the exact problem (and its solution) in the commit
659743b02c41 ("[SCSI] libiscsi: Reduce locking contention in fast path").
A test kernel was patched to revert the offend commit - Prashantha is running tests to check if the problem is solved.
With the patched kernel, I am unable to recreate the crash. The patch appears
to be working.
A discussion is ongoing in linux-scsi mailing list, to revert the patch upstream (look the following link).
http://
Another quick discussion, started by me, it's on open-iscsi mailing list, on Google Groups:
https:/
The iscsi maintainer wants to revert, but patch co-author wants more study before reverting. Prashantha is performing some performance analysis to check the impact of the patch on iscsi performance.
Mirroring to Launchpad for Canonical's awareness. Once the discussion settles on the final solution, a patch or link to the upstream commit will be provided for Canonical to review for acceptance in the 14.04 LTS kernel and SRU.
| tags: | added: architecture-ppc64le bugnameltc-133001 severity-critical targetmilestone-inin14043 |
| Changed in ubuntu: | |
| assignee: | nobody → Taco Screen team (taco-screen-team) |
| affects: | ubuntu → linux (Ubuntu) |
| tags: | added: bisect-done |
| Changed in linux (Ubuntu): | |
| importance: | Undecided → Medium |
| status: | New → Triaged |
| tags: |
added: severity-high removed: severity-critical |
| Michael Hohnbaum (hohnbaum) wrote | #1 |
| bugproxy (bugproxy) wrote Comment bridged from LTC Bugzilla | #2 |
| Tim Gardner (timg-tpi) wrote | #3 |
| bugproxy (bugproxy) wrote | #4 |
| bugproxy (bugproxy) wrote | #5 |
| Changed in linux (Ubuntu Vivid): | |
| status: | New → Fix Committed |
| Tim Gardner (timg-tpi) wrote | #6 |
| Changed in linux (Ubuntu Wily): | |
| status: | New → Fix Committed |
| Changed in linux (Ubuntu Xenial): | |
| status: | Triaged → Fix Committed |
| Luis Henriques (henrix) wrote | #7 |
| tags: | added: verification-needed-vivid verification-needed-wily |
| Luis Henriques (henrix) wrote | #8 |
| bugproxy (bugproxy) wrote | #9 |
| Tim Gardner (timg-tpi) wrote | #10 |
| bugproxy (bugproxy) wrote | #11 |
| tags: |
added: verification-done-vivid verification-done-wily removed: verification-needed-vivid verification-needed-wily |
| Launchpad Janitor (janitor) wrote | #12 |
| Changed in linux (Ubuntu Xenial): | |
| status: | Fix Committed → Fix Released |
| Launchpad Janitor (janitor) wrote | #13 |
| Changed in linux (Ubuntu Vivid): | |
| status: | Fix Committed → Fix Released |
| Launchpad Janitor (janitor) wrote | #14 |
| Changed in linux (Ubuntu Wily): | |
| status: | Fix Committed → Fix Released |
| bugproxy (bugproxy) wrote | #15 |
IBM, any updates on the recommended fix for this issue?