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Bug 1602151 - General Protection Fault unlocking UDS callback mutex
Summary: General Protection Fault unlocking UDS callback mutex
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: kmod-kvdo
Version: 7.6
Hardware: Unspecified
OS: Unspecified
unspecified
high
Target Milestone: rc
: ---
Assignee: Thomas Jaskiewicz
QA Contact: Jakub Krysl
URL:
Whiteboard:
: 1693695 (view as bug list)
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2018-07-17 21:36 UTC by Thomas Jaskiewicz
Modified: 2021-09-03 12:05 UTC (History)
5 users (show)

Fixed In Version: 6.1.1.117
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2018-10-30 09:39:49 UTC
Target Upstream Version:
Embargoed:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Knowledge Base (Solution) 5982481 0 None None None 2021-04-21 12:45:19 UTC
Red Hat Product Errata RHBA-2018:3094 0 None None None 2018-10-30 09:40:14 UTC

Description Thomas Jaskiewicz 2018-07-17 21:36:30 UTC
Description of problem:

In our nightly testing, we have seen an occasional general protection fault related to the UDS callback code path.  Examining the source code, we have found a code path that was doing a bad thing and fixed it in bug 1533260.  After doing the fix, we still see
a similar error happening in the same code path.

We believe there is a race condition in some synchronization code that came from the user mode implementation of UDS.  Since this code is a reimplementation of the Linux kernel wait_for_condition mechanism, we have chosen to change the code to just use the existing kernel mechanism.


Version-Release number of selected component (if applicable):


How reproducible:

Very difficult.  We have a test that does 1024 start/stop cycles of a single VDO device.  Its purpose is to ensure that VDO instance numbers behave properly, but it was the first test to see the general protection fault (after 500 cycles).  We run this test 2 or 3 times a night, and have seen this failure 5 times in the last six months.

SanityOnly is the reasonable test plan.


Steps to Reproduce:
1.
2.
3.

Actual results:

A general protection fault in the kvdo%u:callbsckW kernel process.

Expected results:

no general protection fault.
Additional info:

Comment 3 Jakub Krysl 2018-08-30 15:00:35 UTC
Sanity testing on kmod-kvdo-6.1.1.120-2.el7 passed.

Comment 5 errata-xmlrpc 2018-10-30 09:39:49 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:3094

Comment 6 Thomas Jaskiewicz 2019-08-20 19:35:24 UTC
*** Bug 1693695 has been marked as a duplicate of this bug. ***


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