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Bug 675304 - Fix potential deadlock in intel-iommu
Summary: Fix potential deadlock in intel-iommu
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: kernel
Version: 6.1
Hardware: x86_64
OS: Unspecified
medium
medium
Target Milestone: rc
: ---
Assignee: Alex Williamson
QA Contact: Red Hat Kernel QE team
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2011-02-04 20:24 UTC by Alex Williamson
Modified: 2013-01-09 23:32 UTC (History)
1 user (show)

Fixed In Version: kernel-2.6.32-117.el6
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2011-05-19 12:28:20 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2011:0542 0 normal SHIPPED_LIVE Important: Red Hat Enterprise Linux 6.1 kernel security, bug fix and enhancement update 2011-05-19 11:58:07 UTC

Description Alex Williamson 2011-02-04 20:24:54 UTC 
Description of problem:
intel-iommu has a double lock fixed in 00dfff77

Version-Release number of selected component (if applicable):
kernel-2.6.32-113.el6

How reproducible:
no hit in practice

Steps to Reproduce:
1.
2.
3.
  
Actual results:


Expected results:


Additional info:
Comment 1 Alex Williamson 2011-02-04 20:28:22 UTC 
For reproducibility, I should say I've never hit it, but according to the
commit log, it is possible:

commit 00dfff77e7184140dc45724c7232e99302f6bf97
Author: Jiri Slaby <jirislaby>
Date:   Mon Jun 14 17:17:32 2010 +0200

    intel-iommu: Fix double lock in get_domain_for_dev()

    stanse found the following double lock.

    In get_domain_for_dev:
      spin_lock_irqsave(&device_domain_lock, flags);
      domain_exit(domain);
        domain_remove_dev_info(domain);
          spin_lock_irqsave(&device_domain_lock, flags);
          spin_unlock_irqrestore(&device_domain_lock, flags);
      spin_unlock_irqrestore(&device_domain_lock, flags);

    This happens when the domain is created by another CPU at the same time
    as this function is creating one, and the other CPU wins the race to
    attach it to the device in question, so we have to destroy our own
    newly-created one.

    Signed-off-by: David Woodhouse <David.Woodhouse>
Comment 2 RHEL Program Management 2011-02-06 07:50:31 UTC 
This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has 
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed 
products. This request is not yet committed for inclusion in an Update release.
Comment 3 Aristeu Rozanski 2011-02-18 22:16:37 UTC 
Patch(es) available on kernel-2.6.32-117.el6
Comment 6 Mike Gahagan 2011-02-24 20:17:46 UTC 
Appears there is no test case for this one. Confirmed the fix is in -118 and setting SanityOnly.
Comment 7 errata-xmlrpc 2011-05-19 12:28:20 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2011-0542.html
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