Bug 152560

Summary: CAN-2005-0937 futex mmap_sem deadlock
Product: Red Hat Enterprise Linux 4 Reporter: Mark J. Cox <mjc>
Component: kernelAssignee: Jason Baron <jbaron>
Status: CLOSED ERRATA QA Contact: Brian Brock <bbrock>
Severity: high Docs Contact:
Priority: medium    
Version: 4.0CC: davej, knoel, riel
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard: impact=important,public=20050222,reported=20050222,source=lkml
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2005-07-26 12:21:51 UTC Type: ---
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:    
Bug Blocks: 147461    

Description Mark J. Cox 2005-03-30 12:30:37 UTC 
"Some futex functions do get_user calls while holding mmap_sem
        for reading. If get_user() faults, and another thread happens
        to be in mmap (or somewhere else holding waiting on down_write
        for the same semaphore), then do_page_fault will
        deadlock. Most architectures seem to be exposed to this."

        http://lkml.org/lkml/2005/2/22/123
        http://lkml.org/lkml/2005/2/22/185

        fixed=2.6-bk (cset@421cfc11zFsK9gxvSJ2t__FCmuUd3Q)

This would allow a local user to easily cause a system crash.  CVE applied for.
Comment 1 Mark J. Cox 2005-07-26 12:21:51 UTC 
This is fixed by linux-2.6.9-futex-mmap_sem-deadlock.patch in RHSA-2005:420