Bug 1531168

Summary: glibc: setcontext/makecontext alignment issues on x86
Product: Red Hat Enterprise Linux 7 Reporter: Florian Weimer <fweimer>
Component: glibcAssignee: Florian Weimer <fweimer>
Status: CLOSED ERRATA QA Contact: Sergey Kolosov <skolosov>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 7.6CC: ashankar, codonell, fweimer, mnewsome, pfrankli, skolosov
Target Milestone: rcKeywords: Patch
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: glibc-2.17-241.el7 Doc Type: Bug Fix
Doc Text:
Cause: The glibc functions startcontext and makecontext did not properly maintain stack alignment on the x86 platforms (32-bit and 64-bit). Consequence: Recent GCC versions, including those which are available through Developer Toolset (DTS), generate code that assumes ABI-mandated stack alignment in more places, and applications which use these functions could crash as a result. Fix: The glibc implementation of startcontext and makecontext was adjusted to follow ABI stack alignment. Result: Applications compiled with recent GCC versions no longer crash due to a misaligned stack.
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Clone Of: Environment:
Last Closed: 2018-10-30 09:36:35 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:    
Bug Blocks: 1565233    

Description Florian Weimer 2018-01-04 17:43:23 UTC 
The makecontext family of functions has alignment issues on i386 and x86-64:

https://sourceware.org/bugzilla/show_bug.cgi?id=18661
  (the change to sysdeps/unix/sysv/linux/x86_64/__start_context.S)
https://sourceware.org/bugzilla/show_bug.cgi?id=22667

We should consider fixing this for the benefit of DTS-compiled code.
Comment 6 errata-xmlrpc 2018-10-30 09:36:35 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/RHSA-2018:3092