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From: "andi-bz at firstfloor dot org" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sources.redhat.com
Subject: [Bug libc/13276] New: assertation failure in realloc when running out of virtual mappings
Date: Sat, 08 Oct 2011 16:24:00 -0000
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http://sourceware.org/bugzilla/show_bug.cgi?id=13276

             Bug #: 13276
           Summary: assertation failure in realloc when running out of
                    virtual mappings
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
        AssignedTo: drepper.fsp@gmail.com
        ReportedBy: andi-bz@firstfloor.org
    Classification: Unclassified


When a process runs out of virtual mappings on Linux
(more mmaps than vm.max_map_count) then munmap can fail because it may 
need to split a mapping.

In this case when there is a realloc() it will get an assertation 
failure because it doesn't expect munmap to fail.

Seen with gcc with a specific input file that fragments memory badly:

lto1: malloc.c:3551: munmap_chunk: Assertion `ret == 0' failed.

realloc should return NULL in this case, not assert. free should cleanly 
return.

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