[Bug malloc/16810] New: malloc modifies errno on success

[Bug malloc/16810] New: malloc modifies errno on success

[mikulas at artax dot karlin.mff.cuni.cz]

https://sourceware.org/bugzilla/show_bug.cgi?id=16810

            Bug ID: 16810
           Summary: malloc modifies errno on success
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: malloc
          Assignee: unassigned at sourceware dot org
          Reporter: mikulas at artax dot karlin.mff.cuni.cz
              Host: arm-linux-gnueabihf
            Target: arm-linux-gnueabihf
             Build: arm-linux-gnueabihf

Created attachment 7532
  --> https://sourceware.org/bugzilla/attachment.cgi?id=7532&action=edit
a simple program that demonstrates that malloc call succeeds and modifies errno

When the brk syscall fails to extend the heap, glibc tries to allocate a new
memory pool using mmap. If mmap succeeds, the block is successfuly allocated
and
returned to the caller - however, in this case, errno is set to ENOMEM.

The attached program demonstrates the problem.

The bug was reproduced on glibc-2.19 on Ununtu Trusy Tahr, glibc-2.13 on Debian
Wheezy and glibc-2.11.3 on Debian Squeeze.

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[Bug malloc/16810] malloc modifies errno on success

[schwab@linux-m68k.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=16810

Andreas Schwab <schwab@linux-m68k.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |INVALID

--- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> ---
Any function may modify errno unless it is documented not to do so.

http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_03

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[Bug malloc/16810] malloc modifies errno on success

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16810

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

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