[Bug malloc/22780] New: Undocumented new behavior with tcache and error/integrity checkings

["joel at porquet dot org" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=22780

            Bug ID: 22780
           Summary: Undocumented new behavior with tcache and
                    error/integrity checkings
           Product: glibc
           Version: 2.26
            Status: UNCONFIRMED
          Severity: critical
          Priority: P2
         Component: malloc
          Assignee: unassigned at sourceware dot org
          Reporter: joel at porquet dot org
  Target Milestone: ---

Discovered yesterday night that mallopt() had no more effect (at least for
small allocations which are now handled by tcache).

=> Open the manpage for mallopt, scroll down to example, copy-paste the snippet
of code, compile, run and observe that nothing works like advertised anymore.

I'm a bit surprised that none of this is properly documented. So far, the only
workaround that someone gave me (see original bugreport:
https://bugs.archlinux.org/task/57350) is to set env variable GLIBC_TUNABLES to
"glibc.malloc.tcache_count=0". This is a very inconvenient solution since it
somehow forces to have a script before running the program to set this
variable.


Assuming that tcache won't disappear anytime soon, would it possible at least
to:
- update the man page accordingly?
- disclose all the workarounds available to get the same behavior as before?

Thank you.

-- 
You are receiving this mail because:
You are on the CC list for the bug.