Bug#859923: linux-image-4.9.0-2-amd64: mmap system call problem

From	Ben Hutchings <ben@decadent.org.uk>
Newsgroups	linux.debian.bugs.dist, linux.debian.kernel
Subject	Bug#859923: linux-image-4.9.0-2-amd64: mmap system call problem
Date	2017-04-12 19:10 +0200
Message-ID	<tvtWi-7dn-25@gated-at.bofh.it> (permalink)
References	(1 earlier) <tuigx-1wq-5@gated-at.bofh.it> <tuKmt-341-3@gated-at.bofh.it> <tvcC6-4Dw-17@gated-at.bofh.it> <tvcC6-4Dw-13@gated-at.bofh.it> <tvlYK-2ed-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Cross-posted to 2 groups.

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Control: severity -1 normal
Control: clone -1 -2
Control: retitle -1 zshbuiltins(1): Explain what data segment means for ulimit
Control: reassign -1 zsh
Control: retitle -2 bash(1): Explain what data segment means for ulimit
Control: reassign -2 bash

On Wed, 2017-04-12 at 10:07 +0200, Fernando Santagata wrote:
[...]
> Right now is at its default state:
[...]
> -d: data seg size (kbytes)          131072

No, the default is unlimited.

[...]
> previously I tried to increase it to 200000, but it didn't work.
> I guess the problem is with the heap, not the data segment.

The 'data segment' includes the heap.  From the setrlimit(2) manual
page:

       RLIMIT_DATA
              The  maximum  size  of  the  process's data segment (initialized
              data, uninitialized data, and heap).  This limit  affects  calls
              to  brk(2)  and  sbrk(2),  which fail with the error ENOMEM upon
              encountering the soft limit of this resource.

Looking at the implementation, I can see that it applies to all memory
mappings that are writable, not shared and not specified as stack.  I
think that the above description is close enough to that.

It looks like you're using zsh, for which the manual page says:

              -d     Kilobytes on the size of the data segment.

While the bash manual page says similarly:

              -d     The maximum size of a process's data segment

These could both benefit from a longer description of 'data segment'.

Ben.

-- 
Ben Hutchings
I'm not a reverse psychological virus.  Please don't copy me into your
sig.

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Bug#859923: linux-image-4.9.0-2-amd64: mmap system call problem Ben Hutchings <ben@decadent.org.uk> - 2017-04-10 18:30 +0200
  Bug#859923: linux-image-4.9.0-2-amd64: mmap system call problem Ben Hutchings <ben@decadent.org.uk> - 2017-04-12 00:40 +0200
    Bug#859923: linux-image-4.9.0-2-amd64: mmap system call problem Fernando Santagata <nando@ipers.net> - 2017-04-12 10:40 +0200
      Bug#859923: linux-image-4.9.0-2-amd64: mmap system call problem Ben Hutchings <ben@decadent.org.uk> - 2017-04-12 19:10 +0200

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