# Facing "mmap 4096 bytes at (nil): Cannot allocate memory"? You're not alone!

**URL:** <https://discourse.haskell.org/t/facing-mmap-4096-bytes-at-nil-cannot-allocate-memory-youre-not-alone/6259>\
**Category:** Uncategorized\
**Created:** [May 9, 2023, 5:20pm UTC](https://discourse.haskell.org/t/facing-mmap-4096-bytes-at-nil-cannot-allocate-memory-youre-not-alone/6259 "2023-05-09T17:20:29Z")\
**Posts on this page:** 1\
**Showing post:** 12

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**Author:** ![juhp](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.haskell.org/juhp/32/323_2.png) [@juhp](https://discourse.haskell.org/u/juhp)\
**Post date:** [May 18, 2023, 6:10am UTC](https://discourse.haskell.org/t/facing-mmap-4096-bytes-at-nil-cannot-allocate-memory-youre-not-alone/6259/12 "2023-05-18T06:10:27Z")

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Unfortunately the ghci 9.2 crash is happening sometimes in current Fedora releases now (~10% of the time in kernel-6.2.15-300; 6.2.9-300 is okay) and more often with kernel-6.3.3-200 and 6.4.0 rc’s (rawhide).  
So I am starting to wonder if this behavior will really change (back) in the Linux kernel or not?  
(Though I am hoping to ship ghc-9.4 in Fedora 39…)

The crash happens for me only sometimes and before ghci even shows the initial prompt  
(the core files are about 4MB apparently).

Also worth mentioning Sylvain’s [draft backport MR](https://gitlab.haskell.org/ghc/ghc/-/merge_requests/10453) too (not a small patch though by any definition). If you are using Fedora 38 you can update to this [temporary scratch build](https://koji.fedoraproject.org/koji/taskinfo?taskID=101285362) which includes the patches, eg using `koji-tool install 101285362`.

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_[View the full topic](https://discourse.haskell.org/t/facing-mmap-4096-bytes-at-nil-cannot-allocate-memory-youre-not-alone/6259)._