Emacs opens only first 16384 bytes of file?!

[Christoph Groth <christoph@grothesque.org>]

Hello,

I just noticed something that made me doubt my own sanity:  With Emacs
27.1 (from Debian stable running Debian’s Linux kernel
6.0.0-0.deb11.6-amd64) the command

  emacs -q -nw /proc/cpuinfo

reproducibly opens cpuinfo only up to a portion of line 272, while the
entire file is 560 lines long on that machine.  I checked on a different
machine (with same Emacs), and I see the same behavior.

C-u C-x = tells that the file is read up to position 16384 (= 2^14).

Running M-x revert-buffer loads the whole file...

Is/was this a known issue?  I could not find anything on the web.

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I’m willing to investigate this further, but it would seem very strange
if Emacs indeed had a bug that prevented it from loading some files
entirely.  Perhaps someone here knows the answer.

Thanks
Christoph