MuPDF unbounded memory growth

[bricewge]

When reading a PDF, scanned pages of a book, I got a crash saying: thread 'main' panicked at 'no entry found for key'. If I remember correctly I was browsing it, which is slow, it went unresponsive and I tried to get back to the shelf by touching the center of the screen. After a few second it rebooted.
I wasn't able to reproduce it.

[baskerville]

Please use the attached release binary (with debug symbols). And in plato.sh, replace:

./plato >> info.log 2>&1 || mv info.log crash.log

with:

RUST_BACKTRACE=1 ./plato >> info.log 2>&1 || mv info.log crash.log

If you manage to reproduce or encounter another crash, crash.log will provide a useful backtrace.

plato-0.7.1-release_debug_binary.zip

[baskerville]

I was able to reproduce this somehow. I've got additional messages:

error: malloc of 2482272 bytes failed
error: malloc of 5911576 bytes failed

I will try to investigate.

[baskerville]

This is quite easy to reproduce:

1. Open a large PDF.
2. Jump to a random page.
3. Go to step 2.

Running free -m on each page jump shows the associated drop in the amount of free memory.

The problem is specific to MuPDF. I'm assuming that it has to do with MuPDF's cache. But the cache shouldn't grow beyond 32 MiB…

[baskerville]

This is a bug in MuPDF.