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littlefs-project / littlefs

A little fail-safe filesystem designed for microcontrollers
BSD 3-Clause "New" or "Revised" License
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Tighten bound on mlist isopen asserts #921

Open geky opened 8 months ago

geky commented 8 months ago

Unbalanced open/close calls continue to be a pain point for users, it doesn't help that this sometimes results in hard-to-debug infinite loops caused by the open-file linked-list (the mlist) getting tangled up in itself.

Moving the mlist isopen asserts lower into the actual list append/remove functions will help:

  1. Make sure coverage of potential linked-list issues is complete.

  2. Also assert against multiple close calls, which isn't an issue for the mlist, but can result in double free and memory corruption.

geky commented 8 months ago

It looks like this doesn't work because of the restriction of LFS_ASSERT to error-returning functions (to allow asserts to return errors).

Tabling this for now. Current thinking is we should eventually split LFS_ASSERT into LFS_ASSERT and LFS_DISK_ASSERT, with only LFS_DISK_ASSERT being limited to error-returning functions.