Fix T91212: BLI_mmap not thread-safe on Linux/macOS
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Authored by Lukas Stockner (lukasstockner97) on Oct 4 2021, 1:40 AM.

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Campbell Barton (campbellbarton)
Bastien Montagne (mont29)

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T91212: BLI_mmap not thread-safe on Linux/macOS (unfreed memory generating thumbnails)

Summary

Since we can't lock in signal handlers, the next-best approach is to use thread-local storage to track open files.
Luckily, SIGBUS is guaranteed to be handled by the same thread that caused it, so as long as mmapped files are only accessed from the thread that opened them, this works fine.

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Repository: rB Blender

Event Timeline

Lukas Stockner (lukasstockner97) requested review of this revision.Oct 4 2021, 1:40 AM

Lukas Stockner (lukasstockner97) created this revision.

Lukas Stockner (lukasstockner97) added a task: T91212: BLI_mmap not thread-safe on Linux/macOS (unfreed memory generating thumbnails).

Minor change suggested, otherwise this works well & LGTM.

source/blender/blenlib/intern/BLI_mmap.c
85–89	While I don't have a strong opinion on this, a `BLI_mmap_init_once()` function would avoid the lock & configured check, I have a slight preference for this over locking for a one-off call.

This revision is now accepted and ready to land.Oct 17 2021, 7:47 AM

Good point, I added BLI_mmap_init_once.

Harbormaster completed remote builds in B19312: Diff 45838.Dec 9 2021, 12:16 AM

Lukas Stockner (lukasstockner97) requested review of this revision.Dec 11 2021, 1:03 AM

Raimund Klink (Raimund58) added a subscriber: Raimund Klink (Raimund58).Jan 24 2022, 11:31 AM