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Bug 4835 - Default for SDL_SIMDAlignment causes crashes on some 64-bit systems
Summary: Default for SDL_SIMDAlignment causes crashes on some 64-bit systems
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: main (show other bugs)
Version: 2.0.10
Hardware: Other OpenBSD
: P2 normal
Assignee: Ryan C. Gordon
QA Contact: Sam Lantinga
URL:
Keywords: target-2.0.12
Depends on:
Blocks:
 
Reported: 2019-10-21 01:52 UTC by Simon Howard
Modified: 2019-10-21 02:19 UTC (History)
1 user (show)

See Also:

Attachments
Patch to fix bug. (526 bytes, patch)
2019-10-21 01:52 UTC, Simon Howard 		Details | Diff
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Description Simon Howard 2019-10-21 01:52:59 UTC 
Created attachment 3989 [details]
Patch to fix bug.

In SDL_cpuinfo.c the default value for SDL_SIMDAlignment is set to 4 unless system-specific CPU features are detected. This can cause SDL_SIMDAlloc() to crash on MIPS64 systems because memory is allocated on 4-byte boundaries, but MIPS64 requires 8-byte alignment (unaligned accesses cause a Bus Error).

Changing to sizeof(void *) should make for a safer default and fixes the crash. Diff attached.
Comment 1 Ryan C. Gordon 2019-10-21 02:19:54 UTC 
Your patch is now https://hg.libsdl.org/SDL/rev/568f67c04841, thanks!

--ryan.