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Bug 2020 - Race condition between SDL_PushEvent and SDL_SetEventFilter.
Summary: Race condition between SDL_PushEvent and SDL_SetEventFilter.
Status: RESOLVED FIXED
Alias: None
Product: SDL
Classification: Unclassified
Component: events (show other bugs)
Version: HG 2.0
Hardware: All All
: P2 normal
Assignee: Sam Lantinga
QA Contact: Sam Lantinga
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2013-08-07 11:43 UTC by Rainer Deyke
Modified: 2019-10-14 15:38 UTC (History)
3 users (show)

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Description Rainer Deyke 2013-08-07 11:43:49 UTC 
SDL_PushEvent is supposed to be thread-safe.  However, SDL_PushEvent reads the event filter function pointer (SDL_EventOK) that is written by SDL_SetEventFilter.  This is a race condition that could lead to SDL_PushEvent reading a corrupted pointer if SDL_SetEventFilter is called in the main thread while SDL_PushEvent is called in another thread.
Comment 1 Sam Lantinga 2013-08-07 12:12:20 UTC 
How does the race condition manifest in your program?
Comment 2 Philipp Wiesemann 2015-10-14 20:33:51 UTC 
SDL_PushEvent() is not really thread-safe but SDL_PeepEvents() should be. If user events need to be added from another thread then SDL_PeepEvents() can be used (it does not access the filters and gestures).
Comment 3 Sylvain 2017-10-24 19:53:32 UTC 
similar issue with bug 2107
Comment 4 Sylvain 2019-10-14 15:38:41 UTC 
Was fixed here: https://hg.libsdl.org/SDL/rev/6d17410edb75