view test/testhread.c @ 1176:dd2a8deeb26d

Date: Mon, 17 Oct 2005 20:09:03 -0400 From: Mark Schreiber <mark7@alumni.cmu.edu> To: ryan@clutteredmind.org Subject: [PATCH]SDL mprotect() crash fix (I'm going to throw this patch your way at the suggestion of #SDL -- for some reason, I had some difficulty sending it to the main list last time, and I go bonkers subscribing to send each email or patch...) Currently, when I run SDL applications as non-root using SDL_VIDEODRIVER=dga, the fbdev fallback mprotect()s read/write the proper size of mmapped /dev/fb0 (7.5MB), but on framebuffer release mprotect()s read-only the range by the entire size of my video memory (128MB), which causes a segfault: #0 0x002a9a27 in ?? () from /lib/libc.so.6 #1 0x04a63eb6 in SDL_XDGAUnmapFramebuffer (screen=3D0) at XF86DGA2.c:978 #2 0x04a63efc in SDL_XDGACloseFramebuffer (dpy=3D0x9d3f008, screen=3D0) at XF86DGA2.c:268 #3 0x04a68b57 in DGA_Available () at SDL_dgavideo.c:98 #4 0x04a53677 in SDL_VideoInit (driver_name=3D0xbfb0bfc7 "dga", flags=3D0) at SDL_video.c:180 #5 0x04a2613f in SDL_InitSubSystem (flags=3D32) at SDL.c:74 #6 0x04a2617c in SDL_Init (flags=3D32) at SDL.c:166 #7 0x08049722 in main (argc=3D1, argv=3D0x0) at testwin.c:32 This is SDL 1.2.8 on Fedora Core 4, radeon driver for a Radeon 9250, xorg-x11-6.8.2-37. I've attached a one-line patch against SDL CVS that updates the size of the framebuffer at framebuffer map time so that the mprotect() on unmap will be the same size. I'm not sure if this is the best approach (i.e. one might want to retain the original value), but it does make my SDL applications work without segfaulting. -- Best of luck, Mark Schreiber
author Ryan C. Gordon <icculus@icculus.org>
date Sat, 19 Nov 2005 18:57:00 +0000
parents be9c9c8f6d53
children 14717b52abc0
line wrap: on
line source


/* Simple test of the SDL threading code */

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>

#include "SDL.h"
#include "SDL_thread.h"

static int alive = 0;

/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void quit(int rc)
{
	SDL_Quit();
	exit(rc);
}

int ThreadFunc(void *data)
{
	printf("Started thread %s: My thread id is %u\n",
				(char *)data, SDL_ThreadID());
	while ( alive ) {
		printf("Thread '%s' is alive!\n", (char *)data);
		SDL_Delay(1*1000);
	}
	printf("Thread '%s' exiting!\n", (char *)data);
	return(0);
}

static void killed(int sig)
{
	printf("Killed with SIGTERM, waiting 5 seconds to exit\n");
	SDL_Delay(5*1000);
	alive = 0;
	quit(0);
}

int main(int argc, char *argv[])
{
	SDL_Thread *thread;

	/* Load the SDL library */
	if ( SDL_Init(0) < 0 ) {
		fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
		return(1);
	}

	alive = 1;
	thread = SDL_CreateThread(ThreadFunc, "#1");
	if ( thread == NULL ) {
		fprintf(stderr, "Couldn't create thread: %s\n", SDL_GetError());
		quit(1);
	}
	SDL_Delay(5*1000);
	printf("Waiting for thread #1\n");
	alive = 0;
	SDL_WaitThread(thread, NULL);

	alive = 1;
	thread = SDL_CreateThread(ThreadFunc, "#2");
	if ( thread == NULL ) {
		fprintf(stderr, "Couldn't create thread: %s\n", SDL_GetError());
		quit(1);
	}
	SDL_Delay(5*1000);
	printf("Killing thread #2\n");
	SDL_KillThread(thread);

	alive = 1;
	signal(SIGTERM, killed);
	thread = SDL_CreateThread(ThreadFunc, "#3");
	if ( thread == NULL ) {
		fprintf(stderr, "Couldn't create thread: %s\n", SDL_GetError());
		quit(1);
	}
	raise(SIGTERM);

	SDL_Quit();	/* Never reached */
	return(0);	/* Never reached */
}