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1 // Demonstrate that moving the "acquire" in iderw after the loop that
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2 // appends to the idequeue results in a race.
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3
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4 // For this to work, you should also add a spin within iderw's
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5 // idequeue traversal loop. Adding the following demonstrated a panic
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6 // after about 5 runs of stressfs in QEMU on a 2.1GHz CPU:
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7 // for (i = 0; i < 40000; i++)
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8 // asm volatile("");
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9
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10 #include "types.h"
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11 #include "stat.h"
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12 #include "user.h"
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13 #include "fs.h"
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14 #include "fcntl.h"
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15
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16 int
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17 main(int argc, char *argv[])
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18 {
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19 int fd, i;
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20 char path[] = "stressfs0";
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21 char data[512];
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22
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23 printf(1, "stressfs starting\n");
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24 memset(data, 'a', sizeof(data));
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25
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26 for(i = 0; i < 4; i++)
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27 if(fork() > 0)
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28 break;
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29
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30 printf(1, "write %d\n", i);
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31
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32 path[8] += i;
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33 fd = open(path, O_CREATE | O_RDWR);
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34 for(i = 0; i < 20; i++)
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35 // printf(fd, "%d\n", i);
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36 write(fd, data, sizeof(data));
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37 close(fd);
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38
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39 printf(1, "read\n");
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40
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41 fd = open(path, O_RDONLY);
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42 for (i = 0; i < 20; i++)
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43 read(fd, data, sizeof(data));
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44 close(fd);
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45
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46 wait();
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47
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48 exit();
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49 }
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