#segmentation-fault
Вопрос:
Я получаю ошибку сброса ядра в вызове функции, которая должна возвращать an. Функция передает векторный элемент, который является указателем на структуру, в качестве параметра функции, но взамен приводит к сбросу ядра.
struct block { int64_t tag; bool valid_bit; bool dirty_bit; block* next; block* prev; }; vectorlt; block* gt; cash_set; ….
int main (int argc, const char *argv[]) { int findcash; ..... if (cash_type == 1) { coutlt;lt;"n Fully Associative"; number_of_blocks = cash_size / block_size; coutlt;lt;"n Enter the Replacement Policy n 0 for Randomn 1 for LRUn 2 for Pseudo LRUn"; cingt;gt;Replacement_policy; // initializing the cache to valid bit as 0 and dirty bit as 0 int i; cash_set.push_back(NULL); //Reading file "traces.txt" associativity=number_of_blocks; int loc; newfile.open ("traces.txt", ios::in); //open a file to perform read operation using file object if (newfile.is_open ()) { //checking whether the file is open int count = 0; while (getline (newfile, tp)) { cash_access ; iss.str (tp); //read data from file object and put it into string. cout lt;lt; "n" lt;lt; count lt;lt; " " lt;lt; tp lt;lt; "n"; //print the data of the string iss gt;gt; std::hex gt;gt; addr; cout lt;lt; " Address:" lt;lt; addr lt;lt; "t"; operation = tp.substr (11, 1); cout lt;lt; operation lt;lt; "n"; //extracting Tag, Index from the address shift = log2 (block_size); index_addr = (addr gt;gt; shift) % number_of_blocks; coutlt;lt;"donen"; shift = log2 (number_of_blocks block_size); tag_addr = addr gt;gt; shift; findcash=find(cash_set[0],tag_addr); //after the above line of code it gives Core dump coutlt;lt;"nfindcache:"lt;lt;findcash; Функция поиска выглядит следующим образом —
int find(block* tmp,int64_t tag1) { **if(tmp==NULL) { compulsry_misses ; coutlt;lt;"Cumpolsary miss:"lt;lt;compulsry_misses; return 0; }** else { block* cashblock=tmp; while(tmp-gt;prev!=NULL) { // Cache Hit. Bring the accessed node to the front of the DLL if (tmp-gt;tag==tag1) { coutlt;lt;"n Cache Hit"lt;lt;cash_hit; (tmp-gt;next)-gt;prev=tmp-gt;prev; (tmp-gt;prev)-gt;next=tmp-gt;next; cashblock-gt;next=tmp; tmp-gt;prev=cashblock; tmp-gt;next=NULL; cashblock-gt;next=tmp; cashblock=tmp; return 1; } tmp=tmp-gt;prev; } return 0; } } Traces.txt file contains data as follows —
0x6b8b4567 w 0x327b23c6 r 0x643c9869 w 0x66334873 r 0x74b0dc51 w 0x19495cff r 0x2ae8944a w ...... The output after running the code on Ubuntu is as follows —
.... Fully Associative Enter the Replacement Policy 0 for Random 1 for LRU 2 for Pseudo LRU 0 0 0x6b8b4567 w Address:1804289383 w done Cumpolsary miss:1 Segmentation fault (core dumped)