your program did not free of memory allocated ==17711== memcheck, memory error detector ==17711== copyright (c) 2002-2009, , gnu gpl'd, julian seward et al. ==17711== using valgrind-3.5.0 , libvex; rerun -h copyright info ==17711== command: ./counter ==17711== ==17711== conditional jump or move depends on uninitialised value(s) ==17711== @ 0x400b98: main (counter.c:105) ==17711== ==17711== conditional jump or move depends on uninitialised value(s) ==17711== @ 0x400bdb: main (counter.c:107) ==17711== ==17711== conditional jump or move depends on uninitialised value(s) ==17711== @ 0x400c1b: main (counter.c:109) ==17711== error ==17711== ==17711== heap summary: ==17711== in use @ exit: 64 bytes in 4 blocks ==17711== total heap usage: 4 allocs, 0 frees, 64 bytes allocated ==17711== ==17711== leak summary: ==17711== lost: 0 bytes in 0 blocks ==17711== indirectly lost: 0 bytes in 0 blocks ==17711== possibly lost: 0 bytes in 0 blocks ==17711== still reachable: 64 bytes in 4 blocks ==17711== suppressed: 0 bytes in 0 blocks ==17711== rerun --leak-check=full see details of leaked memory ==17711== ==17711== counts of detected , suppressed errors, rerun with: -v ==17711== use --track-origins=yes see uninitialised values come ==17711== error summary: 3 errors 3 contexts (suppressed: 6 6) make: *** [test_counter] error 1 i have memory leak in program... pretty sure free dynamic memory.. don't understand leak =\
#include "counter.h" /* ============================================================================ * file-global variables * ========================================================================== */ static int ncounters = 0; static struct counter *counters = null; static int nthreads = 0; static int *ninstructions = null; static struct instruction **instructions = null; /* ============================================================================ * operations * ========================================================================== */ static void decrement(long long *n) { (*n)--; } static void increment(long long *n) { (*n)++; } static void mult2(long long *n) { (*n)=(*n)*2; } /* ============================================================================ * helper functions * ========================================================================== */ pthread_mutex_t lock1; /* ============================================================================ * thread function * ========================================================================== */ static void * worker_thread(void *arg) { pthread_mutex_lock( &lock1 ); long long n = (long long)arg; for(int i=0; < ninstructions[n] ;i++){ for(int j=0; j < instructions[n][i].repetitions ;j++){ (*instructions[n][i].work_fn)(&((instructions[n][i].counter)->counter)); } } pthread_mutex_unlock( &lock1 ); return null; } /* ============================================================================ * main function * ========================================================================== */ int main(void) { scanf(" %d", &ncounters); //ask number of counters int i; if((counters = malloc(sizeof(struct counter)*ncounters))){ for( i=0; < ncounters ;i++){ counters[i].counter = 0; } } scanf(" %d", &nthreads); //ask number of threads if((ninstructions = (int*) malloc(nthreads*sizeof(int)))){ for( i=0; < nthreads ;i++){ ninstructions[i] = 0; } } instructions = malloc(nthreads*sizeof(struct instruction *)); for(i=0; < nthreads ;i++){ scanf(" %d", &ninstructions[i]); //ask number of instructions within threads[i] instructions[i] = malloc(ninstructions[i]*sizeof(struct instruction)); for(int j=0;j < ninstructions[i] ;j++){ int srepetition; char sfunction; int scounter; scanf(" %d %c %d", &scounter, &sfunction, &srepetition); instructions[i][j].repetitions = srepetition; instructions[i][j].counter = (counters+scounter); if(sfunction == 'i'){ instructions[i][j].work_fn = increment; }else if(sfunction == 'd'){ instructions[i][j].work_fn = decrement; }else if(sfunction == '2'){ instructions[i][j].work_fn = mult2; }else{ printf("error\n"); } } } pthread_t thread_id[nthreads]; for(long long i=0; < nthreads ;i++){ pthread_create( &thread_id[i], null, worker_thread, (void *)i); } for(int i=0; < nthreads ;i++){ pthread_join( thread_id[i], null); } for(i=0; < ncounters ;i++){ printf("%lld\n", counters[i].counter); } for(int i=0; i< nthreads;i++){ free(instructions[i]); } free(instructions); free(ninstructions); free(counters); return 0; }
you free memory instructions occupies:
free(instructions); then access memory:
for(int i=0 ; < nthreads ; i++){ free(instructions[i]); } you cannot access instructions after free(instructions).
you need free pointers in instructions first, free instructions array.
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