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ThreadSanitizer (aka TSan) is a data race detector for C/C++. Data races are one of the most common and hardest to debug types of bugs in concurrent systems. A data race occurs when two threads access the same variable concurrently and at least one of the accesses is write. An example is provided below:
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#include <pthread.h>
int global = 0;
void *threadfunc(void *x) {
global = global + 1;
return x;
}
int main() {
pthread_t t1;
pthread_t t2;
pthread_create(&t1, NULL, threadfunc, NULL);
pthread_create(&t2, NULL, threadfunc, NULL);
pthread_join(t1, NULL);
pthread_join(t2, NULL);
return global;
} |
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WARNING: ThreadSanitizer:DEADLYSIGNAL ==204==ERROR: ThreadSanitizer: SEGV on unknown address 0x000000000000 (pc 0x0000004883e8 bp 0x7f697bfbf2f0 sp 0x7f697bfbf2d8 T205) ==204==The signal is caused by a WRITE memory access. ==204==Hint: address points to the zero page. ThreadSanitizer:DEADLYSIGNAL ThreadSanitizer: nested bug in the same thread, aborting. data race (pid=371) Write of size 4 at 0x000000f12358 by thread T2: #0 threadfunc <null> (a.out+0x4b18ee) Previous write of size 4 at 0x000000f12358 by thread T1: #0 threadfunc <null> (a.out+0x4b18ee) Location is global 'global' of size 4 at 0x000000f12358 (a.out+0x000000f12358) Thread T2 (tid=374, running) created by main thread at: #0 pthread_create <null> (a.out+0x424a2b) #1 main <null> (a.out+0x4b1960) Thread T1 (tid=373, finished) created by main thread at: #0 pthread_create <null> (a.out+0x424a2b) #1 main <null> (a.out+0x4b1941) SUMMARY: ThreadSanitizer: data race (/mnt/c/Users/Pascal/netdef/a.out+0x4b18ee) in threadfunc ================== ThreadSanitizer: reported 1 warnings |
Memory Sanitizer
MemorySanitizer (MSan) is a detector of uninitialized memory reads in C/C++ programs.
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