Messages in this thread | | | Date | Fri, 17 Jun 2011 18:21:49 +0300 | From | Vasileios Karakasis <> | Subject | [BUG] Invalid return address of mmap() followed by mbind() in multithreaded context |
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Hi,
I am implementing a multithreaded numa aware code where each thread mmap()'s an anonymous private region and then mbind()'s it to its local node. The threads are performing a series of such mmap() + mbind() operations. My program crashed with SIGSEGV and I noticed that mmap() returned an invalid address.
I am sending you a simple program that reproduces the error. The program creates two threads and each thread starts allocating pages and then binds them to the local node 0. After a number of iterations the program crashes as it tries to dereference the address returned by mmap(). The bug doesn't come up when using a single thread, neither when using only mmap().
I am running a 2.6.39.1 kernel on a 64-bit dual-core machine, but I tracked this bug back down to the 2.6.34.9 version.
This bug also affects libnuma.
Regards, -- V.K.
#include <assert.h> #include <sys/mman.h> #include <pthread.h> #include <numaif.h>
#define NR_ITER 10240 #define PAGE_SIZE 4096
void *thread_func(void *args) { unsigned char *addr; int err, i; unsigned long node = 0x1;
for (i = 0; i < NR_ITER; i++) { addr = mmap(0, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); if (addr == (void *) -1) { assert(0 && "mmap failed"); } *addr = 0;
err = mbind(addr, PAGE_SIZE, MPOL_BIND, &node, sizeof(node), 0); if (err < 0) { assert(0 && "mbind failed"); } } return (void *) 0; }
int main(void) { pthread_t thread; pthread_create(&thread, NULL, thread_func, NULL); thread_func(NULL); pthread_join(thread, NULL); return 0; } [unhandled content-type:application/pgp-keys][unhandled content-type:application/pgp-signature] | |