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995a46bbfb
The implementation of __get_nprocs uses a stactic variable to cache
the value of the current number of processors. The caching breaks when
'time (NULL) == 0':
$ cat nproc.c
#include <stdio.h>
#include <time.h>
#include <sys/time.h>
int main(int argc, char *argv[])
{
time_t t;
struct timeval tv = {0, 0};
printf("settimeofday({0, 0}, NULL) = %d\n", settimeofday(&tv, NULL));
t = time(NULL);
printf("Time: %d, CPUs: %d\n", (unsigned int)t, get_nprocs());
return 0;
}
$ gcc -O3 nproc.c
$ ./a.out
settimeofday({0, 0}, NULL) = -1
Time: 1401311578, CPUs: 4
$ sudo ./a.out
settimeofday({0, 0}, NULL) = 0
Time: 0, CPUs: 0
The problem is with the condition used to check whether a cached
value should be returned or not:
static int cached_result;
static time_t timestamp;
time_t now = time (NULL);
time_t prev = timestamp;
atomic_read_barrier ();
if (now == prev)
return cached_result;
This patch fixes the problem by ensuring that 'cached_result' has
been set at least once before returning it.
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| .. | ||
| alpha | ||
| arm | ||
| bsd | ||
| i386 | ||
| inet | ||
| mips | ||
| powerpc | ||
| sh | ||
| sysv/linux | ||
| x86_64 | ||
| clock_gettime.c | ||
| clock_nanosleep.c | ||
| clock_settime.c | ||
| confstr.h | ||
| get_child_max.c | ||
| getlogin_r.c | ||
| getlogin.c | ||
| getpagesize.c | ||
| grantpt.c | ||
| ifreq.c | ||
| Implies | ||
| make-syscalls.sh | ||
| Makefile | ||
| s-proto-cancel.S | ||
| s-proto.S | ||
| setxid.h | ||
| sockatmark.c | ||
| stime.c | ||
| Subdirs | ||
| syscall-template.S | ||
| syscall.S | ||
| syscalls.list | ||
| sysdep.h | ||