![SeongJae Park](/assets/img/avatar_default.png)
Man page of mmap() says that portable applications should ensure fd argument to be -1 if MAP_ANONYMOUS flag is set as below: ``` The mapping is not backed by any file; its contents are initialized to zero. The fd and offset arguments are ignored; however, some implementations require fd to be -1 if MAP_ANONYMOUS (or MAP_ANON) is specified, and portable applications should ensure this. ``` However, few mmap() calls under selftests/vm/ uses 0 as fd though they use MAP_ANONYMOUS flag. This commit changes the argument to be -1 as recommended. Signed-off-by: SeongJae Park <sj38.park@gmail.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
48 lines
806 B
C
48 lines
806 B
C
#include <sys/mman.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#ifndef MCL_ONFAULT
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#define MCL_ONFAULT (MCL_FUTURE << 1)
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#endif
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static int test_limit(void)
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{
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int ret = 1;
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struct rlimit lims;
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void *map;
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if (getrlimit(RLIMIT_MEMLOCK, &lims)) {
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perror("getrlimit");
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return ret;
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}
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if (mlockall(MCL_ONFAULT | MCL_FUTURE)) {
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perror("mlockall");
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return ret;
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}
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map = mmap(NULL, 2 * lims.rlim_max, PROT_READ | PROT_WRITE,
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MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, -1, 0);
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if (map != MAP_FAILED)
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printf("mmap should have failed, but didn't\n");
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else {
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ret = 0;
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munmap(map, 2 * lims.rlim_max);
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}
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munlockall();
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return ret;
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}
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int main(int argc, char **argv)
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{
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int ret = 0;
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ret += test_limit();
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return ret;
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}
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