On 4/14/19 5:36 AM, Alexey Dobriyan wrote: > F29 bans mapping first 64KB even for root making test fail.
so there is an F29-only patch that prevents that? something that is not in mainline? thanks. > Iterate from address 0 until mmap() works. > > Gentoo (root): > > openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3 > mmap(NULL, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0 > > Gentoo (non-root): > > openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3 > mmap(NULL, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EPERM > (Operation not permitted) > mmap(0x1000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0x1000 > > F29 (root): > > openat(AT_FDCWD, "/dev/zero", O_RDONLY) = 3 > mmap(NULL, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0x1000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0x2000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0x3000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0x4000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0x5000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0x6000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0x7000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0x8000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0x9000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0xa000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0xb000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0xc000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0xd000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0xe000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0xf000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = -1 EACCES > (Permission denied) > mmap(0x10000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0x10000 > > Now all proc tests succeed on F29 if run as root, at last! > > Signed-off-by: Alexey Dobriyan <[email protected]> > --- > > tools/testing/selftests/proc/proc-self-map-files-002.c | 20 > ++++++++--------- > 1 file changed, 10 insertions(+), 10 deletions(-) > > --- a/tools/testing/selftests/proc/proc-self-map-files-002.c > +++ b/tools/testing/selftests/proc/proc-self-map-files-002.c > @@ -46,12 +46,9 @@ static void fail(const char *fmt, unsigned long a, > unsigned long b) > > int main(void) > { > - const unsigned int PAGE_SIZE = sysconf(_SC_PAGESIZE); > -#ifdef __arm__ > - unsigned long va = 2 * PAGE_SIZE; > -#else > - unsigned long va = 0; > -#endif > + const int PAGE_SIZE = sysconf(_SC_PAGESIZE); > + const unsigned long va_max = 1UL << 32; > + unsigned long va; > void *p; > int fd; > unsigned long a, b; > @@ -60,10 +57,13 @@ int main(void) > if (fd == -1) > return 1; > > - p = mmap((void *)va, PAGE_SIZE, PROT_NONE, > MAP_PRIVATE|MAP_FILE|MAP_FIXED, fd, 0); > - if (p == MAP_FAILED) { > - if (errno == EPERM) > - return 4; > + for (va = 0; va < va_max; va += PAGE_SIZE) { > + p = mmap((void *)va, PAGE_SIZE, PROT_NONE, > MAP_PRIVATE|MAP_FILE|MAP_FIXED, fd, 0); > + if (p == (void *)va) > + break; > + } > + if (va == va_max) { > + fprintf(stderr, "error: mmap doesn't like you\n"); > return 1; > } > > -- ~Randy
