Commit 8cd40d1d authored by Alexey Dobriyan's avatar Alexey Dobriyan Committed by Linus Torvalds

proc: fix map_files test on F29

F29 bans mapping first 64KB even for root making test fail.  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!

Link: http://lkml.kernel.org/r/20190414123612.GB12971@avx2Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e8277b3b
......@@ -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;
}
......
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