mm/mempolicy.c: refix mbind_range() vma issue
commit 8aacc9f550 ("mm/mempolicy.c: fix pgoff in mbind vma merge") is the
slightly incorrect fix.
Why? Think following case.
1. map 4 pages of a file at offset 0
[0123]
2. map 2 pages just after the first mapping of the same file but with
page offset 2
[0123][23]
3. mbind() 2 pages from the first mapping at offset 2.
mbind_range() should treat new vma is,
[0123][23]
|23|
mbind vma
but it does
[0123][23]
|01|
mbind vma
Oops. then, it makes wrong vma merge and splitting ([01][0123] or similar).
This patch fixes it.
[testcase]
test result - before the patch
case4: 126: test failed. expect '2,4', actual '2,2,2'
case5: passed
case6: passed
case7: passed
case8: passed
case_n: 246: test failed. expect '4,2', actual '1,4'
------------[ cut here ]------------
kernel BUG at mm/filemap.c:135!
invalid opcode: 0000 [#4] SMP DEBUG_PAGEALLOC
(snip long bug on messages)
test result - after the patch
case4: passed
case5: passed
case6: passed
case7: passed
case8: passed
case_n: passed
source: mbind_vma_test.c
============================================================
#include <numaif.h>
#include <numa.h>
#include <sys/mman.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
static unsigned long pagesize;
void* mmap_addr;
struct bitmask *nmask;
char buf[1024];
FILE *file;
char retbuf[10240] = "";
int mapped_fd;
char *rubysrc = "ruby -e '\
pid = %d; \
vstart = 0x%llx; \
vend = 0x%llx; \
s = `pmap -q #{pid}`; \
rary = []; \
s.each_line {|line|; \
ary=line.split(\" \"); \
addr = ary[0].to_i(16); \
if(vstart <= addr && addr < vend) then \
rary.push(ary[1].to_i()/4); \
end; \
}; \
print rary.join(\",\"); \
'";
void init(void)
{
void* addr;
char buf[128];
nmask = numa_allocate_nodemask();
numa_bitmask_setbit(nmask, 0);
pagesize = getpagesize();
sprintf(buf, "%s", "mbind_vma_XXXXXX");
mapped_fd = mkstemp(buf);
if (mapped_fd == -1)
perror("mkstemp "), exit(1);
unlink(buf);
if (lseek(mapped_fd, pagesize*8, SEEK_SET) < 0)
perror("lseek "), exit(1);
if (write(mapped_fd, "\0", 1) < 0)
perror("write "), exit(1);
addr = mmap(NULL, pagesize*8, PROT_NONE,
MAP_SHARED, mapped_fd, 0);
if (addr == MAP_FAILED)
perror("mmap "), exit(1);
if (mprotect(addr+pagesize, pagesize*6, PROT_READ|PROT_WRITE) < 0)
perror("mprotect "), exit(1);
mmap_addr = addr + pagesize;
/* make page populate */
memset(mmap_addr, 0, pagesize*6);
}
void fin(void)
{
void* addr = mmap_addr - pagesize;
munmap(addr, pagesize*8);
memset(buf, 0, sizeof(buf));
memset(retbuf, 0, sizeof(retbuf));
}
void mem_bind(int index, int len)
{
int err;
err = mbind(mmap_addr+pagesize*index, pagesize*len,
MPOL_BIND, nmask->maskp, nmask->size, 0);
if (err)
perror("mbind "), exit(err);
}
void mem_interleave(int index, int len)
{
int err;
err = mbind(mmap_addr+pagesize*index, pagesize*len,
MPOL_INTERLEAVE, nmask->maskp, nmask->size, 0);
if (err)
perror("mbind "), exit(err);
}
void mem_unbind(int index, int len)
{
int err;
err = mbind(mmap_addr+pagesize*index, pagesize*len,
MPOL_DEFAULT, NULL, 0, 0);
if (err)
perror("mbind "), exit(err);
}
void Assert(char *expected, char *value, char *name, int line)
{
if (strcmp(expected, value) == 0) {
fprintf(stderr, "%s: passed\n", name);
return;
}
else {
fprintf(stderr, "%s: %d: test failed. expect '%s', actual '%s'\n",
name, line,
expected, value);
// exit(1);
}
}
/*
AAAA
PPPPPPNNNNNN
might become
PPNNNNNNNNNN
case 4 below
*/
void case4(void)
{
init();
sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);
mem_bind(0, 4);
mem_unbind(2, 2);
file = popen(buf, "r");
fread(retbuf, sizeof(retbuf), 1, file);
Assert("2,4", retbuf, "case4", __LINE__);
fin();
}
/*
AAAA
PPPPPPNNNNNN
might become
PPPPPPPPPPNN
case 5 below
*/
void case5(void)
{
init();
sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);
mem_bind(0, 2);
mem_bind(2, 2);
file = popen(buf, "r");
fread(retbuf, sizeof(retbuf), 1, file);
Assert("4,2", retbuf, "case5", __LINE__);
fin();
}
/*
AAAA
PPPPNNNNXXXX
might become
PPPPPPPPPPPP 6
*/
void case6(void)
{
init();
sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);
mem_bind(0, 2);
mem_bind(4, 2);
mem_bind(2, 2);
file = popen(buf, "r");
fread(retbuf, sizeof(retbuf), 1, file);
Assert("6", retbuf, "case6", __LINE__);
fin();
}
/*
AAAA
PPPPNNNNXXXX
might become
PPPPPPPPXXXX 7
*/
void case7(void)
{
init();
sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);
mem_bind(0, 2);
mem_interleave(4, 2);
mem_bind(2, 2);
file = popen(buf, "r");
fread(retbuf, sizeof(retbuf), 1, file);
Assert("4,2", retbuf, "case7", __LINE__);
fin();
}
/*
AAAA
PPPPNNNNXXXX
might become
PPPPNNNNNNNN 8
*/
void case8(void)
{
init();
sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);
mem_bind(0, 2);
mem_interleave(4, 2);
mem_interleave(2, 2);
file = popen(buf, "r");
fread(retbuf, sizeof(retbuf), 1, file);
Assert("2,4", retbuf, "case8", __LINE__);
fin();
}
void case_n(void)
{
init();
sprintf(buf, rubysrc, getpid(), mmap_addr, mmap_addr+pagesize*6);
/* make redundunt mappings [0][1234][34][7] */
mmap(mmap_addr + pagesize*4, pagesize*2, PROT_READ|PROT_WRITE,
MAP_FIXED|MAP_SHARED, mapped_fd, pagesize*3);
/* Expect to do nothing. */
mem_unbind(2, 2);
file = popen(buf, "r");
fread(retbuf, sizeof(retbuf), 1, file);
Assert("4,2", retbuf, "case_n", __LINE__);
fin();
}
int main(int argc, char** argv)
{
case4();
case5();
case6();
case7();
case8();
case_n();
return 0;
}
=============================================================
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Caspar Zhang <caspar@casparzhang.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: <stable@vger.kernel.org> [3.1.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed