linux/mm
KOSAKI Motohiro a477097d9c mlock() fix return values
Halesh says:

Please find the below testcase provide to test mlock.

Test Case :
===========================

#include <sys/resource.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <errno.h>
#include <stdlib.h>

int main(void)
{
  int fd,ret, i = 0;
  char *addr, *addr1 = NULL;
  unsigned int page_size;
  struct rlimit rlim;

  if (0 != geteuid())
  {
   printf("Execute this pgm as root\n");
   exit(1);
  }

  /* create a file */
  if ((fd = open("mmap_test.c",O_RDWR|O_CREAT,0755)) == -1)
  {
   printf("cant create test file\n");
   exit(1);
  }

  page_size = sysconf(_SC_PAGE_SIZE);

  /* set the MEMLOCK limit */
  rlim.rlim_cur = 2000;
  rlim.rlim_max = 2000;

  if ((ret = setrlimit(RLIMIT_MEMLOCK,&rlim)) != 0)
  {
   printf("Cant change limit values\n");
   exit(1);
  }

  addr = 0;
  while (1)
  {
  /* map a page into memory each time*/
  if ((addr = (char *) mmap(addr,page_size, PROT_READ |
PROT_WRITE,MAP_SHARED,fd,0)) == MAP_FAILED)
  {
   printf("cant do mmap on file\n");
   exit(1);
  }

  if (0 == i)
    addr1 = addr;
  i++;
  errno = 0;
  /* lock the mapped memory pagewise*/
  if ((ret = mlock((char *)addr, 1500)) == -1)
  {
   printf("errno value is %d\n", errno);
   printf("cant lock maped region\n");
   exit(1);
  }
  addr = addr + page_size;
 }
}
======================================================

This testcase results in an mlock() failure with errno 14 that is EFAULT,
but it has nowhere been specified that mlock() will return EFAULT.  When I
tested the same on older kernels like 2.6.18, I got the correct result i.e
errno 12 (ENOMEM).

I think in source code mlock(2), setting errno ENOMEM has been missed in
do_mlock() , on mlock_fixup() failure.

SUSv3 requires the following behavior frmo mlock(2).

[ENOMEM]
    Some or all of the address range specified by the addr and
    len arguments does not correspond to valid mapped pages
    in the address space of the process.

[EAGAIN]
    Some or all of the memory identified by the operation could not
    be locked when the call was made.

This rule isn't so nice and slighly strange.  but many people think
POSIX/SUS compliance is important.

Reported-by: Halesh Sadashiv <halesh.sadashiv@ap.sony.com>
Tested-by: Halesh Sadashiv <halesh.sadashiv@ap.sony.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <stable@kernel.org>		[2.6.25.x, 2.6.26.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-04 16:58:45 -07:00
..
allocpercpu.c mm/allocpercpu.c: make 4 functions static 2008-07-26 12:00:12 -07:00
backing-dev.c mm: bdi: fix race in bdi_class device creation 2008-05-20 13:31:53 -07:00
bootmem.c bootmem: replace node_boot_start in struct bootmem_data 2008-07-24 10:47:20 -07:00
bounce.c block: Initial support for data-less (or empty) barrier support 2007-10-16 11:03:56 +02:00
dmapool.c dmapool: enable debugging for CONFIG_SLUB_DEBUG_ON too 2008-04-28 08:58:20 -07:00
fadvise.c xip: support non-struct page backed memory 2008-04-28 08:58:23 -07:00
filemap_xip.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
filemap.c Fix off-by-one error in iov_iter_advance() 2008-07-30 14:50:18 -07:00
fremap.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
highmem.c highmem: Export totalhigh_pages. 2008-07-19 22:39:46 -07:00
hugetlb.c mm/hugetlb: don't crash when HPAGE_SHIFT is 0 2008-08-01 12:46:41 -07:00
internal.h mm: export prep_compound_page to mm 2008-07-24 10:47:17 -07:00
Kconfig mmu-notifiers: core 2008-07-28 16:30:21 -07:00
maccess.c kgdb: fix optional arch functions and probe_kernel_* 2008-04-17 20:05:39 +02:00
madvise.c madvise: update function comment of madvise_dontneed 2008-07-30 09:41:45 -07:00
Makefile mmu-notifiers: core 2008-07-28 16:30:21 -07:00
memcontrol.c memcg: remove redundant check in move_task() 2008-07-30 09:41:44 -07:00
memory_hotplug.c memory-hotplug: add sysfs removable attribute for hotplug memory remove 2008-07-24 10:47:21 -07:00
memory.c mlock() fix return values 2008-08-04 16:58:45 -07:00
mempolicy.c hugetlb: modular state for hugetlb page size 2008-07-24 10:47:17 -07:00
mempool.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
migrate.c mm: spinlock tree_lock 2008-07-26 12:00:06 -07:00
mincore.c mm: remove nopage 2008-04-28 08:58:18 -07:00
mlock.c mlock() fix return values 2008-08-04 16:58:45 -07:00
mm_init.c mm: create /sys/kernel/mm 2008-07-24 10:47:17 -07:00
mmap.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mmu_notifier.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mmzone.c mm: filter based on a nodemask as well as a gfp_mask 2008-04-28 08:58:19 -07:00
mprotect.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
mremap.c mmu-notifiers: core 2008-07-28 16:30:21 -07:00
msync.c Detach sched.h from mm.h 2007-05-21 09:18:19 -07:00
nommu.c tracehook: tracehook_expect_breakpoints 2008-07-26 12:00:09 -07:00
oom_kill.c oom_kill: remove unused parameter in badness() 2008-04-28 08:58:26 -07:00
page_alloc.c mm: remove find_max_pfn_with_active_regions 2008-07-30 09:41:44 -07:00
page_io.c mm: fix PageUptodate data race 2008-02-05 09:44:19 -08:00
page_isolation.c memory hotremove: unset migrate type "ISOLATE" after removal 2007-11-14 18:45:38 -08:00
page-writeback.c mm: spinlock tree_lock 2008-07-26 12:00:06 -07:00
pagewalk.c pagemap: pass mm into pagewalkers 2008-06-12 18:05:41 -07:00
pdflush.c pdflush: use time_after() instead of open-coding it 2008-07-25 10:53:28 -07:00
prio_tree.c spelling fixes: mm/ 2007-10-20 01:27:18 +02:00
quicklist.c quicklists: Only consider memory that can be used with GFP_KERNEL 2008-01-14 08:52:22 -08:00
readahead.c mm: readahead scan lockless 2008-07-26 12:00:06 -07:00
rmap.c [S390] Optimize storage key operations for anon pages 2008-08-01 16:39:30 +02:00
shmem_acl.c [PATCH] sanitize ->permission() prototype 2008-07-26 20:53:14 -04:00
shmem.c tmpfs: fix kernel BUG in shmem_delete_inode 2008-07-28 16:30:20 -07:00
slab.c SL*B: drop kmem cache argument from constructor 2008-07-26 12:00:07 -07:00
slob.c SL*B: drop kmem cache argument from constructor 2008-07-26 12:00:07 -07:00
slub.c SL*B: drop kmem cache argument from constructor 2008-07-26 12:00:07 -07:00
sparse-vmemmap.c Christoph has moved 2008-07-04 10:40:04 -07:00
sparse.c make mm/sparse.c: make a function static 2008-07-26 12:00:12 -07:00
swap_state.c mm: print swapcache page count in show_swap_cache_info() 2008-07-26 12:00:10 -07:00
swap.c swap: update function comment of release_pages 2008-07-30 09:41:46 -07:00
swapfile.c swapfile/vmscan: update comments related to vmscan functions 2008-07-30 09:41:46 -07:00
thrash.c Bug in mm/thrash.c function grab_swap_token() 2007-05-11 08:29:32 -07:00
tiny-shmem.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 2008-03-25 08:57:47 -07:00
truncate.c mm: dont clear PG_uptodate on truncate/invalidate 2008-08-02 09:12:34 -07:00
util.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2008-07-26 20:17:56 -07:00
vmalloc.c Use WARN() in mm/vmalloc.c 2008-07-26 12:00:07 -07:00
vmscan.c do_try_to_free_page: update comments related to vmscan functions 2008-07-30 09:41:46 -07:00
vmstat.c mm/vmstat.c: proper externs 2008-07-24 10:47:14 -07:00