David Howells
7e6608724c
nommu: fix shared mmap after truncate shrinkage problems ...
Fix a problem in NOMMU mmap with ramfs whereby a shared mmap can happen
over the end of a truncation. The problem is that
ramfs_nommu_check_mappings() checks that the reduced file size against the
VMA tree, but not the vm_region tree.
The following sequence of events can cause the problem:
fd = open("/tmp/x", O_RDWR|O_TRUNC|O_CREAT, 0600);
ftruncate(fd, 32 * 1024);
a = mmap(NULL, 32 * 1024, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
b = mmap(NULL, 16 * 1024, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
munmap(a, 32 * 1024);
ftruncate(fd, 16 * 1024);
c = mmap(NULL, 32 * 1024, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
Mapping 'a' creates a vm_region covering 32KB of the file. Mapping 'b'
sees that the vm_region from 'a' is covering the region it wants and so
shares it, pinning it in memory.
Mapping 'a' then goes away and the file is truncated to the end of VMA
'b'. However, the region allocated by 'a' is still in effect, and has
_not_ been reduced.
Mapping 'c' is then created, and because there's a vm_region covering the
desired region, get_unmapped_area() is _not_ called to repeat the check,
and the mapping is granted, even though the pages from the latter half of
the mapping have been discarded.
However:
d = mmap(NULL, 16 * 1024, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
Mapping 'd' should work, and should end up sharing the region allocated by
'a'.
To deal with this, we shrink the vm_region struct during the truncation,
lest do_mmap_pgoff() take it as licence to share the full region
automatically without calling the get_unmapped_area() file op again.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-16 12:15:40 -08:00
9p: fix build breakage introduced by FS-Cache
2009-12-01 07:35:11 -08:00
adfs: remove redundant test on unsigned
2009-09-24 07:21:05 -07:00
afs: remove manual O_SYNC handling
2009-12-10 15:02:50 +01:00
trivial: remove unnecessary semicolons
2009-09-21 15:14:58 +02:00
autofs4: always use lookup for lookup
2009-12-16 07:19:58 -08:00
fs: Make unload_nls() NULL pointer safe
2009-09-24 07:47:42 -04:00
headers: smp_lock.h redux
2009-07-12 12:22:34 -07:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
2009-12-17 16:01:03 -08:00
Untangling ima mess, part 2: deal with counters
2009-12-16 12:16:47 -05:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
2009-12-31 15:17:26 -08:00
sysctl: Drop & in front of every proc_handler.
2009-11-18 08:37:40 -08:00
writeback: add name to backing_dev_info
2009-09-11 09:20:26 +02:00
debugfs: fix create mutex racy fops and private data
2009-12-11 11:24:53 -08:00
devpts_get_tty() should validate inode
2009-12-11 15:18:05 -08:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/dlm
2009-12-10 09:33:59 -08:00
fsstack/ecryptfs: remove unused get_nlinks param to fsstack_copy_attr_all
2009-12-17 10:57:30 -05:00
exofs: simple_write_end does not mark_inode_dirty
2010-01-05 09:14:32 +02:00
nfs: new subdir Documentation/filesystems/nfs
2009-10-27 19:34:04 -04:00
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
2009-12-16 12:04:02 -08:00
ext3: Replace lock/unlock_super() with an explicit lock for resizing
2009-12-23 13:44:12 +01:00
ext4: Calculate metadata requirements more accurately
2010-01-01 02:41:30 -05:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/hirofumi/fatfs-2.6
2009-12-16 10:29:26 -08:00
headers: smp_lock.h redux
2009-07-12 12:22:34 -07:00
FS-Cache: Avoid maybe-used-uninitialised warning on variable
2009-12-16 07:20:13 -08:00
fuse: reject O_DIRECT flag also in fuse_create
2009-11-27 16:37:13 +01:00
GFS2: Use MAX_LFS_FILESIZE for meta inode size
2010-01-11 08:57:55 +00:00
hfs: fix a potential buffer overflow
2009-12-15 08:53:10 -08:00
hfsplus: refuse to mount volumes larger than 2TB
2009-10-29 07:39:27 -07:00
hostfs: set maximum filesize in superblock for proper LFS support
2009-06-30 18:56:03 -07:00
hpfs: use bitmap_weight()
2009-12-16 07:20:06 -08:00
Untangling ima mess, part 1: alloc_file()
2009-12-16 12:16:47 -05:00
Merge branch 'for-2.6.33' of git://linux-nfs.org/~bfields/linux
2009-12-16 10:43:34 -08:00
jbd: jbd-debug and jbd2-debug should be writable
2009-12-23 13:44:13 +01:00
jbd2: don't use __GFP_NOFAIL in journal_init_common()
2009-12-23 08:05:15 -05:00
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
2009-12-16 12:04:02 -08:00
jfs: Fix 32bit build warning
2009-12-22 12:27:35 -05:00
Merge branch 'for-2.6.33' of git://linux-nfs.org/~bfields/linux
2009-12-16 10:43:34 -08:00
V3 minixfs: add missing directory type checking
2009-09-23 07:39:57 -07:00
tree-wide: fix assorted typos all over the place
2009-12-04 15:39:55 +01:00
nfs: fix oops in nfs_rename()
2010-01-06 18:48:26 -05:00
Merge branch 'for-2.6.33' of git://linux-nfs.org/~bfields/linux
2010-01-06 18:10:15 -08:00
nilfs2: Storage class should be before const qualifier
2009-12-25 13:01:50 +09:00
Merge git://git.kernel.org/pub/scm/linux/kernel/git/hirofumi/fatfs-2.6
2009-09-30 09:31:14 -07:00
inotify: only warn once for inotify problems
2010-01-15 14:49:23 -08:00
kill I_LOCK
2009-12-17 11:03:25 -05:00
ocfs2: Handle O_DIRECT when writing to a refcounted cluster.
2009-12-30 19:53:35 -08:00
tree-wide: fix assorted typos all over the place
2009-12-04 15:39:55 +01:00
partitions: read whole sector with EFI GPT header
2009-11-23 09:29:58 +01:00
smaps: fix wrong rss count
2010-01-11 09:34:07 -08:00
qnx4: use hweight8
2009-12-16 07:20:18 -08:00
quota: Fix dquot_transfer for filesystems different from ext4
2010-01-11 13:06:41 +01:00
nommu: fix shared mmap after truncate shrinkage problems
2010-01-16 12:15:40 -08:00
Merge branch 'reiserfs/kill-bkl' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing
2010-01-08 14:03:55 -08:00
ROMFS: fix length used with romfs_dev_strnlen() function
2009-10-11 11:33:56 -07:00
fs: Make unload_nls() NULL pointer safe
2009-09-24 07:47:42 -04:00
const: mark remaining super_operations const
2009-09-22 07:17:24 -07:00
sysfs: Add lockdep annotations for the sysfs active reference
2010-01-04 12:34:46 -08:00
lib: Introduce generic list_sort function
2010-01-12 21:02:00 -08:00
udf: Avoid IO in udf_clear_inode
2009-12-14 21:40:04 +01:00
ufs: NFS support
2009-12-16 07:20:06 -08:00
xfs: Ensure we force all busy extents in range to disk
2010-01-10 12:22:02 -06:00
aio: remove unused field
2009-12-16 07:20:13 -08:00
Sanitize f_flags helpers
2009-12-22 12:27:34 -05:00
truncate: new helpers
2009-09-24 08:41:47 -04:00
mm: introduce coredump parameter structure
2009-12-17 15:45:31 -08:00
mm: introduce coredump parameter structure
2009-12-17 15:45:31 -08:00
FDPIC: Respect PT_GNU_STACK exec protection markings when creating NOMMU stack
2010-01-06 18:16:02 -08:00
mm: introduce coredump parameter structure
2009-12-17 15:45:31 -08:00
mm: introduce coredump parameter structure
2009-12-17 15:45:31 -08:00
block: Create bip slabs with embedded integrity vectors
2009-07-01 10:56:25 +02:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
2009-12-09 19:43:33 -08:00
Merge branch 'for-linus' into for-2.6.33
2009-11-03 21:14:39 +01:00
Merge branch 'writeback' of git://git.kernel.dk/linux-2.6-block
2009-09-25 09:27:30 -07:00
fs/char_dev.c: remove useless loop
2009-09-24 07:21:03 -07:00
compat.c: Remove dependence on nfsd private headers
2009-12-14 18:12:10 -05:00
fs/compat_ioctl.c: fix build error when !BLOCK
2009-12-22 12:27:33 -05:00
libfs: move EXPORT_SYMBOL for d_alloc_name
2009-12-16 12:16:48 -05:00
dio: fix use-after-free
2009-12-17 04:52:13 -05:00
sysctl: remove "struct file *" argument of ->proc_handler
2009-09-24 07:21:04 -07:00
anonfd: Allow making anon files read-only
2009-12-22 12:27:34 -05:00
anonfd: Allow making anon files read-only
2009-12-22 12:27:34 -05:00
mm: introduce coredump parameter structure
2009-12-17 15:45:31 -08:00
fasync: split 'fasync_helper()' into separate add/remove functions
2009-12-16 10:05:29 -08:00
headers: remove sched.h from interrupt.h
2009-10-11 11:20:58 -07:00
alloc_file(): simplify handling of mnt_clone_write() errors
2009-12-22 12:27:33 -05:00
writeback: add missing kernel-doc notation
2010-01-02 10:09:44 -08:00
make generic_acl slightly more generic
2009-12-16 12:16:49 -05:00
kill I_LOCK
2009-12-17 11:03:25 -05:00
Fix f_flags/f_mode in case of lookup_instantiate_filp() from open(pathname, 3)
2009-12-22 12:27:34 -05:00
__generic_block_fiemap(): fix for files bigger than 4GB
2009-11-12 07:26:01 -08:00
Revert "task_struct: make journal_info conditional"
2009-12-17 13:23:24 -08:00
libfs: move EXPORT_SYMBOL for d_alloc_name
2009-12-16 12:16:48 -05:00
const: make lock_manager_operations const
2009-09-22 07:17:25 -07:00
generic_permission: MAY_OPEN is not write access
2009-12-30 12:35:44 -08:00
Revert "fix mismerge with Trond's stuff (create_mnt_ns() export is gone now)"
2009-12-17 12:51:05 -08:00
vfs: nfsctl.c un-used nfsd #includes
2009-12-14 18:12:11 -05:00
Sanitize f_flags helpers
2009-12-22 12:27:34 -05:00
fs: no games with DCACHE_UNHASHED
2009-12-17 10:51:40 -05:00
sendfile(): check f_op.splice_write() rather than f_op.sendpage()
2009-11-04 09:09:52 +01:00
headers: remove sched.h from poll.h
2009-10-04 15:05:10 -07:00
vfs: seq_file: add helpers for data filling
2009-09-24 07:47:35 -04:00
anonfd: Allow making anon files read-only
2009-12-22 12:27:34 -05:00
sendfile(): check f_op.splice_write() rather than f_op.sendpage()
2009-11-04 09:09:52 +01:00
VFS/fsstack: handle 32-bit smp + preempt + large files in fsstack_copy_inode_size
2009-12-17 10:58:17 -05:00
Add unlocked version of inode_add_bytes() function
2009-12-23 13:33:54 +01:00
vfs: get_sb_single() - do not pass options twice
2009-12-23 11:23:43 -08:00
fold do_sync_file_range into sys_sync_file_range
2009-12-17 11:03:25 -05:00
anonfd: Allow making anon files read-only
2009-12-22 12:27:34 -05:00
sanitize xattr handler prototypes
2009-12-16 12:16:49 -05:00
VFS: Use GFP_NOFS in posix_acl_from_xattr()
2009-12-03 11:48:07 +00:00
7e6608724c