linux-stable.git/mm, branch v3.16.40

vfs,mm: fix return value of read() at s_maxbytes

2017-02-23T03:54:48+00:00

commit d05c5f7ba164aed3db02fb188c26d0dd94f5455b upstream.

We truncated the possible read iterator to s_maxbytes in commit
c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()"),
but our end condition handling was wrong: it's not an error to try to
read at the end of the file.

Reading past the end should return EOF (0), not EINVAL.

See for example

  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1649342
  http://lists.gnu.org/archive/html/bug-coreutils/2016-12/msg00008.html

where a md5sum of a maximally sized file fails because the final read is
exactly at s_maxbytes.

Fixes: c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()")
Reported-by: Joseph Salisbury 
Cc: Wei Fang 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Al Viro 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

swapfile: fix memory corruption via malformed swapfile

2017-02-23T03:54:32+00:00

commit dd111be69114cc867f8e826284559bfbc1c40e37 upstream.

When root activates a swap partition whose header has the wrong
endianness, nr_badpages elements of badpages are swabbed before
nr_badpages has been checked, leading to a buffer overrun of up to 8GB.

This normally is not a security issue because it can only be exploited
by root (more specifically, a process with CAP_SYS_ADMIN or the ability
to modify a swap file/partition), and such a process can already e.g.
modify swapped-out memory of any other userspace process on the system.

Link: http://lkml.kernel.org/r/1477949533-2509-1-git-send-email-jann@thejh.net
Signed-off-by: Jann Horn 
Acked-by: Kees Cook 
Acked-by: Jerome Marchand 
Acked-by: Johannes Weiner 
Cc: "Kirill A. Shutemov" 
Cc: Vlastimil Babka 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

vfs,mm: fix a dead loop in truncate_inode_pages_range()

2017-02-23T03:54:10+00:00

commit c2a9737f45e27d8263ff9643f994bda9bac0b944 upstream.

We triggered a deadloop in truncate_inode_pages_range() on 32 bits
architecture with the test case bellow:

	...
	fd = open();
	write(fd, buf, 4096);
	preadv64(fd, &iovec, 1, 0xffffffff000);
	ftruncate(fd, 0);
	...

Then ftruncate() will not return forever.

The filesystem used in this case is ubifs, but it can be triggered on
many other filesystems.

When preadv64() is called with offset=0xffffffff000, a page with
index=0xffffffff will be added to the radix tree of ->mapping.  Then
this page can be found in ->mapping with pagevec_lookup().  After that,
truncate_inode_pages_range(), which is called in ftruncate(), will fall
into an infinite loop:

 - find a page with index=0xffffffff, since index>=end, this page won't
   be truncated

 - index++, and index become 0

 - the page with index=0xffffffff will be found again

The data type of index is unsigned long, so index won't overflow to 0 on
64 bits architecture in this case, and the dead loop won't happen.

Since truncate_inode_pages_range() is executed with holding lock of
inode->i_rwsem, any operation related with this lock will be blocked,
and a hung task will happen, e.g.:

  INFO: task truncate_test:3364 blocked for more than 120 seconds.
  ...
     call_rwsem_down_write_failed+0x17/0x30
     generic_file_write_iter+0x32/0x1c0
     ubifs_write_iter+0xcc/0x170
     __vfs_write+0xc4/0x120
     vfs_write+0xb2/0x1b0
     SyS_write+0x46/0xa0

The page with index=0xffffffff added to ->mapping is useless.  Fix this
by checking the read position before allocating pages.

Link: http://lkml.kernel.org/r/1475151010-40166-1-git-send-email-fangwei1@huawei.com
Signed-off-by: Wei Fang 
Cc: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

mm/hugetlb: check for reserved hugepages during memory offline

2017-02-23T03:54:10+00:00

commit 082d5b6b60e9f25e1511557fcfcb21eedd267446 upstream.

In dissolve_free_huge_pages(), free hugepages will be dissolved without
making sure that there are enough of them left to satisfy hugepage
reservations.

Fix this by adding a return value to dissolve_free_huge_pages() and
checking h->free_huge_pages vs.  h->resv_huge_pages.  Note that this may
lead to the situation where dissolve_free_huge_page() returns an error
and all free hugepages that were dissolved before that error are lost,
while the memory block still cannot be set offline.

Fixes: c8721bbb ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Link: http://lkml.kernel.org/r/20160926172811.94033-3-gerald.schaefer@de.ibm.com
Signed-off-by: Gerald Schaefer 
Acked-by: Michal Hocko 
Acked-by: Naoya Horiguchi 
Cc: "Kirill A . Shutemov" 
Cc: Vlastimil Babka 
Cc: Mike Kravetz 
Cc: "Aneesh Kumar K . V" 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Rui Teng 
Cc: Dave Hansen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

mm/hugetlb: fix memory offline with hugepage size > memory block size

2017-02-23T03:54:10+00:00

commit 2247bb335ab9c40058484cac36ea74ee652f3b7b upstream.

Patch series "mm/hugetlb: memory offline issues with hugepages", v4.

This addresses several issues with hugepages and memory offline.  While
the first patch fixes a panic, and is therefore rather important, the
last patch is just a performance optimization.

The second patch fixes a theoretical issue with reserved hugepages,
while still leaving some ugly usability issue, see description.

This patch (of 3):

dissolve_free_huge_pages() will either run into the VM_BUG_ON() or a
list corruption and addressing exception when trying to set a memory
block offline that is part (but not the first part) of a "gigantic"
hugetlb page with a size > memory block size.

When no other smaller hugetlb page sizes are present, the VM_BUG_ON()
will trigger directly.  In the other case we will run into an addressing
exception later, because dissolve_free_huge_page() will not work on the
head page of the compound hugetlb page which will result in a NULL
hstate from page_hstate().

To fix this, first remove the VM_BUG_ON() because it is wrong, and then
use the compound head page in dissolve_free_huge_page().  This means
that an unused pre-allocated gigantic page that has any part of itself
inside the memory block that is going offline will be dissolved
completely.  Losing an unused gigantic hugepage is preferable to failing
the memory offline, for example in the situation where a (possibly
faulty) memory DIMM needs to go offline.

Fixes: c8721bbb ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Link: http://lkml.kernel.org/r/20160926172811.94033-2-gerald.schaefer@de.ibm.com
Signed-off-by: Gerald Schaefer 
Acked-by: Michal Hocko 
Acked-by: Naoya Horiguchi 
Cc: "Kirill A . Shutemov" 
Cc: Vlastimil Babka 
Cc: Mike Kravetz 
Cc: "Aneesh Kumar K . V" 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Cc: Rui Teng 
Cc: Dave Hansen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

mm: filemap: fix mapping->nrpages double accounting in fuse

2017-02-23T03:54:09+00:00

commit 3ddf40e8c31964b744ff10abb48c8e36a83ec6e7 upstream.

Commit 22f2ac51b6d6 ("mm: workingset: fix crash in shadow node shrinker
caused by replace_page_cache_page()") switched replace_page_cache() from
raw radix tree operations to page_cache_tree_insert() but didn't take
into account that the latter function, unlike the raw radix tree op,
handles mapping->nrpages.  As a result, that counter is bumped for each
page replacement rather than balanced out even.

The mapping->nrpages counter is used to skip needless radix tree walks
when invalidating, truncating, syncing inodes without pages, as well as
statistics for userspace.  Since the error is positive, we'll do more
page cache tree walks than necessary; we won't miss a necessary one.
And we'll report more buffer pages to userspace than there are.  The
error is limited to fuse inodes.

Fixes: 22f2ac51b6d6 ("mm: workingset: fix crash in shadow node shrinker caused by replace_page_cache_page()")
Signed-off-by: Johannes Weiner 
Cc: Andrew Morton 
Cc: Miklos Szeredi 
Signed-off-by: Linus Torvalds 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

fs: Give dentry to inode_change_ok() instead of inode

2017-02-23T03:53:52+00:00

commit 31051c85b5e2aaaf6315f74c72a732673632a905 upstream.

inode_change_ok() will be resposible for clearing capabilities and IMA
extended attributes and as such will need dentry. Give it as an argument
to inode_change_ok() instead of an inode. Also rename inode_change_ok()
to setattr_prepare() to better relect that it does also some
modifications in addition to checks.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Jan Kara 
[bwh: Backported to 3.16:
 - Drop changes to orangefs, overlayfs
 - Adjust filenames, context
 - In nfsd, pass dentry to nfsd_sanitize_attrs()
 - Update ext3 as well]
Signed-off-by: Ben Hutchings

Revert "fs: Give dentry to inode_change_ok() instead of inode"

2017-02-23T03:53:52+00:00

This reverts commit be9df699432235753c3824b0f5a27d46de7fdc9e, which was
commit 31051c85b5e2aaaf6315f74c72a732673632a905 upstream.  The backport
breaks fuse and makes a mess of xfs, which can be improved by picking
further upstream commits as I should have done in the first place.

Signed-off-by: Ben Hutchings

mm: filemap: don't plant shadow entries without radix tree node

2016-11-20T01:17:40+00:00

commit d3798ae8c6f3767c726403c2ca6ecc317752c9dd upstream.

When the underflow checks were added to workingset_node_shadow_dec(),
they triggered immediately:

  kernel BUG at ./include/linux/swap.h:276!
  invalid opcode: 0000 [#1] SMP
  Modules linked in: isofs usb_storage fuse xt_CHECKSUM ipt_MASQUERADE nf_nat_masquerade_ipv4 tun nf_conntrack_netbios_ns nf_conntrack_broadcast ip6t_REJECT nf_reject_ipv6
   soundcore wmi acpi_als pinctrl_sunrisepoint kfifo_buf tpm_tis industrialio acpi_pad pinctrl_intel tpm_tis_core tpm nfsd auth_rpcgss nfs_acl lockd grace sunrpc dm_crypt
  CPU: 0 PID: 20929 Comm: blkid Not tainted 4.8.0-rc8-00087-gbe67d60ba944 #1
  Hardware name: System manufacturer System Product Name/Z170-K, BIOS 1803 05/06/2016
  task: ffff8faa93ecd940 task.stack: ffff8faa7f478000
  RIP: page_cache_tree_insert+0xf1/0x100
  Call Trace:
    __add_to_page_cache_locked+0x12e/0x270
    add_to_page_cache_lru+0x4e/0xe0
    mpage_readpages+0x112/0x1d0
    blkdev_readpages+0x1d/0x20
    __do_page_cache_readahead+0x1ad/0x290
    force_page_cache_readahead+0xaa/0x100
    page_cache_sync_readahead+0x3f/0x50
    generic_file_read_iter+0x5af/0x740
    blkdev_read_iter+0x35/0x40
    __vfs_read+0xe1/0x130
    vfs_read+0x96/0x130
    SyS_read+0x55/0xc0
    entry_SYSCALL_64_fastpath+0x13/0x8f
  Code: 03 00 48 8b 5d d8 65 48 33 1c 25 28 00 00 00 44 89 e8 75 19 48 83 c4 18 5b 41 5c 41 5d 41 5e 5d c3 0f 0b 41 bd ef ff ff ff eb d7 <0f> 0b e8 88 68 ef ff 0f 1f 84 00
  RIP  page_cache_tree_insert+0xf1/0x100

This is a long-standing bug in the way shadow entries are accounted in
the radix tree nodes. The shrinker needs to know when radix tree nodes
contain only shadow entries, no pages, so node->count is split in half
to count shadows in the upper bits and pages in the lower bits.

Unfortunately, the radix tree implementation doesn't know of this and
assumes all entries are in node->count. When there is a shadow entry
directly in root->rnode and the tree is later extended, the radix tree
implementation will copy that entry into the new node and and bump its
node->count, i.e. increases the page count bits. Once the shadow gets
removed and we subtract from the upper counter, node->count underflows
and triggers the warning. Afterwards, without node->count reaching 0
again, the radix tree node is leaked.

Limit shadow entries to when we have actual radix tree nodes and can
count them properly. That means we lose the ability to detect refaults
from files that had only the first page faulted in at eviction time.

Fixes: 449dd6984d0e ("mm: keep page cache radix tree nodes in check")
Signed-off-by: Johannes Weiner 
Reported-and-tested-by: Linus Torvalds 
Reviewed-by: Jan Kara 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds 
[Johannes Weiner: it's drastically different than the upstream change,
 but a lot simpler because it predates the DAX stuff.]
Signed-off-by: Ben Hutchings

fs: Give dentry to inode_change_ok() instead of inode

2016-11-20T01:17:38+00:00

commit 31051c85b5e2aaaf6315f74c72a732673632a905 upstream.

inode_change_ok() will be resposible for clearing capabilities and IMA
extended attributes and as such will need dentry. Give it as an argument
to inode_change_ok() instead of an inode. Also rename inode_change_ok()
to setattr_prepare() to better relect that it does also some
modifications in addition to checks.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Jan Kara 
[bwh: Backported to 3.16:
 - Drop changes to orangefs, overlayfs
 - Adjust filenames, context
 - In fuse, pass dentry to fuse_do_setattr()
 - In nfsd, pass dentry to nfsd_sanitize_attrs()
 - In xfs, pass dentry to xfs_setattr_nonsize() and xfs_setattr_size()
 - Update ext3 as well]
Signed-off-by: Ben Hutchings