Anatoly Trosinenko reports that a corrupted squashfs image can cause a
kernel oops.  It turns out that squashfs can end up being confused about
negative fragment lengths.

The regular squashfs_read_data() does check for negative lengths, but
squashfs_read_metadata() did not, and the fragment size code just
blindly trusted the on-disk value.  Fix both the fragment parsing and
the metadata reading code.
Reported-by: NAnatoly Trosinenko <anatoly.trosinenko@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 8844618d: "ext4: only look at the bg_flags field if it is
valid" will complain if block group zero does not have the
EXT4_BG_INODE_ZEROED flag set.  Unfortunately, this is not correct,
since a freshly created file system has this flag cleared.  It gets
almost immediately after the file system is mounted read-write --- but
the following somewhat unlikely sequence will end up triggering a
false positive report of a corrupted file system:

   mkfs.ext4 /dev/vdc
   mount -o ro /dev/vdc /vdc
   mount -o remount,rw /dev/vdc

Instead, when initializing the inode table for block group zero, test
to make sure that itable_unused count is not too large, since that is
the case that will result in some or all of the reserved inodes
getting cleared.

This fixes the failures reported by Eric Whiteney when running
generic/230 and generic/231 in the the nojournal test case.

Fixes: 8844618d ("ext4: only look at the bg_flags field if it is valid")
Reported-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

vma_is_anonymous() relies on ->vm_ops being NULL to detect anonymous
VMA.  This is unreliable as ->mmap may not set ->vm_ops.

False-positive vma_is_anonymous() may lead to crashes:

	next ffff8801ce5e7040 prev ffff8801d20eca50 mm ffff88019c1e13c0
	prot 27 anon_vma ffff88019680cdd8 vm_ops 0000000000000000
	pgoff 0 file ffff8801b2ec2d00 private_data 0000000000000000
	flags: 0xff(read|write|exec|shared|mayread|maywrite|mayexec|mayshare)
	------------[ cut here ]------------
	kernel BUG at mm/memory.c:1422!
	invalid opcode: 0000 [#1] SMP KASAN
	CPU: 0 PID: 18486 Comm: syz-executor3 Not tainted 4.18.0-rc3+ #136
	Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google
	01/01/2011
	RIP: 0010:zap_pmd_range mm/memory.c:1421 [inline]
	RIP: 0010:zap_pud_range mm/memory.c:1466 [inline]
	RIP: 0010:zap_p4d_range mm/memory.c:1487 [inline]
	RIP: 0010:unmap_page_range+0x1c18/0x2220 mm/memory.c:1508
	Call Trace:
	 unmap_single_vma+0x1a0/0x310 mm/memory.c:1553
	 zap_page_range_single+0x3cc/0x580 mm/memory.c:1644
	 unmap_mapping_range_vma mm/memory.c:2792 [inline]
	 unmap_mapping_range_tree mm/memory.c:2813 [inline]
	 unmap_mapping_pages+0x3a7/0x5b0 mm/memory.c:2845
	 unmap_mapping_range+0x48/0x60 mm/memory.c:2880
	 truncate_pagecache+0x54/0x90 mm/truncate.c:800
	 truncate_setsize+0x70/0xb0 mm/truncate.c:826
	 simple_setattr+0xe9/0x110 fs/libfs.c:409
	 notify_change+0xf13/0x10f0 fs/attr.c:335
	 do_truncate+0x1ac/0x2b0 fs/open.c:63
	 do_sys_ftruncate+0x492/0x560 fs/open.c:205
	 __do_sys_ftruncate fs/open.c:215 [inline]
	 __se_sys_ftruncate fs/open.c:213 [inline]
	 __x64_sys_ftruncate+0x59/0x80 fs/open.c:213
	 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
	 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Reproducer:

	#include <stdio.h>
	#include <stddef.h>
	#include <stdint.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <sys/ioctl.h>
	#include <sys/mman.h>
	#include <unistd.h>
	#include <fcntl.h>

	#define KCOV_INIT_TRACE			_IOR('c', 1, unsigned long)
	#define KCOV_ENABLE			_IO('c', 100)
	#define KCOV_DISABLE			_IO('c', 101)
	#define COVER_SIZE			(1024<<10)

	#define KCOV_TRACE_PC  0
	#define KCOV_TRACE_CMP 1

	int main(int argc, char **argv)
	{
		int fd;
		unsigned long *cover;

		system("mount -t debugfs none /sys/kernel/debug");
		fd = open("/sys/kernel/debug/kcov", O_RDWR);
		ioctl(fd, KCOV_INIT_TRACE, COVER_SIZE);
		cover = mmap(NULL, COVER_SIZE * sizeof(unsigned long),
				PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
		munmap(cover, COVER_SIZE * sizeof(unsigned long));
		cover = mmap(NULL, COVER_SIZE * sizeof(unsigned long),
				PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
		memset(cover, 0, COVER_SIZE * sizeof(unsigned long));
		ftruncate(fd, 3UL << 20);
		return 0;
	}

This can be fixed by assigning anonymous VMAs own vm_ops and not relying
on it being NULL.

If ->mmap() failed to set ->vm_ops, mmap_region() will set it to
dummy_vm_ops.  This way we will have non-NULL ->vm_ops for all VMAs.

Link: http://lkml.kernel.org/r/20180724121139.62570-4-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: syzbot+3f84280d52be9b7083cc@syzkaller.appspotmail.com
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make sure to initialize all VMAs properly, not only those which come
from vm_area_cachep.

Link: http://lkml.kernel.org/r/20180724121139.62570-3-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fixes: 72ecad22 ("block: support a full bio worth of IO for simplified bdev direct-io")
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin Wilck <mwilck@suse.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

If we meet a conflicting object that is marked FSCACHE_OBJECT_IS_LIVE in
the active object tree, we have been emitting a BUG after logging
information about it and the new object.

Instead, we should wait for the CACHEFILES_OBJECT_ACTIVE flag to be cleared
on the old object (or return an error).  The ACTIVE flag should be cleared
after it has been removed from the active object tree.  A timeout of 60s is
used in the wait, so we shouldn't be able to get stuck there.

Fixes: 9ae326a6 ("CacheFiles: A cache that backs onto a mounted filesystem")
Signed-off-by: NKiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

In cachefiles_mark_object_active(), the new object is marked active and
then we try to add it to the active object tree.  If a conflicting object
is already present, we want to wait for that to go away.  After the wait,
we go round again and try to re-mark the object as being active - but it's
already marked active from the first time we went through and a BUG is
issued.

Fix this by clearing the CACHEFILES_OBJECT_ACTIVE flag before we try again.

Analysis from Kiran Kumar Modukuri:

[Impact]
Oops during heavy NFS + FSCache + Cachefiles

CacheFiles: Error: Overlong wait for old active object to go away.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000002

CacheFiles: Error: Object already active kernel BUG at
fs/cachefiles/namei.c:163!

[Cause]
In a heavily loaded system with big files being read and truncated, an
fscache object for a cookie is being dropped and a new object being
looked. The new object being looked for has to wait for the old object
to go away before the new object is moved to active state.

[Fix]
Clear the flag 'CACHEFILES_OBJECT_ACTIVE' for the new object when
retrying the object lookup.

[Testcase]
Have run ~100 hours of NFS stress tests and have not seen this bug recur.

[Regression Potential]
 - Limited to fscache/cachefiles.

Fixes: 9ae326a6 ("CacheFiles: A cache that backs onto a mounted filesystem")
Signed-off-by: NKiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

When a cookie is allocated that causes fscache_object structs to be
allocated, those objects are initialised with the cookie pointer, but
aren't blessed with a ref on that cookie unless the attachment is
successfully completed in fscache_attach_object().

If attachment fails because the parent object was dying or there was a
collision, fscache_attach_object() returns without incrementing the cookie
counter - but upon failure of this function, the object is released which
then puts the cookie, whether or not a ref was taken on the cookie.

Fix this by taking a ref on the cookie when it is assigned in
fscache_object_init(), even when we're creating a root object.


Analysis from Kiran Kumar:

This bug has been seen in 4.4.0-124-generic #148-Ubuntu kernel

BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1776277

fscache cookie ref count updated incorrectly during fscache object
allocation resulting in following Oops.

kernel BUG at /build/linux-Y09MKI/linux-4.4.0/fs/fscache/internal.h:321!
kernel BUG at /build/linux-Y09MKI/linux-4.4.0/fs/fscache/cookie.c:639!

[Cause]
Two threads are trying to do operate on a cookie and two objects.

(1) One thread tries to unmount the filesystem and in process goes over a
    huge list of objects marking them dead and deleting the objects.
    cookie->usage is also decremented in following path:

      nfs_fscache_release_super_cookie
       -> __fscache_relinquish_cookie
        ->__fscache_cookie_put
        ->BUG_ON(atomic_read(&cookie->usage) <= 0);

(2) A second thread tries to lookup an object for reading data in following
    path:

    fscache_alloc_object
    1) cachefiles_alloc_object
        -> fscache_object_init
           -> assign cookie, but usage not bumped.
    2) fscache_attach_object -> fails in cant_attach_object because the
         cookie's backing object or cookie's->parent object are going away
    3) fscache_put_object
        -> cachefiles_put_object
          ->fscache_object_destroy
            ->fscache_cookie_put
               ->BUG_ON(atomic_read(&cookie->usage) <= 0);

[NOTE from dhowells] It's unclear as to the circumstances in which (2) can
take place, given that thread (1) is in nfs_kill_super(), however a
conflicting NFS mount with slightly different parameters that creates a
different superblock would do it.  A backtrace from Kiran seems to show
that this is a possibility:

    kernel BUG at/build/linux-Y09MKI/linux-4.4.0/fs/fscache/cookie.c:639!
    ...
    RIP: __fscache_cookie_put+0x3a/0x40 [fscache]
    Call Trace:
     __fscache_relinquish_cookie+0x87/0x120 [fscache]
     nfs_fscache_release_super_cookie+0x2d/0xb0 [nfs]
     nfs_kill_super+0x29/0x40 [nfs]
     deactivate_locked_super+0x48/0x80
     deactivate_super+0x5c/0x60
     cleanup_mnt+0x3f/0x90
     __cleanup_mnt+0x12/0x20
     task_work_run+0x86/0xb0
     exit_to_usermode_loop+0xc2/0xd0
     syscall_return_slowpath+0x4e/0x60
     int_ret_from_sys_call+0x25/0x9f

[Fix] Bump up the cookie usage in fscache_object_init, when it is first
being assigned a cookie atomically such that the cookie is added and bumped
up if its refcount is not zero.  Remove the assignment in
fscache_attach_object().

[Testcase]
I have run ~100 hours of NFS stress tests and not seen this bug recur.

[Regression Potential]
 - Limited to fscache/cachefiles.

Fixes: ccc4fc3d ("FS-Cache: Implement the cookie management part of the netfs API")
Signed-off-by: NKiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

cachefiles_read_waiter() has the right to access a 'monitor' object by
virtue of being called under the waitqueue lock for one of the pages in its
purview.  However, it has no ref on that monitor object or on the
associated operation.

What it is allowed to do is to move the monitor object to the operation's
to_do list, but once it drops the work_lock, it's actually no longer
permitted to access that object.  However, it is trying to enqueue the
retrieval operation for processing - but it can only do this via a pointer
in the monitor object, something it shouldn't be doing.

If it doesn't enqueue the operation, the operation may not get processed.
If the order is flipped so that the enqueue is first, then it's possible
for the work processor to look at the to_do list before the monitor is
enqueued upon it.

Fix this by getting a ref on the operation so that we can trust that it
will still be there once we've added the monitor to the to_do list and
dropped the work_lock.  The op can then be enqueued after the lock is
dropped.

The bug can manifest in one of a couple of ways.  The first manifestation
looks like:

 FS-Cache:
 FS-Cache: Assertion failed
 FS-Cache: 6 == 5 is false
 ------------[ cut here ]------------
 kernel BUG at fs/fscache/operation.c:494!
 RIP: 0010:fscache_put_operation+0x1e3/0x1f0
 ...
 fscache_op_work_func+0x26/0x50
 process_one_work+0x131/0x290
 worker_thread+0x45/0x360
 kthread+0xf8/0x130
 ? create_worker+0x190/0x190
 ? kthread_cancel_work_sync+0x10/0x10
 ret_from_fork+0x1f/0x30

This is due to the operation being in the DEAD state (6) rather than
INITIALISED, COMPLETE or CANCELLED (5) because it's already passed through
fscache_put_operation().

The bug can also manifest like the following:

 kernel BUG at fs/fscache/operation.c:69!
 ...
    [exception RIP: fscache_enqueue_operation+246]
 ...
 #7 [ffff883fff083c10] fscache_enqueue_operation at ffffffffa0b793c6
 #8 [ffff883fff083c28] cachefiles_read_waiter at ffffffffa0b15a48
 #9 [ffff883fff083c48] __wake_up_common at ffffffff810af028

I'm not entirely certain as to which is line 69 in Lei's kernel, so I'm not
entirely clear which assertion failed.

Fixes: 9ae326a6 ("CacheFiles: A cache that backs onto a mounted filesystem")
Reported-by: NLei Xue <carmark.dlut@gmail.com>
Reported-by: NVegard Nossum <vegard.nossum@gmail.com>
Reported-by: NAnthony DeRobertis <aderobertis@metrics.net>
Reported-by: NNeilBrown <neilb@suse.com>
Reported-by: NDaniel Axtens <dja@axtens.net>
Reported-by: NKiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Reviewed-by: NDaniel Axtens <dja@axtens.net>

Alter the state-check assertion in fscache_enqueue_operation() to allow
cancelled operations to be given processing time so they can be cleaned up.

Also fix a debugging statement that was requiring such operations to have
an object assigned.

Fixes: 9ae326a6 ("CacheFiles: A cache that backs onto a mounted filesystem")
Reported-by: NKiran Kumar Modukuri <kiran.modukuri@gmail.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

When inodes are freed in xfs_ifree(), di_flags is cleared (so extent size
hints are removed) but the actual extent size fields are left intact.
This causes the extent hint validators to fail on freed inodes which once
had extent size hints.

This can be observed (for example) by running xfs/229 twice on a
non-crc xfs filesystem, or presumably on V5 with ikeep.

Fixes: 7d71a671 ("xfs: verify extent size hint is valid in inode verifier")
Fixes: 02a0fda8 ("xfs: verify COW extent size hint is valid in inode verifier")
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Reviewed-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>

Like vm_area_dup(), it initializes the anon_vma_chain head, and the
basic mm pointer.

The rest of the fields end up being different for different users,
although the plan is to also initialize the 'vm_ops' field to a dummy
entry.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The vm_area_struct is one of the most fundamental memory management
objects, but the management of it is entirely open-coded evertwhere,
ranging from allocation and freeing (using kmem_cache_[z]alloc and
kmem_cache_free) to initializing all the fields.

We want to unify this in order to end up having some unified
initialization of the vmas, and the first step to this is to at least
have basic allocation functions.

Right now those functions are literally just wrappers around the
kmem_cache_*() calls.  This is a purely mechanical conversion:

    # new vma:
    kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL) -> vm_area_alloc()

    # copy old vma
    kmem_cache_alloc(vm_area_cachep, GFP_KERNEL) -> vm_area_dup(old)

    # free vma
    kmem_cache_free(vm_area_cachep, vma) -> vm_area_free(vma)

to the point where the old vma passed in to the vm_area_dup() function
isn't even used yet (because I've left all the old manual initialization
alone).
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In parse_options(), if match_strdup() failed, parse_options() leaves
opts->iocharset in unexpected state (i.e.  still pointing the freed
string).  And this can be the cause of double free.

To fix, this initialize opts->iocharset always when freeing.

Link: http://lkml.kernel.org/r/8736wp9dzc.fsf@mail.parknet.co.jpSigned-off-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reported-by: syzbot+90b8e10515ae88228a92@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When we clone a range into a file we can end up dropping existing
extent maps (or trimming them) and replacing them with new ones if the
range to be cloned overlaps with a range in the destination inode.
When that happens we add the new extent maps to the list of modified
extents in the inode's extent map tree, so that a "fast" fsync (the flag
BTRFS_INODE_NEEDS_FULL_SYNC not set in the inode) will see the extent maps
and log corresponding extent items. However, at the end of range cloning
operation we do truncate all the pages in the affected range (in order to
ensure future reads will not get stale data). Sometimes this truncation
will release the corresponding extent maps besides the pages from the page
cache. If this happens, then a "fast" fsync operation will miss logging
some extent items, because it relies exclusively on the extent maps being
present in the inode's extent tree, leading to data loss/corruption if
the fsync ends up using the same transaction used by the clone operation
(that transaction was not committed in the meanwhile). An extent map is
released through the callback btrfs_invalidatepage(), which gets called by
truncate_inode_pages_range(), and it calls __btrfs_releasepage(). The
later ends up calling try_release_extent_mapping() which will release the
extent map if some conditions are met, like the file size being greater
than 16Mb, gfp flags allow blocking and the range not being locked (which
is the case during the clone operation) nor being the extent map flagged
as pinned (also the case for cloning).

The following example, turned into a test for fstests, reproduces the
issue:

  $ mkfs.btrfs -f /dev/sdb
  $ mount /dev/sdb /mnt

  $ xfs_io -f -c "pwrite -S 0x18 9000K 6908K" /mnt/foo
  $ xfs_io -f -c "pwrite -S 0x20 2572K 156K" /mnt/bar

  $ xfs_io -c "fsync" /mnt/bar
  # reflink destination offset corresponds to the size of file bar,
  # 2728Kb minus 4Kb.
  $ xfs_io -c ""reflink ${SCRATCH_MNT}/foo 0 2724K 15908K" /mnt/bar
  $ xfs_io -c "fsync" /mnt/bar

  $ md5sum /mnt/bar
  95a95813a8c2abc9aa75a6c2914a077e  /mnt/bar

  <power fail>

  $ mount /dev/sdb /mnt
  $ md5sum /mnt/bar
  207fd8d0b161be8a84b945f0df8d5f8d  /mnt/bar
  # digest should be 95a95813a8c2abc9aa75a6c2914a077e like before the
  # power failure

In the above example, the destination offset of the clone operation
corresponds to the size of the "bar" file minus 4Kb. So during the clone
operation, the extent map covering the range from 2572Kb to 2728Kb gets
trimmed so that it ends at offset 2724Kb, and a new extent map covering
the range from 2724Kb to 11724Kb is created. So at the end of the clone
operation when we ask to truncate the pages in the range from 2724Kb to
2724Kb + 15908Kb, the page invalidation callback ends up removing the new
extent map (through try_release_extent_mapping()) when the page at offset
2724Kb is passed to that callback.

Fix this by setting the bit BTRFS_INODE_NEEDS_FULL_SYNC whenever an extent
map is removed at try_release_extent_mapping(), forcing the next fsync to
search for modified extents in the fs/subvolume tree instead of relying on
the presence of extent maps in memory. This way we can continue doing a
"fast" fsync if the destination range of a clone operation does not
overlap with an existing range or if any of the criteria necessary to
remove an extent map at try_release_extent_mapping() is not met (file
size not bigger then 16Mb or gfp flags do not allow blocking).

CC: stable@vger.kernel.org # 3.16+
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

glibc uses a different defintion of sigset_t than the kernel does,
and the current version would pull in both.  To fix this just do not
expose the type at all - this somewhat mirrors pselect() where we
do not even have a type for the magic sigmask argument, but just
use pointer arithmetics.

Fixes: 7a074e96 ("aio: implement io_pgetevents")
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reported-by: NAdrian Reber <adrian@lisas.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

In commit ac0b4145 ("btrfs: scrub: Don't use inode pages for device
replace") we removed the branch of copy_nocow_pages() to avoid
corruption for compressed nodatasum extents.

However above commit only solves the problem in scrub_extent(), if
during scrub_pages() we failed to read some pages,
sctx->no_io_error_seen will be non-zero and we go to fixup function
scrub_handle_errored_block().

In scrub_handle_errored_block(), for sctx without csum (no matter if
we're doing replace or scrub) we go to scrub_fixup_nodatasum() routine,
which does the similar thing with copy_nocow_pages(), but does it
without the extra check in copy_nocow_pages() routine.

So for test cases like btrfs/100, where we emulate read errors during
replace/scrub, we could corrupt compressed extent data again.

This patch will fix it just by avoiding any "optimization" for
nodatasum, just falls back to the normal fixup routine by try read from
any good copy.

This also solves WARN_ON() or dead lock caused by lame backref iteration
in scrub_fixup_nodatasum() routine.

The deadlock or WARN_ON() won't be triggered before commit ac0b4145
("btrfs: scrub: Don't use inode pages for device replace") since
copy_nocow_pages() have better locking and extra check for data extent,
and it's already doing the fixup work by try to read data from any good
copy, so it won't go scrub_fixup_nodatasum() anyway.

This patch disables the faulty code and will be removed completely in a
followup patch.

Fixes: ac0b4145 ("btrfs: scrub: Don't use inode pages for device replace")
Signed-off-by: NQu Wenruo <wqu@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

ReiserFS prepares log messages into a 1024-byte buffer with no bounds
checks.  Long messages, such as the "unknown mount option" warning when
userspace passes a crafted mount options string, overflow this buffer.
This causes KASAN to report a global-out-of-bounds write.

Fix it by truncating messages to the buffer size.

Link: http://lkml.kernel.org/r/20180707203621.30922-1-ebiggers3@gmail.com
Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reported-by: syzbot+b890b3335a4d8c608963@syzkaller.appspotmail.com
Signed-off-by: NEric Biggers <ebiggers@google.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current code does not make sure to page align bss before calling
vm_brk(), and this can lead to a VM_BUG_ON() in __mm_populate() due to
the requested lenght not being correctly aligned.

Let us make sure to align it properly.

Kees: only applicable to CONFIG_USELIB kernels: 32-bit and configured
for libc5.

Link: http://lkml.kernel.org/r/20180705145539.9627-1-osalvador@techadventures.netSigned-off-by: NOscar Salvador <osalvador@suse.de>
Reported-by: syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com
Tested-by: NTetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Acked-by: NKees Cook <keescook@chromium.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The autofs subsystem does not check that the "path" parameter is present
for all cases where it is required when it is passed in via the "param"
struct.

In particular it isn't checked for the AUTOFS_DEV_IOCTL_OPENMOUNT_CMD
ioctl command.

To solve it, modify validate_dev_ioctl(function to check that a path has
been provided for ioctl commands that require it.

Link: http://lkml.kernel.org/r/153060031527.26631.18306637892746301555.stgit@pluto.themaw.netSigned-off-by: NTomas Bortoli <tomasbortoli@gmail.com>
Signed-off-by: NIan Kent <raven@themaw.net>
Reported-by: syzbot+60c837b428dc84e83a93@syzkaller.appspotmail.com
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Thomas reports:
 "While looking around in /proc on my v4.14.52 system I noticed that all
  processes got a lot of "Locked" memory in /proc/*/smaps. A lot more
  memory than a regular user can usually lock with mlock().

  Commit 493b0e9d (in v4.14-rc1) seems to have changed the behavior
  of "Locked".

  Before that commit the code was like this. Notice the VM_LOCKED check.

           (vma->vm_flags & VM_LOCKED) ?
                (unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);

  After that commit Locked is now the same as Pss:

	  (unsigned long)(mss->pss >> (10 + PSS_SHIFT)));

  This looks like a mistake."

Indeed, the commit has added mss->pss_locked with the correct value that
depends on VM_LOCKED, but forgot to actually use it.  Fix it.

Link: http://lkml.kernel.org/r/ebf6c7fb-fec3-6a26-544f-710ed193c154@suse.cz
Fixes: 493b0e9d ("mm: add /proc/pid/smaps_rollup")
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Reported-by: NThomas Lindroth <thomas.lindroth@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Daniel Colascione <dancol@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

btrfs_cmp_data_free() puts cmp's src_pages and dst_pages, but leaves
their page address intact. Now, if you hit "goto again" in
btrfs_extent_same_range() and hit some error in
btrfs_cmp_data_prepare(), you'll try to unlock/put already put pages.

This is simple fix to reset the address to avoid use-after-free.

Fixes: 67b07bd4 ("Btrfs: reuse cmp workspace in EXTENT_SAME ioctl")
Signed-off-by: NNaohiro Aota <naota@elisp.net>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Commit 542c5908 ("btrfs: replace uuid_mutex by
device_list_mutex in btrfs_open_devices") switched to device_list_mutex
as we need that for the device list traversal, but we also need
uuid_mutex to protect access to fs_devices::opened to be consistent with
other users of that.

Fixes: 542c5908 ("btrfs: replace uuid_mutex by device_list_mutex in btrfs_open_devices")
Reviewed-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

With commit 044e6e3d: "ext4: don't update checksum of new
initialized bitmaps" the buffer valid bit will get set without
actually setting up the checksum for the allocation bitmap, since the
checksum will get calculated once we actually allocate an inode or
block.

If we are doing this, then we need to (re-)check the verified bit
after we take the block group lock.  Otherwise, we could race with
another process reading and verifying the bitmap, which would then
complain about the checksum being invalid.

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1780137Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

Failure of ->open() should *not* be followed by fput().  Fixed by
using filp_clone_open(), which gets the cleanups right.

Cc: stable@vger.kernel.org
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The inline data code was updating the raw inode directly; this is
problematic since if metadata checksums are enabled,
ext4_mark_inode_dirty() must be called to update the inode's checksum.
In addition, the jbd2 layer requires that get_write_access() be called
before the metadata buffer is modified.  Fix both of these problems.

https://bugzilla.kernel.org/show_bug.cgi?id=200443Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

Previously, when an MMP-protected file system is remounted read-only,
the kmmpd thread would exit the next time it woke up (a few seconds
later), without resetting the MMP sequence number back to
EXT4_MMP_SEQ_CLEAN.

Fix this by explicitly killing the MMP thread when the file system is
remounted read-only.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: Andreas Dilger <adilger@dilger.ca>

Ext4_check_descriptors() was getting called before s_gdb_count was
initialized.  So for file systems w/o the meta_bg feature, allocation
bitmaps could overlap the block group descriptors and ext4 wouldn't
notice.

For file systems with the meta_bg feature enabled, there was a
fencepost error which would cause the ext4_check_descriptors() to
incorrectly believe that the block allocation bitmap overlaps with the
block group descriptor blocks, and it would reject the mount.

Fix both of these problems.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

sgid directories have special semantics, making newly created files in
the directory belong to the group of the directory, and newly created
subdirectories will also become sgid.  This is historically used for
group-shared directories.

But group directories writable by non-group members should not imply
that such non-group members can magically join the group, so make sure
to clear the sgid bit on non-directories for non-members (but remember
that sgid without group execute means "mandatory locking", just to
confuse things even more).
Reported-by: NJann Horn <jannh@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

smb{2,3}_create_lease_buf() store a lease key in the lease
context for later usage on a lease break.

In most paths, the key is currently sourced from data that
happens to be on the stack near local variables for oplock in
SMB2_open() callers, e.g. from open_shroot(), whereas
smb2_open_file() properly allocates space on its stack for it.

The address of those local variables holding the oplock is then
passed to create_lease_buf handlers via SMB2_open(), and 16
bytes near oplock are used. This causes a stack out-of-bounds
access as reported by KASAN on SMB2.1 and SMB3 mounts (first
out-of-bounds access is shown here):

[  111.528823] BUG: KASAN: stack-out-of-bounds in smb3_create_lease_buf+0x399/0x3b0 [cifs]
[  111.530815] Read of size 8 at addr ffff88010829f249 by task mount.cifs/985
[  111.532838] CPU: 3 PID: 985 Comm: mount.cifs Not tainted 4.18.0-rc3+ #91
[  111.534656] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  111.536838] Call Trace:
[  111.537528]  dump_stack+0xc2/0x16b
[  111.540890]  print_address_description+0x6a/0x270
[  111.542185]  kasan_report+0x258/0x380
[  111.544701]  smb3_create_lease_buf+0x399/0x3b0 [cifs]
[  111.546134]  SMB2_open+0x1ef8/0x4b70 [cifs]
[  111.575883]  open_shroot+0x339/0x550 [cifs]
[  111.591969]  smb3_qfs_tcon+0x32c/0x1e60 [cifs]
[  111.617405]  cifs_mount+0x4f3/0x2fc0 [cifs]
[  111.674332]  cifs_smb3_do_mount+0x263/0xf10 [cifs]
[  111.677915]  mount_fs+0x55/0x2b0
[  111.679504]  vfs_kern_mount.part.22+0xaa/0x430
[  111.684511]  do_mount+0xc40/0x2660
[  111.698301]  ksys_mount+0x80/0xd0
[  111.701541]  do_syscall_64+0x14e/0x4b0
[  111.711807]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  111.713665] RIP: 0033:0x7f372385b5fa
[  111.715311] Code: 48 8b 0d 99 78 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 66 78 2c 00 f7 d8 64 89 01 48
[  111.720330] RSP: 002b:00007ffff27049d8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
[  111.722601] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f372385b5fa
[  111.724842] RDX: 000055c2ecdc73b2 RSI: 000055c2ecdc73f9 RDI: 00007ffff270580f
[  111.727083] RBP: 00007ffff2705804 R08: 000055c2ee976060 R09: 0000000000001000
[  111.729319] R10: 0000000000000000 R11: 0000000000000206 R12: 00007f3723f4d000
[  111.731615] R13: 000055c2ee976060 R14: 00007f3723f4f90f R15: 0000000000000000

[  111.735448] The buggy address belongs to the page:
[  111.737420] page:ffffea000420a7c0 count:0 mapcount:0 mapping:0000000000000000 index:0x0
[  111.739890] flags: 0x17ffffc0000000()
[  111.741750] raw: 0017ffffc0000000 0000000000000000 dead000000000200 0000000000000000
[  111.744216] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[  111.746679] page dumped because: kasan: bad access detected

[  111.750482] Memory state around the buggy address:
[  111.752562]  ffff88010829f100: 00 f2 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 00
[  111.754991]  ffff88010829f180: 00 00 f2 f2 00 00 00 00 00 00 00 00 00 00 00 00
[  111.757401] >ffff88010829f200: 00 00 00 00 00 f1 f1 f1 f1 01 f2 f2 f2 f2 f2 f2
[  111.759801]                                               ^
[  111.762034]  ffff88010829f280: f2 02 f2 f2 f2 f2 f2 f2 f2 00 00 00 00 00 00 00
[  111.764486]  ffff88010829f300: f2 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[  111.766913] ==================================================================

Lease keys are however already generated and stored in fid data
on open and create paths: pass them down to the lease context
creation handlers and use them.
Suggested-by: NAurélien Aptel <aaptel@suse.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Fixes: b8c32dbb ("CIFS: Request SMB2.1 leases")
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

For every request we send, whether it is SMB1 or SMB2+, we attempt to
reconnect tcon (cifs_reconnect_tcon or smb2_reconnect) before carrying
out the request.

So, while server->tcpStatus != CifsNeedReconnect, we wait for the
reconnection to succeed on wait_event_interruptible_timeout(). If it
returns, that means that either the condition was evaluated to true, or
timeout elapsed, or it was interrupted by a signal.

Since we're not handling the case where the process woke up due to a
received signal (-ERESTARTSYS), the next call to
wait_event_interruptible_timeout() will _always_ fail and we end up
looping forever inside either cifs_reconnect_tcon() or smb2_reconnect().

Here's an example of how to trigger that:

$ mount.cifs //foo/share /mnt/test -o
username=foo,password=foo,vers=1.0,hard

(break connection to server before executing bellow cmd)
$ stat -f /mnt/test & sleep 140
[1] 2511

$ ps -aux -q 2511
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root      2511  0.0  0.0  12892  1008 pts/0    S    12:24   0:00 stat -f
/mnt/test

$ kill -9 2511

(wait for a while; process is stuck in the kernel)
$ ps -aux -q 2511
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root      2511 83.2  0.0  12892  1008 pts/0    R    12:24  30:01 stat -f
/mnt/test

By using 'hard' mount point means that cifs.ko will keep retrying
indefinitely, however we must allow the process to be killed otherwise
it would hang the system.
Signed-off-by: NPaulo Alcantara <palcantara@suse.de>
Cc: stable@vger.kernel.org
Reviewed-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

A "small" CIFS buffer is not big enough in general to hold a
setacl request for SMB2, and we end up overflowing the buffer in
send_set_info(). For instance:

 # mount.cifs //127.0.0.1/test /mnt/test -o username=test,password=test,nounix,cifsacl
 # touch /mnt/test/acltest
 # getcifsacl /mnt/test/acltest
 REVISION:0x1
 CONTROL:0x9004
 OWNER:S-1-5-21-2926364953-924364008-418108241-1000
 GROUP:S-1-22-2-1001
 ACL:S-1-5-21-2926364953-924364008-418108241-1000:ALLOWED/0x0/0x1e01ff
 ACL:S-1-22-2-1001:ALLOWED/0x0/R
 ACL:S-1-22-2-1001:ALLOWED/0x0/R
 ACL:S-1-5-21-2926364953-924364008-418108241-1000:ALLOWED/0x0/0x1e01ff
 ACL:S-1-1-0:ALLOWED/0x0/R
 # setcifsacl -a "ACL:S-1-22-2-1004:ALLOWED/0x0/R" /mnt/test/acltest

this setacl will cause the following KASAN splat:

[  330.777927] BUG: KASAN: slab-out-of-bounds in send_set_info+0x4dd/0xc20 [cifs]
[  330.779696] Write of size 696 at addr ffff88010d5e2860 by task setcifsacl/1012

[  330.781882] CPU: 1 PID: 1012 Comm: setcifsacl Not tainted 4.18.0-rc2+ #2
[  330.783140] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[  330.784395] Call Trace:
[  330.784789]  dump_stack+0xc2/0x16b
[  330.786777]  print_address_description+0x6a/0x270
[  330.787520]  kasan_report+0x258/0x380
[  330.788845]  memcpy+0x34/0x50
[  330.789369]  send_set_info+0x4dd/0xc20 [cifs]
[  330.799511]  SMB2_set_acl+0x76/0xa0 [cifs]
[  330.801395]  set_smb2_acl+0x7ac/0xf30 [cifs]
[  330.830888]  cifs_xattr_set+0x963/0xe40 [cifs]
[  330.840367]  __vfs_setxattr+0x84/0xb0
[  330.842060]  __vfs_setxattr_noperm+0xe6/0x370
[  330.843848]  vfs_setxattr+0xc2/0xd0
[  330.845519]  setxattr+0x258/0x320
[  330.859211]  path_setxattr+0x15b/0x1b0
[  330.864392]  __x64_sys_setxattr+0xc0/0x160
[  330.866133]  do_syscall_64+0x14e/0x4b0
[  330.876631]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  330.878503] RIP: 0033:0x7ff2e507db0a
[  330.880151] Code: 48 8b 0d 89 93 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 bc 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 56 93 2c 00 f7 d8 64 89 01 48
[  330.885358] RSP: 002b:00007ffdc4903c18 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
[  330.887733] RAX: ffffffffffffffda RBX: 000055d1170de140 RCX: 00007ff2e507db0a
[  330.890067] RDX: 000055d1170de7d0 RSI: 000055d115b39184 RDI: 00007ffdc4904818
[  330.892410] RBP: 0000000000000001 R08: 0000000000000000 R09: 000055d1170de7e4
[  330.894785] R10: 00000000000002b8 R11: 0000000000000246 R12: 0000000000000007
[  330.897148] R13: 000055d1170de0c0 R14: 0000000000000008 R15: 000055d1170de550

[  330.901057] Allocated by task 1012:
[  330.902888]  kasan_kmalloc+0xa0/0xd0
[  330.904714]  kmem_cache_alloc+0xc8/0x1d0
[  330.906615]  mempool_alloc+0x11e/0x380
[  330.908496]  cifs_small_buf_get+0x35/0x60 [cifs]
[  330.910510]  smb2_plain_req_init+0x4a/0xd60 [cifs]
[  330.912551]  send_set_info+0x198/0xc20 [cifs]
[  330.914535]  SMB2_set_acl+0x76/0xa0 [cifs]
[  330.916465]  set_smb2_acl+0x7ac/0xf30 [cifs]
[  330.918453]  cifs_xattr_set+0x963/0xe40 [cifs]
[  330.920426]  __vfs_setxattr+0x84/0xb0
[  330.922284]  __vfs_setxattr_noperm+0xe6/0x370
[  330.924213]  vfs_setxattr+0xc2/0xd0
[  330.926008]  setxattr+0x258/0x320
[  330.927762]  path_setxattr+0x15b/0x1b0
[  330.929592]  __x64_sys_setxattr+0xc0/0x160
[  330.931459]  do_syscall_64+0x14e/0x4b0
[  330.933314]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[  330.936843] Freed by task 0:
[  330.938588] (stack is not available)

[  330.941886] The buggy address belongs to the object at ffff88010d5e2800
 which belongs to the cache cifs_small_rq of size 448
[  330.946362] The buggy address is located 96 bytes inside of
 448-byte region [ffff88010d5e2800, ffff88010d5e29c0)
[  330.950722] The buggy address belongs to the page:
[  330.952789] page:ffffea0004357880 count:1 mapcount:0 mapping:ffff880108fdca80 index:0x0 compound_mapcount: 0
[  330.955665] flags: 0x17ffffc0008100(slab|head)
[  330.957760] raw: 0017ffffc0008100 dead000000000100 dead000000000200 ffff880108fdca80
[  330.960356] raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
[  330.963005] page dumped because: kasan: bad access detected

[  330.967039] Memory state around the buggy address:
[  330.969255]  ffff88010d5e2880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[  330.971833]  ffff88010d5e2900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[  330.974397] >ffff88010d5e2980: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
[  330.976956]                                            ^
[  330.979226]  ffff88010d5e2a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  330.981755]  ffff88010d5e2a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  330.984225] ==================================================================

Fix this by allocating a regular CIFS buffer in
smb2_plain_req_init() if the request command is SMB2_SET_INFO.
Reported-by: NJianhong Yin <jiyin@redhat.com>
Fixes: 366ed846 ("cifs: Use smb 2 - 3 and cifsacl mount options setacl function")
CC: Stable <stable@vger.kernel.org>
Signed-off-by: NStefano Brivio <sbrivio@redhat.com>
Reviewed-and-tested-by: NAurelien Aptel <aaptel@suse.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

This patch fixes a memory leak when doing a setxattr(2) in SMB2+.
Signed-off-by: NPaulo Alcantara <palcantara@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NAurelien Aptel <aaptel@suse.com>

SMB1 mounting broke in commit 35e2cc1b
("cifs: Use correct packet length in SMB2_TRANSFORM header")
Fix it and also rename smb2_rqst_len to smb_rqst_len
to make it less unobvious that the function is also called from
CIFS/SMB1

Good job by Paulo reviewing and cleaning up Ronnie's original patch.
Signed-off-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NPaulo Alcantara <palcantara@suse.de>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Fixes: c713c877 ("cifs: push rfc1002 generation down the stack")

We failed to validate signed data returned by the server because
__cifs_calc_signature() now expects to sign the actual data in iov but
we were also passing down the rfc1002 length.

Fix smb3_calc_signature() to calculate signature of rfc1002 length prior
to passing only the actual data iov[1-N] to __cifs_calc_signature(). In
addition, there are a few cases where no rfc1002 length is passed so we
make sure there's one (iov_len == 4).
Signed-off-by: NPaulo Alcantara <palcantara@suse.de>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

Fixes: c713c877 ("cifs: push rfc1002 generation down the stack")

We failed to validate signed data returned by the server because
__cifs_calc_signature() now expects to sign the actual data in iov but
we were also passing down the rfc1002 length.

Fix smb3_calc_signature() to calculate signature of rfc1002 length prior
to passing only the actual data iov[1-N] to __cifs_calc_signature(). In
addition, there are a few cases where no rfc1002 length is passed so we
make sure there's one (iov_len == 4).
Signed-off-by: NPaulo Alcantara <palcantara@suse.de>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

With protocol version 2.0 mounts we have seen crashes with corrupt mid
entries. Either the server->pending_mid_q list becomes corrupt with a
cyclic reference in one element or a mid object fetched by the
demultiplexer thread becomes overwritten during use.

Code review identified a race between the demultiplexer thread and the
request issuing thread. The demultiplexer thread seems to be written
with the assumption that it is the sole user of the mid object until
it calls the mid callback which either wakes the issuer task or
deletes the mid.

This assumption is not true because the issuer task can be woken up
earlier by a signal. If the demultiplexer thread has proceeded as far
as setting the mid_state to MID_RESPONSE_RECEIVED then the issuer
thread will happily end up calling cifs_delete_mid while the
demultiplexer thread still is using the mid object.

Inserting a delay in the cifs demultiplexer thread widens the race
window and makes reproduction of the race very easy:

		if (server->large_buf)
			buf = server->bigbuf;

+		usleep_range(500, 4000);

		server->lstrp = jiffies;

To resolve this I think the proper solution involves putting a
reference count on the mid object. This patch makes sure that the
demultiplexer thread holds a reference until it has finished
processing the transaction.

Cc: stable@vger.kernel.org
Signed-off-by: NLars Persson <larper@axis.com>
Acked-by: NPaulo Alcantara <palcantara@suse.de>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>

It turns out that systemd has a bug: it wants to load the autofs module
early because of some initialization ordering with udev, and it doesn't
do that correctly.  Everywhere else it does the proper "look up module
name" that does the proper alias resolution, but in that early code, it
just uses a hardcoded "autofs4" for the module name.

The result of that is that as of commit a2225d93 ("autofs: remove
left-over autofs4 stubs"), you get

    systemd[1]: Failed to insert module 'autofs4': No such file or directory

in the system logs, and a lack of module loading.  All this despite the
fact that we had very clearly marked 'autofs4' as an alias for this
module.

What's so ridiculous about this is that literally everything else does
the module alias handling correctly, including really old versions of
systemd (that just used 'modprobe' to do this), and even all the other
systemd module loading code.

Only that special systemd early module load code is broken, hardcoding
the module names for not just 'autofs4', but also "ipv6", "unix",
"ip_tables" and "virtio_rng".  Very annoying.

Instead of creating an _additional_ separate compatibility 'autofs4'
module, just rely on the fact that everybody else gets this right, and
just call the module 'autofs4' for compatibility reasons, with 'autofs'
as the alias name.

That will allow the systemd people to fix their bugs, adding the proper
alias handling, and maybe even fix the name of the module to be just
"autofs" (so that they can _test_ the alias handling).  And eventually,
we can revert this silly compatibility hack.

See also

    https://github.com/systemd/systemd/issues/9501
    https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=902946

for the systemd bug reports upstream and in the Debian bug tracker
respectively.

Fixes: a2225d93 ("autofs: remove left-over autofs4 stubs")
Reported-by: NBen Hutchings <ben@decadent.org.uk>
Reported-by: NMichael Biebl <biebl@debian.org>
Cc: Ian Kent <raven@themaw.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use huge_ptep_get() to translate huge ptes to normal ptes so we can
check them with the huge_pte_* functions.  Otherwise some architectures
will check the wrong values and will not wait for userspace to bring in
the memory.

Link: http://lkml.kernel.org/r/20180626132421.78084-1-frankja@linux.ibm.com
Fixes: 369cd212 ("userfaultfd: hugetlbfs: userfaultfd_huge_must_wait for hugepmd ranges")
Signed-off-by: NJanosch Frank <frankja@linux.ibm.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch attempts to close a hole leading to a BUG seen with hot
removals during writes [1].

A block device (NVME namespace in this test case) is formatted to EXT4
without partitions. It's mounted and write I/O is run to a file, then
the device is hot removed from the slot. The superblock attempts to be
written to the drive which is no longer present.

The typical chain of events leading to the BUG:
ext4_commit_super()
  __sync_dirty_buffer()
    submit_bh()
      submit_bh_wbc()
        BUG_ON(!buffer_mapped(bh));

This fix checks for the superblock's buffer head being mapped prior to
syncing.

[1] https://www.spinics.net/lists/linux-ext4/msg56527.htmlSigned-off-by: NJon Derrick <jonathan.derrick@intel.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org