Commit Graph

635448 Commits

Author SHA1 Message Date
Al Viro
9763f7a4a5 Merge branch 'work.autofs' into for-linus
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-16 16:34:52 -05:00
Al Viro
3c55d6bcfe Merge remote-tracking branch 'djwong/ocfs2-vfs-reflink-6' into for-linus 2016-12-16 16:21:05 -05:00
Al Viro
4da00fd1b9 Merge branch 'work.write_end' into for-linus 2016-12-16 16:19:49 -05:00
Darrick J. Wong
29ac8e856c ocfs2: implement the VFS clone_range, copy_range, and dedupe_range features
Connect the new VFS clone_range, copy_range, and dedupe_range features
to the existing reflink capability of ocfs2.  Compared to the existing
ocfs2 reflink ioctl We have to do things a little differently to support
the VFS semantics (we can clone subranges of a file but we don't clone
xattrs), but the VFS ioctls are more broadly supported.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
v2: Convert inline data files to extents files before reflinking,
and fix i_blocks so that stat(2) output is correct.
v3: Make zero-length dedupe consistent with btrfs behavior.
v4: Use VFS double-inode lock routines and remove MAX_DEDUPE_LEN.
2016-12-10 12:39:45 -08:00
Darrick J. Wong
86e59436d4 ocfs2: charge quota for reflinked blocks
When ocfs2 shares blocks from one file to another, it's necessary to
charge that many blocks to the quota because ocfs2 tallies block charges
according to the number of blocks mapped, not the number of physical
blocks used.

Without this patch, reflinking X blocks and then CoWing all of them
causes quota usage to *decrease* by X as seen in generic/305.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-12-10 12:39:45 -08:00
Darrick J. Wong
aef73a61c0 ocfs2: fix bad pointer cast
generic/188 triggered a dmesg stack trace because the dio completion
was casting a buffer head to an on-disk inode, which is whacky.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-12-10 12:39:45 -08:00
Darrick J. Wong
dbf896fc28 ocfs2: always unlock when completing dio writes
Always unlock the inode when completing dio writes, even if an error
has occurrred.  The caller already checks the inode and unlocks it
if needed, so we might as well reduce contention.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-12-10 12:39:45 -08:00
Darrick J. Wong
085549553d ocfs2: don't eat io errors during _dio_end_io_write
ocfs2_dio_end_io_write eats whatever errors may happen,
which means that write errors do not propagate to userspace.
Fix that.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-12-10 12:39:45 -08:00
Darrick J. Wong
3e10b793fc ocfs2: budget for extent tree splits when adding refcount flag
When we're adding the refcount flag to an extent, we have to budget
enough space to handle a full extent btree split in addition to
whatever modifications have to be made to the refcount btree.  We
don't currently do this, with the result that generic/186 crashes
when we need an extent split but not a refcount split because meta_ac
never gets allocated.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-12-10 12:39:45 -08:00
Darrick J. Wong
06a7030581 ocfs2: prohibit refcounted swapfiles
The swapfile mechanism calls bmap once to find all the swap file
mappings, which means that we cannot properly support CoW remapping.
Therefore, error out if the swap code tries to call bmap on a
refcounted file.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-12-10 12:39:45 -08:00
Darrick J. Wong
86544fbd85 ocfs2: add newlines to some error messages
These two error messages are missing the trailing newline.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-12-10 12:39:45 -08:00
Darrick J. Wong
84e40080bd ocfs2: convert inode refcount test to a helper
Replace the open-coded inode refcount flag test with a helper function
to reduce the potential for bugs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-12-10 12:39:45 -08:00
Al Viro
04fff6416c simple_write_end(): don't zero in short copy into uptodate
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-10 14:25:19 -05:00
Al Viro
92e50d2d42 exofs: don't mess with simple_write_{begin,end}
... and don't zero anything on short copy; just unlock
and return 0 if that has happened on non-uptodate page.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-10 14:25:19 -05:00
Al Viro
77469c3f57 9p: saner ->write_end() on failing copy into non-uptodate page
If we had a short copy into an uptodate page, there's no reason
whatsoever to zero anything; OTOH, if that page had _not_ been
uptodate, we must have been trying to overwrite it completely
and got a short copy.  In that case, overwriting the end with
zeroes, marking uptodate and sending to server is just plain
wrong.  Just unlock, keep it non-uptodate and return 0.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-10 14:25:18 -05:00
Al Viro
43388b21e7 fix gfs2_stuffed_write_end() on short copies
a) the page is uptodate - ->write_begin() would either fail (in which
case we don't reach ->write_end()), or unstuff the inode, or find the
page already uptodate, or do a successful call of stuffed_readpage(),
which would've made it uptodate

b) zeroing the tail in pagecache is wrong.  kill -9 at the right time
while writing unmodified file contents to the same file should _not_
leave us in a situation when read() from the file will be reporting
it full of zeroes.  Especially since that effect will be transient -
at some later point the page will be evicted and then we'll be back
to the real file contents.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-10 14:25:18 -05:00
Al Viro
b9de313cf0 fix ceph_write_end()
don't zero on short copies; if the page was uptodate it's just plain
wrong, and if it wasn't we'll be better off just returning 0 and
buggering off.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-10 14:24:45 -05:00
Al Viro
c0cf3ef5e0 nfs_write_end(): fix handling of short copies
What matters when deciding if we should make a page uptodate is
not how much we _wanted_ to copy, but how much we actually have
copied.  As it is, on architectures that do not zero tail on
short copy we can leave uninitialized data in page marked uptodate.

Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-09 22:41:47 -05:00
Darrick J. Wong
876bec6f9b vfs: refactor clone/dedupe_file_range common functions
Hoist both the XFS reflink inode state and preparation code and the XFS
file blocks compare functions into the VFS so that ocfs2 can take
advantage of it for reflink and dedupe.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2016-12-09 16:18:30 -08:00
Christoph Hellwig
a76b5b0437 fs: try to clone files first in vfs_copy_file_range
A clone is a perfectly fine implementation of a file copy, so most
file systems just implement the copy that way.  Instead of duplicating
this logic move it to the VFS.  Currently btrfs and XFS implement copies
the same way as clones and there is no behavior change for them, cifs
only implements clones and grow support for copy_file_range with this
patch.  NFS implements both, so this will allow copy_file_range to work
on servers that only implement CLONE and be lot more efficient on servers
that implements CLONE and COPY.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-12-09 16:17:19 -08:00
Al Viro
f0bb5aaf2c vfs: misc struct path constification
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:03:49 -05:00
Al Viro
ca71cf71ee namespace.c: constify struct path passed to a bunch of primitives
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:03:12 -05:00
Al Viro
8c54ca9c68 quota: constify struct path in quota_on
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:03:06 -05:00
Al Viro
a4141d7cf8 constify alloc_file()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:01:16 -05:00
Al Viro
92872094a1 constify btrfs_mksubvol()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:01:16 -05:00
Al Viro
5b5577e4eb autofs: constify find_autofs_mount() callback
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:01:16 -05:00
Al Viro
71215a75ce constify get_dcookie() and friends
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:01:16 -05:00
Al Viro
8bd107633b audit_log_{name,link_denied}: constify struct path
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 19:00:38 -05:00
Al Viro
40212d531d fsnotify: constify the places working with ->f_path
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 18:58:32 -05:00
Al Viro
12c7f9dc0f constify fsnotify_parent()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 18:58:32 -05:00
Al Viro
e637835ecc fsnotify(): constify 'data'
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 18:58:31 -05:00
Al Viro
3cd5eca8d7 fsnotify: constify 'data' passed to ->handle_event()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 18:58:31 -05:00
Mickaël Salaün
640eb7e7b5 fs: Constify path_is_under()'s arguments
The function path_is_under() doesn't modify the paths pointed by its
arguments but only browse them. Constifying this pointers make a cleaner
interface to be used by (future) code which may only have access to
const struct path pointers (e.g. LSM hooks).

Signed-off-by: Mickaël Salaün <mic@digikod.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-05 18:55:47 -05:00
Linus Torvalds
3e5de27e94 Linux 4.9-rc8 2016-12-04 12:50:51 -08:00
Ian Kent
1c4344a50d autofs - dont hold spin lock over direct mount expire
Commit 7cbdb4a286 altered the autofs indirect mount expire to
not hold a spin lock during the expire check.

The direct mount expire needs the same treatment because to
make autofs expires namespace aware may_umount_tree() needs to
to use a similar method to may_umount() when checking if a mount
tree is in use.

This means may_umount_tree() will end up taking the namespace_sem
for the check so the autofs direct mount expire won't be allowed
to hold a spin lock over the check.

Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-03 20:51:50 -05:00
Ian Kent
455e8f1030 autofs - constify misc struct path instances
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-03 20:51:50 -05:00
Ian Kent
f74e7b33c3 vfs: remove unused have_submounts() function
Now that path_has_submounts() has been added have_submounts() is no
longer used so remove it.

Link: http://lkml.kernel.org/r/20161011053428.27645.12310.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-03 20:51:49 -05:00
Ian Kent
6035974147 autofs: use path_has_submounts() to fix unreliable have_submount() checks
If an automount mount is clone(2)ed into a file system that is propagation
private, when it later expires in the originating namespace, subsequent
calls to autofs ->d_automount() for that dentry in the original namespace
will return ELOOP until the mount is umounted in the cloned namespace.

Now that a struct path is available where needed use path_has_submounts()
instead of have_submounts() so we don't get false positives when checking
if a dentry is a mount point or contains mounts in the current namespace.

Link: http://lkml.kernel.org/r/20161011053423.27645.91233.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-03 20:51:49 -05:00
Ian Kent
cfaf86ab6c autofs: use path_is_mountpoint() to fix unreliable d_mountpoint() checks
If an automount mount is clone(2)ed into a file system that is propagation
private, when it later expires in the originating namespace, subsequent
calls to autofs ->d_automount() for that dentry in the original namespace
will return ELOOP until the mount is umounted in the cloned namespace.

Now that a struct path is available where needed use path_is_mountpoint()
instead of d_mountpoint() so we don't get false positives when checking if
a dentry is a mount point in the current namespace.

Link: http://lkml.kernel.org/r/20161011053418.27645.15241.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-03 20:51:48 -05:00
Ian Kent
dd36a882e7 autofs: change autofs4_wait() to take struct path
In order to use the functions path_is_mountpoint() and path_has_submounts()
autofs needs to pass a struct path in several places.

Now change autofs4_wait() to take a struct path instead of a struct
dentry.

Link: http://lkml.kernel.org/r/20161011053413.27645.84666.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-03 20:51:48 -05:00
Ian Kent
74f504cff5 autofs: change autofs4_expire_wait()/do_expire_wait() to take struct path
In order to use the functions path_is_mountpoint() and path_has_submounts()
autofs needs to pass a struct path in several places.

Start by changing autofs4_expire_wait() and do_expire_wait() to take
a struct path instead of a struct dentry.

Link: http://lkml.kernel.org/r/20161011053408.27645.40091.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-03 20:51:47 -05:00
Ian Kent
01619491a5 vfs: add path_has_submounts()
d_mountpoint() can only be used reliably to establish if a dentry is
not mounted in any namespace. It isn't aware of the possibility there
may be multiple mounts using the given dentry, possibly in a different
namespace.

Add function, path_has_submounts(), that checks is a struct path contains
mounts (or is a mountpoint itself) to handle this case.

Link: http://lkml.kernel.org/r/20161011053403.27645.55242.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-03 20:51:47 -05:00
Ian Kent
c6609c0a1c vfs: add path_is_mountpoint() helper
d_mountpoint() can only be used reliably to establish if a dentry is
not mounted in any namespace. It isn't aware of the possibility there
may be multiple mounts using a given dentry that may be in a different
namespace.

Add helper functions, path_is_mountpoint(), that checks if a struct path
is a mountpoint for this case.

Link: http://lkml.kernel.org/r/20161011053358.27645.9729.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-03 20:51:35 -05:00
Linus Torvalds
0cb65c8330 Merge tag 'drm-fixes-for-v4.9-rc8' of git://people.freedesktop.org/~airlied/linux
Pull drm fixes from Dave Airlie:
 "A pretty small pull request: a couple of AMD powerxpress regression
  fixes and a power management fix, a couple of i915 fixes and one hdlcd
  fix, along with one core don't oops because of incorrect API usage fix"

* tag 'drm-fixes-for-v4.9-rc8' of git://people.freedesktop.org/~airlied/linux:
  drm/i915: drop the struct_mutex when wedged or trying to reset
  drm/i915: Don't touch NULL sg on i915_gem_object_get_pages_gtt() error
  drm: Don't call drm_for_each_crtc with a non-KMS driver
  drm/radeon: fix check for port PM availability
  drm/amdgpu: fix check for port PM availability
  drm/amd/powerplay: initialize the soft_regs offset in struct smu7_hwmgr
  drm: hdlcd: Fix cleanup order
2016-12-03 16:40:21 -08:00
Dave Airlie
ab7cd8d83e Merge tag 'drm-intel-fixes-2016-12-01' of git://anongit.freedesktop.org/git/drm-intel into drm-fixes
2 intel fixes.

* tag 'drm-intel-fixes-2016-12-01' of git://anongit.freedesktop.org/git/drm-intel:
  drm/i915: drop the struct_mutex when wedged or trying to reset
  drm/i915: Don't touch NULL sg on i915_gem_object_get_pages_gtt() error
2016-12-04 06:31:26 +10:00
Ian Kent
fb5f51c742 vfs: change d_manage() to take a struct path
For the autofs module to be able to reliably check if a dentry is a
mountpoint in a multiple namespace environment the ->d_manage() dentry
operation will need to take a path argument instead of a dentry.

Link: http://lkml.kernel.org/r/20161011053352.27645.83962.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-02 22:15:53 -05:00
Linus Torvalds
3c49de52d5 Merge branch 'akpm' (patches from Andrew)
Merge more fixes from Andrew Morton:
 "2 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm, vmscan: add cond_resched() into shrink_node_memcg()
  mm: workingset: fix NULL ptr in count_shadow_nodes
2016-12-02 18:48:11 -08:00
Michal Hocko
bd041733c9 mm, vmscan: add cond_resched() into shrink_node_memcg()
Boris Zhmurov has reported RCU stalls during the kswapd reclaim:

  INFO: rcu_sched detected stalls on CPUs/tasks:
   23-...: (22 ticks this GP) idle=92f/140000000000000/0 softirq=2638404/2638404 fqs=23
   (detected by 4, t=6389 jiffies, g=786259, c=786258, q=42115)
  Task dump for CPU 23:
  kswapd1         R  running task        0   148      2 0x00000008
  Call Trace:
    shrink_node+0xd2/0x2f0
    kswapd+0x2cb/0x6a0
    mem_cgroup_shrink_node+0x160/0x160
    kthread+0xbd/0xe0
    __switch_to+0x1fa/0x5c0
    ret_from_fork+0x1f/0x40
    kthread_create_on_node+0x180/0x180

a closer code inspection has shown that we might indeed miss all the
scheduling points in the reclaim path if no pages can be isolated from
the LRU list.  This is a pathological case but other reports from Donald
Buczek have shown that we might indeed hit such a path:

        clusterd-989   [009] .... 118023.654491: mm_vmscan_direct_reclaim_end: nr_reclaimed=193
         kswapd1-86    [001] dN.. 118023.987475: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239830 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118024.320968: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239844 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118024.654375: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239858 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118024.987036: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239872 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118025.319651: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239886 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118025.652248: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239900 nr_taken=0 file=1
         kswapd1-86    [001] dN.. 118025.984870: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4239914 nr_taken=0 file=1
  [...]
         kswapd1-86    [001] dN.. 118084.274403: mm_vmscan_lru_isolate: isolate_mode=0 classzone=0 order=0 nr_requested=32 nr_scanned=4241133 nr_taken=0 file=1

this is minute long snapshot which didn't take a single page from the
LRU.  It is not entirely clear why only 1303 pages have been scanned
during that time (maybe there was a heavy IRQ activity interfering).

In any case it looks like we can really hit long periods without
scheduling on non preemptive kernels so an explicit cond_resched() in
shrink_node_memcg which is independent on the reclaim operation is due.

Link: http://lkml.kernel.org/r/20161202095841.16648-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Boris Zhmurov <bb@kernelpanic.ru>
Tested-by: Boris Zhmurov <bb@kernelpanic.ru>
Reported-by: Donald Buczek <buczek@molgen.mpg.de>
Reported-by: "Christopher S. Aker" <caker@theshore.net>
Reported-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-02 18:48:03 -08:00
Michal Hocko
20ab67a563 mm: workingset: fix NULL ptr in count_shadow_nodes
Commit 0a6b76dd23 ("mm: workingset: make shadow node shrinker memcg
aware") has made the workingset shadow nodes shrinker memcg aware.  The
implementation is not correct though because memcg_kmem_enabled() might
become true while we are doing a global reclaim when the sc->memcg might
be NULL which is exactly what Marek has seen:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000400
  IP: [<ffffffff8122d520>] mem_cgroup_node_nr_lru_pages+0x20/0x40
  PGD 0
  Oops: 0000 [#1] SMP
  CPU: 0 PID: 60 Comm: kswapd0 Tainted: G           O   4.8.10-12.pvops.qubes.x86_64 #1
  task: ffff880011863b00 task.stack: ffff880011868000
  RIP: mem_cgroup_node_nr_lru_pages+0x20/0x40
  RSP: e02b:ffff88001186bc70  EFLAGS: 00010293
  RAX: 0000000000000000 RBX: ffff88001186bd20 RCX: 0000000000000002
  RDX: 000000000000000c RSI: 0000000000000000 RDI: 0000000000000000
  RBP: ffff88001186bc70 R08: 28f5c28f5c28f5c3 R09: 0000000000000000
  R10: 0000000000006c34 R11: 0000000000000333 R12: 00000000000001f6
  R13: ffffffff81c6f6a0 R14: 0000000000000000 R15: 0000000000000000
  FS:  0000000000000000(0000) GS:ffff880013c00000(0000) knlGS:ffff880013d00000
  CS:  e033 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000400 CR3: 00000000122f2000 CR4: 0000000000042660
  Call Trace:
    count_shadow_nodes+0x9a/0xa0
    shrink_slab.part.42+0x119/0x3e0
    shrink_node+0x22c/0x320
    kswapd+0x32c/0x700
    kthread+0xd8/0xf0
    ret_from_fork+0x1f/0x40
  Code: 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 3b 35 dd eb b1 00 55 48 89 e5 73 2c 89 d2 31 c9 31 c0 4c 63 ce 48 0f a3 ca 73 13 <4a> 8b b4 cf 00 04 00 00 41 89 c8 4a 03 84 c6 80 00 00 00 83 c1
  RIP  mem_cgroup_node_nr_lru_pages+0x20/0x40
   RSP <ffff88001186bc70>
  CR2: 0000000000000400
  ---[ end trace 100494b9edbdfc4d ]---

This patch fixes the issue by checking sc->memcg rather than
memcg_kmem_enabled() which is sufficient because shrink_slab makes sure
that only memcg aware shrinkers will get non-NULL memcgs and only if
memcg_kmem_enabled is true.

Fixes: 0a6b76dd23 ("mm: workingset: make shadow node shrinker memcg aware")
Link: http://lkml.kernel.org/r/20161201132156.21450-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Marek Marczykowski-Górecki <marmarek@mimuw.edu.pl>
Tested-by: Marek Marczykowski-Górecki <marmarek@mimuw.edu.pl>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: <stable@vger.kernel.org>	[4.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-02 18:48:03 -08:00
Nicolas Pitre
8655639240 kbuild: fix building bzImage with CONFIG_TRIM_UNUSED_KSYMS enabled
When building a specific target such as bzImage, modules aren't normally
built.  However if CONFIG_TRIM_UNUSED_KSYMS is enabled, no built modules
means none of the exported symbols are used and therefore they will all
be trimmed away from the final kernel.  A subsequent "make modules" will
fail because modpost cannot find the needed symbols for those modules in
the kernel binary.

Let's make sure modules are also built whenever CONFIG_TRIM_UNUSED_KSYMS
is enabled and that the kernel binary is properly rebuilt accordingly.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-02 14:46:42 -08:00