Series "Handle oom bypass more gracefully", V5
The following 10 patches should put some order to very rare cases of mm
shared between processes and make the paths which bypass the oom killer
oom reapable and therefore much more reliable finally. Even though mm
shared outside of thread group is rare (either vforked tasks for a short
period, use_mm by kernel threads or exotic thread model of
clone(CLONE_VM) without CLONE_SIGHAND) it is better to cover them. Not
only it makes the current oom killer logic quite hard to follow and
reason about it can lead to weird corner cases. E.g. it is possible to
select an oom victim which shares the mm with unkillable process or
bypass the oom killer even when other processes sharing the mm are still
alive and other weird cases.
Patch 1 drops bogus task_lock and mm check from oom_{score_}adj_write.
This can be considered a bug fix with a low impact as nobody has noticed
for years.
Patch 2 drops sighand lock because it is not needed anymore as pointed
by Oleg.
Patch 3 is a clean up of oom_score_adj handling and a preparatory work
for later patches.
Patch 4 enforces oom_adj_score to be consistent between processes
sharing the mm to behave consistently with the regular thread groups.
This can be considered a user visible behavior change because one thread
group updating oom_score_adj will affect others which share the same mm
via clone(CLONE_VM). I argue that this should be acceptable because we
already have the same behavior for threads in the same thread group and
sharing the mm without signal struct is just a different model of
threading. This is probably the most controversial part of the series,
I would like to find some consensus here. There were some suggestions
to hook some counter/oom_score_adj into the mm_struct but I feel that
this is not necessary right now and we can rely on proc handler +
oom_kill_process to DTRT. I can be convinced otherwise but I strongly
think that whatever we do the userspace has to have a way to see the
current oom priority as consistently as possible.
Patch 5 makes sure that no vforked task is selected if it is sharing the
mm with oom unkillable task.
Patch 6 ensures that all user tasks sharing the mm are killed which in
turn makes sure that all oom victims are oom reapable.
Patch 7 guarantees that task_will_free_mem will always imply reapable
bypass of the oom killer.
Patch 8 is new in this version and it addresses an issue pointed out by
0-day OOM report where an oom victim was reaped several times.
Patch 9 puts an upper bound on how many times oom_reaper tries to reap a
task and hides it from the oom killer to move on when no progress can be
made. This will give an upper bound to how long an oom_reapable task
can block the oom killer from selecting another victim if the oom_reaper
is not able to reap the victim.
Patch 10 tries to plug the (hopefully) last hole when we can still lock
up when the oom victim is shared with oom unkillable tasks (kthreads and
global init). We just try to be best effort in that case and rather
fallback to kill something else than risk a lockup.
This patch (of 10):
Both oom_adj_write and oom_score_adj_write are using task_lock, check for
task->mm and fail if it is NULL. This is not needed because the
oom_score_adj is per signal struct so we do not need mm at all. The code
has been introduced by 3d5992d2ac ("oom: add per-mm oom disable count")
but we do not do per-mm oom disable since c9f01245b6 ("oom: remove
oom_disable_count").
The task->mm check is even not correct because the current thread might
have exited but the thread group might be still alive - e.g. thread group
leader would lead that echo $VAL > /proc/pid/oom_score_adj would always
fail with EINVAL while /proc/pid/task/$other_tid/oom_score_adj would
succeed. This is unexpected at best.
Remove the lock along with the check to fix the unexpected behavior and
also because there is not real need for the lock in the first place.
Link: http://lkml.kernel.org/r/1466426628-15074-2-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This prevents a double-fetch from user space that can lead to to an
undersized allocation and heap overflow.
Fixes: 54dbc15172 ("vfs: hoist the btrfs deduplication ioctl to the vfs")
Signed-off-by: Scott Bauer <sbauer@plzdonthack.me>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull quota update from Jan Kara:
"time64 support for quota"
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
quota: use time64_t internally
Pull vfs updates from Al Viro:
"Assorted cleanups and fixes.
Probably the most interesting part long-term is ->d_init() - that will
have a bunch of followups in (at least) ceph and lustre, but we'll
need to sort the barrier-related rules before it can get used for
really non-trivial stuff.
Another fun thing is the merge of ->d_iput() callers (dentry_iput()
and dentry_unlink_inode()) and a bunch of ->d_compare() ones (all
except the one in __d_lookup_lru())"
* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
fs/dcache.c: avoid soft-lockup in dput()
vfs: new d_init method
vfs: Update lookup_dcache() comment
bdev: get rid of ->bd_inodes
Remove last traces of ->sync_page
new helper: d_same_name()
dentry_cmp(): use lockless_dereference() instead of smp_read_barrier_depends()
vfs: clean up documentation
vfs: document ->d_real()
vfs: merge .d_select_inode() into .d_real()
unify dentry_iput() and dentry_unlink_inode()
binfmt_misc: ->s_root is not going anywhere
drop redundant ->owner initializations
ufs: get rid of redundant checks
orangefs: constify inode_operations
missed comment updates from ->direct_IO() prototype change
file_inode(f)->i_mapping is f->f_mapping
trim fsnotify hooks a bit
9p: new helper - v9fs_parent_fid()
debugfs: ->d_parent is never NULL or negative
...
This changes the vfs dentry hashing to mix in the parent pointer at the
_beginning_ of the hash, rather than at the end.
That actually improves both the hash and the code generation, because we
can move more of the computation to the "static" part of the dcache
setup, and do less at lookup runtime.
It turns out that a lot of other hash users also really wanted to mix in
a base pointer as a 'salt' for the hash, and so the slightly extended
interface ends up working well for other cases too.
Users that want a string hash that is purely about the string pass in a
'salt' pointer of NULL.
* merge branch 'salted-string-hash':
fs/dcache.c: Save one 32-bit multiply in dcache lookup
vfs: make the string hashes salt the hash
A LAYOUTCOMMIT then subsequent GETATTR may both return the same attributes,
and in that case NFS_INO_INVALID_ATTR is never set on the second pass
through nfs_update_inode(). The existing check to skip the clearing of
NFS_INO_INVALID_ATTR if a LAYOUTCOMMIT is outstanding does not help in this
case (see commit 10b7e9ad44: "pNFS: Don't mark the inode as revalidated
if a LAYOUTCOMMIT is outstanding"). We know that if a LAYOUTCOMMIT is
outstanding then attributes will need upating, so always set
NFS_INO_INVALID_ATTR.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
During following a symbolic link we received err_buf from SMB2_open().
While the validity of SMB2 error response is checked previously
in smb2_check_message() a symbolic link payload is not checked at all.
Fix it by adding such checks.
Cc: Dan Carpenter <dan.carpenter@oracle.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
if, when mounting //HOST/share/sub/dir/foo we can query /sub/dir/foo but
not any of the path components above:
- store the /sub/dir/foo prefix in the cifs super_block info
- in the superblock, set root dentry to the subpath dentry (instead of
the share root)
- set a flag in the superblock to remember it
- use prefixpath when building path from a dentry
fixes bso#8950
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>
Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
Now that the generic changes are in place, this can be enabled on m68k
with the use of proper user space accessors in the flat_get_addr_from_rp()
and flat_put_addr_at_rp() handlers as rp actually holds a user space
address.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Let's take the simple and obvious approach by decompressing the binary
into a kernel buffer and then copying it to user space. Those who are
looking for top performance on an MMU system are unlikely to choose this
executable format anyway.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Not much else to do at this point except for the different stack setups.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
This is needed on systems with a MMU. This also gets rid of the
strangest C code I've seen lateli i.e. an integer indexed with a
pointer value within square brackets. That really looked backwards.
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
ceph_llseek does not correctly return NXIO errors because the 'out' path
always returns 'offset'.
Fixes: 06222e491e ("fs: handle SEEK_HOLE/SEEK_DATA properly in all fs's that define their own llseek")
Signed-off-by: Phil Turnbull <phil.turnbull@oracle.com>
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Ceph creates multiple caches with the SLAB_RECLAIMABLE flag set, so
that it can satisfy its internal needs. Inspecting the code shows that
most of the caches are indeed reclaimable since they are directly
related to the generic inode/dentry shrinkers. However, one of the
cache used to satisfy struct file is not reclaimable since its
entries are freed only when the last reference to the file is
dropped. If a heavily loaded node opens a lot of files it can
introduce non-trivial discrepancies between memory shown as reclaimable
and what is actually reclaimed when drop_caches is used.
Fix this by removing the reclaimable flag for the file's cache.
Signed-off-by: Nikolay Borisov <n.borisov.lkml@gmail.com>
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Add a 'wake' flag to ceph_cap_flush struct, which indicates if there
is someone waiting for it to finish. When getting flush ack message,
we check the 'wake' flag in corresponding ceph_cap_flush struct to
decide if we should wake up waiters. One corner case is that the
acked cap flush has 'wake' flags is set, but it is not the first one
on the flushing list. We do not wake up waiters in this case, set
'wake' flags of preceding ceph_cap_flush struct instead
Signed-off-by: Yan, Zheng <zyan@redhat.com>
This patch devide __ceph_flush_snaps() into two stags. In the first
stage, __ceph_flush_snaps() assign snapcaps flush TIDs and add them
to cap flush lists. __ceph_flush_snaps() keeps holding the
i_ceph_lock in this stagge. So inode's auth cap can not change. In
the second stage, __ceph_flush_snaps() send flushsnap cap messages.
i_ceph_lock is unlocked before sending each cap message. If auth cap
changes in the middle, __ceph_flush_snaps() just stops. This is OK
because kick_flushing_inode_caps() will re-send flushsnap cap messages
to inode's new auth MDS.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
make ceph_kick_flushing_caps() ignore inodes whose cap flushes
have already been re-sent by ceph_early_kick_flushing_caps()
Signed-off-by: Yan, Zheng <zyan@redhat.com>
This patch includes following changes
- Assign flush tid to snapcap flush
- Remove session's s_cap_snaps_flushing list. Add inode to session's
s_cap_flushing list instead. Inode is removed from the list when
there is no pending snapcap flush or cap flush.
- make __kick_flushing_caps() re-send both snapcap flushes and cap
flushes.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
We don't have requirement of searching cap flush by TID. In most cases,
we just need to know TID of the oldest cap flush. List is ideal for this
usage.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
To mount non-default filesytem, user currently needs to provide mds
namespace ID. This is inconvenience.
This patch makes user be able to mount filesystem by name. If user
wants to mount non-default filesystem. Client first subscribes to
fsmap.user. Subscribe to mdsmap.<ID> after getting ID of filesystem.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
We can now handle the snapshot cases under RCU, as well as the
non-snapshot case when we don't need to queue up a lease renewal
allow LOOKUP_RCU walks to proceed under those conditions.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
Under rcuwalk, we need to take extra care when dereferencing d_parent.
We want to do that once and pass a pointer to dentry_lease_is_valid.
Also, we must ensure that that function can handle the case where we're
racing with d_release. Check whether "di" is NULL under the d_lock, and
just return 0 if so.
Finally, we still need to kick off a renewal job if the lease is getting
close to expiration. If that's the case, then just drop out of rcuwalk
mode since that could block.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
To check for a valid dentry lease, we need to get at the
ceph_dentry_info. Under rcuwalk though, we may end up with a dentry that
is on its way to destruction. Since we need to take the d_lock in
dentry_lease_is_valid already, we can just ensure that we clear the
d_fsinfo pointer out under the same lock before destroying it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
This patch adds codes that decode pool namespace information in
cap message and request reply. Pool namespace is saved in i_layout,
it will be passed to libceph when doing read/write.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Add pool namesapce pointer to struct ceph_file_layout and struct
ceph_object_locator. Pool namespace is used by when mapping object
to PG, it's also used when composing OSD request.
The namespace pointer in struct ceph_file_layout is RCU protected.
So libceph can read namespace without taking lock.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
[idryomov@gmail.com: ceph_oloc_destroy(), misc minor changes]
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Define new ceph_file_layout structure and rename old ceph_file_layout
to ceph_file_layout_legacy. This is preparation for adding namespace
to ceph_file_layout structure.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
An on-stack oid in ceph_ioctl_get_dataloc() is not initialized,
resulting in a WARN and a NULL pointer dereference later on. We will
have more of these on-stack in the future, so fix it with a convenience
macro.
Fixes: d30291b985 ("libceph: variable-sized ceph_object_id")
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Pull networking updates from David Miller:
1) Unified UDP encapsulation offload methods for drivers, from
Alexander Duyck.
2) Make DSA binding more sane, from Andrew Lunn.
3) Support QCA9888 chips in ath10k, from Anilkumar Kolli.
4) Several workqueue usage cleanups, from Bhaktipriya Shridhar.
5) Add XDP (eXpress Data Path), essentially running BPF programs on RX
packets as soon as the device sees them, with the option to mirror
the packet on TX via the same interface. From Brenden Blanco and
others.
6) Allow qdisc/class stats dumps to run lockless, from Eric Dumazet.
7) Add VLAN support to b53 and bcm_sf2, from Florian Fainelli.
8) Simplify netlink conntrack entry layout, from Florian Westphal.
9) Add ipv4 forwarding support to mlxsw spectrum driver, from Ido
Schimmel, Yotam Gigi, and Jiri Pirko.
10) Add SKB array infrastructure and convert tun and macvtap over to it.
From Michael S Tsirkin and Jason Wang.
11) Support qdisc packet injection in pktgen, from John Fastabend.
12) Add neighbour monitoring framework to TIPC, from Jon Paul Maloy.
13) Add NV congestion control support to TCP, from Lawrence Brakmo.
14) Add GSO support to SCTP, from Marcelo Ricardo Leitner.
15) Allow GRO and RPS to function on macsec devices, from Paolo Abeni.
16) Support MPLS over IPV4, from Simon Horman.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1622 commits)
xgene: Fix build warning with ACPI disabled.
be2net: perform temperature query in adapter regardless of its interface state
l2tp: Correctly return -EBADF from pppol2tp_getname.
net/mlx5_core/health: Remove deprecated create_singlethread_workqueue
net: ipmr/ip6mr: update lastuse on entry change
macsec: ensure rx_sa is set when validation is disabled
tipc: dump monitor attributes
tipc: add a function to get the bearer name
tipc: get monitor threshold for the cluster
tipc: make cluster size threshold for monitoring configurable
tipc: introduce constants for tipc address validation
net: neigh: disallow transition to NUD_STALE if lladdr is unchanged in neigh_update()
MAINTAINERS: xgene: Add driver and documentation path
Documentation: dtb: xgene: Add MDIO node
dtb: xgene: Add MDIO node
drivers: net: xgene: ethtool: Use phy_ethtool_gset and sset
drivers: net: xgene: Use exported functions
drivers: net: xgene: Enable MDIO driver
drivers: net: xgene: Add backward compatibility
drivers: net: phy: xgene: Add MDIO driver
...
Pull dlm updates from David Teigland:
"This set includes two trivial changes, one to use kmemdup and another
to control the log level of recovery messages"
* tag 'dlm-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
dlm: Use kmemdup instead of kmalloc and memcpy
dlm: add log_info config option
Pull f2fs updates from Jaegeuk Kim:
"The major change in this version is mitigating cpu overheads on write
paths by replacing redundant inode page updates with mark_inode_dirty
calls. And we tried to reduce lock contentions as well to improve
filesystem scalability. Other feature is setting F2FS automatically
when detecting host-managed SMR.
Enhancements:
- ioctl to move a range of data between files
- inject orphan inode errors
- avoid flush commands congestion
- support lazytime
Bug fixes:
- return proper results for some dentry operations
- fix deadlock in add_link failure
- disable extent_cache for fcollapse/finsert"
* tag 'for-f2fs-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (68 commits)
f2fs: clean up coding style and redundancy
f2fs: get victim segment again after new cp
f2fs: handle error case with f2fs_bug_on
f2fs: avoid data race when deciding checkpoin in f2fs_sync_file
f2fs: support an ioctl to move a range of data blocks
f2fs: fix to report error number of f2fs_find_entry
f2fs: avoid memory allocation failure due to a long length
f2fs: reset default idle interval value
f2fs: use blk_plug in all the possible paths
f2fs: fix to avoid data update racing between GC and DIO
f2fs: add maximum prefree segments
f2fs: disable extent_cache for fcollapse/finsert inodes
f2fs: refactor __exchange_data_block for speed up
f2fs: fix ERR_PTR returned by bio
f2fs: avoid mark_inode_dirty
f2fs: move i_size_write in f2fs_write_end
f2fs: fix to avoid redundant discard during fstrim
f2fs: avoid mismatching block range for discard
f2fs: fix incorrect f_bfree calculation in ->statfs
f2fs: use percpu_rw_semaphore
...
Pull xfs updates from Dave Chinner:
"The major addition is the new iomap based block mapping
infrastructure. We've been kicking this about locally for years, but
there are other filesystems want to use it too (e.g. gfs2). Now it
is fully working, reviewed and ready for merge and be used by other
filesystems.
There are a lot of other fixes and cleanups in the tree, but those are
XFS internal things and none are of the scale or visibility of the
iomap changes. See below for details.
I am likely to send another pull request next week - we're just about
ready to merge some new functionality (on disk block->owner reverse
mapping infrastructure), but that's a huge chunk of code (74 files
changed, 7283 insertions(+), 1114 deletions(-)) so I'm keeping that
separate to all the "normal" pull request changes so they don't get
lost in the noise.
Summary of changes in this update:
- generic iomap based IO path infrastructure
- generic iomap based fiemap implementation
- xfs iomap based Io path implementation
- buffer error handling fixes
- tracking of in flight buffer IO for unmount serialisation
- direct IO and DAX io path separation and simplification
- shortform directory format definition changes for wider platform
compatibility
- various buffer cache fixes
- cleanups in preparation for rmap merge
- error injection cleanups and fixes
- log item format buffer memory allocation restructuring to prevent
rare OOM reclaim deadlocks
- sparse inode chunks are now fully supported"
* tag 'xfs-for-linus-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (53 commits)
xfs: remove EXPERIMENTAL tag from sparse inode feature
xfs: bufferhead chains are invalid after end_page_writeback
xfs: allocate log vector buffers outside CIL context lock
libxfs: directory node splitting does not have an extra block
xfs: remove dax code from object file when disabled
xfs: skip dirty pages in ->releasepage()
xfs: remove __arch_pack
xfs: kill xfs_dir2_inou_t
xfs: kill xfs_dir2_sf_off_t
xfs: split direct I/O and DAX path
xfs: direct calls in the direct I/O path
xfs: stop using generic_file_read_iter for direct I/O
xfs: split xfs_file_read_iter into buffered and direct I/O helpers
xfs: remove s_maxbytes enforcement in xfs_file_read_iter
xfs: kill ioflags
xfs: don't pass ioflags around in the ioctl path
xfs: track and serialize in-flight async buffers against unmount
xfs: exclude never-released buffers from buftarg I/O accounting
xfs: don't reset b_retries to 0 on every failure
xfs: remove extraneous buffer flag changes
...
Merge updates from Andrew Morton:
- a few misc bits
- ocfs2
- most(?) of MM
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (125 commits)
thp: fix comments of __pmd_trans_huge_lock()
cgroup: remove unnecessary 0 check from css_from_id()
cgroup: fix idr leak for the first cgroup root
mm: memcontrol: fix documentation for compound parameter
mm: memcontrol: remove BUG_ON in uncharge_list
mm: fix build warnings in <linux/compaction.h>
mm, thp: convert from optimistic swapin collapsing to conservative
mm, thp: fix comment inconsistency for swapin readahead functions
thp: update Documentation/{vm/transhuge,filesystems/proc}.txt
shmem: split huge pages beyond i_size under memory pressure
thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHE
khugepaged: add support of collapse for tmpfs/shmem pages
shmem: make shmem_inode_info::lock irq-safe
khugepaged: move up_read(mmap_sem) out of khugepaged_alloc_page()
thp: extract khugepaged from mm/huge_memory.c
shmem, thp: respect MADV_{NO,}HUGEPAGE for file mappings
shmem: add huge pages support
shmem: get_unmapped_area align huge page
shmem: prepare huge= mount option and sysfs knob
mm, rmap: account shmem thp pages
...
