Age | Commit message (Collapse) | Author |
|
Pull networking updates from David Miller:
"Highlights:
1) Support TX_RING in AF_PACKET TPACKET_V3 mode, from Sowmini
Varadhan.
2) Simplify classifier state on sk_buff in order to shrink it a bit.
From Willem de Bruijn.
3) Introduce SIPHASH and it's usage for secure sequence numbers and
syncookies. From Jason A. Donenfeld.
4) Reduce CPU usage for ICMP replies we are going to limit or
suppress, from Jesper Dangaard Brouer.
5) Introduce Shared Memory Communications socket layer, from Ursula
Braun.
6) Add RACK loss detection and allow it to actually trigger fast
recovery instead of just assisting after other algorithms have
triggered it. From Yuchung Cheng.
7) Add xmit_more and BQL support to mvneta driver, from Simon Guinot.
8) skb_cow_data avoidance in esp4 and esp6, from Steffen Klassert.
9) Export MPLS packet stats via netlink, from Robert Shearman.
10) Significantly improve inet port bind conflict handling, especially
when an application is restarted and changes it's setting of
reuseport. From Josef Bacik.
11) Implement TX batching in vhost_net, from Jason Wang.
12) Extend the dummy device so that VF (virtual function) features,
such as configuration, can be more easily tested. From Phil
Sutter.
13) Avoid two atomic ops per page on x86 in bnx2x driver, from Eric
Dumazet.
14) Add new bpf MAP, implementing a longest prefix match trie. From
Daniel Mack.
15) Packet sample offloading support in mlxsw driver, from Yotam Gigi.
16) Add new aquantia driver, from David VomLehn.
17) Add bpf tracepoints, from Daniel Borkmann.
18) Add support for port mirroring to b53 and bcm_sf2 drivers, from
Florian Fainelli.
19) Remove custom busy polling in many drivers, it is done in the core
networking since 4.5 times. From Eric Dumazet.
20) Support XDP adjust_head in virtio_net, from John Fastabend.
21) Fix several major holes in neighbour entry confirmation, from
Julian Anastasov.
22) Add XDP support to bnxt_en driver, from Michael Chan.
23) VXLAN offloads for enic driver, from Govindarajulu Varadarajan.
24) Add IPVTAP driver (IP-VLAN based tap driver) from Sainath Grandhi.
25) Support GRO in IPSEC protocols, from Steffen Klassert"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1764 commits)
Revert "ath10k: Search SMBIOS for OEM board file extension"
net: socket: fix recvmmsg not returning error from sock_error
bnxt_en: use eth_hw_addr_random()
bpf: fix unlocking of jited image when module ronx not set
arch: add ARCH_HAS_SET_MEMORY config
net: napi_watchdog() can use napi_schedule_irqoff()
tcp: Revert "tcp: tcp_probe: use spin_lock_bh()"
net/hsr: use eth_hw_addr_random()
net: mvpp2: enable building on 64-bit platforms
net: mvpp2: switch to build_skb() in the RX path
net: mvpp2: simplify MVPP2_PRS_RI_* definitions
net: mvpp2: fix indentation of MVPP2_EXT_GLOBAL_CTRL_DEFAULT
net: mvpp2: remove unused register definitions
net: mvpp2: simplify mvpp2_bm_bufs_add()
net: mvpp2: drop useless fields in mvpp2_bm_pool and related code
net: mvpp2: remove unused 'tx_skb' field of 'struct mvpp2_tx_queue'
net: mvpp2: release reference to txq_cpu[] entry after unmapping
net: mvpp2: handle too large value in mvpp2_rx_time_coal_set()
net: mvpp2: handle too large value handling in mvpp2_rx_pkts_coal_set()
net: mvpp2: remove useless arguments in mvpp2_rx_{pkts, time}_coal_set
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull usercopy test updates from Kees Cook:
"This improves the usercopy tests:
- check zeroing on failed copy_from_user()/get_user() (caught bug on
ARM)
- adjust tests for SMAP/PAN (can't zero userspace memory on failure)"
* tag 'usercopy-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
usercopy: Add tests for all get_user() sizes
usercopy: Adjust tests to deal with SMAP/PAN
usercopy: add testcases to check zeroing on failure
|
|
The existing test was only exercising native unsigned long size
get_user(). For completeness, we should check all sizes. But we
must skip some 32-bit architectures that don't implement a 64-bit
get_user().
These new tests actually uncovered a bug in ARM's 64-bit get_user()
zeroing.
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
Pull block layer updates from Jens Axboe:
- blk-mq scheduling framework from me and Omar, with a port of the
deadline scheduler for this framework. A port of BFQ from Paolo is in
the works, and should be ready for 4.12.
- Various fixups and improvements to the above scheduling framework
from Omar, Paolo, Bart, me, others.
- Cleanup of the exported sysfs blk-mq data into debugfs, from Omar.
This allows us to export more information that helps debug hangs or
performance issues, without cluttering or abusing the sysfs API.
- Fixes for the sbitmap code, the scalable bitmap code that was
migrated from blk-mq, from Omar.
- Removal of the BLOCK_PC support in struct request, and refactoring of
carrying SCSI payloads in the block layer. This cleans up the code
nicely, and enables us to kill the SCSI specific parts of struct
request, shrinking it down nicely. From Christoph mainly, with help
from Hannes.
- Support for ranged discard requests and discard merging, also from
Christoph.
- Support for OPAL in the block layer, and for NVMe as well. Mainly
from Scott Bauer, with fixes/updates from various others folks.
- Error code fixup for gdrom from Christophe.
- cciss pci irq allocation cleanup from Christoph.
- Making the cdrom device operations read only, from Kees Cook.
- Fixes for duplicate bdi registrations and bdi/queue life time
problems from Jan and Dan.
- Set of fixes and updates for lightnvm, from Matias and Javier.
- A few fixes for nbd from Josef, using idr to name devices and a
workqueue deadlock fix on receive. Also marks Josef as the current
maintainer of nbd.
- Fix from Josef, overwriting queue settings when the number of
hardware queues is updated for a blk-mq device.
- NVMe fix from Keith, ensuring that we don't repeatedly mark and IO
aborted, if we didn't end up aborting it.
- SG gap merging fix from Ming Lei for block.
- Loop fix also from Ming, fixing a race and crash between setting loop
status and IO.
- Two block race fixes from Tahsin, fixing request list iteration and
fixing a race between device registration and udev device add
notifiations.
- Double free fix from cgroup writeback, from Tejun.
- Another double free fix in blkcg, from Hou Tao.
- Partition overflow fix for EFI from Alden Tondettar.
* tag 'for-4.11/linus-merge-signed' of git://git.kernel.dk/linux-block: (156 commits)
nvme: Check for Security send/recv support before issuing commands.
block/sed-opal: allocate struct opal_dev dynamically
block/sed-opal: tone down not supported warnings
block: don't defer flushes on blk-mq + scheduling
blk-mq-sched: ask scheduler for work, if we failed dispatching leftovers
blk-mq: don't special case flush inserts for blk-mq-sched
blk-mq-sched: don't add flushes to the head of requeue queue
blk-mq: have blk_mq_dispatch_rq_list() return if we queued IO or not
block: do not allow updates through sysfs until registration completes
lightnvm: set default lun range when no luns are specified
lightnvm: fix off-by-one error on target initialization
Maintainers: Modify SED list from nvme to block
Move stack parameters for sed_ioctl to prevent oversized stack with CONFIG_KASAN
uapi: sed-opal fix IOW for activate lsp to use correct struct
cdrom: Make device operations read-only
elevator: fix loading wrong elevator type for blk-mq devices
cciss: switch to pci_irq_alloc_vectors
block/loop: fix race between I/O and set_status
blk-mq-sched: don't hold queue_lock when calling exit_icq
block: set make_request_fn manually in blk_mq_update_nr_hw_queues
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"For this cycle we add support for the shutdown ioctl, which is
primarily used for testing, but which can be useful on production
systems when a scratch volume is being destroyed and the data on it
doesn't need to be saved.
This found (and we fixed) a number of bugs with ext4's recovery to
corrupted file system --- the bugs increased the amount of data that
could be potentially lost, and in the case of the inline data feature,
could cause the kernel to BUG.
Also included are a number of other bug fixes, including in ext4's
fscrypt, DAX, inline data support"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (26 commits)
ext4: rename EXT4_IOC_GOINGDOWN to EXT4_IOC_SHUTDOWN
ext4: fix fencepost in s_first_meta_bg validation
ext4: don't BUG when truncating encrypted inodes on the orphan list
ext4: do not use stripe_width if it is not set
ext4: fix stripe-unaligned allocations
dax: assert that i_rwsem is held exclusive for writes
ext4: fix DAX write locking
ext4: add EXT4_IOC_GOINGDOWN ioctl
ext4: add shutdown bit and check for it
ext4: rename s_resize_flags to s_ext4_flags
ext4: return EROFS if device is r/o and journal replay is needed
ext4: preserve the needs_recovery flag when the journal is aborted
jbd2: don't leak modified metadata buffers on an aborted journal
ext4: fix inline data error paths
ext4: move halfmd4 into hash.c directly
ext4: fix use-after-iput when fscrypt contexts are inconsistent
jbd2: fix use after free in kjournald2()
ext4: fix data corruption in data=journal mode
ext4: trim allocation requests to group size
ext4: replace BUG_ON with WARN_ON in mb_find_extent()
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"The main changes in this cycle were:
- Implement wraparound-safe refcount_t and kref_t types based on
generic atomic primitives (Peter Zijlstra)
- Improve and fix the ww_mutex code (Nicolai Hähnle)
- Add self-tests to the ww_mutex code (Chris Wilson)
- Optimize percpu-rwsems with the 'rcuwait' mechanism (Davidlohr
Bueso)
- Micro-optimize the current-task logic all around the core kernel
(Davidlohr Bueso)
- Tidy up after recent optimizations: remove stale code and APIs,
clean up the code (Waiman Long)
- ... plus misc fixes, updates and cleanups"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits)
fork: Fix task_struct alignment
locking/spinlock/debug: Remove spinlock lockup detection code
lockdep: Fix incorrect condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS
lkdtm: Convert to refcount_t testing
kref: Implement 'struct kref' using refcount_t
refcount_t: Introduce a special purpose refcount type
sched/wake_q: Clarify queue reinit comment
sched/wait, rcuwait: Fix typo in comment
locking/mutex: Fix lockdep_assert_held() fail
locking/rtmutex: Flip unlikely() branch to likely() in __rt_mutex_slowlock()
locking/rwsem: Reinit wake_q after use
locking/rwsem: Remove unnecessary atomic_long_t casts
jump_labels: Move header guard #endif down where it belongs
locking/atomic, kref: Implement kref_put_lock()
locking/ww_mutex: Turn off __must_check for now
locking/atomic, kref: Avoid more abuse
locking/atomic, kref: Use kref_get_unless_zero() more
locking/atomic, kref: Kill kref_sub()
locking/atomic, kref: Add kref_read()
locking/atomic, kref: Add KREF_INIT()
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
"The RCU changes in this cycle are:
- Dynticks updates, consolidating open-coded counter accesses into a
well-defined API
- SRCU updates: Simplify algorithm, add formal verification
- Documentation updates
- Miscellaneous fixes
- Torture-test updates
Most of the diffstat comes from the relatively large documentation
update"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
srcu: Reduce probability of SRCU ->unlock_count[] counter overflow
rcutorture: Add CBMC-based formal verification for SRCU
srcu: Force full grace-period ordering
srcu: Implement more-efficient reader counts
rcu: Adjust FQS offline checks for exact online-CPU detection
rcu: Check cond_resched_rcu_qs() state less often to reduce GP overhead
rcu: Abstract extended quiescent state determination
rcu: Abstract dynticks extended quiescent state enter/exit operations
rcu: Add lockdep checks to synchronous expedited primitives
rcu: Eliminate unused expedited_normal counter
llist: Clarify comments about when locking is needed
rcu: Fix comment in rcu_organize_nocb_kthreads()
rcu: Enable RCU tracepoints by default to aid in debugging
rcu: Make rcu_cpu_starting() use its "cpu" argument
rcu: Add comment headers to expedited-grace-period counter functions
rcu: Don't wake rcuc/X kthreads on NOCB CPUs
rcu: Re-enable TASKS_RCU for User Mode Linux
rcu: Once again use NMI-based stack traces in stall warnings
rcu: Remove short-term CPU kicking
rcu: Add long-term CPU kicking
...
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull debugobjects updates from Ingo Molnar:
"A number of scalability improvements by Waimang Long"
* 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
debugobjects: Improve variable naming
debugobjects: Reduce contention on the global pool_lock
debugobjects: Scale thresholds with # of CPUs
debugobjects: Track number of kmem_cache_alloc/kmem_cache_free done
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
"Nothing exciting, just the usual pile of fixes, updates and cleanups:
- A bunch of clocksource driver updates
- Removal of CONFIG_TIMER_STATS and the related /proc file
- More posix timer slim down work
- A scalability enhancement in the tick broadcast code
- Math cleanups"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
hrtimer: Catch invalid clockids again
math64, tile: Fix build failure
clocksource/drivers/arm_arch_timer:: Mark cyclecounter __ro_after_init
timerfd: Protect the might cancel mechanism proper
timer_list: Remove useless cast when printing
time: Remove CONFIG_TIMER_STATS
clocksource/drivers/arm_arch_timer: Work around Hisilicon erratum 161010101
clocksource/drivers/arm_arch_timer: Introduce generic errata handling infrastructure
clocksource/drivers/arm_arch_timer: Remove fsl-a008585 parameter
clocksource/drivers/arm_arch_timer: Add dt binding for hisilicon-161010101 erratum
clocksource/drivers/ostm: Add renesas-ostm timer driver
clocksource/drivers/ostm: Document renesas-ostm timer DT bindings
clocksource/drivers/tcb_clksrc: Use 32 bit tcb as sched_clock
clocksource/drivers/gemini: Add driver for the Cortina Gemini
clocksource: add DT bindings for Cortina Gemini
clockevents: Add a clkevt-of mechanism like clksrc-of
tick/broadcast: Reduce lock cacheline contention
timers: Omit POSIX timer stuff from task_struct when disabled
x86/timer: Make delay() work during early bootup
delay: Add explanation of udelay() inaccuracy
...
|
|
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
This patch adds code that handles GFP_ATOMIC kmalloc failure on
insertion. As we cannot use vmalloc, we solve it by making our
hash table nested. That is, we allocate single pages at each level
and reach our desired table size by nesting them.
When a nested table is created, only a single page is allocated
at the top-level. Lower levels are allocated on demand during
insertion. Therefore for each insertion to succeed, only two
(non-consecutive) pages are needed.
After a nested table is created, a rehash will be scheduled in
order to switch to a vmalloced table as soon as possible. Also,
the rehash code will never rehash into a nested table. If we
detect a nested table during a rehash, the rehash will be aborted
and a new rehash will be scheduled.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Under SMAP/PAN/etc, we cannot write directly to userspace memory, so
this rearranges the test bytes to get written through copy_to_user().
Additionally drops the bad copy_from_user() test that would trigger a
memcpy() against userspace on failure.
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
During usercopy the destination buffer will be zeroed if copy_from_user()
or get_user() fails. This patch adds testcases for it. The destination
buffer is set with non-zero value before illegal copy_from_user() or
get_user() is executed and the buffer is compared to zero after usercopy
is done.
Signed-off-by: Hoeun Ryu <hoeun.ryu@gmail.com>
[kees: clarified commit log, dropped second kmalloc]
Signed-off-by: Kees Cook <keescook@chromium.org>
|
|
Currently CONFIG_TIMER_STATS exposes process information across namespaces:
kernel/time/timer_list.c print_timer():
SEQ_printf(m, ", %s/%d", tmp, timer->start_pid);
/proc/timer_list:
#11: <0000000000000000>, hrtimer_wakeup, S:01, do_nanosleep, cron/2570
Given that the tracer can give the same information, this patch entirely
removes CONFIG_TIMER_STATS.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: linux-doc@vger.kernel.org
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Xing Gao <xgao01@email.wm.edu>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jessica Frazelle <me@jessfraz.com>
Cc: kernel-hardening@lists.openwall.com
Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Michal Marek <mmarek@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-api@vger.kernel.org
Cc: Arjan van de Ven <arjan@linux.intel.com>
Link: http://lkml.kernel.org/r/20170208192659.GA32582@beast
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
As suggested by Ingo, the debug_objects_alloc counter is now renamed to
debug_objects_allocated with minor twist in comment and debug output.
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1486503630-1501-1-git-send-email-longman@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Provide refcount_t, an atomic_t like primitive built just for
refcounting.
It provides saturation semantics such that overflow becomes impossible
and thereby 'spurious' use-after-free is avoided.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
On a large SMP system with many CPUs, the global pool_lock may become
a performance bottleneck as all the CPUs that need to allocate or
free debug objects have to take the lock. That can sometimes cause
soft lockups like:
NMI watchdog: BUG: soft lockup - CPU#35 stuck for 22s! [rcuos/1:21]
...
RIP: 0010:[<ffffffff817c216b>] [<ffffffff817c216b>]
_raw_spin_unlock_irqrestore+0x3b/0x60
...
Call Trace:
[<ffffffff813f40d1>] free_object+0x81/0xb0
[<ffffffff813f4f33>] debug_check_no_obj_freed+0x193/0x220
[<ffffffff81101a59>] ? trace_hardirqs_on_caller+0xf9/0x1c0
[<ffffffff81284996>] ? file_free_rcu+0x36/0x60
[<ffffffff81251712>] kmem_cache_free+0xd2/0x380
[<ffffffff81284960>] ? fput+0x90/0x90
[<ffffffff81284996>] file_free_rcu+0x36/0x60
[<ffffffff81124c23>] rcu_nocb_kthread+0x1b3/0x550
[<ffffffff81124b71>] ? rcu_nocb_kthread+0x101/0x550
[<ffffffff81124a70>] ? sync_exp_work_done.constprop.63+0x50/0x50
[<ffffffff810c59d1>] kthread+0x101/0x120
[<ffffffff81101a59>] ? trace_hardirqs_on_caller+0xf9/0x1c0
[<ffffffff817c2d32>] ret_from_fork+0x22/0x50
To reduce the amount of contention on the pool_lock, the actual
kmem_cache_free() of the debug objects will be delayed if the pool_lock
is busy. This will temporarily increase the amount of free objects
available at the free pool when the system is busy. As a result,
the number of kmem_cache allocation and freeing is reduced.
To further reduce the lock operations free debug objects in batches of
four.
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "Du Changbin" <changbin.du@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Stancek <jstancek@redhat.com>
Link: http://lkml.kernel.org/r/1483647425-4135-4-git-send-email-longman@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
On a large SMP systems with hundreds of CPUs, the current thresholds
for allocating and freeing debug objects (256 and 1024 respectively)
may not work well. This can cause a lot of needless calls to
kmem_aloc() and kmem_free() on those systems.
To alleviate this thrashing problem, the object freeing threshold
is now increased to "1024 + # of CPUs * 32". Whereas the object
allocation threshold is increased to "256 + # of CPUs * 4". That
should make the debug objects subsystem scale better with the number
of CPUs available in the system.
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "Du Changbin" <changbin.du@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Stancek <jstancek@redhat.com>
Link: http://lkml.kernel.org/r/1483647425-4135-3-git-send-email-longman@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
New debugfs stat counters are added to track the numbers of
kmem_cache_alloc() and kmem_cache_free() function calls to get a
sense of how the internal debug objects cache management is performing.
Signed-off-by: Waiman Long <longman@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "Du Changbin" <changbin.du@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Stancek <jstancek@redhat.com>
Link: http://lkml.kernel.org/r/1483647425-4135-2-git-send-email-longman@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
This introduces a infrastructure for management of linear priority
areas. Priority order in an array matters, however order of items inside
a priority group does not matter.
As an initial implementation, L-sort algorithm is used. It is quite
trivial. More advanced algorithm called P-sort will be introduced as a
follow-up. The infrastructure is prepared for other algos.
Alongside this, a testing module is introduced as well.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
The "half md4" transform should not be used by any new code. And
fortunately, it's only used now by ext4. Since ext4 supports several
hashing methods, at some point it might be desirable to move to
something like SipHash. As an intermediate step, remove half md4 from
cryptohash.h and lib, and make it just a local function in ext4's
hash.c. There's precedent for doing this; the other function ext can use
for its hashes -- TEA -- is also implemented in the same place. Also, by
being a local function, this might allow gcc to perform some additional
optimizations.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU changes from Paul E. McKenney:
- Dynticks updates, consolidating open-coded counter accesses into a well-defined API
- SRCU updates: Simplify algorithm, add formal verification
- Documentation updates
- Miscellaneous fixes
- Torture-test updates
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Two trivial overlapping changes conflicts in MPLS and mlx5.
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
This is useful debugging information that will be used in the blk-mq
debugfs directory.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Changed 'weight' to 'busy'.
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
Recently, I've found cases in which ioremap_page_range was used
incorrectly, in external modules, leading to crashes. This can be
partly attributed to the fact that ioremap_page_range is lower-level,
with fewer protections, as compared to the other functions that an
external module would typically call. Those include:
ioremap_cache
ioremap_nocache
ioremap_prot
ioremap_uc
ioremap_wc
ioremap_wt
...each of which wraps __ioremap_caller, which in turn provides a safer
way to achieve the mapping.
Therefore, stop EXPORT-ing ioremap_page_range.
Link: http://lkml.kernel.org/r/1485173220-29010-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Suggested-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The newly introduced warning in radix_tree_free_nodes() was testing the
wrong variable; it should have been 'old' instead of 'node'.
Fixes: ea07b862ac8e ("mm: workingset: fix use-after-free in shadow node shrinker")
Link: http://lkml.kernel.org/r/20170118163746.GA32495@cmpxchg.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
While debugging a performance issue I needed to understand why
RCU sofitrqs were firing so frequently.
Unfortunately, the RCU callback tracepoints are hidden behind
CONFIG_RCU_TRACE which defaults to off in the upstream kernel and is
likely to also be disabled in enterprise distribution configs.
Enable it by default for CONFIG_TREE_RCU. However, we must keep it
disabled for tiny RCU, because it would otherwise pull in a large
amount of code that would make tiny RCU less than tiny.
I ran some file system metadata intensive workloads (git checkout,
FS-Mark) on a variety of machines with this patch and saw no
detectable change in performance.
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
|
|
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/0d5cf199ac43792df0b6f7e2145545c30fa1dbbe.1482222135.git.geliangtang@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
When we resize a struct sbitmap_queue, we update the wakeup batch size,
but we don't update the wait count in the struct sbq_wait_states. If we
resized down from a size which could use a bigger batch size, these
counts could be too large and cause us to miss necessary wakeups. To fix
this, update the wait counts when we resize (ensuring some careful
memory ordering so that it's safe w.r.t. concurrent clears).
This also fixes a theoretical issue where two threads could end up
bumping the wait count up by the batch size, which could also
potentially lead to hangs.
Reported-by: Martin Raiber <martin@urbackup.org>
Fixes: e3a2b3f931f5 ("blk-mq: allow changing of queue depth through sysfs")
Fixes: 2971c35f3588 ("blk-mq: bitmap tag: fix race on blk_mq_bitmap_tags::wake_cnt")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
We always do an atomic clear_bit() right before we call sbq_wake_up(),
so we can use smp_mb__after_atomic(). While we're here, comment the
memory barriers in here a little more.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
|
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb
Pull swiotlb fix from Konrad Rzeszutek Wilk:
"A tiny fix to make sure that page-sized mappings are page-aligned (and
not say straddle two pages). This is important for some drivers (such
as NVME)"
* 'stable/for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb:
swiotlb: ensure that page-sized mappings are page-aligned
|
|
Some drivers do depend on page mappings to be page aligned.
Swiotlb already enforces such alignment for mappings greater than page,
extend that to page-sized mappings as well.
Without this fix, nvme hits BUG() in nvme_setup_prps(), because that routine
assumes page-aligned mappings.
Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Konrad Rzeszutek Wilk <konrad@kernel.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro.
The most notable fix here is probably the fix for a splice regression
("fix a fencepost error in pipe_advance()") noticed by Alan Wylie.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fix a fencepost error in pipe_advance()
coredump: Ensure proper size of sparse core files
aio: fix lock dep warning
tmpfs: clear S_ISGID when setting posix ACLs
|
|
The logics in pipe_advance() used to release all buffers past the new
position failed in cases when the number of buffers to release was equal
to pipe->buffers. If that happened, none of them had been released,
leaving pipe full. Worse, it was trivial to trigger and we end up with
pipe full of uninitialized pages. IOW, it's an infoleak.
Cc: stable@vger.kernel.org # v4.9
Reported-by: "Alan J. Wylie" <alan@wylie.me.uk>
Tested-by: "Alan J. Wylie" <alan@wylie.me.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maarten Lankhorst <dev@mblankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161201114711.28697-4-chris@chris-wilson.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Two AF_* families adding entries to the lockdep tables
at the same time.
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
The build of frv allmodconfig was failing with the errors like:
/tmp/cc0JSPc3.s: Assembler messages:
/tmp/cc0JSPc3.s:1839: Error: symbol `.LSLT0' is already defined
/tmp/cc0JSPc3.s:1842: Error: symbol `.LASLTP0' is already defined
/tmp/cc0JSPc3.s:1969: Error: symbol `.LELTP0' is already defined
/tmp/cc0JSPc3.s:1970: Error: symbol `.LELT0' is already defined
Commit 866ced950bcd ("kbuild: Support split debug info v4") introduced
splitting the debug info and keeping that in a separate file. Somehow,
the frv-linux gcc did not like that and I am guessing that instead of
splitting it started copying. The first report about this is at:
https://lists.01.org/pipermail/kbuild-all/2015-July/010527.html.
I will try and see if this can work with frv and if still fails I will
open a bug report with gcc. But meanwhile this is the easiest option to
solve build failure of frv.
Fixes: 866ced950bcd ("kbuild: Support split debug info v4")
Link: http://lkml.kernel.org/r/1482062348-5352-1-git-send-email-sudipm.mukherjee@gmail.com
Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
|
|
HalfSipHash, or hsiphash, is a shortened version of SipHash, which
generates 32-bit outputs using a weaker 64-bit key. It has *much* lower
security margins, and shouldn't be used for anything too sensitive, but
it could be used as a hashtable key function replacement, if the output
is never exposed, and if the security requirement is not too high.
The goal is to make this something that performance-critical jhash users
would be willing to use.
On 64-bit machines, HalfSipHash1-3 is slower than SipHash1-3, so we alias
SipHash1-3 to HalfSipHash1-3 on those systems.
64-bit x86_64:
[ 0.509409] test_siphash: SipHash2-4 cycles: 4049181
[ 0.510650] test_siphash: SipHash1-3 cycles: 2512884
[ 0.512205] test_siphash: HalfSipHash1-3 cycles: 3429920
[ 0.512904] test_siphash: JenkinsHash cycles: 978267
So, we map hsiphash() -> SipHash1-3
32-bit x86:
[ 0.509868] test_siphash: SipHash2-4 cycles: 14812892
[ 0.513601] test_siphash: SipHash1-3 cycles: 9510710
[ 0.515263] test_siphash: HalfSipHash1-3 cycles: 3856157
[ 0.515952] test_siphash: JenkinsHash cycles: 1148567
So, we map hsiphash() -> HalfSipHash1-3
hsiphash() is roughly 3 times slower than jhash(), but comes with a
considerable security improvement.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
SipHash is a 64-bit keyed hash function that is actually a
cryptographically secure PRF, like HMAC. Except SipHash is super fast,
and is meant to be used as a hashtable keyed lookup function, or as a
general PRF for short input use cases, such as sequence numbers or RNG
chaining.
For the first usage:
There are a variety of attacks known as "hashtable poisoning" in which an
attacker forms some data such that the hash of that data will be the
same, and then preceeds to fill up all entries of a hashbucket. This is
a realistic and well-known denial-of-service vector. Currently
hashtables use jhash, which is fast but not secure, and some kind of
rotating key scheme (or none at all, which isn't good). SipHash is meant
as a replacement for jhash in these cases.
There are a modicum of places in the kernel that are vulnerable to
hashtable poisoning attacks, either via userspace vectors or network
vectors, and there's not a reliable mechanism inside the kernel at the
moment to fix it. The first step toward fixing these issues is actually
getting a secure primitive into the kernel for developers to use. Then
we can, bit by bit, port things over to it as deemed appropriate.
While SipHash is extremely fast for a cryptographically secure function,
it is likely a bit slower than the insecure jhash, and so replacements
will be evaluated on a case-by-case basis based on whether or not the
difference in speed is negligible and whether or not the current jhash usage
poses a real security risk.
For the second usage:
A few places in the kernel are using MD5 or SHA1 for creating secure
sequence numbers, syn cookies, port numbers, or fast random numbers.
SipHash is a faster and more fitting, and more secure replacement for MD5
in those situations. Replacing MD5 and SHA1 with SipHash for these uses is
obvious and straight-forward, and so is submitted along with this patch
series. There shouldn't be much of a debate over its efficacy.
Dozens of languages are already using this internally for their hash
tables and PRFs. Some of the BSDs already use this in their kernels.
SipHash is a widely known high-speed solution to a widely known set of
problems, and it's time we catch-up.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Several people report seeing warnings about inconsistent radix tree
nodes followed by crashes in the workingset code, which all looked like
use-after-free access from the shadow node shrinker.
Dave Jones managed to reproduce the issue with a debug patch applied,
which confirmed that the radix tree shrinking indeed frees shadow nodes
while they are still linked to the shadow LRU:
WARNING: CPU: 2 PID: 53 at lib/radix-tree.c:643 delete_node+0x1e4/0x200
CPU: 2 PID: 53 Comm: kswapd0 Not tainted 4.10.0-rc2-think+ #3
Call Trace:
delete_node+0x1e4/0x200
__radix_tree_delete_node+0xd/0x10
shadow_lru_isolate+0xe6/0x220
__list_lru_walk_one.isra.4+0x9b/0x190
list_lru_walk_one+0x23/0x30
scan_shadow_nodes+0x2e/0x40
shrink_slab.part.44+0x23d/0x5d0
shrink_node+0x22c/0x330
kswapd+0x392/0x8f0
This is the WARN_ON_ONCE(!list_empty(&node->private_list)) placed in the
inlined radix_tree_shrink().
The problem is with 14b468791fa9 ("mm: workingset: move shadow entry
tracking to radix tree exceptional tracking"), which passes an update
callback into the radix tree to link and unlink shadow leaf nodes when
tree entries change, but forgot to pass the callback when reclaiming a
shadow node.
While the reclaimed shadow node itself is unlinked by the shrinker, its
deletion from the tree can cause the left-most leaf node in the tree to
be shrunk. If that happens to be a shadow node as well, we don't unlink
it from the LRU as we should.
Consider this tree, where the s are shadow entries:
root->rnode
|
[0 n]
| |
[s ] [sssss]
Now the shadow node shrinker reclaims the rightmost leaf node through
the shadow node LRU:
root->rnode
|
[0 ]
|
[s ]
Because the parent of the deleted node is the first level below the
root and has only one child in the left-most slot, the intermediate
level is shrunk and the node containing the single shadow is put in
its place:
root->rnode
|
[s ]
The shrinker again sees a single left-most slot in a first level node
and thus decides to store the shadow in root->rnode directly and free
the node - which is a leaf node on the shadow node LRU.
root->rnode
|
s
Without the update callback, the freed node remains on the shadow LRU,
where it causes later shrinker runs to crash.
Pass the node updater callback into __radix_tree_delete_node() in case
the deletion causes the left-most branch in the tree to collapse too.
Also add warnings when linked nodes are freed right away, rather than
wait for the use-after-free when the list is scanned much later.
Fixes: 14b468791fa9 ("mm: workingset: move shadow entry tracking to radix tree exceptional tracking")
Reported-by: Dave Chinner <david@fromorbit.com>
Reported-by: Hugh Dickins <hughd@google.com>
Reported-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-and-tested-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Leech <cleech@redhat.com>
Cc: Lee Duncan <lduncan@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@linuxonhyperv.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb
Pull swiotlb fixes from Konrad Rzeszutek Wilk:
"This has one fix to make i915 work when using Xen SWIOTLB, and a
feature from Geert to aid in debugging of devices that can't do DMA
outside the 32-bit address space.
The feature from Geert is on top of v4.10 merge window commit
(specifically you pulling my previous branch), as his changes were
dependent on the Documentation/ movement patches.
I figured it would just easier than me trying than to cherry-pick the
Documentation patches to satisfy git.
The patches have been soaking since 12/20, albeit I updated the last
patch due to linux-next catching an compiler error and adding an
Tested-and-Reported-by tag"
* 'stable/for-linus-4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb:
swiotlb: Export swiotlb_max_segment to users
swiotlb: Add swiotlb=noforce debug option
swiotlb: Convert swiotlb_force from int to enum
x86, swiotlb: Simplify pci_swiotlb_detect_override()
|
|
So they can figure out what is the optimal number of pages
that can be contingously stitched together without fear of
bounce buffer.
We also expose an mechanism for sub-users of SWIOTLB API, such
as Xen-SWIOTLB to set the max segment value. And lastly
if swiotlb=force is set (which mandates we bounce buffer everything)
we set max_segment so at least we can bounce buffer one 4K page
instead of a giant 512KB one for which we may not have space.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reported-and-Tested-by: Juergen Gross <jgross@suse.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer type cleanups from Thomas Gleixner:
"This series does a tree wide cleanup of types related to
timers/timekeeping.
- Get rid of cycles_t and use a plain u64. The type is not really
helpful and caused more confusion than clarity
- Get rid of the ktime union. The union has become useless as we use
the scalar nanoseconds storage unconditionally now. The 32bit
timespec alike storage got removed due to the Y2038 limitations
some time ago.
That leaves the odd union access around for no reason. Clean it up.
Both changes have been done with coccinelle and a small amount of
manual mopping up"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ktime: Get rid of ktime_equal()
ktime: Cleanup ktime_set() usage
ktime: Get rid of the union
clocksource: Use a plain u64 instead of cycle_t
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull SMP hotplug notifier removal from Thomas Gleixner:
"This is the final cleanup of the hotplug notifier infrastructure. The
series has been reintgrated in the last two days because there came a
new driver using the old infrastructure via the SCSI tree.
Summary:
- convert the last leftover drivers utilizing notifiers
- fixup for a completely broken hotplug user
- prevent setup of already used states
- removal of the notifiers
- treewide cleanup of hotplug state names
- consolidation of state space
There is a sphinx based documentation pending, but that needs review
from the documentation folks"
* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/armada-xp: Consolidate hotplug state space
irqchip/gic: Consolidate hotplug state space
coresight/etm3/4x: Consolidate hotplug state space
cpu/hotplug: Cleanup state names
cpu/hotplug: Remove obsolete cpu hotplug register/unregister functions
staging/lustre/libcfs: Convert to hotplug state machine
scsi/bnx2i: Convert to hotplug state machine
scsi/bnx2fc: Convert to hotplug state machine
cpu/hotplug: Prevent overwriting of callbacks
x86/msr: Remove bogus cleanup from the error path
bus: arm-ccn: Prevent hotplug callback leak
perf/x86/intel/cstate: Prevent hotplug callback leak
ARM/imx/mmcd: Fix broken cpu hotplug handling
scsi: qedi: Convert to hotplug state machine
|
|
ktime is a union because the initial implementation stored the time in
scalar nanoseconds on 64 bit machine and in a endianess optimized timespec
variant for 32bit machines. The Y2038 cleanup removed the timespec variant
and switched everything to scalar nanoseconds. The union remained, but
become completely pointless.
Get rid of the union and just keep ktime_t as simple typedef of type s64.
The conversion was done with coccinelle and some manual mopping up.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
|
|
hotcpu_notifier(), cpu_notifier(), __hotcpu_notifier(), __cpu_notifier(),
register_hotcpu_notifier(), register_cpu_notifier(),
__register_hotcpu_notifier(), __register_cpu_notifier(),
unregister_hotcpu_notifier(), unregister_cpu_notifier(),
__unregister_hotcpu_notifier(), __unregister_cpu_notifier()
are unused now. Remove them and all related code.
Remove also the now pointless cpu notifier error injection mechanism. The
states can be executed step by step and error rollback is the same as cpu
down, so any state transition can be tested w/o requiring the notifier
error injection.
Some CPU hotplug states are kept as they are (ab)used for hotplug state
tracking.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20161221192112.005642358@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
|
|
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull final vfs updates from Al Viro:
"Assorted cleanups and fixes all over the place"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
sg_write()/bsg_write() is not fit to be called under KERNEL_DS
ufs: fix function declaration for ufs_truncate_blocks
fs: exec: apply CLOEXEC before changing dumpable task flags
seq_file: reset iterator to first record for zero offset
vfs: fix isize/pos/len checks for reflink & dedupe
[iov_iter] fix iterate_all_kinds() on empty iterators
move aio compat to fs/aio.c
reorganize do_make_slave()
clone_private_mount() doesn't need to touch namespace_sem
remove a bogus claim about namespace_sem being held by callers of mnt_alloc_id()
|