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Historically, an UNLOCK+LOCK pair executed by one CPU, by one
task, or on a given lock variable has implied a full memory
barrier. In a recent LKML thread, the wisdom of this historical
approach was called into question:
http://www.spinics.net/lists/linux-mm/msg65653.html, in part due
to the memory-order complexities of low-handoff-overhead queued
locks on x86 systems.
This patch therefore removes this guarantee from the
documentation, and further documents how to restore it via a new
smp_mb__after_unlock_lock() primitive.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1386799151-2219-6-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The Linux kernel has traditionally required that an UNLOCK+LOCK
pair act as a full memory barrier when either (1) that
UNLOCK+LOCK pair was executed by the same CPU or task, or (2)
the same lock variable was used for the UNLOCK and LOCK. It now
seems likely that very few places in the kernel rely on this
full-memory-barrier semantic, and with the advent of queued
locks, providing this semantic either requires complex
reasoning, or for some architectures, added overhead.
This commit therefore adds a smp_mb__after_unlock_lock(), which
may be placed after a LOCK primitive to restore the
full-memory-barrier semantic. All definitions are currently
no-ops, but will be upgraded for some architectures when queued
locks arrive.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1386799151-2219-5-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The situations in which ACCESS_ONCE() is required are not well
documented, so this commit adds some verbiage to
memory-barriers.txt.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1386799151-2219-4-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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No SMP architecture currently supporting Linux allows
speculative writes, so this commit updates
Documentation/memory-barriers.txt to prohibit them in Linux core
code. It also records restrictions on their use.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1386799151-2219-3-git-send-email-paulmck@linux.vnet.ibm.com
[ Paul modified the original patch from Peter. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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memory-barriers.txt
Although the atomic_long_t functions are quite useful, they are
a bit obscure. This commit therefore adds the common ones
alongside their atomic_t counterparts in
Documentation/memory-barriers.txt.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1386799151-2219-2-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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memory-barriers.txt
The Documentation/memory-barriers.txt file was written before
the need for ACCESS_ONCE() was fully appreciated. It therefore
contains no ACCESS_ONCE() calls, which can be a problem when
people lift examples from it. This commit therefore adds
ACCESS_ONCE() calls.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1386799151-2219-1-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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dependency"
This reverts commit 9dd1220114e00d8ec5cdc20085bbe198b21e1985.
Revert it until Linus's concerns are addressed: this option should not
allow nonsensical CONFIG_CPUMASK_OFFSTACK and CONFIG_NR_CPUS values, and
it should probably select sane defaults as well.
Cc: Josh Boyer <jwboyer@fedoraproject.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-etcruvuw9neycYf0Rripxrjv@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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A strictly monotonically increasing sequence is normally used in
numbered lists as they provide an intuitive ordering of the
elements.
However, in situations where race conditions can appear, this
assumption breaks down and you can end up with unpredictable
results, leading to a rather confusing list :-)
This changes the numbered list 1,2,2,2 to the more intuitive
1,2,3,4.
Introduced in:
2eec9ad91f71 [PATCH] lightweight robust futexes: docs
Signed-off-by: Henrik Austad <henrik@austad.us>
Link: http://lkml.kernel.org/r/1385590680-8110-1-git-send-email-henrik@austad.us
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1371163284-6346-10-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This is a simple wrapper to make using liblockdep on existing
applications much easier.
After running 'make && make install', it becomes quite simple to
test things with liblockdep. For example, to try it on perf:
lockdep perf
No other integration required.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1371163284-6346-9-git-send-email-sasha.levin@oracle.com
[ Changed it to load ./liblockdep.so, so it can be tested in situ. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This allows lockdep to be used without being compiled in the
original program.
Usage is quite simple:
LD_PRELOAD=/path/to/liblockdep.so /path/to/my/program
And magically, you'll have lockdep checking in your program!
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1371163284-6346-8-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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A simple test to make sure we handle rwlocks correctly.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1371163284-6346-7-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Both pthreads and lockdep support dealing with rwlocks, so
here's the liblockdep implementation for those.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1371163284-6346-6-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This is a rather simple and basic test suite to test common
locking issues.
Beyond tests, it also shows how to use the library.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1371163284-6346-5-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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These headers provide the same API as their pthread mutex
counterparts.
The design here is to allow to easily switch to liblockdep lock
validation just by adding a "liblockdep_" to pthread_mutex_*()
calls, which means that it's easy to integrate liblockdep into
existing codebases.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1371163284-6346-4-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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kernel/locking/lockdep.c deals with validating locking scenarios for
various architectures supported by the kernel. There isn't
anything kernel specific going on in lockdep, and when we
compare userspace to other architectures that don't have to deal
with irqs such as s390, they become all too similar.
We wrap kernel/locking/lockdep.c and include/linux/lockdep.h with
several headers which allow us to build and use lockdep from
userspace. We don't touch the kernel code itself which means
that any work done on lockdep in the kernel will automatically
benefit userspace lockdep as well!
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1371163284-6346-3-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Lockdep is an awesome piece of code which detects locking issues
which are relevant both to userspace and kernelspace. We can
easily make lockdep work in userspace since there is really no
kernel spacific magic going on in the code.
All we need is to wrap two functions which are used by lockdep
and are very kernel specific.
Doing that will allow tools located in tools/ to easily utilize
lockdep's code for their own use.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: penberg@kernel.org
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/1352753446-24109-1-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Instead of saving the hardirq state on a per CPU variable, which require
an explicit call before the softirq handling and some complication,
just save and restore the hardirq tracing state through functions
return values and parameters.
It simplifies a bit the black magic that works around the fact that
softirqs can be called from hardirqs while hardirqs can nest on softirqs
but those two cases have very different semantics and only the latter
case assume both states.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1384906054-30676-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Prepare for dependent patch.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This typo has been there forever, it is 7.5 years old, looks like this
section of our memory ordering documentation is a place where most eyes
are glazed over already ;-)
[ Also fix some stray spaces and stray tabs while at it, shrinking the
file by 49 bytes. Visual output unchanged. ]
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-gncea9cb8igosblizfqMXrie@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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It appears that driver runs into a problem here if fibsize is too small
because we allocate user_srbcmd with fibsize size only but later we
access it until user_srbcmd->sg.count to copy it over to srbcmd.
It is not correct to test (fibsize < sizeof(*user_srbcmd)) because this
structure already includes one sg element and this is not needed for
commands without data. So, we would recommend to add the following
(instead of test for fibsize == 0).
Signed-off-by: Mahesh Rajashekhara <Mahesh.Rajashekhara@pmcs.com>
Reported-by: Nico Golde <nico@ngolde.de>
Reported-by: Fabian Yamaguchi <fabs@goesec.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull networking fixes from David Miller:
"Mostly these are fixes for fallout due to merge window changes, as
well as cures for problems that have been with us for a much longer
period of time"
1) Johannes Berg noticed two major deficiencies in our genetlink
registration. Some genetlink protocols we passing in constant
counts for their ops array rather than something like
ARRAY_SIZE(ops) or similar. Also, some genetlink protocols were
using fixed IDs for their multicast groups.
We have to retain these fixed IDs to keep existing userland tools
working, but reserve them so that other multicast groups used by
other protocols can not possibly conflict.
In dealing with these two problems, we actually now use less state
management for genetlink operations and multicast groups.
2) When configuring interface hardware timestamping, fix several
drivers that simply do not validate that the hwtstamp_config value
is one the driver actually supports. From Ben Hutchings.
3) Invalid memory references in mwifiex driver, from Amitkumar Karwar.
4) In dev_forward_skb(), set the skb->protocol in the right order
relative to skb_scrub_packet(). From Alexei Starovoitov.
5) Bridge erroneously fails to use the proper wrapper functions to make
calls to netdev_ops->ndo_vlan_rx_{add,kill}_vid. Fix from Toshiaki
Makita.
6) When detaching a bridge port, make sure to flush all VLAN IDs to
prevent them from leaking, also from Toshiaki Makita.
7) Put in a compromise for TCP Small Queues so that deep queued devices
that delay TX reclaim non-trivially don't have such a performance
decrease. One particularly problematic area is 802.11 AMPDU in
wireless. From Eric Dumazet.
8) Fix crashes in tcp_fastopen_cache_get(), we can see NULL socket dsts
here. Fix from Eric Dumzaet, reported by Dave Jones.
9) Fix use after free in ipv6 SIT driver, from Willem de Bruijn.
10) When computing mergeable buffer sizes, virtio-net fails to take the
virtio-net header into account. From Michael Dalton.
11) Fix seqlock deadlock in ip4_datagram_connect() wrt. statistic
bumping, this one has been with us for a while. From Eric Dumazet.
12) Fix NULL deref in the new TIPC fragmentation handling, from Erik
Hugne.
13) 6lowpan bit used for traffic classification was wrong, from Jukka
Rissanen.
14) macvlan has the same issue as normal vlans did wrt. propagating LRO
disabling down to the real device, fix it the same way. From Michal
Kubecek.
15) CPSW driver needs to soft reset all slaves during suspend, from
Daniel Mack.
16) Fix small frame pacing in FQ packet scheduler, from Eric Dumazet.
17) The xen-netfront RX buffer refill timer isn't properly scheduled on
partial RX allocation success, from Ma JieYue.
18) When ipv6 ping protocol support was added, the AF_INET6 protocol
initialization cleanup path on failure was borked a little. Fix
from Vlad Yasevich.
19) If a socket disconnects during a read/recvmsg/recvfrom/etc that
blocks we can do the wrong thing with the msg_name we write back to
userspace. From Hannes Frederic Sowa. There is another fix in the
works from Hannes which will prevent future problems of this nature.
20) Fix route leak in VTI tunnel transmit, from Fan Du.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (106 commits)
genetlink: make multicast groups const, prevent abuse
genetlink: pass family to functions using groups
genetlink: add and use genl_set_err()
genetlink: remove family pointer from genl_multicast_group
genetlink: remove genl_unregister_mc_group()
hsr: don't call genl_unregister_mc_group()
quota/genetlink: use proper genetlink multicast APIs
drop_monitor/genetlink: use proper genetlink multicast APIs
genetlink: only pass array to genl_register_family_with_ops()
tcp: don't update snd_nxt, when a socket is switched from repair mode
atm: idt77252: fix dev refcnt leak
xfrm: Release dst if this dst is improper for vti tunnel
netlink: fix documentation typo in netlink_set_err()
be2net: Delete secondary unicast MAC addresses during be_close
be2net: Fix unconditional enabling of Rx interface options
net, virtio_net: replace the magic value
ping: prevent NULL pointer dereference on write to msg_name
bnx2x: Prevent "timeout waiting for state X"
bnx2x: prevent CFC attention
bnx2x: Prevent panic during DMAE timeout
...
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Pull sparc fixes from David Miller:
"Two merge window fallout build fixes"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
sparc64: merge fix
sparc64: fix build regession
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git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux
Pull ia64 fix from Tony Luck:
"Unbreak ia64 build by avoiding circular dependency"
* tag 'please-pull-fixia64' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
kernel/bounds: avoid circular dependencies in generated headers
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<linux/spinlock.h> has heavy dependencies on other header files.
It triggers circular dependencies in generated headers on IA64, at
least:
CC kernel/bounds.s
In file included from /home/space/kas/git/public/linux/arch/ia64/include/asm/thread_info.h:9:0,
from include/linux/thread_info.h:54,
from include/asm-generic/preempt.h:4,
from arch/ia64/include/generated/asm/preempt.h:1,
from include/linux/preempt.h:18,
from include/linux/spinlock.h:50,
from kernel/bounds.c:14:
/home/space/kas/git/public/linux/arch/ia64/include/asm/asm-offsets.h:1:35: fatal error: generated/asm-offsets.h: No such file or directory
compilation terminated.
Let's replace <linux/spinlock.h> with <linux/spinlock_types.h>, it's
enough to find out size of spinlock_t.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-and-Tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
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Johannes Berg says:
====================
genetlink: clean up multicast group APIs
The generic netlink multicast group registration doesn't have to
be dynamic, and can thus be simplified just like I did with the
ops. This removes some complexity in registration code.
Additionally, two users of generic netlink already use multicast
groups in a wrong way, add workarounds for those two to keep the
userspace API working, but at the same time make them not clash
with other users of multicast groups as might happen now.
While making it all a bit easier, also prevent such abuse by adding
checks to the APIs so each family can only use the groups it owns.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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Register generic netlink multicast groups as an array with
the family and give them contiguous group IDs. Then instead
of passing the global group ID to the various functions that
send messages, pass the ID relative to the family - for most
families that's just 0 because the only have one group.
This avoids the list_head and ID in each group, adding a new
field for the mcast group ID offset to the family.
At the same time, this allows us to prevent abusing groups
again like the quota and dropmon code did, since we can now
check that a family only uses a group it owns.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This doesn't really change anything, but prepares for the
next patch that will change the APIs to pass the group ID
within the family, rather than the global group ID.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add a static inline to generic netlink to wrap netlink_set_err()
to make it easier to use here - use it in openvswitch (the only
generic netlink user of netlink_set_err()).
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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There's no reason to have the family pointer there since it
can just be passed internally where needed, so remove it.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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There are no users of this API remaining, and we'll soon
change group registration to be static (like ops are now)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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There's no need to unregister the multicast group if the
generic netlink family is registered immediately after.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The quota code is abusing the genetlink API and is using
its family ID as the multicast group ID, which is invalid
and may belong to somebody else (and likely will.)
Make the quota code use the correct API, but since this
is already used as-is by userspace, reserve a family ID
for this code and also reserve that group ID to not break
userspace assumptions.
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The drop monitor code is abusing the genetlink API and is
statically using the generic netlink multicast group 1, even
if that group belongs to somebody else (which it invariably
will, since it's not reserved.)
Make the drop monitor code use the proper APIs to reserve a
group ID, but also reserve the group id 1 in generic netlink
code to preserve the userspace API. Since drop monitor can
be a module, don't clear the bit for it on unregistration.
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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As suggested by David Miller, make genl_register_family_with_ops()
a macro and pass only the array, evaluating ARRAY_SIZE() in the
macro, this is a little safer.
The openvswitch has some indirection, assing ops/n_ops directly in
that code. This might ultimately just assign the pointers in the
family initializations, saving the struct genl_family_and_ops and
code (once mcast groups are handled differently.)
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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snd_nxt must be updated synchronously with sk_send_head. Otherwise
tp->packets_out may be updated incorrectly, what may bring a kernel panic.
Here is a kernel panic from my host.
[ 103.043194] BUG: unable to handle kernel NULL pointer dereference at 0000000000000048
[ 103.044025] IP: [<ffffffff815aaaaf>] tcp_rearm_rto+0xcf/0x150
...
[ 146.301158] Call Trace:
[ 146.301158] [<ffffffff815ab7f0>] tcp_ack+0xcc0/0x12c0
Before this panic a tcp socket was restored. This socket had sent and
unsent data in the write queue. Sent data was restored in repair mode,
then the socket was switched from reapair mode and unsent data was
restored. After that the socket was switched back into repair mode.
In that moment we had a socket where write queue looks like this:
snd_una snd_nxt write_seq
|_________|________|
|
sk_send_head
After a second switching from repair mode the state of socket was
changed:
snd_una snd_nxt, write_seq
|_________ ________|
|
sk_send_head
This state is inconsistent, because snd_nxt and sk_send_head are not
synchronized.
Bellow you can find a call trace, how packets_out can be incremented
twice for one skb, if snd_nxt and sk_send_head are not synchronized.
In this case packets_out will be always positive, even when
sk_write_queue is empty.
tcp_write_wakeup
skb = tcp_send_head(sk);
tcp_fragment
if (!before(tp->snd_nxt, TCP_SKB_CB(buff)->end_seq))
tcp_adjust_pcount(sk, skb, diff);
tcp_event_new_data_sent
tp->packets_out += tcp_skb_pcount(skb);
I think update of snd_nxt isn't required, when a socket is switched from
repair mode. Because it's initialized in tcp_connect_init. Then when a
write queue is restored, snd_nxt is incremented in tcp_event_new_data_sent,
so it's always is in consistent state.
I have checked, that the bug is not reproduced with this patch and
all tests about restoring tcp connections work fine.
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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init_card() calls dev_get_by_name() to get a network deceive. But it
doesn't decrease network device reference count after the device is
used.
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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After searching rt by the vti tunnel dst/src parameter,
if this rt has neither attached to any transformation
nor the transformation is not tunnel oriented, this rt
should be released back to ip layer.
otherwise causing dst memory leakage.
Signed-off-by: Fan Du <fan.du@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The parameter is just 'group', not 'groups', fix the documentation typo.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull second set of ARC changes from Vineet Gupta:
- Support for Perf from Mischa
- Enabling GPIO/Pinctrl drivers for Abilis TB10x platform
- New defconfig for buildroot
* tag 'arc-v3.13-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
ARC: [plat-arcfpga] Add defconfig without initramfs location
ARC: perf: ARC 700 PMU doesn't support sampling events
ARC: Add documentation on DT binding for ARC700 PMU
ARC: Add perf support for ARC700 cores
ARC: [TB10x] Updates for GPIO and pinctrl
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull second set of s390 patches from Martin Schwidefsky:
"The handling of the PCI hotplug notifications has been improved, the
zfcp dumper can now detect the HSA size dynamically and the default
install kernel has been changed to the compressed bzImage. And two
bug-fixes for scm and 3720"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/pci: implement hotplug notifications
s390/scm_block: do not hide eadm subchannel dependency
s390/sclp: Consolidate early sclp init calls to sclp_early_detect()
s390/sclp: Move early code from sclp_cmd.c to sclp_early.c
s390/sclp: Determine HSA size dynamically for zfcpdump
s390/sclp: Move declarations for sclp_sdias into separate header file
s390/pci: implement pcibios_remove_bus
s390/pci: improve handling of bus resources
s390/3270: fix missing device_destroy() call
s390/boot: Install bzImage as default kernel image
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Pull UML changes from Richard Weinberger:
"This pile contains a nice defconfig cleanup, a rewritten stack
unwinder and various cleanups"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: Remove unused declarations from <as-layout.h>
um: remove used STDIO_CONSOLE Kconfig param
um/vdso: add .gitignore for a couple of targets
arch/um: make it work with defconfig and x86_64
um: Make kstack_depth_to_print conform to arch/x86
um: Get rid of thread_struct->saved_task
um: Make stack trace reliable against kernel mode faults
um: Rewrite show_stack()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Ingo Molnar:
"A modular build fix for certain .config's"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Export 'boot_cpu_physical_apicid' to modules
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq cleanups from Ingo Molnar:
"This is a multi-arch cleanup series from Thomas Gleixner, which we
kept to near the end of the merge window, to not interfere with
architecture updates.
This series (motivated by the -rt kernel) unifies more aspects of IRQ
handling and generalizes PREEMPT_ACTIVE"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
preempt: Make PREEMPT_ACTIVE generic
sparc: Use preempt_schedule_irq
ia64: Use preempt_schedule_irq
m32r: Use preempt_schedule_irq
hardirq: Make hardirq bits generic
m68k: Simplify low level interrupt handling code
genirq: Prevent spurious detection for unconditionally polled interrupts
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There was a reported deadlock on -rt which lockdep didn't report.
It turns out that in irq_exit() we tell lockdep that the hardirq
context ends and then do all kinds of locking afterwards.
To fix it, move trace_hardirq_exit() to the very end of irq_exit(), this
ensures all locking in tick_irq_exit() and rcu_irq_exit() are properly
recorded as happening from hardirq context.
This however leads to the 'fun' little problem of running softirqs
while in hardirq context. To cure this make the softirq code a little
more complex (in the CONFIG_TRACE_IRQFLAGS case).
Due to stack swizzling arch dependent trickery we cannot pass an
argument to __do_softirq() to tell it if it was done from hardirq
context or not; so use a side-band argument.
When we do __do_softirq() from hardirq context, 'atomically' flip to
softirq context and back, so that no locking goes without being in
either hard- or soft-irq context.
I didn't find any new problems in mainline using this patch, but it
did show the -rt problem.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-dgwc5cdksbn0jk09vbmcc9sa@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Once we'd freed m->buf, m->count should become zero - we have no valid
contents reachable via m->buf.
Reported-by: Charley (Hao Chuan) Chu <charley.chu@broadcom.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull watchdog changes from Wim Van Sebroeck:
- addition of MOXA ART watchdog driver (moxart_wdt)
- addition of CSR SiRFprimaII and SiRFatlasVI watchdog driver
(sirfsoc_wdt)
- addition of ralink watchdog driver (rt2880_wdt)
- various fixes and cleanups (__user annotation, ioctl return codes,
removal of redundant of_match_ptr, removal of unnecessary
amba_set_drvdata(), use allocated buffer for usb_control_msg, ...)
- removal of MODULE_ALIAS_MISCDEV statements
- watchdog related DT bindings
- first set of improvements on the w83627hf_wdt driver
* git://www.linux-watchdog.org/linux-watchdog: (26 commits)
watchdog: w83627hf: Use helper functions to access superio registers
watchdog: w83627hf: Enable watchdog device only if not already enabled
watchdog: w83627hf: Enable watchdog only once
watchdog: w83627hf: Convert to watchdog infrastructure
watchdog: omap_wdt: raw read and write endian fix
watchdog: sirf: don't depend on dummy value of CLOCK_TICK_RATE
watchdog: pcwd_usb: overflow in usb_pcwd_send_command()
watchdog: rt2880_wdt: fix return value check in rt288x_wdt_probe()
watchdog: watchdog_core: Fix a trivial typo
watchdog: dw: Enable OF support for DW watchdog timer
watchdog: Get rid of MODULE_ALIAS_MISCDEV statements
watchdog: ts72xx_wdt: Propagate return value from timeout_to_regval
watchdog: pcwd_usb: Use allocated buffer for usb_control_msg
watchdog: sp805_wdt: Remove unnecessary amba_set_drvdata()
watchdog: sirf: add watchdog driver of CSR SiRFprimaII and SiRFatlasVI
watchdog: Remove redundant of_match_ptr
watchdog: ts72xx_wdt: cleanup return codes in ioctl
documentation/devicetree: Move DT bindings from gpio to watchdog
watchdog: add ralink watchdog driver
watchdog: Add MOXA ART watchdog driver
...
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git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c changes from Wolfram Sang:
- new drivers for exynos5, bcm kona, and st micro
- bigger overhauls for drivers mxs and rcar
- typical driver bugfixes, cleanups, improvements
- got rid of the superfluous 'driver' member in i2c_client struct This
touches a few drivers in other subsystems. All acked.
* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (38 commits)
i2c: bcm-kona: fix error return code in bcm_kona_i2c_probe()
i2c: i2c-eg20t: do not print error message in syslog if no ACK received
i2c: bcm-kona: Introduce Broadcom I2C Driver
i2c: cbus-gpio: Fix device tree binding
i2c: wmt: add missing clk_disable_unprepare() on error
i2c: designware: add new ACPI IDs
i2c: i801: Add Device IDs for Intel Wildcat Point-LP PCH
i2c: exynos5: Remove incorrect clk_disable_unprepare
i2c: i2c-st: Add ST I2C controller
i2c: exynos5: add High Speed I2C controller driver
i2c: rcar: fixup rcar type naming
i2c: scmi: remove some bogus NULL checks
i2c: sh_mobile & rcar: Enable the driver on all ARM platforms
i2c: sh_mobile: Convert to clk_prepare/unprepare
i2c: mux: gpio: use reg value for i2c_add_mux_adapter
i2c: mux: gpio: use gpio_set_value_cansleep()
i2c: Include linux/of.h header
i2c: mxs: Fix PIO mode on i.MX23
i2c: mxs: Rework the PIO mode operation
i2c: mxs: distinguish i.MX23 and i.MX28 based I2C controller
...
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git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband
Pull infiniband/rdma updates from Roland Dreier:
- Re-enable flow steering verbs with new improved userspace ABI
- Fixes for slow connection due to GID lookup scalability
- IPoIB fixes
- Many fixes to HW drivers including mlx4, mlx5, ocrdma and qib
- Further improvements to SRP error handling
- Add new transport type for Cisco usNIC
* tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband: (66 commits)
IB/core: Re-enable create_flow/destroy_flow uverbs
IB/core: extended command: an improved infrastructure for uverbs commands
IB/core: Remove ib_uverbs_flow_spec structure from userspace
IB/core: Use a common header for uverbs flow_specs
IB/core: Make uverbs flow structure use names like verbs ones
IB/core: Rename 'flow' structs to match other uverbs structs
IB/core: clarify overflow/underflow checks on ib_create/destroy_flow
IB/ucma: Convert use of typedef ctl_table to struct ctl_table
IB/cm: Convert to using idr_alloc_cyclic()
IB/mlx5: Fix page shift in create CQ for userspace
IB/mlx4: Fix device max capabilities check
IB/mlx5: Fix list_del of empty list
IB/mlx5: Remove dead code
IB/core: Encorce MR access rights rules on kernel consumers
IB/mlx4: Fix endless loop in resize CQ
RDMA/cma: Remove unused argument and minor dead code
RDMA/ucma: Discard events for IDs not yet claimed by user space
IB/core: Add Cisco usNIC rdma node and transport types
RDMA/nes: Remove self-assignment from nes_query_qp()
IB/srp: Report receive errors correctly
...
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Pull battery updates from Anton Vorontsov:
"Highlights:
- A new driver for TI BQ24735 Battery Chargers, courtesy of NVidia.
- Device tree bindings for TWL4030 chips.
- Random fixes and cleanups"
* tag 'for-v3.13' of git://git.infradead.org/battery-2.6:
pm2301-charger: Remove unneeded NULL checks
twl4030_charger: Add devicetree support
power_supply: Fix documentation for TEMP_*ALERT* properties
max17042_battery: Support regmap to access device's registers
max17042_battery: Use SIMPLE_DEV_PM_OPS
charger-manager : Replace kzalloc to devm_kzalloc and remove uneccessary code
bq2415x_charger: Fix max battery regulation voltage
tps65090-charger: Use "IS_ENABLED(CONFIG_OF)" for DT code
tps65090-charger: Drop devm_free_irq of devm_ allocated irq
power_supply: Add support for bq24735 charger
pm2301-charger: Staticize pm2xxx_charger_die_therm_mngt
pm2301-charger: Check return value of regulator_enable
ab8500-charger: Remove redundant break
ab8500-charger: Check return value of regulator_enable
isp1704_charger: Fix driver to work with changes introduced in v3.5
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