Paul E. McKenney [Sun, 27 Mar 2011 05:01:35 +0000 (22:01 -0700)]
rcu: further lower priority in rcu_yield()
Although rcu_yield() dropped from real-time to normal priority, there
is always the possibility that the competing tasks have been niced.
So nice to 19 in rcu_yield() to help ensure that other tasks have a
better chance of running.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Lai Jiangshan [Fri, 18 Mar 2011 03:15:47 +0000 (11:15 +0800)]
rcu: introduce kfree_rcu()
Many rcu callbacks functions just call kfree() on the base structure.
These functions are trivial, but their size adds up, and furthermore
when they are used in a kernel module, that module must invoke the
high-latency rcu_barrier() function at module-unload time.
The kfree_rcu() function introduced by this commit addresses this issue.
Rather than encoding a function address in the embedded rcu_head
structure, kfree_rcu() instead encodes the offset of the rcu_head
structure within the base structure. Because the functions are not
allowed in the low-order 4096 bytes of kernel virtual memory, offsets
up to 4095 bytes can be accommodated. If the offset is larger than
4095 bytes, a compile-time error will be generated in __kfree_rcu().
If this error is triggered, you can either fall back to use of call_rcu()
or rearrange the structure to position the rcu_head structure into the
first 4096 bytes.
Note that the allowable offset might decrease in the future, for example,
to allow something like kmem_cache_free_rcu().
The new kfree_rcu() function can replace code as follows:
call_rcu(&p->rcu, simple_kfree_callback);
where "simple_kfree_callback()" might be defined as follows:
Note that the "rcu" is the name of a field in the structure being
freed. The reason for using this rather than passing in a pointer
to the base structure is that the above approach allows better type
checking.
This commit is based on earlier work by Lai Jiangshan and Manfred Spraul:
Lai Jiangshan [Fri, 25 Feb 2011 19:37:59 +0000 (11:37 -0800)]
rcu: call __rcu_read_unlock() in exit_rcu for tree RCU
Using __rcu_read_lock() in place of rcu_read_lock() leaves any debug
state as it really should be, namely with the lock still held.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Fri, 25 Feb 2011 03:26:21 +0000 (19:26 -0800)]
rcu: Converge TINY_RCU expedited and normal boosting
This applies a trick from TREE_RCU boosting to TINY_RCU, eliminating
code and adding comments. The key point is that it is possible for
the booster thread itself to work out whether there is a normal or
expedited boost required based solely on local information. There
is therefore no need for boost initiation to know or care what type
of boosting is required. In addition, when boosting is complete for
a given grace period, then by definition there cannot be any more
boosting for that grace period. This allows eliminating yet more
state and statistics.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Thu, 24 Feb 2011 23:25:21 +0000 (15:25 -0800)]
rcu: remove useless ->boosted_this_gp field
The ->boosted_this_gp field is a holdover from an earlier design that
was to carry out multiple boost operations in parallel. It is not required
by the current design, which boosts one task at a time.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Thu, 24 Feb 2011 01:03:06 +0000 (17:03 -0800)]
rcu: code cleanups in TINY_RCU priority boosting.
Extraneous semicolon, bad comment, and fold INIT_LIST_HEAD() into
list_del() to get list_del_init().
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Wed, 23 Feb 2011 19:10:52 +0000 (11:10 -0800)]
rcu: Switch to this_cpu() primitives
This removes a couple of lines from invoke_rcu_cpu_kthread(), improving
readability.
Reported-by: Christoph Lameter <cl@linux.com> Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Wed, 30 Mar 2011 16:10:44 +0000 (09:10 -0700)]
rcu: mark rcutorture boosting callback as being on-stack
The CONFIG_DEBUG_OBJECTS_RCU_HEAD facility requires that on-stack RCU
callbacks be flagged explicitly to debug-objects using the
init_rcu_head_on_stack() and destroy_rcu_head_on_stack() functions.
This commit applies those functions to the rcutorture code that tests
RCU priority boosting.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Sat, 23 Apr 2011 01:08:51 +0000 (18:08 -0700)]
rcu: Add forward-progress diagnostic for per-CPU kthreads
Increment a per-CPU counter on each pass through rcu_cpu_kthread()'s
service loop, and add it to the rcudata trace output.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
rcu: add grace-period age and more kthread state to tracing
This commit adds the age in jiffies of the current grace period along
with the duration in jiffies of the longest grace period since boot
to the rcu/rcugp debugfs file. It also adds an additional "O" state
to kthread tracing to differentiate between the kthread waiting due to
having nothing to do on the one hand and waiting due to being on the
wrong CPU on the other hand.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
rcu: fix tracing bug thinko on boost-balk attribution
The rcu_initiate_boost_trace() function mis-attributed refusals to
initiate RCU priority boosting that were in fact due to its not yet
being time to boost. This patch fixes the faulty comparison.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
rcu: make rcutorture version numbers available through debugfs
It is not possible to accurately correlate rcutorture output with that
of debugfs. This patch therefore adds a debugfs file that prints out
the rcutorture version number, permitting easy correlation.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Wed, 30 Mar 2011 00:48:28 +0000 (17:48 -0700)]
rcu: add tracing for RCU's kthread run states.
Add tracing to help debugging situations when RCU's kthreads are not
running but are supposed to be.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Mon, 28 Mar 2011 22:47:07 +0000 (15:47 -0700)]
rcu: add callback-queue information to rcudata output
This commit adds an indication of the state of the callback queue using
a string of four characters following the "ql=" integer queue length.
The first character is "N" if there are callbacks that have been
queued that are not yet ready to be handled by the next grace period, or
"." otherwise. The second character is "R" if there are callbacks queued
that are ready to be handled by the next grace period, or "." otherwise.
The third character is "W" if there are callbacks waiting for the current
grace period, or "." otherwise. Finally, the fourth character is "D"
if there are callbacks that have been handled by a prior grace period
and are waiting to be invoked, or ".".
Note that callbacks that are in the process of being invoked are
not shown. These callbacks would have been removed from the rcu_data
structure's list by rcu_do_batch() prior to being executed. (These
callbacks are also not reflected in the "ql=" total, FWIW.)
Also, document the new callback-queue trace information.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Mon, 28 Mar 2011 04:37:58 +0000 (21:37 -0700)]
rcu: Update RCU's trace.txt documentation for new format
The trace.txt file had obsolete output for the debugfs rcu/rcudata
file, so update it.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Tue, 22 Feb 2011 21:42:43 +0000 (13:42 -0800)]
rcu: Add boosting to TREE_PREEMPT_RCU tracing
Includes total number of tasks boosted, number boosted on behalf of each
of normal and expedited grace periods, and statistics on attempts to
initiate boosting that failed for various reasons.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Mon, 21 Feb 2011 21:31:55 +0000 (13:31 -0800)]
rcu: eliminate unused boosting statistics
The n_rcu_torture_boost_allocerror and n_rcu_torture_boost_afferror
statistics are not actually incremented anymore, so eliminate them.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Mon, 18 Apr 2011 06:45:23 +0000 (23:45 -0700)]
rcu: avoid hammering sched with yet another bound RT kthread
The scheduler does not appear to take kindly to having multiple
real-time threads bound to a CPU that is going offline. So this
commit is a temporary hack-around to avoid that happening.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Paul E. McKenney [Mon, 18 Apr 2011 22:31:26 +0000 (15:31 -0700)]
rcu: put per-CPU kthread at non-RT priority during CPU hotplug operations
If you are doing CPU hotplug operations, it is best not to have
CPU-bound realtime tasks running CPU-bound on the outgoing CPU.
So this commit makes per-CPU kthreads run at non-realtime priority
during that time.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Thu, 14 Apr 2011 19:13:53 +0000 (12:13 -0700)]
rcu: Force per-rcu_node kthreads off of the outgoing CPU
The scheduler has had some heartburn in the past when too many real-time
kthreads were affinitied to the outgoing CPU. So, this commit lightens
the load by forcing the per-rcu_node and the boost kthreads off of the
outgoing CPU. Note that RCU's per-CPU kthread remains on the outgoing
CPU until the bitter end, as it must in order to preserve correctness.
Also avoid disabling hardirqs across calls to set_cpus_allowed_ptr(),
given that this function can block.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Add priority boosting for TREE_PREEMPT_RCU, similar to that for
TINY_PREEMPT_RCU. This is enabled by the default-off RCU_BOOST
kernel parameter. The priority to which to boost preempted
RCU readers is controlled by the RCU_BOOST_PRIO kernel parameter
(defaulting to real-time priority 1) and the time to wait before
boosting the readers who are blocking a given grace period is
controlled by the RCU_BOOST_DELAY kernel parameter (defaulting to
500 milliseconds).
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Wed, 12 Jan 2011 22:10:23 +0000 (14:10 -0800)]
rcu: move TREE_RCU from softirq to kthread
If RCU priority boosting is to be meaningful, callback invocation must
be boosted in addition to preempted RCU readers. Otherwise, in presence
of CPU real-time threads, the grace period ends, but the callbacks don't
get invoked. If the callbacks don't get invoked, the associated memory
doesn't get freed, so the system is still subject to OOM.
But it is not reasonable to priority-boost RCU_SOFTIRQ, so this commit
moves the callback invocations to a kthread, which can be boosted easily.
Also add comments and properly synchronized all accesses to
rcu_cpu_kthread_task, as suggested by Lai Jiangshan.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Paul E. McKenney [Tue, 30 Nov 2010 05:56:39 +0000 (21:56 -0800)]
rcu: merge TREE_PREEPT_RCU blocked_tasks[] lists
Combine the current TREE_PREEMPT_RCU ->blocked_tasks[] lists in the
rcu_node structure into a single ->blkd_tasks list with ->gp_tasks
and ->exp_tasks tail pointers. This is in preparation for RCU priority
boosting, which will add a third dimension to the combinatorial explosion
in the ->blocked_tasks[] case, but simply a third pointer in the new
->blkd_tasks case.
Also update documentation to reflect blocked_tasks[] merge
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
rcu: Decrease memory-barrier usage based on semi-formal proof
Commit d09b62d fixed grace-period synchronization, but left some smp_mb()
invocations in rcu_process_callbacks() that are no longer needed, but
sheer paranoia prevented them from being removed. This commit removes
them and provides a proof of correctness in their absence. It also adds
a memory barrier to rcu_report_qs_rsp() immediately before the update to
rsp->completed in order to handle the theoretical possibility that the
compiler or CPU might move massive quantities of code into a lock-based
critical section. This also proves that the sheer paranoia was not
entirely unjustified, at least from a theoretical point of view.
In addition, the old dyntick-idle synchronization depended on the fact
that grace periods were many milliseconds in duration, so that it could
be assumed that no dyntick-idle CPU could reorder a memory reference
across an entire grace period. Unfortunately for this design, the
addition of expedited grace periods breaks this assumption, which has
the unfortunate side-effect of requiring atomic operations in the
functions that track dyntick-idle state for RCU. (There is some hope
that the algorithms used in user-level RCU might be applied here, but
some work is required to handle the NMIs that user-space applications
can happily ignore. For the short term, better safe than sorry.)
This proof assumes that neither compiler nor CPU will allow a lock
acquisition and release to be reordered, as doing so can result in
deadlock. The proof is as follows:
1. A given CPU declares a quiescent state under the protection of
its leaf rcu_node's lock.
2. If there is more than one level of rcu_node hierarchy, the
last CPU to declare a quiescent state will also acquire the
->lock of the next rcu_node up in the hierarchy, but only
after releasing the lower level's lock. The acquisition of this
lock clearly cannot occur prior to the acquisition of the leaf
node's lock.
3. Step 2 repeats until we reach the root rcu_node structure.
Please note again that only one lock is held at a time through
this process. The acquisition of the root rcu_node's ->lock
must occur after the release of that of the leaf rcu_node.
4. At this point, we set the ->completed field in the rcu_state
structure in rcu_report_qs_rsp(). However, if the rcu_node
hierarchy contains only one rcu_node, then in theory the code
preceding the quiescent state could leak into the critical
section. We therefore precede the update of ->completed with a
memory barrier. All CPUs will therefore agree that any updates
preceding any report of a quiescent state will have happened
before the update of ->completed.
5. Regardless of whether a new grace period is needed, rcu_start_gp()
will propagate the new value of ->completed to all of the leaf
rcu_node structures, under the protection of each rcu_node's ->lock.
If a new grace period is needed immediately, this propagation
will occur in the same critical section that ->completed was
set in, but courtesy of the memory barrier in #4 above, is still
seen to follow any pre-quiescent-state activity.
6. When a given CPU invokes __rcu_process_gp_end(), it becomes
aware of the end of the old grace period and therefore makes
any RCU callbacks that were waiting on that grace period eligible
for invocation.
If this CPU is the same one that detected the end of the grace
period, and if there is but a single rcu_node in the hierarchy,
we will still be in the single critical section. In this case,
the memory barrier in step #4 guarantees that all callbacks will
be seen to execute after each CPU's quiescent state.
On the other hand, if this is a different CPU, it will acquire
the leaf rcu_node's ->lock, and will again be serialized after
each CPU's quiescent state for the old grace period.
On the strength of this proof, this commit therefore removes the memory
barriers from rcu_process_callbacks() and adds one to rcu_report_qs_rsp().
The effect is to reduce the number of memory barriers by one and to
reduce the frequency of execution from about once per scheduling tick
per CPU to once per grace period.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
rcu: Remove conditional compilation for RCU CPU stall warnings
The RCU CPU stall warnings can now be controlled using the
rcu_cpu_stall_suppress boot-time parameter or via the same parameter
from sysfs. There is therefore no longer any reason to have
kernel config parameters for this feature. This commit therefore
removes the RCU_CPU_STALL_DETECTOR and RCU_CPU_STALL_DETECTOR_RUNNABLE
kernel config parameters. The RCU_CPU_STALL_TIMEOUT parameter remains
to allow the timeout to be tuned and the RCU_CPU_STALL_VERBOSE parameter
remains to allow task-stall information to be suppressed if desired.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Linus Torvalds [Wed, 4 May 2011 01:52:09 +0000 (18:52 -0700)]
Merge branch 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/radeon/kms: fix gart setup on fusion parts (v2)
drm: Send pending vblank events before disabling vblank.
drm/radeon: fix regression on atom cards with hardcoded EDID record.
drm/radeon/kms: add some new pci ids
drm: Send pending vblank events before disabling vblank.
This is the least-bad behaviour. It means that we signal the
vblank event before it actually happens, but since we're disabling
vblanks there's no guarantee that it will *ever* happen otherwise.
This prevents GL applications which use WaitMSC from hanging
indefinitely.
Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
Linus Torvalds [Tue, 3 May 2011 23:10:25 +0000 (16:10 -0700)]
logfs: initialize superblock entries earlier
In particular, s_freeing_list needs to be initialized early, since it is
used on some of the error paths when mounts fail. The mapping inode,
for example, would be initialized and then free'd on an error path
before s_freeing_list was initialized, but the inode drop operation
needs the s_freeing_list to be set up.
Normally you'd never see this, because not only is logfs fairly rare,
but a successful mount will never have any issues.
Reported-by: werner <w.landgraf@ru.ru> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus Torvalds [Tue, 3 May 2011 16:25:42 +0000 (09:25 -0700)]
Merge branch 'stable/bug-fixes-for-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen
* 'stable/bug-fixes-for-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
xen: mask_rw_pte mark RO all pagetable pages up to pgt_buf_top
xen/mmu: Add workaround "x86-64, mm: Put early page table high"
Linus Torvalds [Tue, 3 May 2011 03:26:32 +0000 (20:26 -0700)]
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: wm831x-ts - move BTN_TOUCH reporting to data transfer
Input: wm831x-ts - allow IRQ flags to be specified
Input: wm831x-ts - fix races with IRQ management
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (47 commits)
sysctl: net: call unregister_net_sysctl_table where needed
Revert: veth: remove unneeded ifname code from veth_newlink()
smsc95xx: fix reset check
tg3: Fix failure to enable WoL by default when possible
networking: inappropriate ioctl operation should return ENOTTY
amd8111e: trivial typo spelling: Negotitate -> Negotiate
ipv4: don't spam dmesg with "Using LC-trie" messages
af_unix: Only allow recv on connected seqpacket sockets.
mii: add support of pause frames in mii_get_an
net: ftmac100: fix scheduling while atomic during PHY link status change
usbnet: Transfer of maintainership
usbnet: add support for some Huawei modems with cdc-ether ports
bnx2: cancel timer on device removal
iwl4965: fix "Received BA when not expected"
iwlagn: fix "Received BA when not expected"
dsa/mv88e6131: fix unknown multicast/broadcast forwarding on mv88e6085
usbnet: Resubmit interrupt URB if device is open
iwl4965: fix "TX Power requested while scanning"
iwlegacy: led stay solid on when no traffic
b43: trivial: update module info about ucode16_mimo firmware
...
Revert: veth: remove unneeded ifname code from veth_newlink()
84c49d8c3e4abefb0a41a77b25aa37ebe8d6b743 ("veth: remove unneeded
ifname code from veth_newlink()") caused regression on veth
creation. This patch reverts the original one.
Reported-by: Michał Mirosław <mirqus@gmail.com> Signed-off-by: Jiri Pirko <jpirko@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Rabin Vincent [Sat, 30 Apr 2011 08:29:27 +0000 (08:29 +0000)]
smsc95xx: fix reset check
The reset loop check should check the MII_BMCR register value for
BMCR_RESET rather than for MII_BMCR (the register address, which also
happens to be zero).
Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: David S. Miller <davem@davemloft.net>
tg3: Fix failure to enable WoL by default when possible
tg3 is supposed to enable WoL by default on adapters which support
that, but it fails to do so unless the adapter's
/sys/devices/.../power/wakeup file contains 'enabled' during the
initialization of the adapter. Fix that by making tg3 use
device_set_wakeup_enable() to enable wakeup automatically whenever
WoL should be enabled by default.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: David S. Miller <davem@davemloft.net>
H. Peter Anvin [Mon, 2 May 2011 21:33:24 +0000 (14:33 -0700)]
x86, reboot: Fix relocations in reboot_32.S
The use of base for %ebx in this file is arbitrary, *except* that we
also use it to compute the real-mode segment. Therefore, make it so
that r_base really is the true address to which %ebx points.
xen: mask_rw_pte mark RO all pagetable pages up to pgt_buf_top
mask_rw_pte is currently checking if a pfn is a pagetable page if it
falls in the range pgt_buf_start - pgt_buf_end but that is incorrect
because pgt_buf_end is a moving target: pgt_buf_top is the real
boundary.
Acked-by: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
mapping kernel into physical memory
Xen: setup ISA identity maps
about to get started...
(XEN) mm.c:2466:d0 Bad type (saw 7400000000000001 != exp 1000000000000000) for mfn b1d89 (pfn bacf7)
(XEN) mm.c:3027:d0 Error while pinning mfn b1d89
(XEN) traps.c:481:d0 Unhandled invalid opcode fault/trap [#6] on VCPU 0 [ec=0000]
(XEN) domain_crash_sync called from entry.S
(XEN) Domain 0 (vcpu#0) crashed on cpu#0:
...
The reason is that at some point init_memory_mapping is going to reach
the pagetable pages area and map those pages too (mapping them as normal
memory that falls in the range of addresses passed to init_memory_mapping
as argument). Some of those pages are already pagetable pages (they are
in the range pgt_buf_start-pgt_buf_end) therefore they are going to be
mapped RO and everything is fine.
Some of these pages are not pagetable pages yet (they fall in the range
pgt_buf_end-pgt_buf_top; for example the page at pgt_buf_end) so they
are going to be mapped RW. When these pages become pagetable pages and
are hooked into the pagetable, xen will find that the guest has already
a RW mapping of them somewhere and fail the operation.
The reason Xen requires pagetables to be RO is that the hypervisor needs
to verify that the pagetables are valid before using them. The validation
operations are called "pinning" (more details in arch/x86/xen/mmu.c).
In order to fix the issue we mark all the pages in the entire range
pgt_buf_start-pgt_buf_top as RO, however when the pagetable allocation
is completed only the range pgt_buf_start-pgt_buf_end is reserved by
init_memory_mapping. Hence the kernel is going to crash as soon as one
of the pages in the range pgt_buf_end-pgt_buf_top is reused (b/c those
ranges are RO).
For this reason, this function is introduced which is called _after_
the init_memory_mapping has completed (in a perfect world we would
call this function from init_memory_mapping, but lets ignore that).
Because we are called _after_ init_memory_mapping the pgt_buf_[start,
end,top] have all changed to new values (b/c another init_memory_mapping
is called). Hence, the first time we enter this function, we save
away the pgt_buf_start value and update the pgt_buf_[end,top].
When we detect that the "old" pgt_buf_start through pgt_buf_end
PFNs have been reserved (so memblock_x86_reserve_range has been called),
we immediately set out to RW the "old" pgt_buf_end through pgt_buf_top.
And then we update those "old" pgt_buf_[end|top] with the new ones
so that we can redo this on the next pagetable.
Acked-by: "H. Peter Anvin" <hpa@zytor.com> Reviewed-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
[v1: Updated with Jeremy's comments]
[v2: Added the crash output] Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Linus Torvalds [Mon, 2 May 2011 19:17:29 +0000 (12:17 -0700)]
Merge branch 'for-linus' of git://git.infradead.org/ubifs-2.6
* 'for-linus' of git://git.infradead.org/ubifs-2.6:
UBIFS: seek journal heads to the latest bud in replay
UBIFS: do not free write-buffers when in R/O mode
Linus Torvalds [Mon, 2 May 2011 19:17:05 +0000 (12:17 -0700)]
Merge branch 'fixes' of master.kernel.org:/home/rmk/linux-2.6-arm
* 'fixes' of master.kernel.org:/home/rmk/linux-2.6-arm: (47 commits)
CLKDEV: Fix clkdev return value for NULL clk case
ARM: 6891/1: prevent heap corruption in OABI semtimedop
ARM: kprobes: Tidy-up kprobes-decode.c
ARM: kprobes: Add emulation of hint instructions like NOP and WFI
ARM: kprobes: Add emulation of SBFX, UBFX, BFI and BFC instructions
ARM: kprobes: Add emulation of MOVW and MOVT instructions
ARM: kprobes: Reject probing of undefined data processing instructions
ARM: kprobes: Remove redundant code in space_1111
ARM: kprobes: Fix emulation of PLD instructions
ARM: kprobes: Reject probing of SETEND instructions
ARM: kprobes: Consolidate stub decoding functions
ARM: kprobes: Reject probing of all coprocessor instructions
ARM: kprobes: Fix emulation of USAD8 instructions
ARM: kprobes: Fix emulation of SMUAD, SMUSD and SMMUL instructions
ARM: kprobes: Fix emulation of SXTB16, SXTB, SXTH, UXTB16, UXTB and UXTH instructions
ARM: kprobes: Reject probing of undefined media instructions
ARM: kprobes: Add emulation of RBIT instruction
ARM: kprobes: Reject probing of LDRB instructions which load PC
ARM: kprobes: Fix emulation of LDRD and STRD instructions
ARM: kprobes: Reject probing of LDR/STR instructions which update PC unpredictably
...
commit ab7798ffcf98b11a9525cf65bacdae3fd58d357f ("genirq: Expand generic
show_interrupts()") added the Kconfig option GENERIC_IRQ_SHOW_LEVEL to
accomodate PowerPC, but this doesn't actually enable the functionality due
to a typo in the #ifdef check.
UBIFS: seek journal heads to the latest bud in replay
This is the second fix of the following symptom:
UBIFS error (pid 34456): could not find an empty LEB
which sometimes happens after power cuts when we mount the file-system - UBIFS
refuses it with the above error message which comes from the
'ubifs_rcvry_gc_commit()' function. I can reproduce this using the integck test
with the UBIFS power cut emulation enabled.
Analysis of the problem.
Currently UBIFS replay seeks the journal heads to the last _replayed_ bud.
But the buds are replayed out-of-order, so the replay basically seeks journal
heads to the "random" bud belonging to this head, and not to the _last_ one.
The result of this is that the GC head may be seeked to a full LEB with no free
space, or very little free space. And 'ubifs_rcvry_gc_commit()' tries to find a
fully or mostly dirty LEB to match the current GC head (because we need to
garbage-collect that dirty LEB at one go, because we do not have @c->gc_lnum).
So 'ubifs_find_dirty_leb()' fails and we fall back to finding an empty LEB and
also fail. As a result - recovery fails and mounting fails.
This patch teaches the replay to initialize the GC heads exactly to the latest
buds, i.e. the buds which have the largest sequence number in corresponding
log reference nodes.
Currently UBIFS has a small optimization - it frees write-buffers when it is
re-mounted from R/W mode to R/O mode. Of course, when it is mounted R/O, it
does not allocate write-buffers as well.
This optimization is nice but it leads to subtle problems and complications
in recovery, which I can reproduce using the integck test. The symptoms are
that after a power cut the file-system cannot be mounted if we first mount
it R/O, and then re-mount R/W - 'ubifs_rcvry_gc_commit()' prints:
UBIFS error (pid 34456): could not find an empty LEB
Analysis of the problem.
When mounting R/W, the reply process sets journal heads to buds [1], but
when mounting R/O - it does not do this, because the write-buffers are not
allocated. So 'ubifs_rcvry_gc_commit()' works completely differently for the
same file-system but for the following 2 cases:
1. mounting R/W after a power cut and recover
2. mounting R/O after a power cut, re-mounting R/W and run deferred recovery
In the former case, we have journal heads seeked to the a bud, in the latter
case, they are non-seeked (wbuf->lnum == -1). So in the latter case we do not
try to recover the GC LEB by garbage-collecting to the GC head, but we just
try to find an empty LEB, and there may be no empty LEBs, so we just fail.
On the other hand, in the former case (mount R/W), we are able to make a GC LEB
(@c->gc_lnum) by garbage-collecting.
Thus, let's remove this small nice optimization and always allocate
write-buffers. This should not make too big difference - we have only 3
of them, each of max. write unit size, which is usually 2KiB. So this is
about 6KiB of RAM for the typical case, and only when mounted R/O.
[1]: Note, currently the replay process is setting (seeking) the journal heads
to _some_ buds, not necessarily to the buds which had been the journal heads
before the power cut happened. This will be fixed separately.
Linus Torvalds [Mon, 2 May 2011 15:46:50 +0000 (08:46 -0700)]
Merge branch 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging
* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
i2c-parport: Fix adapter list handling
i2c-i801: Move device ID definitions to driver
Lasse Collin [Sun, 1 May 2011 16:38:42 +0000 (19:38 +0300)]
XZ decompressor: Fix decoding of empty LZMA2 streams
The old code considered valid empty LZMA2 streams to be corrupt.
Note that a typical empty .xz file has no LZMA2 data at all,
and thus most .xz files having no uncompressed data are handled
correctly even without this fix.
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It turned out that there are different pin configurations for this
PCI SSID, including multi-channel modes. And more proper fix for
allowing line-out mutes will come up in 2.6.40 tree, so we won't need
this fixup any more there.
af_unix: Only allow recv on connected seqpacket sockets.
This fixes the following oops discovered by Dan Aloni:
> Anyway, the following is the output of the Oops that I got on the
> Ubuntu kernel on which I first detected the problem
> (2.6.37-12-generic). The Oops that followed will be more useful, I
> guess.
The bug was that unix domain sockets use a pseduo packet for
connecting and accept uses that psudo packet to get the socket.
In the buggy seqpacket case we were allowing unconnected
sockets to call recvmsg and try to receive the pseudo packet.
That is always wrong and as of commit 7361c36c5 the pseudo
packet had become enough different from a normal packet
that the kernel started oopsing.
Do for seqpacket_recv what was done for seqpacket_send in 2.5
and only allow it on connected seqpacket sockets.
Cc: stable@kernel.org Tested-by: Dan Aloni <dan@aloni.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Yinghai Lu [Sun, 1 May 2011 17:12:04 +0000 (19:12 +0200)]
x86, NUMA: Fix empty memblk detection in numa_cleanup_meminfo()
numa_cleanup_meminfo() trims each memblk between low (0) and
high (max_pfn) limits and discards empty ones. However, the
emptiness detection incorrectly used equality test. If the
start of a memblk is higher than max_pfn, it is empty but fails
the equality test and doesn't get discarded.
The condition triggers when max_pfn is lower than start of a
NUMA node and results in memory misconfiguration - leading to
WARN_ON()s and other funnies. The bug was discovered in devel
branch where 32bit too uses this code path for NUMA init. If a
node is above the addressing limit, max_pfn ends up lower than
the node triggering this problem.
The failure hasn't been observed on x86-64 but is still possible
with broken hardware e820/NUMA info. As the fix is very low
risk, it would be better to apply it even for 64bit.
Fix it by using >= instead of ==.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
[ Extracted the actual fix from the original patch and rewrote patch description. ] Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/20110501171204.GO29280@htj.dyndns.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
Older AMD K8 processors (Revisions A-E) are affected by erratum
400 (APIC timer interrupts don't occur in C states greater than
C1). This, for example, means that X86_FEATURE_ARAT flag should
not be set for these parts.
This addresses regression introduced by commit b87cf80af3ba4b4c008b4face3c68d604e1715c6 ("x86, AMD: Set ARAT
feature on AMD processors") where the system may become
unresponsive until external interrupt (such as keyboard input)
occurs. This results, for example, in time not being reported
correctly, lack of progress on the system and other lockups.
Jean Delvare [Sun, 1 May 2011 16:18:49 +0000 (18:18 +0200)]
i2c-parport: Fix adapter list handling
Use a standard list with proper locking to handle the list of
adapters. Thankfully it only matters on systems with more than one
parallel port, which are very rare.
Thanks to Lukasz Kapiec for reporting the problem to me.
Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: stable@kernel.org
Jean Delvare [Sun, 1 May 2011 16:18:49 +0000 (18:18 +0200)]
i2c-i801: Move device ID definitions to driver
Move the SMBus device ID definitions of recent devices from pci_ids.h
to the i2c-i801.c driver file. They don't have to be shared, as they
are clearly identified and only used in this driver. In the future,
such IDs will go to i2c-i801 directly. This will make adding support
for new devices much faster and easier, as it will avoid cross-
subsystem patch sets and merge conflicts.
Russell King [Sat, 30 Apr 2011 09:14:08 +0000 (10:14 +0100)]
CLKDEV: Fix clkdev return value for NULL clk case
clkdev may incorrectly cause a clkdev entry with a NULL clk to return
-ENOENT. This is not the intention of this code; -ENOENT should only
be returned if the clock entry can not be found in the table. Fix
this.
Reported-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf, x86, nmi: Move LVT un-masking into irq handlers
perf events, x86: Work around the Nehalem AAJ80 erratum
perf, x86: Fix BTS condition
ftrace: Build without frame pointers on Microblaze
Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: ce4100: Configure IOAPIC pins for USB and SATA to level type
x86: devicetree: Configure IOAPIC pin only once
x86, setup: When probing memory with e801, use ax/bx as a pair
Merge branch 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
hwmon: (lm85) Fix error paths in probe function
hwmon: (lm85) Add missing list terminators
hwmon: (adm1021) Clarify documentation regarding Xeon processors
hwmon: (lm90) Fix update interval information in driver documentation
hwmon: (lm90) Add support for ADT7461A and NCT1008
Add support of pause frames advertise in mii_get_an. This provides all drivers
that use mii_ethtool_gset to represent their own and Link partner flow control
abilities in ethtool.
Signed-off-by: Artem Polyakov <artpol84@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Adam Jaremko [Thu, 28 Apr 2011 07:41:18 +0000 (07:41 +0000)]
net: ftmac100: fix scheduling while atomic during PHY link status change
Signed-off-by: Adam Jaremko <adam.jaremko@gmail.com> Acked-by: Po-Yu Chuang <ratbert@faraday-tech.com> Signed-off-by: David S. Miller <davem@davemloft.net>
It occured during some stress testing, in which the reporter was repeatedly
removing and modprobing the bnx2 module while doing various other random
operations on the bnx2 registered net device. Noting that this error occured on
a serdes based device, we noted that there were a few ethtool operations (most
notably self_test and set_phys_id) that have execution paths that lead into
bnx2_setup_serdes_phy. This function is notable because it executes a mod_timer
call, which starts the bp->timer running. Currently bnx2 is setup to assume
that this timer only nees to be stopped when bnx2_close or bnx2_suspend is
called. Since the above ethtool operations are not gated on the net device
having been opened however, that assumption is incorrect, and can lead to the
timer still running after the module has been removed, leading to the oops above
(as well as other simmilar oopses).
Fix the problem by ensuring that the timer is stopped when pci_device_unregister
is called.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Reported-by: Hushan Jia <hjia@redhat.com> CC: Michael Chan <mchan@broadcom.com> CC: "David S. Miller" <davem@davemloft.net> Acked-by: Michael Chan <mchan@broadcom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Patch partially resolve:
https://bugzilla.kernel.org/show_bug.cgi?id=16691
However, there are still 11n performance problems on 4965 and 5xxx
devices that need to be investigated.
Cc: stable@kernel.org # 2.6.35+ Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Wey-Yi Guy <wey-yi.w.guy@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
workqueue: fix deadlock in worker_maybe_bind_and_lock()
If a rescuer and stop_machine() bringing down a CPU race with each
other, they may deadlock on non-preemptive kernel. The CPU won't
accept a new task, so the rescuer can't migrate to the target CPU,
while stop_machine() can't proceed because the rescuer is holding one
of the CPU retrying migration. GCWQ_DISASSOCIATED is never cleared
and worker_maybe_bind_and_lock() retries indefinitely.
This problem can be reproduced semi reliably while the system is
entering suspend.
Merge branch 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6
* 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6:
OMAP3+: voltage: remove initial voltage
OMAP4: Intialize IVA Device in addition to DSP device.
omap: rx51: mark reserved memory earlier
OMAP3: l3: fix for "irq 10: nobody cared" message
arm: omap2: enable smc instruction for sleep34xx
OMAP2/3: hwmod: fix gpio-reset timeouts seen during bootup.
OMAP3: PM: Do not rely on ROM code to restore CM_AUTOIDLE_PLL.AUTO_PERIPH_DPLL
OMAP2+: PM: Fix the saving of CM_AUTOIDLE_PLL register on scratchpad area
OMAP4: clock data: Change DSS clock aliases
OMAP2+: hwmod data: Fix wrong dma_system end address
Dan Rosenberg [Fri, 29 Apr 2011 14:48:07 +0000 (15:48 +0100)]
ARM: 6891/1: prevent heap corruption in OABI semtimedop
When CONFIG_OABI_COMPAT is set, the wrapper for semtimedop does not
bound the nsops argument. A sufficiently large value will cause an
integer overflow in allocation size, followed by copying too much data
into the allocated buffer. Fix this by restricting nsops to SEMOPM.
Untested.
Cc: stable@kernel.org Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Recent Xeon processor thermal sensors are supported by the coretemp
driver and not the adm1021 driver. Only one old generation of Xeon
processors (the first Netburst ones) are supported by the adm1021
driver.
Reported-by: Darren Hart <dvhart@linux.intel.com> Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
hwmon: (lm90) Add support for ADT7461A and NCT1008
This patch adds support for ADT7461A and NCT1008 to the lm90 driver.
Both chips have identical functionality and report the same manufacturing ID
and device ID values.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
The PCI SSID is 1025:031c and the codec SSID is 1025:031d,
so the driver mistakes this for a SKU value, but looking at
the numbers, this is obviously wrong.
Thomas Gleixner [Thu, 28 Apr 2011 22:02:00 +0000 (00:02 +0200)]
hrtimer: Initialize CLOCK_ID to HRTIMER_BASE table statically
Sedat and Bruno reported RCU stalls which turned out to be caused by
the following;
sched_init() calls init_rt_bandwidth() which calls hrtimer_init()
_BEFORE_ hrtimers_init() is called. While not entirely correct this
worked because hrtimer_init() only accessed statically initialized
data (hrtimer_bases.clock_base[CLOCK_MONOTONIC])
Commit e06383db9 (hrtimers: extend hrtimer base code to handle more
then 2 clockids) added an indirection to the hrtimer_bases.clock_base
lookup to avoid gap handling in the hot path. The table which is used
for the translataion from CLOCK_ID to HRTIMER_BASE index is
initialized at runtime in hrtimers_init(). So the early call of the
scheduler code translates CLOCK_MONOTONIC to HRTIMER_BASE_REALTIME.
Thus the rt_bandwith timer ends up on CLOCK_REALTIME. If the timer is
armed and the wall clock time is set (e.g. ntpdate in the early boot
process - which also gives the problem deterministic behaviour
i.e. magic recovery after N hours), then the timer ends up with an
expiry time far into the future. That breaks the RT throttler
mechanism as rt runtime is accumulated and never cleared, so the rt
throttler detects a false cpu hog condition and blocks all RT tasks
until the timer finally expires. That in turn stalls the RCU thread of
TINYRCU which leads to an huge amount of RCU callbacks piling up.
Make the translation table statically initialized, so we are back to
the status of <= 2.6.39.
Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reported-by: Bruno Prémont <bonbons@linux-vserver.org> Cc: John stultz <johnstul@us.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104282353140.3005%40ionos%3E Reviewed-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[S390] irqstats: fix counting of pfault, dasd diag and virtio irqs
pfault, dasd diag and virtio all use the same external interrupt number.
The respective interrupt handlers decide by the subcode if they are
meant to handle the interrupt.
Counting is currently done before looking at the subcode which means
each handler counts an interrupt even if it is not handling it.
Fix this by moving the kstat code after the code which looks at the
subcode.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Jon Medhurst [Tue, 19 Apr 2011 09:52:20 +0000 (10:52 +0100)]
ARM: kprobes: Tidy-up kprobes-decode.c
- Remove coding standard violations reported by checkpatch.pl
- Delete comment about handling of conditional branches which is no
longer true.
- Delete comment at end of file which lists all ARM instructions. This
duplicates data available in the ARM ARM and seems like an
unnecessary maintenance burden to keep this up to date and accurate.
Signed-off-by: Jon Medhurst <tixy@yxit.co.uk> Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
projects / linux-beck.git / log