The role of the ->wake() platform callback for suspend-to-idle is to
deal with possible spurious wakeups, among other things. The ACPI
implementation of it, acpi_s2idle_wake(), additionally checks the
conditions for entering the Low Power S0 Idle state by the platform
and reports the ones that have not been met.
However, the ->wake() platform callback is invoked after calling
dpm_noirq_resume_devices(), which means that the power states of some
devices may have changed since s2idle_enter() returned, so some unmet
Low Power S0 Idle conditions may be reported incorrectly as a result
of that.
To avoid these false positives, reorder the invocations of the
dpm_noirq_resume_devices() routine and the ->wake() platform callback
in s2idle_loop().
Fixes: 726fb6b4f2 (ACPI / PM: Check low power idle constraints for debug only)
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull seccomp fix from Kees Cook:
"Fix refcounting bug in CRIU interface, noticed by Chris Salls (Oleg &
Tycho)"
* tag 'seccomp-v4.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
seccomp: fix the usage of get/put_seccomp_filter() in seccomp_get_filter()
BPF_NEG takes only one operand, unlike the bulk of BPF_ALU[64] which are
compound-assignments. So give it its own format in print_bpf_insn().
Signed-off-by: Edward Cree <ecree@solarflare.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
print_bpf_insn() was treating all BPF_ALU[64] the same, but BPF_END has a
different structure: it has a size in insn->imm (even if it's BPF_X) and
uses the BPF_SRC (X or K) to indicate which endianness to use. So it
needs different code to print it.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
When generic irq chips are allocated for an irq domain the domain name is
set to the irq chip name. That was done to have named domains before the
recent changes which enforce domain naming were done.
Since then the overwrite causes a memory leak when the domain name is
dynamically allocated and even worse it would cause the domain free code to
free the wrong name pointer, which might point to a constant.
Remove the name assignment to prevent this.
Fixes: d59f6617ee ("genirq: Allow fwnode to carry name information only")
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20170928043731.4764-1-jeffy.chen@rock-chips.com
As Chris explains, get_seccomp_filter() and put_seccomp_filter() can end
up using different filters. Once we drop ->siglock it is possible for
task->seccomp.filter to have been replaced by SECCOMP_FILTER_FLAG_TSYNC.
Fixes: f8e529ed94 ("seccomp, ptrace: add support for dumping seccomp filters")
Reported-by: Chris Salls <chrissalls5@gmail.com>
Cc: stable@vger.kernel.org # needs s/refcount_/atomic_/ for v4.12 and earlier
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
[tycho: add __get_seccomp_filter vs. open coding refcount_inc()]
Signed-off-by: Tycho Andersen <tycho@docker.com>
[kees: tweak commit log]
Signed-off-by: Kees Cook <keescook@chromium.org>
This work enables generic transfer of metadata from XDP into skb. The
basic idea is that we can make use of the fact that the resulting skb
must be linear and already comes with a larger headroom for supporting
bpf_xdp_adjust_head(), which mangles xdp->data. Here, we base our work
on a similar principle and introduce a small helper bpf_xdp_adjust_meta()
for adjusting a new pointer called xdp->data_meta. Thus, the packet has
a flexible and programmable room for meta data, followed by the actual
packet data. struct xdp_buff is therefore laid out that we first point
to data_hard_start, then data_meta directly prepended to data followed
by data_end marking the end of packet. bpf_xdp_adjust_head() takes into
account whether we have meta data already prepended and if so, memmove()s
this along with the given offset provided there's enough room.
xdp->data_meta is optional and programs are not required to use it. The
rationale is that when we process the packet in XDP (e.g. as DoS filter),
we can push further meta data along with it for the XDP_PASS case, and
give the guarantee that a clsact ingress BPF program on the same device
can pick this up for further post-processing. Since we work with skb
there, we can also set skb->mark, skb->priority or other skb meta data
out of BPF, thus having this scratch space generic and programmable
allows for more flexibility than defining a direct 1:1 transfer of
potentially new XDP members into skb (it's also more efficient as we
don't need to initialize/handle each of such new members). The facility
also works together with GRO aggregation. The scratch space at the head
of the packet can be multiple of 4 byte up to 32 byte large. Drivers not
yet supporting xdp->data_meta can simply be set up with xdp->data_meta
as xdp->data + 1 as bpf_xdp_adjust_meta() will detect this and bail out,
such that the subsequent match against xdp->data for later access is
guaranteed to fail.
The verifier treats xdp->data_meta/xdp->data the same way as we treat
xdp->data/xdp->data_end pointer comparisons. The requirement for doing
the compare against xdp->data is that it hasn't been modified from it's
original address we got from ctx access. It may have a range marking
already from prior successful xdp->data/xdp->data_end pointer comparisons
though.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The code is only for blkcg not for all cgroups
Fixes: d4478e92d6 ("block/loop: make loop cgroup aware")
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
kthread usually runs jobs on behalf of other threads. The jobs should be
charged to cgroup of original threads. But the jobs run in a kthread,
where we lose the cgroup context of original threads. The patch adds a
machanism to record cgroup info of original threads in kthread context.
Later we can retrieve the cgroup info and attach the cgroup info to jobs.
Since this mechanism is only required by kthread, we store the cgroup
info in kthread data instead of generic task_struct.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull block fixes from Jens Axboe:
- Two sets of NVMe pull requests from Christoph:
- Fixes for the Fibre Channel host/target to fix spec compliance
- Allow a zero keep alive timeout
- Make the debug printk for broken SGLs work better
- Fix queue zeroing during initialization
- Set of RDMA and FC fixes
- Target div-by-zero fix
- bsg double-free fix.
- ndb unknown ioctl fix from Josef.
- Buffered vs O_DIRECT page cache inconsistency fix. Has been floating
around for a long time, well reviewed. From Lukas.
- brd overflow fix from Mikulas.
- Fix for a loop regression in this merge window, where using a union
for two members of the loop_cmd turned out to be a really bad idea.
From Omar.
- Fix for an iostat regression fix in this series, using the wrong API
to get at the block queue. From Shaohua.
- Fix for a potential blktrace delection deadlock. From Waiman.
* 'for-linus' of git://git.kernel.dk/linux-block: (30 commits)
nvme-fcloop: fix port deletes and callbacks
nvmet-fc: sync header templates with comments
nvmet-fc: ensure target queue id within range.
nvmet-fc: on port remove call put outside lock
nvme-rdma: don't fully stop the controller in error recovery
nvme-rdma: give up reconnect if state change fails
nvme-core: Use nvme_wq to queue async events and fw activation
nvme: fix sqhd reference when admin queue connect fails
block: fix a crash caused by wrong API
fs: Fix page cache inconsistency when mixing buffered and AIO DIO
nvmet: implement valid sqhd values in completions
nvme-fabrics: Allow 0 as KATO value
nvme: allow timed-out ios to retry
nvme: stop aer posting if controller state not live
nvme-pci: Print invalid SGL only once
nvme-pci: initialize queue memory before interrupts
nvmet-fc: fix failing max io queue connections
nvme-fc: use transport-specific sgl format
nvme: add transport SGL definitions
nvme.h: remove FC transport-specific error values
...
Pull tracing fixes from Steven Rostedt:
"Stack tracing and RCU has been having issues with each other and
lockdep has been pointing out constant problems.
The changes have been going into the stack tracer, but it has been
discovered that the problem isn't with the stack tracer itself, but it
is with calling save_stack_trace() from within the internals of RCU.
The stack tracer is the one that can trigger the issue the easiest,
but examining the problem further, it could also happen from a WARN()
in the wrong place, or even if an NMI happened in this area and it did
an rcu_read_lock().
The critical area is where RCU is not watching. Which can happen while
going to and from idle, or bringing up or taking down a CPU.
The final fix was to put the protection in kernel_text_address() as it
is the one that requires RCU to be watching while doing the stack
trace.
To make this work properly, Paul had to allow rcu_irq_enter() happen
after rcu_nmi_enter(). This should have been done anyway, since an NMI
can page fault (reading vmalloc area), and a page fault triggers
rcu_irq_enter().
One patch is just a consolidation of code so that the fix only needed
to be done in one location"
* tag 'trace-v4.14-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Remove RCU work arounds from stack tracer
extable: Enable RCU if it is not watching in kernel_text_address()
extable: Consolidate *kernel_text_address() functions
rcu: Allow for page faults in NMI handlers
Before the delete operator was added, this datastructure maintained
an invariant that intermediate nodes were only present when necessary
to build the tree. This patch updates the delete operation to reinstate
that invariant by removing unnecessary intermediate nodes after a node is
removed and thus keeping the tree structure at a minimal size.
Suggested-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Craig Gallek <kraig@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
cfb766da54 ("sched/cputime: Expose cputime_adjust()") made
cputime_adjust() public for cgroup basic cpu stat support; however,
the commit forgot to add a dummy implementaiton for
CONFIG_VIRT_CPU_ACCOUNTING_NATIVE leading to compiler errors on some
s390 configurations.
Fix it by adding the missing dummy implementation.
Reported-by: “kbuild-all@01.org” <kbuild-all@01.org>
Fixes: cfb766da54 ("sched/cputime: Expose cputime_adjust()")
Signed-off-by: Tejun Heo <tj@kernel.org>
Add a sysfs file to one-time fail a specific state. This can be used
to test the state rollback code paths.
Something like this (hotplug-up.sh):
#!/bin/bash
echo 0 > /debug/sched_debug
echo 1 > /debug/tracing/events/cpuhp/enable
ALL_STATES=`cat /sys/devices/system/cpu/hotplug/states | cut -d':' -f1`
STATES=${1:-$ALL_STATES}
for state in $STATES
do
echo 0 > /sys/devices/system/cpu/cpu1/online
echo 0 > /debug/tracing/trace
echo Fail state: $state
echo $state > /sys/devices/system/cpu/cpu1/hotplug/fail
cat /sys/devices/system/cpu/cpu1/hotplug/fail
echo 1 > /sys/devices/system/cpu/cpu1/online
cat /debug/tracing/trace > hotfail-${state}.trace
sleep 1
done
Can be used to test for all possible rollback (barring multi-instance)
scenarios on CPU-up, CPU-down is a trivial modification of the above.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: bigeasy@linutronix.de
Cc: efault@gmx.de
Cc: rostedt@goodmis.org
Cc: max.byungchul.park@gmail.com
Link: https://lkml.kernel.org/r/20170920170546.972581715@infradead.org
With lockdep-crossrelease we get deadlock reports that span cpu-up and
cpu-down chains. Such deadlocks cannot possibly happen because cpu-up
and cpu-down are globally serialized.
takedown_cpu()
irq_lock_sparse()
wait_for_completion(&st->done)
cpuhp_thread_fun
cpuhp_up_callback
cpuhp_invoke_callback
irq_affinity_online_cpu
irq_local_spare()
irq_unlock_sparse()
complete(&st->done)
Now that we have consistent AP state, we can trivially separate the
AP completion between up and down using st->bringup.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: max.byungchul.park@gmail.com
Cc: bigeasy@linutronix.de
Cc: efault@gmx.de
Cc: rostedt@goodmis.org
Link: https://lkml.kernel.org/r/20170920170546.872472799@infradead.org
With lockdep-crossrelease we get deadlock reports that span cpu-up and
cpu-down chains. Such deadlocks cannot possibly happen because cpu-up
and cpu-down are globally serialized.
CPU0 CPU1 CPU2
cpuhp_up_callbacks: takedown_cpu: cpuhp_thread_fun:
cpuhp_state
irq_lock_sparse()
irq_lock_sparse()
wait_for_completion()
cpuhp_state
complete()
Now that we have consistent AP state, we can trivially separate the
AP-work class between up and down using st->bringup.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: max.byungchul.park@gmail.com
Cc: bigeasy@linutronix.de
Cc: efault@gmx.de
Cc: rostedt@goodmis.org
Link: https://lkml.kernel.org/r/20170920170546.922524234@infradead.org
While the generic callback functions have an 'int' return and thus
appear to be allowed to return error, this is not true for all states.
Specifically, what used to be STARTING/DYING are ran with IRQs
disabled from critical parts of CPU bringup/teardown and are not
allowed to fail. Add WARNs to enforce this rule.
But since some callbacks are indeed allowed to fail, we have the
situation where a state-machine rollback encounters a failure, in this
case we're stuck, we can't go forward and we can't go back. Also add a
WARN for that case.
AFAICT this is a fundamental 'problem' with no real obvious solution.
We want the 'prepare' callbacks to allow failure on either up or down.
Typically on prepare-up this would be things like -ENOMEM from
resource allocations, and the typical usage in prepare-down would be
something like -EBUSY to avoid CPUs being taken away.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: bigeasy@linutronix.de
Cc: efault@gmx.de
Cc: rostedt@goodmis.org
Cc: max.byungchul.park@gmail.com
Link: https://lkml.kernel.org/r/20170920170546.819539119@infradead.org
There is currently no explicit state change on rollback. That is,
st->bringup, st->rollback and st->target are not consistent when doing
the rollback.
Rework the AP state handling to be more coherent. This does mean we
have to do a second AP kick-and-wait for rollback, but since rollback
is the slow path of a slowpath, this really should not matter.
Take this opportunity to simplify the AP thread function to only run a
single callback per invocation. This unifies the three single/up/down
modes is supports. The looping it used to do for up/down are achieved
by retaining should_run and relying on the main smpboot_thread_fn()
loop.
(I have most of a patch that does the same for the BP state handling,
but that's not critical and gets a little complicated because
CPUHP_BRINGUP_CPU does the AP handoff from a callback, which gets
recursive @st usage, I still have de-fugly that.)
[ tglx: Move cpuhp_down_callbacks() et al. into the HOTPLUG_CPU section to
avoid gcc complaining about unused functions. Make the HOTPLUG_CPU
one piece instead of having two consecutive ifdef sections of the
same type. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: bigeasy@linutronix.de
Cc: efault@gmx.de
Cc: rostedt@goodmis.org
Cc: max.byungchul.park@gmail.com
Link: https://lkml.kernel.org/r/20170920170546.769658088@infradead.org
The configurable printk timestamping wants access to clock realtime. Right
now there is no ktime_get_real_fast_ns() accessor because reading the
monotonic base and the realtime offset cannot be done atomically. Contrary
to boot time this offset can change during runtime and cause half updated
readouts.
struct tk_read_base was fully packed when the fast timekeeper access was
implemented. commit ceea5e3771 ("time: Fix clock->read(clock) race around
clocksource changes") removed the 'read' function pointer from the
structure, but of course left the comment stale.
So now the structure can fit a new 64bit member w/o violating the cache
line constraints.
Add real_base to tk_read_base and update it in the fast timekeeper update
sequence.
Implement an accessor which follows the same scheme as the accessor to
clock monotonic, but uses the new real_base to access clock real time.
The runtime overhead for updating real_base is minimal as it just adds two
cache hot values and stores them into an already dirtied cache line along
with the other fast timekeeper updates.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead,org>
Link: https://lkml.kernel.org/r/1505757060-2004-3-git-send-email-prarit@redhat.com
Implement the infrastructure for a simple bitmap based allocator, which
will replace the x86 vector allocator. It's in the core code as other
architectures might be able to reuse/extend it. For now it only implements
allocations for single CPUs, but it's simple to add multi CPU allocation
support if required.
The concept is rather simple:
Global information:
system_vector bitmap
global accounting
PerCPU information:
allocation bitmap
managed allocation bitmap
local accounting
The system vector bitmap is used to exclude vectors system wide from the
allocation space.
The allocation bitmap is used to keep track of per cpu used vectors.
The managed allocation bitmap is used to reserve vectors for managed
interrupts.
When a regular (non managed) interrupt allocation happens then the
following rule applies:
tmpmap = system_map | alloc_map | managed_map
find_zero_bit(tmpmap)
Oring the bitmaps together gives the real available space. The same rule
applies for reserving a managed interrupt vector. But contrary to the
regular interrupts the reservation only marks the bit in the managed map
and therefor excludes it from the regular allocations. The managed map is
only cleaned out when the a managed interrupt is completely released and it
stays alive accross CPU offline/online operations.
For managed interrupt allocations the rule is:
tmpmap = managed_map & ~alloc_map
find_first_bit(tmpmap)
This returns the first bit which is in the managed map, but not yet
allocated in the allocation map. The allocation marks it in the allocation
map and hands it back to the caller for use.
The rest of the code are helper functions to handle the various
requirements and the accounting which are necessary to replace the x86
vector allocation code. The result is a single patch as the evolution of
this infrastructure cannot be represented in bits and pieces.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213153.185437174@linutronix.de
for_each_cpu() unintuitively reports CPU0 as set independend of the actual
cpumask content on UP kernels. That leads to a NULL pointer dereference
when the cleanup function is invoked and there is no event to clean up.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
In cgroup1, while cpuacct isn't actually controlling any resources, it
is a separate controller due to combination of two factors -
1. enabling cpu controller has significant side effects, and 2. we
have to pick one of the hierarchies to account CPU usages on. cpuacct
controller is effectively used to designate a hierarchy to track CPU
usages on.
cgroup2's unified hierarchy removes the second reason and we can
account basic CPU usages by default. While we can use cpuacct for
this purpose, both its interface and implementation leave a lot to be
desired - it collects and exposes two sources of truth which don't
agree with each other and some of the exposed statistics don't make
much sense. Also, it propagates all the way up the hierarchy on each
accounting event which is unnecessary.
This patch adds basic resource accounting mechanism to cgroup2's
unified hierarchy and accounts CPU usages using it.
* All accountings are done per-cpu and don't propagate immediately.
It just bumps the per-cgroup per-cpu counters and links to the
parent's updated list if not already on it.
* On a read, the per-cpu counters are collected into the global ones
and then propagated upwards. Only the per-cpu counters which have
changed since the last read are propagated.
* CPU usage stats are collected and shown in "cgroup.stat" with "cpu."
prefix. Total usage is collected from scheduling events. User/sys
breakdown is sourced from tick sampling and adjusted to the usage
using cputime_adjust().
This keeps the accounting side hot path O(1) and per-cpu and the read
side O(nr_updated_since_last_read).
v2: Minor changes and documentation updates as suggested by Waiman and
Roman.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Roman Gushchin <guro@fb.com>
Introduce cgroup_account_cputime[_field]() which wrap cpuacct_charge()
and cgroup_account_field(). This doesn't introduce any functional
changes and will be used to add cgroup basic resource accounting.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
The lockdep code had reported the following unsafe locking scenario:
CPU0 CPU1
---- ----
lock(s_active#228);
lock(&bdev->bd_mutex/1);
lock(s_active#228);
lock(&bdev->bd_mutex);
*** DEADLOCK ***
The deadlock may happen when one task (CPU1) is trying to delete a
partition in a block device and another task (CPU0) is accessing
tracing sysfs file (e.g. /sys/block/dm-1/trace/act_mask) in that
partition.
The s_active isn't an actual lock. It is a reference count (kn->count)
on the sysfs (kernfs) file. Removal of a sysfs file, however, require
a wait until all the references are gone. The reference count is
treated like a rwsem using lockdep instrumentation code.
The fact that a thread is in the sysfs callback method or in the
ioctl call means there is a reference to the opended sysfs or device
file. That should prevent the underlying block structure from being
removed.
Instead of using bd_mutex in the block_device structure, a new
blk_trace_mutex is now added to the request_queue structure to protect
access to the blk_trace structure.
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Fix typo in patch subject line, and prune a comment detailing how
the code used to work.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There was a reported suspicion about a race between exit_pi_state_list()
and put_pi_state(). The same report mentioned the comment with
put_pi_state() said it should be called with hb->lock held, and it no
longer is in all places.
As it turns out, the pi_state->owner serialization is indeed broken. As per
the new rules:
734009e96d ("futex: Change locking rules")
pi_state->owner should be serialized by pi_state->pi_mutex.wait_lock.
For the sites setting pi_state->owner we already hold wait_lock (where
required) but exit_pi_state_list() and put_pi_state() were not and
raced on clearing it.
Fixes: 734009e96d ("futex: Change locking rules")
Reported-by: Gratian Crisan <gratian.crisan@ni.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: dvhart@infradead.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20170922154806.jd3ffltfk24m4o4y@hirez.programming.kicks-ass.net
Currently the stack tracer calls rcu_irq_enter() to make sure RCU
is watching when it records a stack trace. But if the stack tracer
is triggered while tracing inside of a rcu_irq_enter(), calling
rcu_irq_enter() unconditionally can be problematic.
The reason for having rcu_irq_enter() in the first place has been
fixed from within the saving of the stack trace code, and there's no
reason for doing it in the stack tracer itself. Just remove it.
Cc: stable@vger.kernel.org
Fixes: 0be964be0 ("module: Sanitize RCU usage and locking")
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Suggested-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
If kernel_text_address() is called when RCU is not watching, it can cause an
RCU bug because is_module_text_address(), the is_kprobe_*insn_slot()
and is_bpf_text_address() functions require the use of RCU.
Only enable RCU if it is not currently watching before it calls
is_module_text_address(). The use of rcu_nmi_enter() is used to enable RCU
because kernel_text_address() can happen pretty much anywhere (like an NMI),
and even from within an NMI. It is called via save_stack_trace() that can be
called by any WARN() or tracing function, which can happen while RCU is not
watching (for example, going to or coming from idle, or during CPU take down
or bring up).
Cc: stable@vger.kernel.org
Fixes: 0be964be0 ("module: Sanitize RCU usage and locking")
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The functionality between kernel_text_address() and _kernel_text_address()
is the same except that _kernel_text_address() does a little more (that
function needs a rename, but that can be done another time). Instead of
having duplicate code in both, simply have _kernel_text_address() calls
kernel_text_address() instead.
This is marked for stable because there's an RCU bug that can happen if
one of these functions gets called while RCU is not watching. That fix
depends on this fix to keep from having to write the fix twice.
Cc: stable@vger.kernel.org
Fixes: 0be964be0 ("module: Sanitize RCU usage and locking")
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
