Use raw-locks in stop_machine() to allow locking in irq-off and
preempt-disabled regions on -RT. This also documents the possible locking
context in general.
[bigeasy: update patch description.]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20180423191635.6014-1-bigeasy@linutronix.de
try_to_wake_up() might invoke delayacct_blkio_end() while holding the
pi_lock (which is a raw_spinlock_t). delayacct_blkio_end() acquires
task_delay_info.lock which is a spinlock_t. This causes a might sleep splat
on -RT where non raw spinlocks are converted to 'sleeping' spinlocks.
task_delay_info.lock is only held for a short amount of time so it's not a
problem latency wise to make convert it to a raw spinlock.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Link: https://lkml.kernel.org/r/20180423161024.6710-1-bigeasy@linutronix.de
The native clear_pending() function is identical to the PV version, so the
latter can simply be removed.
This fixes the build for systems with >= 16K CPUs using the PV lock implementation.
Reported-by: Waiman Long <longman@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/20180427101619.GB21705@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently, the qspinlock_stat code tracks only statistical counts in the
PV qspinlock code. However, it may also be useful to track the number
of locking operations done via the pending code vs. the MCS lock queue
slowpath for the non-PV case.
The qspinlock stat code is modified to do that. The stat counter
pv_lock_slowpath is renamed to lock_slowpath so that it can be used by
both the PV and non-PV cases.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/1524738868-31318-14-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When reaching the head of an uncontended queue on the qspinlock slow-path,
using a try_cmpxchg() instead of a cmpxchg() operation to transition the
lock work to _Q_LOCKED_VAL generates slightly better code for x86 and
pretty much identical code for arm64.
Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-13-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The qspinlock slowpath must ensure that the MCS node is fully initialised
before it can be reached by another other CPU. This is currently enforced
by using a RELEASE operation when updating the tail and also when linking
the node into the waitqueue, since the control dependency off xchg_tail
is insufficient to enforce sufficient ordering, see:
95bcade33a ("locking/qspinlock: Ensure node is initialised before updating prev->next")
Back-to-back RELEASE operations may be expensive on some architectures,
particularly those that implement them using fences under the hood. We
can replace the two RELEASE operations with a single smp_wmb() fence and
use RELAXED operations for the subsequent publishing of the node.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-12-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When a locker reaches the head of the queue and takes the lock, a
concurrent locker may enqueue and force the lock holder to spin
whilst its node->next field is initialised. Rather than open-code
a READ_ONCE/cpu_relax() loop, this can be implemented using
smp_cond_load_relaxed() instead.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-10-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
For qspinlocks on ARM64, we would like to use WFE instead
of purely spinning. Qspinlocks internally have lock
contenders spin on an MCS lock.
Update arch_mcs_spin_lock_contended() such that it uses
the new smp_cond_load_acquire() so that ARM64 can also
override this spin loop with its own implementation using WFE.
On x86, this can also be cheaper than spinning on
smp_load_acquire().
Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-9-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rather than dig into the counter field of the atomic_t inside the
qspinlock structure so that we can call smp_cond_load_acquire(), use
atomic_cond_read_acquire() instead, which operates on the atomic_t
directly.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-8-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When a queued locker reaches the head of the queue, it claims the lock
by setting _Q_LOCKED_VAL in the lockword. If there isn't contention, it
must also clear the tail as part of this operation so that subsequent
lockers can avoid taking the slowpath altogether.
Currently this is expressed as a cmpxchg() loop that practically only
runs up to two iterations. This is confusing to the reader and unhelpful
to the compiler. Rewrite the cmpxchg() loop without the loop, so that a
failed cmpxchg() implies that there is contention and we just need to
write to _Q_LOCKED_VAL without considering the rest of the lockword.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-7-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The qspinlock locking slowpath utilises a "pending" bit as a simple form
of an embedded test-and-set lock that can avoid the overhead of explicit
queuing in cases where the lock is held but uncontended. This bit is
managed using a cmpxchg() loop which tries to transition the uncontended
lock word from (0,0,0) -> (0,0,1) or (0,0,1) -> (0,1,1).
Unfortunately, the cmpxchg() loop is unbounded and lockers can be starved
indefinitely if the lock word is seen to oscillate between unlocked
(0,0,0) and locked (0,0,1). This could happen if concurrent lockers are
able to take the lock in the cmpxchg() loop without queuing and pass it
around amongst themselves.
This patch fixes the problem by unconditionally setting _Q_PENDING_VAL
using atomic_fetch_or, and then inspecting the old value to see whether
we need to spin on the current lock owner, or whether we now effectively
hold the lock. The tricky scenario is when concurrent lockers end up
queuing on the lock and the lock becomes available, causing us to see
a lockword of (n,0,0). With pending now set, simply queuing could lead
to deadlock as the head of the queue may not have observed the pending
flag being cleared. Conversely, if the head of the queue did observe
pending being cleared, then it could transition the lock from (n,0,0) ->
(0,0,1) meaning that any attempt to "undo" our setting of the pending
bit could race with a concurrent locker trying to set it.
We handle this race by preserving the pending bit when taking the lock
after reaching the head of the queue and leaving the tail entry intact
if we saw pending set, because we know that the tail is going to be
updated shortly.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-6-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
If a locker taking the qspinlock slowpath reads a lock value indicating
that only the pending bit is set, then it will spin whilst the
concurrent pending->locked transition takes effect.
Unfortunately, there is no guarantee that such a transition will ever be
observed since concurrent lockers could continuously set pending and
hand over the lock amongst themselves, leading to starvation. Whilst
this would probably resolve in practice, it means that it is not
possible to prove liveness properties about the lock and means that lock
acquisition time is unbounded.
Rather than removing the pending->locked spinning from the slowpath
altogether (which has been shown to heavily penalise a 2-threaded
locking stress test on x86), this patch replaces the explicit spinning
with a call to atomic_cond_read_relaxed and allows the architecture to
provide a bound on the number of spins. For architectures that can
respond to changes in cacheline state in their smp_cond_load implementation,
it should be sufficient to use the default bound of 1.
Suggested-by: Waiman Long <longman@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
'struct __qspinlock' provides a handy union of fields so that
subcomponents of the lockword can be accessed by name, without having to
manage shifts and masks explicitly and take endianness into account.
This is useful in qspinlock.h and also potentially in arch headers, so
move the 'struct __qspinlock' into 'struct qspinlock' and kill the extra
definition.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-3-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
If the user specifies an invalid field modifier for a hist trigger,
the current code correctly flags that as an error, but doesn't tell
the user what happened.
Fix this by invoking hist_err() with an appropriate message when
invalid modifiers are specified.
Before:
# echo 'hist:keys=pid:ts0=common_timestamp.junkusecs' >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
-su: echo: write error: Invalid argument
# cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/hist
After:
# echo 'hist:keys=pid:ts0=common_timestamp.junkusecs' >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
-su: echo: write error: Invalid argument
# cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/hist
ERROR: Invalid field modifier: junkusecs
Last command: keys=pid:ts0=common_timestamp.junkusecs
Link: http://lkml.kernel.org/r/b043c59fa79acd06a5f14a1d44dee9e5a3cd1248.1524790601.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
If the user specifies a nonexistent field for a hist trigger, the
current code correctly flags that as an error, but doesn't tell the
user what happened.
Fix this by invoking hist_err() with an appropriate message when
nonexistent fields are specified.
Before:
# echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
-su: echo: write error: Invalid argument
# cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
After:
# echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
-su: echo: write error: Invalid argument
# cat /sys/kernel/debug/tracing/events/sched/sched_switch/hist
ERROR: Couldn't find field: pid
Last command: keys=pid:ts0=common_timestamp.usecs
Link: http://lkml.kernel.org/r/fdc8746969d16906120f162b99dd71c741e0b62c.1524790601.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
The flag-printing code used when displaying hist triggers somehow got
dropped during refactoring of the inter-event patchset. This restores
it.
Below are a couple examples - in the first case, .usecs wasn't being
displayed properly for common_timestamps and the second illustrates
the same for other flags such as .execname.
Before:
# echo 'hist:key=common_pid.execname:val=count:sort=count' > /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
# cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
hist:keys=common_pid:vals=hitcount,count:sort=count:size=2048 [active]
# echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"' >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
# cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
hist:keys=pid:vals=hitcount:ts0=common_timestamp:sort=hitcount:size=2048:clock=global if comm=="cyclictest" [active]
After:
# echo 'hist:key=common_pid.execname:val=count:sort=count' > /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
# cat /sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
hist:keys=common_pid.execname:vals=hitcount,count:sort=count:size=2048 [active]
# echo 'hist:keys=pid:ts0=common_timestamp.usecs if comm=="cyclictest"' >> /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
# cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
hist:keys=pid:vals=hitcount:ts0=common_timestamp.usecs:sort=hitcount:size=2048:clock=global if comm=="cyclictest" [active]
Link: http://lkml.kernel.org/r/492bab42ff21806600af98a8ea901af10efbee0c.1524790601.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Daniel Borkmann says:
====================
pull-request: bpf-next 2018-04-27
The following pull-request contains BPF updates for your *net-next* tree.
The main changes are:
1) Add extensive BPF helper description into include/uapi/linux/bpf.h
and a new script bpf_helpers_doc.py which allows for generating a
man page out of it. Thus, every helper in BPF now comes with proper
function signature, detailed description and return code explanation,
from Quentin.
2) Migrate the BPF collect metadata tunnel tests from BPF samples over
to the BPF selftests and further extend them with v6 vxlan, geneve
and ipip tests, simplify the ipip tests, improve documentation and
convert to bpf_ntoh*() / bpf_hton*() api, from William.
3) Currently, helpers that expect ARG_PTR_TO_MAP_{KEY,VALUE} can only
access stack and packet memory. Extend this to allow such helpers
to also use map values, which enabled use cases where value from
a first lookup can be directly used as a key for a second lookup,
from Paul.
4) Add a new helper bpf_skb_get_xfrm_state() for tc BPF programs in
order to retrieve XFRM state information containing SPI, peer
address and reqid values, from Eyal.
5) Various optimizations in nfp driver's BPF JIT in order to turn ADD
and SUB instructions with negative immediate into the opposite
operation with a positive immediate such that nfp can better fit
small immediates into instructions. Savings in instruction count
up to 4% have been observed, from Jakub.
6) Add the BPF prog's gpl_compatible flag to struct bpf_prog_info
and add support for dumping this through bpftool, from Jiri.
7) Move the BPF sockmap samples over into BPF selftests instead since
sockmap was rather a series of tests than sample anyway and this way
this can be run from automated bots, from John.
8) Follow-up fix for bpf_adjust_tail() helper in order to make it work
with generic XDP, from Nikita.
9) Some follow-up cleanups to BTF, namely, removing unused defines from
BTF uapi header and renaming 'name' struct btf_* members into name_off
to make it more clear they are offsets into string section, from Martin.
10) Remove test_sock_addr from TEST_GEN_PROGS in BPF selftests since
not run directly but invoked from test_sock_addr.sh, from Yonghong.
11) Remove redundant ret assignment in sample BPF loader, from Wang.
12) Add couple of missing files to BPF selftest's gitignore, from Anders.
There are two trivial merge conflicts while pulling:
1) Remove samples/sockmap/Makefile since all sockmap tests have been
moved to selftests.
2) Add both hunks from tools/testing/selftests/bpf/.gitignore to the
file since git should ignore all of them.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Update the siginfo_layout function and enum siginfo_layout to represent
all of the possible field layouts of struct siginfo.
This allows the uses of siginfo_layout in um and arm64 where they are testing
for SIL_FAULT to be more accurate as this rules out the other cases.
Further this allows the switch statements on siginfo_layout to be simpler
if perhaps a little more wordy. Making it easier to understand what is
actually going on.
As SIL_FAULT_BNDERR and SIL_FAULT_PKUERR are never expected to appear
in signalfd just treat them as SIL_FAULT. To include them would take
20 extra bytes an pretty much fill up what is left of
signalfd_siginfo.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The only architecture that does not support SEGV_PKUERR is ia64 and
ia64 has not had 32bit support since some time in 2008. Therefore
copy_siginfo_to_user32 and copy_siginfo_from_user32 do not need to
include support for a missing SEGV_PKUERR.
Compile test on ia64.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
- Add workqueue forward declaration (for new work, but a nice clean up)
- seftest fixes for the new histogram code
- Print output fix for hwlat tracer
- Fix missing system call events - due to change in x86 syscall naming
- Fix kprobe address being used by perf being hashed
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Merge tag 'trace-v4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
- Add workqueue forward declaration (for new work, but a nice clean up)
- seftest fixes for the new histogram code
- Print output fix for hwlat tracer
- Fix missing system call events - due to change in x86 syscall naming
- Fix kprobe address being used by perf being hashed
* tag 'trace-v4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix missing tab for hwlat_detector print format
selftests: ftrace: Add a testcase for multiple actions on trigger
selftests: ftrace: Fix trigger extended error testcase
kprobes: Fix random address output of blacklist file
tracing: Fix kernel crash while using empty filter with perf
tracing/x86: Update syscall trace events to handle new prefixed syscall func names
tracing: Add missing forward declaration
cgroup_rstat_updated() ensures that the cgroup's rstat is linked to
the parent. If there's no parent, it never gets linked and the
function ends up grabbing and releasing the cgroup_rstat_lock each
time for no reason which can be expensive.
This hasn't been a problem till now because nobody was calling the
function for the root cgroup but rstat is gonna be exposed to
controllers and use cases, so let's get ready. Make
cgroup_rstat_updated() an no-op for the root cgroup.
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup_rstat_updated() has a small race window where an updated
signaling can race with flush and could be lost till the next update.
This wasn't a problem for the existing usages, but we plan to use
rstat to track counters which need to be accurate.
This patch plugs the race window by synchronizing
cgroup_rstat_updated() and flush path with memory barriers around
cgroup_rstat_cpu->updated_next pointer.
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch adds cgroup_subsys->css_rstat_flush(). If a subsystem has
this callback, its csses are linked on cgrp->css_rstat_list and rstat
will call the function whenever the associated cgroup is flushed.
Flush is also performed when such csses are released so that residual
counts aren't lost.
Combined with the rstat API previous patches factored out, this allows
controllers to plug into rstat to manage their statistics in a
scalable way.
Signed-off-by: Tejun Heo <tj@kernel.org>
Currently, rstat flush path is protected with a mutex which is fine as
all the existing users are from interface file show path. However,
rstat is being generalized for use by controllers and flushing from
atomic contexts will be necessary.
This patch replaces cgroup_rstat_mutex with a spinlock and adds a
irq-safe flush function - cgroup_rstat_flush_irqsafe(). Explicit
yield handling is added to the flush path so that other flush
functions can yield to other threads and flushers.
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup_rstat is being generalized so that controllers can use it too.
This patch factors out and exposes the following interface functions.
* cgroup_rstat_updated(): Renamed from cgroup_rstat_cpu_updated() for
consistency.
* cgroup_rstat_flush_hold/release(): Factored out from base stat
implementation.
* cgroup_rstat_flush(): Verbatim expose.
While at it, drop assert on cgroup_rstat_mutex in
cgroup_base_stat_flush() as it crosses layers and make a minor comment
update.
v2: Added EXPORT_SYMBOL_GPL(cgroup_rstat_updated) to fix a build bug.
Signed-off-by: Tejun Heo <tj@kernel.org>
Currently, rstat.c has rstat and base stat implementations intermixed.
Collect base stat implementation at the end of the file. Also,
reorder the prototypes.
This patch doesn't make any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Base resource stat accounts universial (not specific to any
controller) resource consumptions on top of rstat. Currently, its
implementation is intermixed with rstat implementation making the code
confusing to follow.
This patch clarifies the distintion by doing the followings.
* Encapsulate base resource stat counters, currently only cputime, in
struct cgroup_base_stat.
* Move prev_cputime into struct cgroup and initialize it with cgroup.
* Rename the related functions so that they start with cgroup_base_stat.
* Prefix the related variables and field names with b.
This patch doesn't make any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
stat is too generic a name and ends up causing subtle confusions.
It'll be made generic so that controllers can plug into it, which will
make the problem worse. Let's rename it to something more specific -
cgroup_rstat for cgroup recursive stat.
This patch does the following renames. No other changes.
* cpu_stat -> rstat_cpu
* stat -> rstat
* ?cstat -> ?rstatc
Note that the renames are selective. The unrenamed are the ones which
implement basic resource statistics on top of rstat. This will be
further cleaned up in the following patches.
Signed-off-by: Tejun Heo <tj@kernel.org>
stat is too generic a name and ends up causing subtle confusions.
It'll be made generic so that controllers can plug into it, which will
make the problem worse. Let's rename it to something more specific -
cgroup_rstat for cgroup recursive stat.
First, rename kernel/cgroup/stat.c to kernel/cgroup/rstat.c. No
content changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
".events" files generate file modified event to notify userland of
possible new events. Some of the events can be quite bursty
(e.g. memory high event) and generating notification each time is
costly and pointless.
This patch implements a event rate limit mechanism. If a new
notification is requested before 10ms has passed since the previous
notification, the new notification is delayed till then.
As this only delays from the second notification on in a given close
cluster of notifications, userland reactions to notifications
shouldn't be delayed at all in most cases while avoiding notification
storms.
Signed-off-by: Tejun Heo <tj@kernel.org>
The "cgroup." core interface files bypass the usual interface removal
path and get removed recursively along with the cgroup itself. While
this works now, the subtle discrepancy gets in the way of implementing
common mechanisms.
This patch updates cgroup core interface file handling so that it's
consistent with controller interface files. When added, the css is
marked CSS_VISIBLE and they're explicitly removed before the cgroup is
destroyed.
This doesn't cause user-visible behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Adding gpl_compatible flag to struct bpf_prog_info
so it can be dumped via bpf_prog_get_info_by_fd and
displayed via bpftool progs dump.
Alexei noticed 4-byte hole in struct bpf_prog_info,
so we put the u32 flags field in there, and we can
keep adding bit fields in there without breaking
user space.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
There is the SPDX license identifier now in the irq simulator. Remove the
license boilerplate.
While at it: update the copyright notice, since I did some changes in 2018.
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20180426200747.8344-1-brgl@bgdev.pl
Caller of uprobe_register is required to keep the inode and containing
mount point referenced.
There was misuse of igrab() in uprobes.c and trace_uprobe.c. This is
because igrab() will not prevent umount of the containing mount point.
To fix this, we added path to struct trace_uprobe, which keeps the inode
and containing mount reference.
For uprobes.c, it is not necessary to call igrab() in uprobe_register(),
as the caller is required to keep the inode reference. The igrab() is
removed and comments on this requirement is added to uprobe_register().
Link: http://lkml.kernel.org/r/CAELBmZB2XX=qEOLAdvGG4cPx4GEntcSnWQquJLUK1ongRj35cA@mail.gmail.com
Link: http://lkml.kernel.org/r/20180423172135.4050588-2-songliubraving@fb.com
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Howard McLauchlan <hmclauchlan@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
As Miklos reported and suggested:
This pattern repeats two times in trace_uprobe.c and in
kernel/events/core.c as well:
ret = kern_path(filename, LOOKUP_FOLLOW, &path);
if (ret)
goto fail_address_parse;
inode = igrab(d_inode(path.dentry));
path_put(&path);
And it's wrong. You can only hold a reference to the inode if you
have an active ref to the superblock as well (which is normally
through path.mnt) or holding s_umount.
This way unmounting the containing filesystem while the tracepoint is
active will give you the "VFS: Busy inodes after unmount..." message
and a crash when the inode is finally put.
Solution: store path instead of inode.
This patch fixes two instances in trace_uprobe.c. struct path is added to
struct trace_uprobe to keep the inode and containing mount point
referenced.
Link: http://lkml.kernel.org/r/20180423172135.4050588-1-songliubraving@fb.com
Fixes: f3f096cfed ("tracing: Provide trace events interface for uprobes")
Fixes: 33ea4b2427 ("perf/core: Implement the 'perf_uprobe' PMU")
Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Howard McLauchlan <hmclauchlan@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Reported-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Revert commits
92af4dcb4e ("tracing: Unify the "boot" and "mono" tracing clocks")
127bfa5f43 ("hrtimer: Unify MONOTONIC and BOOTTIME clock behavior")
7250a4047a ("posix-timers: Unify MONOTONIC and BOOTTIME clock behavior")
d6c7270e91 ("timekeeping: Remove boot time specific code")
f2d6fdbfd2 ("Input: Evdev - unify MONOTONIC and BOOTTIME clock behavior")
d6ed449afd ("timekeeping: Make the MONOTONIC clock behave like the BOOTTIME clock")
72199320d4 ("timekeeping: Add the new CLOCK_MONOTONIC_ACTIVE clock")
As stated in the pull request for the unification of CLOCK_MONOTONIC and
CLOCK_BOOTTIME, it was clear that we might have to revert the change.
As reported by several folks systemd and other applications rely on the
documented behaviour of CLOCK_MONOTONIC on Linux and break with the above
changes. After resume daemons time out and other timeout related issues are
observed. Rafael compiled this list:
* systemd kills daemons on resume, after >WatchdogSec seconds
of suspending (Genki Sky). [Verified that that's because systemd uses
CLOCK_MONOTONIC and expects it to not include the suspend time.]
* systemd-journald misbehaves after resume:
systemd-journald[7266]: File /var/log/journal/016627c3c4784cd4812d4b7e96a34226/system.journal
corrupted or uncleanly shut down, renaming and replacing.
(Mike Galbraith).
* NetworkManager reports "networking disabled" and networking is broken
after resume 50% of the time (Pavel). [May be because of systemd.]
* MATE desktop dims the display and starts the screensaver right after
system resume (Pavel).
* Full system hang during resume (me). [May be due to systemd or NM or both.]
That happens on debian and open suse systems.
It's sad, that these problems were neither catched in -next nor by those
folks who expressed interest in this change.
Reported-by: Rafael J. Wysocki <rjw@rjwysocki.net>
Reported-by: Genki Sky <sky@genki.is>,
Reported-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kevin Easton <kevin@guarana.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Kaike reported that in tests rdma hrtimers occasionaly stopped working. He
did great debugging, which provided enough context to decode the problem.
CPU 3 CPU 2
idle
start sched_timer expires = 712171000000
queue->next = sched_timer
start rdmavt timer. expires = 712172915662
lock(baseof(CPU3))
tick_nohz_stop_tick()
tick = 716767000000 timerqueue_add(tmr)
hrtimer_set_expires(sched_timer, tick);
sched_timer->expires = 716767000000 <---- FAIL
if (tmr->expires < queue->next->expires)
hrtimer_start(sched_timer) queue->next = tmr;
lock(baseof(CPU3))
unlock(baseof(CPU3))
timerqueue_remove()
timerqueue_add()
ts->sched_timer is queued and queue->next is pointing to it, but then
ts->sched_timer.expires is modified.
This not only corrupts the ordering of the timerqueue RB tree, it also
makes CPU2 see the new expiry time of timerqueue->next->expires when
checking whether timerqueue->next needs to be updated. So CPU2 sees that
the rdma timer is earlier than timerqueue->next and sets the rdma timer as
new next.
Depending on whether it had also seen the new time at RB tree enqueue, it
might have queued the rdma timer at the wrong place and then after removing
the sched_timer the RB tree is completely hosed.
The problem was introduced with a commit which tried to solve inconsistency
between the hrtimer in the tick_sched data and the underlying hardware
clockevent. It split out hrtimer_set_expires() to store the new tick time
in both the NOHZ and the NOHZ + HIGHRES case, but missed the fact that in
the NOHZ + HIGHRES case the hrtimer might still be queued.
Use hrtimer_start(timer, tick...) for the NOHZ + HIGHRES case which sets
timer->expires after canceling the timer and move the hrtimer_set_expires()
invocation into the NOHZ only code path which is not affected as it merily
uses the hrtimer as next event storage so code pathes can be shared with
the NOHZ + HIGHRES case.
Fixes: d4af6d933c ("nohz: Fix spurious warning when hrtimer and clockevent get out of sync")
Reported-by: "Wan Kaike" <kaike.wan@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Cc: "Marciniszyn Mike" <mike.marciniszyn@intel.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: linux-rdma@vger.kernel.org
Cc: "Dalessandro Dennis" <dennis.dalessandro@intel.com>
Cc: "Fleck John" <john.fleck@intel.com>
Cc: stable@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "Weiny Ira" <ira.weiny@intel.com>
Cc: "linux-rdma@vger.kernel.org"
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1804241637390.1679@nanos.tec.linutronix.de
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1804242119210.1597@nanos.tec.linutronix.de
Daniel Borkmann says:
====================
pull-request: bpf 2018-04-25
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) Fix to clear the percpu metadata_dst that could otherwise carry
stale ip_tunnel_info, from William.
2) Fix that reduces the number of passes in x64 JIT with regards to
dead code sanitation to avoid risk of prog rejection, from Gianluca.
3) Several fixes of sockmap programs, besides others, fixing a double
page_put() in error path, missing refcount hold for pinned sockmap,
adding required -target bpf for clang in sample Makefile, from John.
4) Fix to disable preemption in __BPF_PROG_RUN_ARRAY() paths, from Roman.
5) Fix tools/bpf/ Makefile with regards to a lex/yacc build error
seen on older gcc-5, from John.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
With the recent architecture cleanups these si_codes are always
defined so there is no need to test for them.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
After the last round of cleanups to siginfo.h SEGV_BNDERR is defined
on all architectures so testing to see if it is defined is unnecessary.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
After more experience with the cases where no one the si_code of 0
is used both as a signal specific si_code, and as SI_USER it appears
that no one cares about the signal specific si_code case and the
good solution is to just fix the architectures by using
a different si_code.
In none of the conversations has anyone even suggested that
anything depends on the signal specific redefinition of SI_USER.
There are at least test cases that care when si_code as 0 does
not work as si_user.
So make things simple and keep the generic code from introducing
problems by removing the special casing of TRAP_FIXME and FPE_FIXME.
This will ensure the generic case of sending a signal with
kill will always set SI_USER and work.
The architecture specific, and signal specific overloads that
set si_code to 0 will now have problems with signalfd and
the 32bit compat versions of siginfo copying. At least
until they are fixed.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Now that every instance of struct siginfo is now initialized it is no
longer necessary to copy struct siginfo piece by piece to userspace
but instead the entire structure can be copied.
As well as making the code simpler and more efficient this means that
copy_sinfo_to_user no longer cares which union member of struct
siginfo is in use.
In practice this means that all 32bit architectures that define
FPE_FIXME will handle properly send SI_USER when kill(SIGFPE) is sent.
While still performing their historic architectural brokenness when 0
is used a floating pointer signal. This matches the current behavior
of 64bit architectures that define FPE_FIXME who get lucky and an
overloaded SI_USER has continuted to work through copy_siginfo_to_user
because the 8 byte si_addr occupies the same bytes in struct siginfo
as the 4 byte si_pid and the 4 byte si_uid.
Problematic architectures still need to fix their ABI so that signalfd
and 32bit compat code will work properly.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
It's been missing for a while but no one is touching that up. Fix it.
Link: http://lkml.kernel.org/r/20180315060639.9578-1-peterx@redhat.com
CC: Ingo Molnar <mingo@kernel.org>
Cc:stable@vger.kernel.org
Fixes: 7b2c862501 ("tracing: Add NMI tracing in hwlat detector")
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
File /sys/kernel/debug/kprobes/blacklist displays random addresses:
[root@s8360046 linux]# cat /sys/kernel/debug/kprobes/blacklist
0x0000000047149a90-0x00000000bfcb099a print_type_x8
....
This breaks 'perf probe' which uses the blacklist file to prohibit
probes on certain functions by checking the address range.
Fix this by printing the correct (unhashed) address.
The file mode is read all but this is not an issue as the file
hierarchy points out:
# ls -ld /sys/ /sys/kernel/ /sys/kernel/debug/ /sys/kernel/debug/kprobes/
/sys/kernel/debug/kprobes/blacklist
dr-xr-xr-x 12 root root 0 Apr 19 07:56 /sys/
drwxr-xr-x 8 root root 0 Apr 19 07:56 /sys/kernel/
drwx------ 16 root root 0 Apr 19 06:56 /sys/kernel/debug/
drwxr-xr-x 2 root root 0 Apr 19 06:56 /sys/kernel/debug/kprobes/
-r--r--r-- 1 root root 0 Apr 19 06:56 /sys/kernel/debug/kprobes/blacklist
Everything in and below /sys/kernel/debug is rwx to root only,
no group or others have access.
Background:
Directory /sys/kernel/debug/kprobes is created by debugfs_create_dir()
which sets the mode bits to rwxr-xr-x. Maybe change that to use the
parent's directory mode bits instead?
Link: http://lkml.kernel.org/r/20180419105556.86664-1-tmricht@linux.ibm.com
Fixes: ad67b74d24 ("printk: hash addresses printed with %p")
Cc: stable@vger.kernel.org
Cc: <stable@vger.kernel.org> # v4.15+
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S Miller <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: acme@kernel.org
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Kernel is crashing when user tries to record 'ftrace:function' event
with empty filter:
# perf record -e ftrace:function --filter="" ls
# dmesg
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
Oops: 0000 [#1] SMP PTI
...
RIP: 0010:ftrace_profile_set_filter+0x14b/0x2d0
RSP: 0018:ffffa4a7c0da7d20 EFLAGS: 00010246
RAX: ffffa4a7c0da7d64 RBX: 0000000000000000 RCX: 0000000000000006
RDX: 0000000000000000 RSI: 0000000000000092 RDI: ffff8c48ffc968f0
...
Call Trace:
_perf_ioctl+0x54a/0x6b0
? rcu_all_qs+0x5/0x30
...
After patch:
# perf record -e ftrace:function --filter="" ls
failed to set filter "" on event ftrace:function with 22 (Invalid argument)
Also, if user tries to echo "" > filter, it used to throw an error.
This behavior got changed by commit 80765597bc ("tracing: Rewrite
filter logic to be simpler and faster"). This patch restores the
behavior as a side effect:
Before patch:
# echo "" > filter
#
After patch:
# echo "" > filter
bash: echo: write error: Invalid argument
#
Link: http://lkml.kernel.org/r/20180420150758.19787-1-ravi.bangoria@linux.ibm.com
Fixes: 80765597bc ("tracing: Rewrite filter logic to be simpler and faster")
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
We wake up klogd very late - only when current console_sem owner
is done pushing pending kernel messages to the serial/net consoles.
In some cases this results in lost syslog messages, because kernel
log buffer is a circular buffer and if we don't wakeup syslog long
enough there are chances that logbuf simply will wrap around.
The patch moves the klogd wake up call to vprintk_emit(), which is
the only legit way for a kernel message to appear in the logbuf,
right after the attempt to handle consoles. As a result, klogd
will get waken either after flushing the new message to consoles
or immediately when consoles are still busy with older messages.
Link: http://lkml.kernel.org/r/20180419014250.5692-1-sergey.senozhatsky@gmail.com
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Pull networking fixes from David Miller:
1) Fix rtnl deadlock in ipvs, from Julian Anastasov.
2) s390 qeth fixes from Julian Wiedmann (control IO completion stalls,
bad MAC address update sequence, request side races on command IO
timeouts).
3) Handle seq_file overflow properly in l2tp, from Guillaume Nault.
4) Fix VLAN priority mappings in cpsw driver, from Ivan Khoronzhuk.
5) Packet scheduler ife action fixes (malformed TLV lengths, etc.) from
Alexander Aring.
6) Fix out of bounds access in tcp md5 option parser, from Jann Horn.
7) Missing netlink attribute policies in rtm_ipv6_policy table, from
Eric Dumazet.
8) Missing socket address length checks in l2tp and pppoe connect, from
Guillaume Nault.
9) Fix netconsole over team and bonding, from Xin Long.
10) Fix race with AF_PACKET socket state bitfields, from Willem de
Bruijn.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (51 commits)
ice: Fix insufficient memory issue in ice_aq_manage_mac_read
sfc: ARFS filter IDs
net: ethtool: Add missing kernel doc for FEC parameters
packet: fix bitfield update race
ice: Do not check INTEVENT bit for OICR interrupts
ice: Fix incorrect comment for action type
ice: Fix initialization for num_nodes_added
igb: Fix the transmission mode of queue 0 for Qav mode
ixgbevf: ensure xdp_ring resources are free'd on error exit
team: fix netconsole setup over team
amd-xgbe: Only use the SFP supported transceiver signals
amd-xgbe: Improve KR auto-negotiation and training
amd-xgbe: Add pre/post auto-negotiation phy hooks
pppoe: check sockaddr length in pppoe_connect()
l2tp: check sockaddr length in pppol2tp_connect()
net: phy: marvell: clear wol event before setting it
ipv6: add RTA_TABLE and RTA_PREFSRC to rtm_ipv6_policy
bonding: do not set slave_dev npinfo before slave_enable_netpoll in bond_enslave
tcp: don't read out-of-bounds opsize
ibmvnic: Clean actual number of RX or TX pools
...
Helpers that expect ARG_PTR_TO_MAP_KEY and ARG_PTR_TO_MAP_VALUE can only
access stack and packet memory. Allow these helpers to directly access
map values by passing registers of type PTR_TO_MAP_VALUE.
This change removes the need for an extra copy to the stack when using a
map value to perform a second map lookup, as in the following:
struct bpf_map_def SEC("maps") infobyreq = {
.type = BPF_MAP_TYPE_HASHMAP,
.key_size = sizeof(struct request *),
.value_size = sizeof(struct info_t),
.max_entries = 1024,
};
struct bpf_map_def SEC("maps") counts = {
.type = BPF_MAP_TYPE_HASHMAP,
.key_size = sizeof(struct info_t),
.value_size = sizeof(u64),
.max_entries = 1024,
};
SEC("kprobe/blk_account_io_start")
int bpf_blk_account_io_start(struct pt_regs *ctx)
{
struct info_t *info = bpf_map_lookup_elem(&infobyreq, &ctx->di);
u64 *count = bpf_map_lookup_elem(&counts, info);
(*count)++;
}
Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
