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This patch replaces/reworks the kernel-internal BPF interpreter with
an optimized BPF instruction set format that is modelled closer to
mimic native instruction sets and is designed to be JITed with one to
one mapping. Thus, the new interpreter is noticeably faster than the
current implementation of sk_run_filter(); mainly for two reasons:
1. Fall-through jumps:
BPF jump instructions are forced to go either 'true' or 'false'
branch which causes branch-miss penalty. The new BPF jump
instructions have only one branch and fall-through otherwise,
which fits the CPU branch predictor logic better. `perf stat`
shows drastic difference for branch-misses between the old and
new code.
2. Jump-threaded implementation of interpreter vs switch
statement:
Instead of single table-jump at the top of 'switch' statement,
gcc will now generate multiple table-jump instructions, which
helps CPU branch predictor logic.
Note that the verification of filters is still being done through
sk_chk_filter() in classical BPF format, so filters from user- or
kernel space are verified in the same way as we do now, and same
restrictions/constraints hold as well.
We reuse current BPF JIT compilers in a way that this upgrade would
even be fine as is, but nevertheless allows for a successive upgrade
of BPF JIT compilers to the new format.
The internal instruction set migration is being done after the
probing for JIT compilation, so in case JIT compilers are able to
create a native opcode image, we're going to use that, and in all
other cases we're doing a follow-up migration of the BPF program's
instruction set, so that it can be transparently run in the new
interpreter.
In short, the *internal* format extends BPF in the following way (more
details can be taken from the appended documentation):
- Number of registers increase from 2 to 10
- Register width increases from 32-bit to 64-bit
- Conditional jt/jf targets replaced with jt/fall-through
- Adds signed > and >= insns
- 16 4-byte stack slots for register spill-fill replaced
with up to 512 bytes of multi-use stack space
- Introduction of bpf_call insn and register passing convention
for zero overhead calls from/to other kernel functions
- Adds arithmetic right shift and endianness conversion insns
- Adds atomic_add insn
- Old tax/txa insns are replaced with 'mov dst,src' insn
Performance of two BPF filters generated by libpcap resp. bpf_asm
was measured on x86_64, i386 and arm32 (other libpcap programs
have similar performance differences):
fprog #1 is taken from Documentation/networking/filter.txt:
tcpdump -i eth0 port 22 -dd
fprog #2 is taken from 'man tcpdump':
tcpdump -i eth0 'tcp port 22 and (((ip[2:2] - ((ip[0]&0xf)<<2)) -
((tcp[12]&0xf0)>>2)) != 0)' -dd
Raw performance data from BPF micro-benchmark: SK_RUN_FILTER on the
same SKB (cache-hit) or 10k SKBs (cache-miss); time in ns per call,
smaller is better:
--x86_64--
fprog #1 fprog #1 fprog #2 fprog #2
cache-hit cache-miss cache-hit cache-miss
old BPF 90 101 192 202
new BPF 31 71 47 97
old BPF jit 12 34 17 44
new BPF jit TBD
--i386--
fprog #1 fprog #1 fprog #2 fprog #2
cache-hit cache-miss cache-hit cache-miss
old BPF 107 136 227 252
new BPF 40 119 69 172
--arm32--
fprog #1 fprog #1 fprog #2 fprog #2
cache-hit cache-miss cache-hit cache-miss
old BPF 202 300 475 540
new BPF 180 270 330 470
old BPF jit 26 182 37 202
new BPF jit TBD
Thus, without changing any userland BPF filters, applications on
top of AF_PACKET (or other families) such as libpcap/tcpdump, cls_bpf
classifier, netfilter's xt_bpf, team driver's load-balancing mode,
and many more will have better interpreter filtering performance.
While we are replacing the internal BPF interpreter, we also need
to convert seccomp BPF in the same step to make use of the new
internal structure since it makes use of lower-level API details
without being further decoupled through higher-level calls like
sk_unattached_filter_{create,destroy}(), for example.
Just as for normal socket filtering, also seccomp BPF experiences
a time-to-verdict speedup:
05-sim-long_jumps.c of libseccomp was used as micro-benchmark:
seccomp_rule_add_exact(ctx,...
seccomp_rule_add_exact(ctx,...
rc = seccomp_load(ctx);
for (i = 0; i < 10000000; i++)
syscall(199, 100);
'short filter' has 2 rules
'large filter' has 200 rules
'short filter' performance is slightly better on x86_64/i386/arm32
'large filter' is much faster on x86_64 and i386 and shows no
difference on arm32
--x86_64-- short filter
old BPF: 2.7 sec
39.12% bench libc-2.15.so [.] syscall
8.10% bench [kernel.kallsyms] [k] sk_run_filter
6.31% bench [kernel.kallsyms] [k] system_call
5.59% bench [kernel.kallsyms] [k] trace_hardirqs_on_caller
4.37% bench [kernel.kallsyms] [k] trace_hardirqs_off_caller
3.70% bench [kernel.kallsyms] [k] __secure_computing
3.67% bench [kernel.kallsyms] [k] lock_is_held
3.03% bench [kernel.kallsyms] [k] seccomp_bpf_load
new BPF: 2.58 sec
42.05% bench libc-2.15.so [.] syscall
6.91% bench [kernel.kallsyms] [k] system_call
6.25% bench [kernel.kallsyms] [k] trace_hardirqs_on_caller
6.07% bench [kernel.kallsyms] [k] __secure_computing
5.08% bench [kernel.kallsyms] [k] sk_run_filter_int_seccomp
--arm32-- short filter
old BPF: 4.0 sec
39.92% bench [kernel.kallsyms] [k] vector_swi
16.60% bench [kernel.kallsyms] [k] sk_run_filter
14.66% bench libc-2.17.so [.] syscall
5.42% bench [kernel.kallsyms] [k] seccomp_bpf_load
5.10% bench [kernel.kallsyms] [k] __secure_computing
new BPF: 3.7 sec
35.93% bench [kernel.kallsyms] [k] vector_swi
21.89% bench libc-2.17.so [.] syscall
13.45% bench [kernel.kallsyms] [k] sk_run_filter_int_seccomp
6.25% bench [kernel.kallsyms] [k] __secure_computing
3.96% bench [kernel.kallsyms] [k] syscall_trace_exit
--x86_64-- large filter
old BPF: 8.6 seconds
73.38% bench [kernel.kallsyms] [k] sk_run_filter
10.70% bench libc-2.15.so [.] syscall
5.09% bench [kernel.kallsyms] [k] seccomp_bpf_load
1.97% bench [kernel.kallsyms] [k] system_call
new BPF: 5.7 seconds
66.20% bench [kernel.kallsyms] [k] sk_run_filter_int_seccomp
16.75% bench libc-2.15.so [.] syscall
3.31% bench [kernel.kallsyms] [k] system_call
2.88% bench [kernel.kallsyms] [k] __secure_computing
--i386-- large filter
old BPF: 5.4 sec
new BPF: 3.8 sec
--arm32-- large filter
old BPF: 13.5 sec
73.88% bench [kernel.kallsyms] [k] sk_run_filter
10.29% bench [kernel.kallsyms] [k] vector_swi
6.46% bench libc-2.17.so [.] syscall
2.94% bench [kernel.kallsyms] [k] seccomp_bpf_load
1.19% bench [kernel.kallsyms] [k] __secure_computing
0.87% bench [kernel.kallsyms] [k] sys_getuid
new BPF: 13.5 sec
76.08% bench [kernel.kallsyms] [k] sk_run_filter_int_seccomp
10.98% bench [kernel.kallsyms] [k] vector_swi
5.87% bench libc-2.17.so [.] syscall
1.77% bench [kernel.kallsyms] [k] __secure_computing
0.93% bench [kernel.kallsyms] [k] sys_getuid
BPF filters generated by seccomp are very branchy, so the new
internal BPF performance is better than the old one. Performance
gains will be even higher when BPF JIT is committed for the
new structure, which is planned in future work (as successive
JIT migrations).
BPF has also been stress-tested with trinity's BPF fuzzer.
Joint work with Daniel Borkmann.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Paul Moore <pmoore@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: linux-kernel@vger.kernel.org
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Takashi Iwai <tiwai@suse.de> says:
> The letter 'X' has been already used for SUSE kernels for very long
> time, to indicate the external supported modules. Can the new flag be
> changed to another letter for avoiding conflict...?
> (BTW, we also use 'N' for "no support", too.)
Note: this code should be cleaned up, so we don't have such maps in
three places!
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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It its possible to configure your PAM stack to refuse login if audit
messages (about the login) were unable to be sent. This is common in
many distros and thus normal configuration of many containers. The PAM
modules determine if audit is enabled/disabled in the kernel based on
the return value from sending an audit message on the netlink socket.
If userspace gets back ECONNREFUSED it believes audit is disabled in the
kernel. If it gets any other error else it refuses to let the login
proceed.
Just about ever since the introduction of namespaces the kernel audit
subsystem has returned EPERM if the task sending a message was not in
the init user or pid namespace. So many forms of containers have never
worked if audit was enabled in the kernel.
BUT if the container was not in net_init then the kernel network code
would send ECONNREFUSED (instead of the audit code sending EPERM). Thus
by pure accident/dumb luck/bug if an admin configured the PAM stack to
reject all logins that didn't talk to audit, but then ran the login
untility in the non-init_net namespace, it would work!! Clearly this was
a bug, but it is a bug some people expected.
With the introduction of network namespace support in 3.14-rc1 the two
bugs stopped cancelling each other out. Now, containers in the
non-init_net namespace refused to let users log in (just like PAM was
configfured!) Obviously some people were not happy that what used to let
users log in, now didn't!
This fix is kinda hacky. We return ECONNREFUSED for all non-init
relevant namespaces. That means that not only will the old broken
non-init_net setups continue to work, now the broken non-init_pid or
non-init_user setups will 'work'. They don't really work, since audit
isn't logging things. But it's what most users want.
In 3.15 we should have patches to support not only the non-init_net
(3.14) namespace but also the non-init_pid and non-init_user namespace.
So all will be right in the world. This just opens the doors wide open
on 3.14 and hopefully makes users happy, if not the audit system...
Reported-by: Andre Tomt <andre@tomt.net>
Reported-by: Adam Richter <adam_richter2004@yahoo.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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cgroup_exit() is called in fork and exit path. If it's called in the
failure path during fork, PF_EXITING isn't set, and then lockdep will
complain.
Fix this by removing cgroup_exit() in that failure path. cgroup_fork()
does nothing that needs cleanup.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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In commit 47a1b796306356f35 ("tick/timekeeping: Call
update_wall_time outside the jiffies lock"), we moved to calling
clock_was_set() due to the fact that we were no longer holding
the timekeeping or jiffies lock.
However, there is still the problem that clock_was_set()
triggers an IPI, which cannot be done from the timer's hard irq
context, and will generate WARN_ON warnings.
Apparently in my earlier testing, I'm guessing I didn't bump the
dmesg log level, so I somehow missed the WARN_ONs.
Thus we need to revert back to calling clock_was_set_delayed().
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1395963049-11923-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"While on my flight to Linux Collaboration Summit, I was working on my
slides for the event trigger tutorial. I booted a 3.14-rc7 kernel to
perform what I wanted to teach and cut and paste it into my slides.
When I tried the traceon event trigger with a condition attached to it
(turns tracing on only if a field of the trigger event matches a
condition set by the user), nothing happened. Tracing would not turn
on. I stopped working on my presentation in order to find what was
wrong.
It ended up being the way trace event triggers work when they have
conditions. Instead of copying the fields, the condition code just
looks at the fields that were copied into the ring buffer. This works
great, unless tracing is off. That's because when the event is
reserved on the ring buffer, the ring buffer returns a NULL pointer,
this tells the tracing code that the ring buffer is disabled. This
ends up being a problem for the traceon trigger if it is using this
information to check its condition.
Luckily the code that checks if tracing is on returns the ring buffer
to use (because the ring buffer is determined by the event file also
passed to that field). I was able to easily solve this bug by
checking in that helper function if the returned ring buffer entry is
NULL, and if so, also check the file flag if it has a trace event
trigger condition, and if so, to pass back a temp ring buffer to use.
This will allow the trace event trigger condition to still test the
event fields, but nothing will be recorded"
* tag 'trace-fixes-v3.14-rc7-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix traceon trigger condition to actually turn tracing on
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While working on my tutorial for 2014 Linux Collaboration Summit
I found that the traceon trigger did not work when conditions were
used. The other triggers worked fine though. Looking into it, it
is because of the way the triggers use the ring buffer to store
the fields it will use for the condition. But if tracing is off, nothing
is stored in the buffer, and the tracepoint exits before calling the
trigger to test the condition. This is fine for all the triggers that
only work when tracing is on, but for traceon trigger that is to
work when tracing is off, nothing happens.
The fix is simple, just use a temp ring buffer to record the event
if tracing is off and the event has a trace event conditional trigger
enabled. The rest of the tracepoint code will work just fine, but
the tracepoint wont be recorded in the other buffers.
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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tick_handle_periodic() is calling ktime_add() at two places, first before the
infinite loop and then at the end of infinite loop. We can rearrange code a bit
to fix code duplication here.
It looks quite simple and shouldn't break anything, I guess :)
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: fweisbec@gmail.com
Link: http://lkml.kernel.org/r/be3481e8f3f71df694a4b43623254fc93ca51b59.1395735873.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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One of the comments in tick_handle_periodic() had 'when' instead of 'which' (My
guess :)). Fix it.
Also fix spelling mistake in 'Possible'.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: skarafotis@gmail.com
Link: http://lkml.kernel.org/r/2b29ca4230c163e44179941d7c7a16c1474385c2.1395743878.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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If a delayed or deferrable work is on stack we need to tell debug
objects that we are destroying the timer and the work. Otherwise we
leak the tracking object.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Acked-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20140323141939.911487677@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU update from Paul E. McKenney:
" [...] one late-breaking commit. This one was requested for 3.15 by Peter Zijlstra.
It is low risk because it adds a new in-kernel API with minimal changes to the
existing code. Those minimal changes are the addition of memory barriers and
ACCESS_ONCE() macro calls, neither of which should be able to break things.
This commit has passed significant rcutorture testing, with these additional
additions to rcutorture slated for 3.16. This commit has also been exposed to
-next testing. "
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This patch replaces rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL)
The rcu_assign_pointer() ensures that the initialization of a structure
is carried out before storing a pointer to that structure.
And in the case of the NULL pointer, there is no structure to initialize.
So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL)
Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
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It is difficult to detect a stack overrun when it
actually occurs.
We have observed that this type of corruption is often
silent and can go unnoticed. Once the corrupted region
is examined, the outcome is undefined and often
results in sporadic system crashes.
When the stack tracing feature is enabled, let's check
for this condition and take appropriate action.
Note: init_task doesn't get its stack end location
set to STACK_END_MAGIC.
Link: http://lkml.kernel.org/r/1395669837-30209-1-git-send-email-atomlin@redhat.com
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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This patch replaces rcu_assign_pointer(x, NULL) with
RCU_INIT_POINTER(x, NULL)
The rcu_assign_pointer() ensures that the initialization of a
structure is carried out before storing a pointer to that structure.
And in the case of the NULL pointer, there is no structure to
initialize. So, rcu_assign_pointer(p, NULL) can be safely converted
to RCU_INIT_POINTER(p, NULL)
Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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This will allow to use the dummy IRQ handler no_action() from drivers
compiled as module. Drivers which use ARM FIQ interrupts can use this
to request the interrupt via the normal request_irq() mechanism w/o
having to copy the dummy handler to their own code.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Link: http://lkml.kernel.org/r/1395476431-16070-1-git-send-email-shc_work@mail.ru
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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After the following commit:
commit b75ef8b44b1cb95f5a26484b0e2fe37a63b12b44
Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed Aug 10 15:18:39 2011 -0400
Tracepoint: Dissociate from module mutex
The following functions became unnecessary:
- tracepoint_probe_register_noupdate,
- tracepoint_probe_unregister_noupdate,
- tracepoint_probe_update_all.
In fact, none of the in-kernel tracers, nor LTTng, nor SystemTAP use
them. Remove those.
Moreover, the functions:
- tracepoint_iter_start,
- tracepoint_iter_next,
- tracepoint_iter_stop,
- tracepoint_iter_reset.
are unused by in-kernel tracers, LTTng and SystemTAP. Remove those too.
Link: http://lkml.kernel.org/r/1395379142-2118-2-git-send-email-mathieu.desnoyers@efficios.com
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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I originally wrote commit 35bb4399bd0e to shrink the size of the overhead of
tracepoints by several kilobytes. Later, I received a patch from Vaibhav
Nagarnaik that fixed a bug in the same code that this commit touches. Not
only did it fix a bug, it also removed code and shrunk the size of the
overhead of trace events even more than this commit did.
Since this commit is scheduled for 3.15 and Vaibhav's patch is already in
mainline, I need to revert this patch in order to keep it from conflicting
with Vaibhav's patch. Not to mention, Vaibhav's patch makes this patch
obsolete.
Link: http://lkml.kernel.org/r/20140320225637.0226041b@gandalf.local.home
Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Srikar Dronamraju reports that commit b0c29f79ecea ("futexes: Avoid
taking the hb->lock if there's nothing to wake up") causes java threads
getting stuck on futexes when runing specjbb on a power7 numa box.
The cause appears to be that the powerpc spinlocks aren't using the same
ticket lock model that we use on x86 (and other) architectures, which in
turn result in the "spin_is_locked()" test in hb_waiters_pending()
occasionally reporting an unlocked spinlock even when there are pending
waiters.
So this reinstates Davidlohr Bueso's original explicit waiter counting
code, which I had convinced Davidlohr to drop in favor of figuring out
the pending waiters by just using the existing state of the spinlock and
the wait queue.
Reported-and-tested-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Original-code-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull trace fix from Steven Rostedt:
"Vaibhav Nagarnaik discovered that since 3.10 a clean-up patch made the
array index in the trace event format bogus.
He supplied an elegant solution that uses __stringify() and also
removes the need for the event_storage and event_storage_mutex and
also cuts off a few K of overhead from the trace events"
* tag 'trace-fixes-v3.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix array size mismatch in format string
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The following pattern is currently not well supported by RCU:
1. Make data element inaccessible to RCU readers.
2. Do work that probably lasts for more than one grace period.
3. Do something to make sure RCU readers in flight before #1 above
have completed.
Here are some things that could currently be done:
a. Do a synchronize_rcu() unconditionally at either #1 or #3 above.
This works, but imposes needless work and latency.
b. Post an RCU callback at #1 above that does a wakeup, then
wait for the wakeup at #3. This works well, but likely results
in an extra unneeded grace period. Open-coding this is also
a bit more semi-tricky code than would be good.
This commit therefore adds get_state_synchronize_rcu() and
cond_synchronize_rcu() APIs. Call get_state_synchronize_rcu() at #1
above and pass its return value to cond_synchronize_rcu() at #3 above.
This results in a call to synchronize_rcu() if no grace period has
elapsed between #1 and #3, but requires only a load, comparison, and
memory barrier if a full grace period did elapse.
Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
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Rename TAINT_UNSAFE_SMP to TAINT_CPU_OUT_OF_SPEC, so we can repurpose
the flag to encompass a wider range of pushing the CPU beyond its
warrany.
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Link: http://lkml.kernel.org/r/20140226154949.GA770@redhat.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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In event format strings, the array size is reported in two locations.
One in array subscript and then via the "size:" attribute. The values
reported there have a mismatch.
For e.g., in sched:sched_switch the prev_comm and next_comm character
arrays have subscript values as [32] where as the actual field size is
16.
name: sched_switch
ID: 301
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1;signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:char prev_comm[32]; offset:8; size:16; signed:1;
field:pid_t prev_pid; offset:24; size:4; signed:1;
field:int prev_prio; offset:28; size:4; signed:1;
field:long prev_state; offset:32; size:8; signed:1;
field:char next_comm[32]; offset:40; size:16; signed:1;
field:pid_t next_pid; offset:56; size:4; signed:1;
field:int next_prio; offset:60; size:4; signed:1;
After bisection, the following commit was blamed:
92edca0 tracing: Use direct field, type and system names
This commit removes the duplication of strings for field->name and
field->type assuming that all the strings passed in
__trace_define_field() are immutable. This is not true for arrays, where
the type string is created in event_storage variable and field->type for
all array fields points to event_storage.
Use __stringify() to create a string constant for the type string.
Also, get rid of event_storage and event_storage_mutex that are not
needed anymore.
also, an added benefit is that this reduces the overhead of events a bit more:
text data bss dec hex filename
8424787 2036472 1302528 11763787 b3804b vmlinux
8420814 2036408 1302528 11759750 b37086 vmlinux.patched
Link: http://lkml.kernel.org/r/1392349908-29685-1-git-send-email-vnagarnaik@google.com
Cc: Laurent Chavey <chavey@google.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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cgroup_tree_mutex should nest above the kernfs active_ref protection;
however, cgroup_create() and cgroup_rename() were grabbing
cgroup_tree_mutex while under kernfs active_ref protection. This has
actualy possibility to lead to deadlocks in case these operations race
against cgroup_rmdir() which invokes kernfs_remove() on directory
kernfs_node while holding cgroup_tree_mutex.
Neither cgroup_create() or cgroup_rename() requires active_ref
protection. The former already has enough synchronization through
cgroup_lock_live_group() and the latter doesn't care, so this can be
fixed by updating both functions to break all active_ref protections
before grabbing cgroup_tree_mutex.
While this patch fixes the immediate issue, it probably needs further
work in the long term - kernfs directories should enable lockdep
annotations and maybe the better way to handle this is marking
directory nodes as not needing active_ref protection rather than
breaking it in each operation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Every caller of syscall_get_arch() uses current for the task and no
implementors of the function need args. So just get rid of both of
those things. Admittedly, since these are inline functions we aren't
wasting stack space, but it just makes the prototypes better.
Signed-off-by: Eric Paris <eparis@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@linux-mips.org
Cc: linux390@de.ibm.com
Cc: x86@kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linux-arch@vger.kernel.org
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There's an unnecessary use of a \n in audit_panic.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
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Calling audit_log_lost with a \n in the format string leads to extra
newlines in dmesg. That function will eventually call audit_panic which
uses pr_err with an explicit \n included. Just make these calls match the
others that lack \n.
Reported-by: Jonathan Kamens <jik@kamens.brookline.ma.us>
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
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The login uid change record does not include the selinux context of the
task logging in. Add that information.
(Updated from 2011-01: RHBZ:670328 -- RGB)
Reported-by: Steve Grubb <sgrubb@redhat.com>
Acked-by: James Morris <jmorris@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Aristeu Rozanski <arozansk@redhat.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
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The new- prefix on ses and auid are un-necessary and break ausearch.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
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Still only permit the audit logging daemon and control to operate from the
initial PID namespace, but allow processes to log from another PID namespace.
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
(informed by ebiederman's c776b5d2)
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
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Store and log all PIDs with reference to the initial PID namespace and
use the access functions task_pid_nr() and task_tgid_nr() for task->pid
and task->tgid.
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
(informed by ebiederman's c776b5d2)
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
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sys_getppid() returns the parent pid of the current process in its own pid
namespace. Since audit filters are based in the init pid namespace, a process
could avoid a filter or trigger an unintended one by being in an alternate pid
namespace or log meaningless information.
Switch to task_ppid_nr() for PPIDs to anchor all audit filters in the
init_pid_ns.
(informed by ebiederman's 6c621b7e)
Cc: stable@vger.kernel.org
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
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"get" usually implies incrementing a refcount into a structure to indicate a
reference being held by another part of code.
Change this function name to indicate it is in fact being taken from it,
returning the value while clearing it in the supplying structure.
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
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In perverse cases of file descriptor passing the current network
namespace of a process and the network namespace of a socket used by
that socket may differ. Therefore use the network namespace of the
appropiate socket to ensure replies always go to the appropiate
socket.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
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While reading through 3.14-rc1 I found a pretty siginficant mishandling
of network namespaces in the recent audit changes.
In struct audit_netlink_list and audit_reply add a reference to the
network namespace of the caller and remove the userspace pid of the
caller. This cleanly remembers the callers network namespace, and
removes a huge class of races and nasty failure modes that can occur
when attempting to relook up the callers network namespace from a pid_t
(including the caller's network namespace changing, pid wraparound, and
the pid simply not being present).
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
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During an audit event, cache and print the value of the process's
proctitle value (proc/<pid>/cmdline). This is useful in situations
where processes are started via fork'd virtual machines where the
comm field is incorrect. Often times, setting the comm field still
is insufficient as the comm width is not very wide and most
virtual machine "package names" do not fit. Also, during execution,
many threads have their comm field set as well. By tying it back to
the global cmdline value for the process, audit records will be more
complete in systems with these properties. An example of where this
is useful and applicable is in the realm of Android. With Android,
their is no fork/exec for VM instances. The bare, preloaded Dalvik
VM listens for a fork and specialize request. When this request comes
in, the VM forks, and the loads the specific application (specializing).
This was done to take advantage of COW and to not require a load of
basic packages by the VM on very app spawn. When this spawn occurs,
the package name is set via setproctitle() and shows up in procfs.
Many of these package names are longer then 16 bytes, the historical
width of task->comm. Having the cmdline in the audit records will
couple the application back to the record directly. Also, on my
Debian development box, some audit records were more useful then
what was printed under comm.
The cached proctitle is tied to the life-cycle of the audit_context
structure and is built on demand.
Proctitle is controllable by userspace, and thus should not be trusted.
It is meant as an aid to assist in debugging. The proctitle event is
emitted during syscall audits, and can be filtered with auditctl.
Example:
type=AVC msg=audit(1391217013.924:386): avc: denied { getattr } for pid=1971 comm="mkdir" name="/" dev="selinuxfs" ino=1 scontext=system_u:system_r:consolekit_t:s0-s0:c0.c255 tcontext=system_u:object_r:security_t:s0 tclass=filesystem
type=SYSCALL msg=audit(1391217013.924:386): arch=c000003e syscall=137 success=yes exit=0 a0=7f019dfc8bd7 a1=7fffa6aed2c0 a2=fffffffffff4bd25 a3=7fffa6aed050 items=0 ppid=1967 pid=1971 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="mkdir" exe="/bin/mkdir" subj=system_u:system_r:consolekit_t:s0-s0:c0.c255 key=(null)
type=UNKNOWN[1327] msg=audit(1391217013.924:386): proctitle=6D6B646972002D70002F7661722F72756E2F636F6E736F6C65
Acked-by: Steve Grubb <sgrubb@redhat.com> (wrt record formating)
Signed-off-by: William Roberts <wroberts@tresys.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
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Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(&foobar_cpu_notifier);
put_online_cpus();
This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).
Instead, the correct and race-free way of performing the callback
registration is:
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
init_cpu(cpu);
/* Note the use of the double underscored version of the API */
__register_cpu_notifier(&foobar_cpu_notifier);
cpu_notifier_register_done();
Fix the profile code by using this latter form of callback registration.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Subsystems that want to register CPU hotplug callbacks, as well as perform
initialization for the CPUs that are already online, often do it as shown
below:
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(&foobar_cpu_notifier);
put_online_cpus();
This is wrong, since it is prone to ABBA deadlocks involving the
cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently
with CPU hotplug operations).
Instead, the correct and race-free way of performing the callback
registration is:
cpu_notifier_register_begin();
for_each_online_cpu(cpu)
init_cpu(cpu);
/* Note the use of the double underscored version of the API */
__register_cpu_notifier(&foobar_cpu_notifier);
cpu_notifier_register_done();
Fix the tracing ring-buffer code by using this latter form of callback
registration.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The following method of CPU hotplug callback registration is not safe
due to the possibility of an ABBA deadlock involving the cpu_add_remove_lock
and the cpu_hotplug.lock.
get_online_cpus();
for_each_online_cpu(cpu)
init_cpu(cpu);
register_cpu_notifier(&foobar_cpu_notifier);
put_online_cpus();
The deadlock is shown below:
CPU 0 CPU 1
----- -----
Acquire cpu_hotplug.lock
[via get_online_cpus()]
CPU online/offline operation
takes cpu_add_remove_lock
[via cpu_maps_update_begin()]
Try to acquire
cpu_add_remove_lock
[via register_cpu_notifier()]
CPU online/offline operation
tries to acquire cpu_hotplug.lock
[via cpu_hotplug_begin()]
*** DEADLOCK! ***
The problem here is that callback registration takes the locks in one order
whereas the CPU hotplug operations take the same locks in the opposite order.
To avoid this issue and to provide a race-free method to register CPU hotplug
callbacks (along with initialization of already online CPUs), introduce new
variants of the callback registration APIs that simply register the callbacks
without holding the cpu_add_remove_lock during the registration. That way,
we can avoid the ABBA scenario. However, we will need to hold the
cpu_add_remove_lock throughout the entire critical section, to protect updates
to the callback/notifier chain.
This can be achieved by writing the callback registration code as follows:
cpu_maps_update_begin(); [ or cpu_notifier_register_begin(); see below ]
for_each_online_cpu(cpu)
init_cpu(cpu);
/* This doesn't take the cpu_add_remove_lock */
__register_cpu_notifier(&foobar_cpu_notifier);
cpu_maps_update_done(); [ or cpu_notifier_register_done(); see below ]
Note that we can't use get_online_cpus() here instead of cpu_maps_update_begin()
because the cpu_hotplug.lock is dropped during the invocation of CPU_POST_DEAD
notifiers, and hence get_online_cpus() cannot provide the necessary
synchronization to protect the callback/notifier chains against concurrent
reads and writes. On the other hand, since the cpu_add_remove_lock protects
the entire hotplug operation (including CPU_POST_DEAD), we can use
cpu_maps_update_begin/done() to guarantee proper synchronization.
Also, since cpu_maps_update_begin/done() is like a super-set of
get/put_online_cpus(), the former naturally protects the critical sections
from concurrent hotplug operations.
Since the names cpu_maps_update_begin/done() don't make much sense in CPU
hotplug callback registration scenarios, we'll introduce new APIs named
cpu_notifier_register_begin/done() and map them to cpu_maps_update_begin/done().
In summary, introduce the lockless variants of un/register_cpu_notifier() and
also export the cpu_notifier_register_begin/done() APIs for use by modules.
This way, we provide a race-free way to register hotplug callbacks as well as
perform initialization for the CPUs that are already online.
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Add lockdep annotations for get/put_online_cpus() and
cpu_hotplug_begin()/cpu_hotplug_end().
Cc: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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* pm-runtime:
PM / Runtime: Update runtime_idle() documentation for return value meaning
* pm-sleep:
PM / sleep: Correct whitespace errors in <linux/pm.h>
PM: Add missing "freeze" state
PM / Hibernate: Spelling s/anonymouns/anonymous/
PM / Runtime: Add missing "it" in comment
PM / suspend: Remove unnecessary !!
PCI / PM: Resume runtime-suspended devices later during system suspend
ACPI / PM: Resume runtime-suspended devices later during system suspend
PM / sleep: Set pm_generic functions to NULL for !CONFIG_PM_SLEEP
PM: fix typo in comment
PM / hibernate: use name_to_dev_t to parse resume
PM / wakeup: Include appropriate header file in kernel/power/wakelock.c
PM / sleep: Move prototype declaration to header file kernel/power/power.h
PM / sleep: Asynchronous threads for suspend_late
PM / sleep: Asynchronous threads for suspend_noirq
PM / sleep: Asynchronous threads for resume_early
PM / sleep: Asynchronous threads for resume_noirq
PM / sleep: Two flags for async suspend_noirq and suspend_late
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* pm-qos:
PM / QoS: Add type to dev_pm_qos_add_ancestor_request() arguments
ACPI / LPSS: Support for device latency tolerance PM QoS
ACPI / scan: Add bind/unbind callbacks to struct acpi_scan_handler
PM / QoS: Introcuce latency tolerance device PM QoS type
PM / QoS: Add no_constraints_value field to struct pm_qos_constraints
PM / QoS: Rename device resume latency QoS items
* pm-domains:
PM / domains: Turn latency warning into debug message
* pm-drivers:
PM: Add pm_runtime_suspend|resume_force functions
PM / runtime: Fetch runtime PM callbacks using a macro
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There are only two users of get_nohz_timer_target(): timer and hrtimer. Both
call it under same circumstances, i.e.
#ifdef CONFIG_NO_HZ_COMMON
if (!pinned && get_sysctl_timer_migration() && idle_cpu(this_cpu))
return get_nohz_timer_target();
#endif
So, it makes more sense to get all this as part of get_nohz_timer_target()
instead of duplicating code at two places. For this another parameter is
required to be passed to this routine, pinned.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: fweisbec@gmail.com
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1e1b53537217d58d48c2d7a222a9c3ac47d5b64c.1395140107.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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We already have a variable 'head' that points to '&work_list', and so
we should use that instead wherever possible.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Link: http://lkml.kernel.org/r/0d8645a6efc8360c4196c9797d59343abbfdcc5e.1395129136.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fix from Tejun Heo:
"One really late cgroup patch to fix error path in create_css().
Hitting this bug would be pretty rare but still possible and it gets
delayed we'd need to backport it through -stable anyway. It only
updates error path in create_css() and has low chance of new
breakages"
* 'for-3.14-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: fix a failure path in create_css()
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cgroup_taskset is used to track and iterate target tasks while
migrating a task or process and should guarantee that the first task
iterated is the task group leader if a process is being migrated.
b3dc094e9390 ("cgroup: use css_set->mg_tasks to track target tasks
during migration") replaced flex array cgroup_taskset->tc_array with
css_set->mg_tasks list to remove process size limit and dynamic
allocation during migration; unfortunately, it incorrectly used list
operations which don't preserve order breaking the guarantee that
cgroup_taskset_first() returns the leader for a process target.
Fix it by using order preserving list operations. Note that as
multiple src_csets may map to a single dst_cset, the iteration order
may change across cgroup_task_migrate(); however, the leader is still
guaranteed to be the first entry.
The switch to list_splice_tail_init() at the end of cgroup_migrate()
isn't strictly necessary. Let's still do it for consistency.
Signed-off-by: Tejun Heo <tj@kernel.org>
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We don't set the type (I/O, memory, etc.) of resources added by
__request_region(), which leads to confusing messages like this:
address space collision: [io 0x1000-0x107f] conflicts with ACPI CPU throttle [??? 0x00001010-0x00001015 flags 0x80000000]
Set the type of a new resource added by __request_region() (used by
request_region() and request_mem_region()) to the type of its parent. This
makes the resource tree internally consistent and fixes messages like the
above, where the ACPI CPU throttle resource really is an I/O port region,
but request_region() didn't fill in the type, so %pR didn't know how to
print it.
Sample dmesg showing the issue at the link below.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=71611
Reported-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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This cftype flag makes the file only appear on the default hierarchy.
This will later be used for cgroup.controllers file.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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cgrp_dfl_root will be used as the default unified hierarchy. This
patch makes cgrp_dfl_root mountable by making the following changes.
* cgroup_init_early() now initializes cgrp_dfl_root w/
CGRP_ROOT_SANE_BEHAVIOR. The default hierarchy is always sane.
* parse_cgroupfs_options() and cgroup_mount() are updated such that
cgrp_dfl_root is mounted if sane_behavior is specified w/o any
subsystems.
* rebind_subsystems() now populates the root directory of
cgrp_dfl_root. Note that the function still guarantees success of
rebinding subsystems to cgrp_dfl_root. If populating fails while
rebinding to cgrp_dfl_root, it whines but ignores the error.
* For backward compatibility, the default hierarchy shows up in
/proc/$PID/cgroup only after it's explicitly mounted so that
userland which doesn't make use of it doesn't see any change.
* "current_css_set_cg_links" file of debug cgroup now treats the
default hierarchy the same as other hierarchies. This is visible to
userland. Given that it's for debug controller, this should be
fine.
* While at it, implement cgroup_on_dfl() which tests whether a give
cgroup is on the default hierarchy or not.
The above changes make cgrp_dfl_root mostly equivalent to other
controllers but the actual unified hierarchy behaviors are not
implemented yet. Let's plug child cgroup creation in cgrp_dfl_root
from create_cgroup() for now.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
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cftype->write_string() just passes on the writeable buffer from kernfs
and there's no reason to add const restriction on the buffer. The
only thing const achieves is unnecessarily complicating parsing of the
buffer. Drop const from @buffer.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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