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Author SHA1 Message Date
Paul E. McKenney
6764100bd2 rcutorture: Complete threading rcu_fwd pointers through functions
This commit threads pointers to rcu_fwd structures through the remaining
functions using rcu_fwds directly, namely rcu_torture_fwd_prog_cbfree(),
rcutorture_oom_notify() and rcu_torture_fwd_prog_init().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 13:00:28 -08:00
Paul E. McKenney
7beba0c06b rcutorture: Move to dynamic initialization of rcu_fwds
In order to add multiple call_rcu() forward-progress kthreads, it will
be necessary to dynamically allocate and initialize.  This commit
therefore moves the initialization from compile time to instead
immediately precede thread-creation time.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 13:00:28 -08:00
Paul E. McKenney
6b1b832546 rcutorture: Thread rcu_fwd pointer through forward-progress functions
In order to add multiple kthreads, it will be necessary to allow
the various functions to operate on a pointer to their kthread's
rcu_fwd structure.  This commit therefore starts the process of
adding the needed "struct rcu_fwd" parameters and arguments to the
various callback forward-progress functions.

Note that rcutorture_oom_notify() and rcu_torture_fwd_cb_hist() will
eventually need to iterate over all kthreads' rcu_fwd structures.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 13:00:28 -08:00
Paul E. McKenney
a289e608b3 rcutorture: Pull callback forward-progress data into rcu_fwd struct
Now that RCU behaves reasonably well with the current single-kthread
call_rcu() forward-progress testing, it is time to add more kthreads.
This commit takes a first step towards that goal by wrapping what
will be the per-kthread data into a new rcu_fwd structure.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 13:00:27 -08:00
Sebastian Andrzej Siewior
90326f0521 rcu: Use CONFIG_PREEMPTION where appropriate
The config option `CONFIG_PREEMPT' is used for the preemption model
"Low-Latency Desktop". The config option `CONFIG_PREEMPTION' is enabled
when kernel preemption is enabled which is true for the preemption model
`CONFIG_PREEMPT' and `CONFIG_PREEMPT_RT'.

Use `CONFIG_PREEMPTION' if it applies to both preemption models and not
just to `CONFIG_PREEMPT'.

Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: rcu@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:37:51 -08:00
Lai Jiangshan
b3e627d3d5 rcu: Make PREEMPT_RCU be a modifier to TREE_RCU
Currently PREEMPT_RCU and TREE_RCU are mutually exclusive Kconfig
options.  But PREEMPT_RCU actually specifies a kind of TREE_RCU,
namely a preemptible TREE_RCU. This commit therefore makes PREEMPT_RCU
be a modifer to the TREE_RCU Kconfig option.  This has the benefit of
simplifying several of the #if expressions that formerly needed to
check both, but now need only check one or the other.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: Lai Jiangshan <jiangshanlai@gmail.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:37:51 -08:00
Paul E. McKenney
03bd2983d7 rcu: Use lockdep rather than comment to enforce lock held
The rcu_preempt_check_blocked_tasks() function has a comment
that states that the rcu_node structure's ->lock must be held,
which might be informative, but which carries little weight if
not read.  This commit therefore removes this comment in favor of
raw_lockdep_assert_held_rcu_node(), which will complain quite
visibly if the required lock is not held.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:37:50 -08:00
Eric Dumazet
6935c3983b rcu: Avoid data-race in rcu_gp_fqs_check_wake()
The rcu_gp_fqs_check_wake() function uses rcu_preempt_blocked_readers_cgp()
to read ->gp_tasks while other cpus might overwrite this field.

We need READ_ONCE()/WRITE_ONCE() pairs to avoid compiler
tricks and KCSAN splats like the following :

BUG: KCSAN: data-race in rcu_gp_fqs_check_wake / rcu_preempt_deferred_qs_irqrestore

write to 0xffffffff85a7f190 of 8 bytes by task 7317 on cpu 0:
 rcu_preempt_deferred_qs_irqrestore+0x43d/0x580 kernel/rcu/tree_plugin.h:507
 rcu_read_unlock_special+0xec/0x370 kernel/rcu/tree_plugin.h:659
 __rcu_read_unlock+0xcf/0xe0 kernel/rcu/tree_plugin.h:394
 rcu_read_unlock include/linux/rcupdate.h:645 [inline]
 __ip_queue_xmit+0x3b0/0xa40 net/ipv4/ip_output.c:533
 ip_queue_xmit+0x45/0x60 include/net/ip.h:236
 __tcp_transmit_skb+0xdeb/0x1cd0 net/ipv4/tcp_output.c:1158
 __tcp_send_ack+0x246/0x300 net/ipv4/tcp_output.c:3685
 tcp_send_ack+0x34/0x40 net/ipv4/tcp_output.c:3691
 tcp_cleanup_rbuf+0x130/0x360 net/ipv4/tcp.c:1575
 tcp_recvmsg+0x633/0x1a30 net/ipv4/tcp.c:2179
 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838
 sock_recvmsg_nosec net/socket.c:871 [inline]
 sock_recvmsg net/socket.c:889 [inline]
 sock_recvmsg+0x92/0xb0 net/socket.c:885
 sock_read_iter+0x15f/0x1e0 net/socket.c:967
 call_read_iter include/linux/fs.h:1864 [inline]
 new_sync_read+0x389/0x4f0 fs/read_write.c:414

read to 0xffffffff85a7f190 of 8 bytes by task 10 on cpu 1:
 rcu_gp_fqs_check_wake kernel/rcu/tree.c:1556 [inline]
 rcu_gp_fqs_check_wake+0x93/0xd0 kernel/rcu/tree.c:1546
 rcu_gp_fqs_loop+0x36c/0x580 kernel/rcu/tree.c:1611
 rcu_gp_kthread+0x143/0x220 kernel/rcu/tree.c:1768
 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 10 Comm: rcu_preempt Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
[ paulmck:  Added another READ_ONCE() for RCU CPU stall warnings. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:37:50 -08:00
Stefan Reiter
610dea36d3 rcu/nocb: Fix dump_tree hierarchy print always active
Commit 18cd8c93e6 ("rcu/nocb: Print gp/cb kthread hierarchy if
dump_tree") added print statements to rcu_organize_nocb_kthreads for
debugging, but incorrectly guarded them, causing the function to always
spew out its message.

This patch fixes it by guarding both pr_alert statements with dump_tree,
while also changing the second pr_alert to a pr_cont, to print the
hierarchy in a single line (assuming that's how it was supposed to
work).

Fixes: 18cd8c93e6 ("rcu/nocb: Print gp/cb kthread hierarchy if dump_tree")
Signed-off-by: Stefan Reiter <stefan@pimaker.at>
[ paulmck: Make single-nocbs-CPU GP kthreads look less erroneous. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:37:50 -08:00
Paul E. McKenney
df1e849ae4 rcu: Enable tick for nohz_full CPUs slow to provide expedited QS
An expedited grace period can be stalled by a nohz_full CPU looping
in kernel context.  This possibility is currently handled by some
carefully crafted checks in rcu_read_unlock_special() that enlist help
from ksoftirqd when permitted by the scheduler.  However, it is exactly
these checks that require the scheduler avoid holding any of its rq or
pi locks across rcu_read_unlock() without also having held them across
the entire RCU read-side critical section.

It would therefore be very nice if expedited grace periods could
handle nohz_full CPUs looping in kernel context without such checks.
This commit therefore adds code to the expedited grace period's wait
and cleanup code that forces the scheduler-clock interrupt on for CPUs
that fail to quickly supply a quiescent state.  "Quickly" is currently
a hard-coded single-jiffy delay.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:32:59 -08:00
Paul E. McKenney
28f0361fdf rcu: Replace synchronize_sched_expedited_wait() "_sched" with "_rcu"
After RCU flavor consolidation, synchronize_sched_expedited_wait() does
both RCU-preempt and RCU-sched, whichever happens to have been built into
the running kernel.  This commit therefore changes this function's name
to synchronize_rcu_expedited_wait() to reflect its new generic nature.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:24:59 -08:00
Paul E. McKenney
de8cd0a533 rcu: Update tree_exp.h function-header comments
The function-header comments in kernel/rcu/tree_exp.h have gotten a bit
out of date, so this commit updates a number of them.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:24:58 -08:00
Paul E. McKenney
6c7d7dbf5b rcu: Rename sync_rcu_preempt_exp_done() to sync_rcu_exp_done()
Now that the RCU flavors have been consolidated, there is one common
function for checking to see if an expedited RCU grace period has
completed, namely sync_rcu_preempt_exp_done().  Because this function is
no longer specific to RCU-preempt, this commit removes the "_preempt" from
its name.  This commit also changes sync_rcu_preempt_exp_done_unlocked()
to sync_rcu_exp_done_unlocked() for the same reason.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:24:58 -08:00
Neeraj Upadhyay
4bc6b745e5 rcu: Allow only one expedited GP to run concurrently with wakeups
The current expedited RCU grace-period code expects that a task
requesting an expedited grace period cannot awaken until that grace
period has reached the wakeup phase.  However, it is possible for a long
preemption to result in the waiting task never sleeping.  For example,
consider the following sequence of events:

1.	Task A starts an expedited grace period by invoking
	synchronize_rcu_expedited().  It proceeds normally up to the
	wait_event() near the end of that function, and is then preempted
	(or interrupted or whatever).

2.	The expedited grace period completes, and a kworker task starts
	the awaken phase, having incremented the counter and acquired
	the rcu_state structure's .exp_wake_mutex.  This kworker task
	is then preempted or interrupted or whatever.

3.	Task A resumes and enters wait_event(), which notes that the
	expedited grace period has completed, and thus doesn't sleep.

4.	Task B starts an expedited grace period exactly as did Task A,
	complete with the preemption (or whatever delay) just before
	the call to wait_event().

5.	The expedited grace period completes, and another kworker
	task starts the awaken phase, having incremented the counter.
	However, it blocks when attempting to acquire the rcu_state
	structure's .exp_wake_mutex because step 2's kworker task has
	not yet released it.

6.	Steps 4 and 5 repeat, resulting in overflow of the rcu_node
	structure's ->exp_wq[] array.

In theory, this is harmless.  Tasks waiting on the various ->exp_wq[]
array will just be spuriously awakened, but they will just sleep again
on noting that the rcu_state structure's ->expedited_sequence value has
not advanced far enough.

In practice, this wastes CPU time and is an accident waiting to happen.
This commit therefore moves the rcu_exp_gp_seq_end() call that officially
ends the expedited grace period (along with associate tracing) until
after the ->exp_wake_mutex has been acquired.  This prevents Task A from
awakening prematurely, thus preventing more than one expedited grace
period from being in flight during a previous expedited grace period's
wakeup phase.

Fixes: 3b5f668e71 ("rcu: Overlap wakeups with next expedited grace period")
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
[ paulmck: Added updated comment. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:24:57 -08:00
Neeraj Upadhyay
fd6bc19d76 rcu: Fix missed wakeup of exp_wq waiters
Tasks waiting within exp_funnel_lock() for an expedited grace period to
elapse can be starved due to the following sequence of events:

1.	Tasks A and B both attempt to start an expedited grace
	period at about the same time.	This grace period will have
	completed when the lower four bits of the rcu_state structure's
	->expedited_sequence field are 0b'0100', for example, when the
	initial value of this counter is zero.	Task A wins, and thus
	does the actual work of starting the grace period, including
	acquiring the rcu_state structure's .exp_mutex and sets the
	counter to 0b'0001'.

2.	Because task B lost the race to start the grace period, it
	waits on ->expedited_sequence to reach 0b'0100' inside of
	exp_funnel_lock(). This task therefore blocks on the rcu_node
	structure's ->exp_wq[1] field, keeping in mind that the
	end-of-grace-period value of ->expedited_sequence (0b'0100')
	is shifted down two bits before indexing the ->exp_wq[] field.

3.	Task C attempts to start another expedited grace period,
	but blocks on ->exp_mutex, which is still held by Task A.

4.	The aforementioned expedited grace period completes, so that
	->expedited_sequence now has the value 0b'0100'.  A kworker task
	therefore acquires the rcu_state structure's ->exp_wake_mutex
	and starts awakening any tasks waiting for this grace period.

5.	One of the first tasks awakened happens to be Task A.  Task A
	therefore releases the rcu_state structure's ->exp_mutex,
	which allows Task C to start the next expedited grace period,
	which causes the lower four bits of the rcu_state structure's
	->expedited_sequence field to become 0b'0101'.

6.	Task C's expedited grace period completes, so that the lower four
	bits of the rcu_state structure's ->expedited_sequence field now
	become 0b'1000'.

7.	The kworker task from step 4 above continues its wakeups.
	Unfortunately, the wake_up_all() refetches the rcu_state
	structure's .expedited_sequence field:

	wake_up_all(&rnp->exp_wq[rcu_seq_ctr(rcu_state.expedited_sequence) & 0x3]);

	This results in the wakeup being applied to the rcu_node
	structure's ->exp_wq[2] field, which is unfortunate given that
	Task B is instead waiting on ->exp_wq[1].

On a busy system, no harm is done (or at least no permanent harm is done).
Some later expedited grace period will redo the wakeup.  But on a quiet
system, such as many embedded systems, it might be a good long time before
there was another expedited grace period.  On such embedded systems,
this situation could therefore result in a system hang.

This issue manifested as DPM device timeout during suspend (which
usually qualifies as a quiet time) due to a SCSI device being stuck in
_synchronize_rcu_expedited(), with the following stack trace:

	schedule()
	synchronize_rcu_expedited()
	synchronize_rcu()
	scsi_device_quiesce()
	scsi_bus_suspend()
	dpm_run_callback()
	__device_suspend()

This commit therefore prevents such delays, timeouts, and hangs by
making rcu_exp_wait_wake() use its "s" argument consistently instead of
refetching from rcu_state.expedited_sequence.

Fixes: 3b5f668e71 ("rcu: Overlap wakeups with next expedited grace period")
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:24:57 -08:00
Paul E. McKenney
aca2991a25 rcu: Substitute lookup for bit-twiddling in sync_rcu_exp_select_node_cpus()
The code in sync_rcu_exp_select_node_cpus() calculates the current
CPU's mask within its rcu_node structure's bitmasks, but this has
already been computed in the ->grpmask field of that CPU's rcu_data
structure.  This commit therefore just uses this ->grpmask field.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:24:57 -08:00
Marco Elver
6cf539a87a rcu: Fix data-race due to atomic_t copy-by-value
This fixes a data-race where `atomic_t dynticks` is copied by value. The
copy is performed non-atomically, resulting in a data-race if `dynticks`
is updated concurrently.

This data-race was found with KCSAN:
==================================================================
BUG: KCSAN: data-race in dyntick_save_progress_counter / rcu_irq_enter

write to 0xffff989dbdbe98e0 of 4 bytes by task 10 on cpu 3:
 atomic_add_return include/asm-generic/atomic-instrumented.h:78 [inline]
 rcu_dynticks_snap kernel/rcu/tree.c:310 [inline]
 dyntick_save_progress_counter+0x43/0x1b0 kernel/rcu/tree.c:984
 force_qs_rnp+0x183/0x200 kernel/rcu/tree.c:2286
 rcu_gp_fqs kernel/rcu/tree.c:1601 [inline]
 rcu_gp_fqs_loop+0x71/0x880 kernel/rcu/tree.c:1653
 rcu_gp_kthread+0x22c/0x3b0 kernel/rcu/tree.c:1799
 kthread+0x1b5/0x200 kernel/kthread.c:255
 <snip>

read to 0xffff989dbdbe98e0 of 4 bytes by task 154 on cpu 7:
 rcu_nmi_enter_common kernel/rcu/tree.c:828 [inline]
 rcu_irq_enter+0xda/0x240 kernel/rcu/tree.c:870
 irq_enter+0x5/0x50 kernel/softirq.c:347
 <snip>

Reported by Kernel Concurrency Sanitizer on:
CPU: 7 PID: 154 Comm: kworker/7:1H Not tainted 5.3.0+ #5
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Workqueue: kblockd blk_mq_run_work_fn
==================================================================

Signed-off-by: Marco Elver <elver@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2019-12-09 12:24:56 -08:00
Boqun Feng
9f08cf0886 rcu: Avoid modifying mask_ofl_ipi in sync_rcu_exp_select_node_cpus()
The "mask_ofl_ipi" is used to track which CPUs get IPIed, however
in the IPI sending loop, "mask_ofl_ipi" along with another variable
"mask_ofl_test" might also get modified to record which CPUs' quiesent
states must be reported by the sync_rcu_exp_select_node_cpus() at
the end of sync_rcu_exp_select_node_cpus().  This overlap of roles
can be confusing, so this patch cleans things a little by using
"mask_ofl_ipi" solely for determining which CPUs must be IPIed  and
"mask_ofl_test" for solely determining on behalf of  which CPUs
sync_rcu_exp_select_node_cpus() must report a quiscent state.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Acked-by: Marco Elver <elver@google.com>
2019-12-09 12:24:56 -08:00
Paul E. McKenney
15c7c972cd rcu: Use *_ONCE() to protect lockless ->expmask accesses
The rcu_node structure's ->expmask field is accessed locklessly when
starting a new expedited grace period and when reporting an expedited
RCU CPU stall warning.  This commit therefore handles the former by
taking a snapshot of ->expmask while the lock is held and the latter
by applying READ_ONCE() to lockless reads and WRITE_ONCE() to the
corresponding updates.

Link: https://lore.kernel.org/lkml/CANpmjNNmSOagbTpffHr4=Yedckx9Rm2NuGqC9UqE+AOz5f1-ZQ@mail.gmail.com
Reported-by: syzbot+134336b86f728d6e55a0@syzkaller.appspotmail.com
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Marco Elver <elver@google.com>
2019-12-09 12:24:56 -08:00
Amol Grover
cb5172d96d audit: Add __rcu annotation to RCU pointer
Add __rcu annotation to RCU-protected global pointer auditd_conn.

auditd_conn is an RCU-protected global pointer,i.e., accessed
via RCU methods rcu_dereference() and rcu_assign_pointer(),
hence it must be annotated with __rcu for sparse to report
warnings/errors correctly.

Fix multiple instances of the sparse error:
error: incompatible types in comparison expression
(different address spaces)

Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Amol Grover <frextrite@gmail.com>
[PM: tweak subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-12-09 15:19:03 -05:00
Linus Torvalds
184b8f7f91 pr_warning() removal for 5.5
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Merge tag 'printk-for-5.5-pr-warning-removal' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk

Pull pr_warning() removal from Petr Mladek.

 - Final removal of the unused pr_warning() alias.

You're supposed to use just "pr_warn()" in the kernel.

* tag 'printk-for-5.5-pr-warning-removal' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk:
  checkpatch: Drop pr_warning check
  printk: Drop pr_warning definition
  Fix up for "printk: Drop pr_warning definition"
  workqueue: Use pr_warn instead of pr_warning
2019-12-09 11:48:21 -08:00
Pankaj Bharadiya
c593642c8b treewide: Use sizeof_field() macro
Replace all the occurrences of FIELD_SIZEOF() with sizeof_field() except
at places where these are defined. Later patches will remove the unused
definition of FIELD_SIZEOF().

This patch is generated using following script:

EXCLUDE_FILES="include/linux/stddef.h|include/linux/kernel.h"

git grep -l -e "\bFIELD_SIZEOF\b" | while read file;
do

	if [[ "$file" =~ $EXCLUDE_FILES ]]; then
		continue
	fi
	sed -i  -e 's/\bFIELD_SIZEOF\b/sizeof_field/g' $file;
done

Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
Link: https://lore.kernel.org/r/20190924105839.110713-3-pankaj.laxminarayan.bharadiya@intel.com
Co-developed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: David Miller <davem@davemloft.net> # for net
2019-12-09 10:36:44 -08:00
Masami Hiramatsu
bf08949cc8 modules: lockdep: Suppress suspicious RCU usage warning
While running kprobe module test, find_module_all() caused
a suspicious RCU usage warning.

-----
 =============================
 WARNING: suspicious RCU usage
 5.4.0-next-20191202+ #63 Not tainted
 -----------------------------
 kernel/module.c:619 RCU-list traversed in non-reader section!!

 other info that might help us debug this:

 rcu_scheduler_active = 2, debug_locks = 1
 1 lock held by rmmod/642:
  #0: ffffffff8227da80 (module_mutex){+.+.}, at: __x64_sys_delete_module+0x9a/0x230

 stack backtrace:
 CPU: 0 PID: 642 Comm: rmmod Not tainted 5.4.0-next-20191202+ #63
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
 Call Trace:
  dump_stack+0x71/0xa0
  find_module_all+0xc1/0xd0
  __x64_sys_delete_module+0xac/0x230
  ? do_syscall_64+0x12/0x1f0
  do_syscall_64+0x50/0x1f0
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
 RIP: 0033:0x4b6d49
-----

This is because list_for_each_entry_rcu(modules) is called
without rcu_read_lock(). This is safe because the module_mutex
is locked.

Pass lockdep_is_held(&module_mutex) to the list_for_each_entry_rcu()
to suppress this warning, This also fixes similar issue in
mod_find() and each_symbol_section().

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
2019-12-09 10:51:23 +01:00
Aleksa Sarai
ce623f8987 nsfs: clean-up ns_get_path() signature to return int
ns_get_path() and ns_get_path_cb() only ever return either NULL or an
ERR_PTR. It is far more idiomatic to simply return an integer, and it
makes all of the callers of ns_get_path() more straightforward to read.

Fixes: e149ed2b80 ("take the targets of /proc/*/ns/* symlinks to separate fs")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-12-08 19:09:37 -05:00
Linus Torvalds
95e6ba5133 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from David Miller:

 1) More jumbo frame fixes in r8169, from Heiner Kallweit.

 2) Fix bpf build in minimal configuration, from Alexei Starovoitov.

 3) Use after free in slcan driver, from Jouni Hogander.

 4) Flower classifier port ranges don't work properly in the HW offload
    case, from Yoshiki Komachi.

 5) Use after free in hns3_nic_maybe_stop_tx(), from Yunsheng Lin.

 6) Out of bounds access in mqprio_dump(), from Vladyslav Tarasiuk.

 7) Fix flow dissection in dsa TX path, from Alexander Lobakin.

 8) Stale syncookie timestampe fixes from Guillaume Nault.

[ Did an evil merge to silence a warning introduced by this pull - Linus ]

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (84 commits)
  r8169: fix rtl_hw_jumbo_disable for RTL8168evl
  net_sched: validate TCA_KIND attribute in tc_chain_tmplt_add()
  r8169: add missing RX enabling for WoL on RTL8125
  vhost/vsock: accept only packets with the right dst_cid
  net: phy: dp83867: fix hfs boot in rgmii mode
  net: ethernet: ti: cpsw: fix extra rx interrupt
  inet: protect against too small mtu values.
  gre: refetch erspan header from skb->data after pskb_may_pull()
  pppoe: remove redundant BUG_ON() check in pppoe_pernet
  tcp: Protect accesses to .ts_recent_stamp with {READ,WRITE}_ONCE()
  tcp: tighten acceptance of ACKs not matching a child socket
  tcp: fix rejected syncookies due to stale timestamps
  lpc_eth: kernel BUG on remove
  tcp: md5: fix potential overestimation of TCP option space
  net: sched: allow indirect blocks to bind to clsact in TC
  net: core: rename indirect block ingress cb function
  net-sysfs: Call dev_hold always in netdev_queue_add_kobject
  net: dsa: fix flow dissection on Tx path
  net/tls: Fix return values to avoid ENOTSUPP
  net: avoid an indirect call in ____sys_recvmsg()
  ...
2019-12-08 13:28:11 -08:00
Sebastian Andrzej Siewior
025f50f386 sched/rt, workqueue: Use PREEMPTION
CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Update the comment to use PREEMPTION because it is true for both
preemption models.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20191015191821.11479-35-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-08 14:37:37 +01:00
Sebastian Andrzej Siewior
1b40cd56f3 sched/rt, locking: Use CONFIG_PREEMPTION
CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Switch the Kconfig dependency to use CONFIG_PREEMPTION.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20191015191821.11479-32-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-08 14:37:36 +01:00
Ingo Molnar
4f797f56c3 Merge branch 'linus' into sched/urgent, to pick up the latest before merging new patches
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-08 14:37:10 +01:00
Stephen Rothwell
ee19545220 Fix up for "printk: Drop pr_warning definition"
Link: http://lkml.kernel.org/r/20191206092503.303d6a57@canb.auug.org.au
Cc: Linux Next Mailing List <linux-next@vger.kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-12-06 10:02:35 +01:00
Kefeng Wang
1d9a6159bd workqueue: Use pr_warn instead of pr_warning
Use pr_warn() instead of the remaining pr_warning() calls.

Link: http://lkml.kernel.org/r/20191128004752.35268-2-wangkefeng.wang@huawei.com
To: joe@perches.com
To: linux-kernel@vger.kernel.org
Cc: gregkh@linuxfoundation.org
Cc: tj@kernel.org
Cc: arnd@arndb.de
Cc: sergey.senozhatsky@gmail.com
Cc: rostedt@goodmis.org
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
2019-12-06 09:59:30 +01:00
Linus Torvalds
0f13741624 Modules updates for v5.5
Summary of modules changes for the 5.5 merge window:
 
 - Refactor include/linux/export.h and remove code duplication between
   EXPORT_SYMBOL and EXPORT_SYMBOL_NS to make it more readable. The most
   notable change is that no namespace is represented by an empty string ""
   rather than NULL.
 
 - Fix a module load/unload race where waiter(s) trying to load the same
   module weren't being woken up when a module finally goes away.
 
 Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Merge tag 'modules-for-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux

Pull modules updates from Jessica Yu:
 "Summary of modules changes for the 5.5 merge window:

   - Refactor include/linux/export.h and remove code duplication between
     EXPORT_SYMBOL and EXPORT_SYMBOL_NS to make it more readable.

     The most notable change is that no namespace is represented by an
     empty string "" rather than NULL.

   - Fix a module load/unload race where waiter(s) trying to load the
     same module weren't being woken up when a module finally goes away"

* tag 'modules-for-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  kernel/module.c: wakeup processes in module_wq on module unload
  moduleparam: fix parameter description mismatch
  export: avoid code duplication in include/linux/export.h
2019-12-05 12:27:16 -08:00
Linus Torvalds
fb3da48a86 Merge branch 'thermal/next' of git://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux
Pull thermal management updates from Zhang Rui:

 - Fix a deadlock regression in thermal core framework, which was
   introduced in 5.3 (Wei Wang)

 - Initialize thermal control framework earlier to enable thermal
   mitigation during boot (Amit Kucheria)

 - Convert the Intelligent Power Allocator (IPA) thermal governor to
   follow the generic PM_EM instead of its own Energy Model (Quentin
   Perret)

 - Introduce a new Amlogic soc thermal driver (Guillaume La Roque)

 - Add interrupt support for tsens thermal driver (Amit Kucheria)

 - Add support for MSM8956/8976 in tsens thermal driver
   (AngeloGioacchino Del Regno)

 - Add support for r8a774b1 in rcar thermal driver (Biju Das)

 - Add support for Thermal Monitor Unit v2 in qoriq thermal driver
   (Yuantian Tang)

 - Some other fixes/cleanups on thermal core framework and soc thermal
   drivers (Colin Ian King, Daniel Lezcano, Hsin-Yi Wang, Tian Tao)

* 'thermal/next' of git://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux: (32 commits)
  thermal: Fix deadlock in thermal thermal_zone_device_check
  thermal: cpu_cooling: Migrate to using the EM framework
  thermal: cpu_cooling: Make the power-related code depend on IPA
  PM / EM: Declare EM data types unconditionally
  arm64: defconfig: Enable CONFIG_ENERGY_MODEL
  drivers: thermal: tsens: fix potential integer overflow on multiply
  thermal: cpu_cooling: Reorder the header file
  thermal: cpu_cooling: Remove pointless dependency on CONFIG_OF
  thermal: no need to set .owner when using module_platform_driver
  thermal: qcom: tsens-v1: Fix kfree of a non-pointer value
  cpufreq: qcom-hw: Move driver initialization earlier
  clk: qcom: Initialize clock drivers earlier
  cpufreq: Initialize cpufreq-dt driver earlier
  cpufreq: Initialize the governors in core_initcall
  thermal: Initialize thermal subsystem earlier
  thermal: Remove netlink support
  dt: thermal: tsens: Document compatible for MSM8976/56
  thermal: qcom: tsens-v1: Add support for MSM8956 and MSM8976
  MAINTAINERS: add entry for Amlogic Thermal driver
  thermal: amlogic: Add thermal driver to support G12 SoCs
  ...
2019-12-05 11:21:24 -08:00
Linus Torvalds
5ecc9d15f7 Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
 "Most of the rest of MM and various other things. Some Kconfig rework
  still awaits merges of dependent trees from linux-next.

  Subsystems affected by this patch series: mm/hotfixes, mm/memcg,
  mm/vmstat, mm/thp, procfs, sysctl, misc, notifiers, core-kernel,
  bitops, lib, checkpatch, epoll, binfmt, init, rapidio, uaccess, kcov,
  ubsan, ipc, bitmap, mm/pagemap"

* akpm: (86 commits)
  mm: remove __ARCH_HAS_4LEVEL_HACK and include/asm-generic/4level-fixup.h
  um: add support for folded p4d page tables
  um: remove unused pxx_offset_proc() and addr_pte() functions
  sparc32: use pgtable-nopud instead of 4level-fixup
  parisc/hugetlb: use pgtable-nopXd instead of 4level-fixup
  parisc: use pgtable-nopXd instead of 4level-fixup
  nds32: use pgtable-nopmd instead of 4level-fixup
  microblaze: use pgtable-nopmd instead of 4level-fixup
  m68k: mm: use pgtable-nopXd instead of 4level-fixup
  m68k: nommu: use pgtable-nopud instead of 4level-fixup
  c6x: use pgtable-nopud instead of 4level-fixup
  arm: nommu: use pgtable-nopud instead of 4level-fixup
  alpha: use pgtable-nopud instead of 4level-fixup
  gpio: pca953x: tighten up indentation
  gpio: pca953x: convert to use bitmap API
  gpio: pca953x: use input from regs structure in pca953x_irq_pending()
  gpio: pca953x: remove redundant variable and check in IRQ handler
  lib/bitmap: introduce bitmap_replace() helper
  lib/test_bitmap: fix comment about this file
  lib/test_bitmap: move exp1 and exp2 upper for others to use
  ...
2019-12-05 09:46:26 -08:00
Yonghong Song
e9eeec58c9 bpf: Fix a bug when getting subprog 0 jited image in check_attach_btf_id
For jited bpf program, if the subprogram count is 1, i.e.,
there is no callees in the program, prog->aux->func will be NULL
and prog->bpf_func points to image address of the program.

If there is more than one subprogram, prog->aux->func is populated,
and subprogram 0 can be accessed through either prog->bpf_func or
prog->aux->func[0]. Other subprograms should be accessed through
prog->aux->func[subprog_id].

This patch fixed a bug in check_attach_btf_id(), where
prog->aux->func[subprog_id] is used to access any subprogram which
caused a segfault like below:
  [79162.619208] BUG: kernel NULL pointer dereference, address:
  0000000000000000
  ......
  [79162.634255] Call Trace:
  [79162.634974]  ? _cond_resched+0x15/0x30
  [79162.635686]  ? kmem_cache_alloc_trace+0x162/0x220
  [79162.636398]  ? selinux_bpf_prog_alloc+0x1f/0x60
  [79162.637111]  bpf_prog_load+0x3de/0x690
  [79162.637809]  __do_sys_bpf+0x105/0x1740
  [79162.638488]  do_syscall_64+0x5b/0x180
  [79162.639147]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ......

Fixes: 5b92a28aae ("bpf: Support attaching tracing BPF program to other BPF programs")
Reported-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191205010606.177774-1-yhs@fb.com
2019-12-04 21:20:07 -08:00
Andrey Konovalov
eec028c938 kcov: remote coverage support
Patch series " kcov: collect coverage from usb and vhost", v3.

This patchset extends kcov to allow collecting coverage from backgound
kernel threads.  This extension requires custom annotations for each of
the places where coverage collection is desired.  This patchset
implements this for hub events in the USB subsystem and for vhost
workers.  See the first patch description for details about the kcov
extension.  The other two patches apply this kcov extension to USB and
vhost.

Examples of other subsystems that might potentially benefit from this
when custom annotations are added (the list is based on
process_one_work() callers for bugs recently reported by syzbot):

1. fs: writeback wb_workfn() worker,
2. net: addrconf_dad_work()/addrconf_verify_work() workers,
3. net: neigh_periodic_work() worker,
4. net/p9: p9_write_work()/p9_read_work() workers,
5. block: blk_mq_run_work_fn() worker.

These patches have been used to enable coverage-guided USB fuzzing with
syzkaller for the last few years, see the details here:

  https://github.com/google/syzkaller/blob/master/docs/linux/external_fuzzing_usb.md

This patchset has been pushed to the public Linux kernel Gerrit
instance:

  https://linux-review.googlesource.com/c/linux/kernel/git/torvalds/linux/+/1524

This patch (of 3):

Add background thread coverage collection ability to kcov.

With KCOV_ENABLE coverage is collected only for syscalls that are issued
from the current process.  With KCOV_REMOTE_ENABLE it's possible to
collect coverage for arbitrary parts of the kernel code, provided that
those parts are annotated with kcov_remote_start()/kcov_remote_stop().

This allows to collect coverage from two types of kernel background
threads: the global ones, that are spawned during kernel boot in a
limited number of instances (e.g.  one USB hub_event() worker thread is
spawned per USB HCD); and the local ones, that are spawned when a user
interacts with some kernel interface (e.g.  vhost workers).

To enable collecting coverage from a global background thread, a unique
global handle must be assigned and passed to the corresponding
kcov_remote_start() call.  Then a userspace process can pass a list of
such handles to the KCOV_REMOTE_ENABLE ioctl in the handles array field
of the kcov_remote_arg struct.  This will attach the used kcov device to
the code sections, that are referenced by those handles.

Since there might be many local background threads spawned from
different userspace processes, we can't use a single global handle per
annotation.  Instead, the userspace process passes a non-zero handle
through the common_handle field of the kcov_remote_arg struct.  This
common handle gets saved to the kcov_handle field in the current
task_struct and needs to be passed to the newly spawned threads via
custom annotations.  Those threads should in turn be annotated with
kcov_remote_start()/kcov_remote_stop().

Internally kcov stores handles as u64 integers.  The top byte of a
handle is used to denote the id of a subsystem that this handle belongs
to, and the lower 4 bytes are used to denote the id of a thread instance
within that subsystem.  A reserved value 0 is used as a subsystem id for
common handles as they don't belong to a particular subsystem.  The
bytes 4-7 are currently reserved and must be zero.  In the future the
number of bytes used for the subsystem or handle ids might be increased.

When a particular userspace process collects coverage by via a common
handle, kcov will collect coverage for each code section that is
annotated to use the common handle obtained as kcov_handle from the
current task_struct.  However non common handles allow to collect
coverage selectively from different subsystems.

Link: http://lkml.kernel.org/r/e90e315426a384207edbec1d6aa89e43008e4caf.1572366574.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04 19:44:14 -08:00
Huang Shijie
964975ac66 lib/genalloc.c: rename addr_in_gen_pool to gen_pool_has_addr
Follow the kernel conventions, rename addr_in_gen_pool to
gen_pool_has_addr.

[sjhuang@iluvatar.ai: fix Documentation/ too]
 Link: http://lkml.kernel.org/r/20181229015914.5573-1-sjhuang@iluvatar.ai
Link: http://lkml.kernel.org/r/20181228083950.20398-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04 19:44:13 -08:00
Joe Perches
5e1aada08c kernel/sys.c: avoid copying possible padding bytes in copy_to_user
Initialization is not guaranteed to zero padding bytes so use an
explicit memset instead to avoid leaking any kernel content in any
possible padding bytes.

Link: http://lkml.kernel.org/r/dfa331c00881d61c8ee51577a082d8bebd61805c.camel@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04 19:44:12 -08:00
Nathan Chancellor
ef70eff9de kernel/profile.c: use cpumask_available to check for NULL cpumask
When building with clang + -Wtautological-pointer-compare, these
instances pop up:

  kernel/profile.c:339:6: warning: comparison of array 'prof_cpu_mask' not equal to a null pointer is always true [-Wtautological-pointer-compare]
          if (prof_cpu_mask != NULL)
              ^~~~~~~~~~~~~    ~~~~
  kernel/profile.c:376:6: warning: comparison of array 'prof_cpu_mask' not equal to a null pointer is always true [-Wtautological-pointer-compare]
          if (prof_cpu_mask != NULL)
              ^~~~~~~~~~~~~    ~~~~
  kernel/profile.c:406:26: warning: comparison of array 'prof_cpu_mask' not equal to a null pointer is always true [-Wtautological-pointer-compare]
          if (!user_mode(regs) && prof_cpu_mask != NULL &&
                                ^~~~~~~~~~~~~    ~~~~
  3 warnings generated.

This can be addressed with the cpumask_available helper, introduced in
commit f7e30f01a9 ("cpumask: Add helper cpumask_available()") to fix
warnings like this while keeping the code the same.

Link: https://github.com/ClangBuiltLinux/linux/issues/747
Link: http://lkml.kernel.org/r/20191022191957.9554-1-natechancellor@gmail.com
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04 19:44:12 -08:00
Xiaoming Ni
260a2679e5 kernel/notifier.c: remove blocking_notifier_chain_cond_register()
blocking_notifier_chain_cond_register() does not consider system_booting
state, which is the only difference between this function and
blocking_notifier_cain_register().  This can be a bug and is a piece of
duplicate code.

Delete blocking_notifier_chain_cond_register()

Link: http://lkml.kernel.org/r/1568861888-34045-4-git-send-email-nixiaoming@huawei.com
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Sam Protsenko <semen.protsenko@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04 19:44:12 -08:00
Xiaoming Ni
5adaabb65a kernel/notifier.c: remove notifier_chain_cond_register()
The only difference between notifier_chain_cond_register() and
notifier_chain_register() is the lack of warning hints for duplicate
registrations.  Use notifier_chain_register() instead of
notifier_chain_cond_register() to avoid duplicate code

Link: http://lkml.kernel.org/r/1568861888-34045-3-git-send-email-nixiaoming@huawei.com
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Sam Protsenko <semen.protsenko@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04 19:44:12 -08:00
Xiaoming Ni
1a50cb80f2 kernel/notifier.c: intercept duplicate registrations to avoid infinite loops
Registering the same notifier to a hook repeatedly can cause the hook
list to form a ring or lose other members of the list.

  case1: An infinite loop in notifier_chain_register() can cause soft lockup
          atomic_notifier_chain_register(&test_notifier_list, &test1);
          atomic_notifier_chain_register(&test_notifier_list, &test1);
          atomic_notifier_chain_register(&test_notifier_list, &test2);

  case2: An infinite loop in notifier_chain_register() can cause soft lockup
          atomic_notifier_chain_register(&test_notifier_list, &test1);
          atomic_notifier_chain_register(&test_notifier_list, &test1);
          atomic_notifier_call_chain(&test_notifier_list, 0, NULL);

  case3: lose other hook test2
          atomic_notifier_chain_register(&test_notifier_list, &test1);
          atomic_notifier_chain_register(&test_notifier_list, &test2);
          atomic_notifier_chain_register(&test_notifier_list, &test1);

  case4: Unregister returns 0, but the hook is still in the linked list,
         and it is not really registered. If you call
         notifier_call_chain after ko is unloaded, it will trigger oops.

If the system is configured with softlockup_panic and the same hook is
repeatedly registered on the panic_notifier_list, it will cause a loop
panic.

Add a check in notifier_chain_register(), intercepting duplicate
registrations to avoid infinite loops

Link: http://lkml.kernel.org/r/1568861888-34045-2-git-send-email-nixiaoming@huawei.com
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Vasily Averin <vvs@virtuozzo.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Sam Protsenko <semen.protsenko@linaro.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-04 19:44:12 -08:00
Linus Torvalds
2f13437b89 Two fixes and one patch that was missed:
Fixes:
 
   - Missing __print_hex_dump undef for processing new function in trace events
   - Stop WARN_ON messages when lockdown disables tracing on boot up
 
  Enhancement:
 
   - Debug option to inject trace events from userspace (for rasdaemon)
 
 The enhancement has its own config option and is non invasive. It's been
 discussed for sever months and should have been added to my original
 push, but I never pulled it into my queue.
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Merge tag 'trace-v5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull more tracing updates from Steven Rostedt:
 "Two fixes and one patch that was missed:

  Fixes:

   - Missing __print_hex_dump undef for processing new function in trace
     events

   - Stop WARN_ON messages when lockdown disables tracing on boot up

  Enhancement:

   - Debug option to inject trace events from userspace (for rasdaemon)"

The enhancement has its own config option and is non invasive. It's been
discussed for sever months and should have been added to my original
push, but I never pulled it into my queue.

* tag 'trace-v5.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Do not create directories if lockdown is in affect
  tracing: Introduce trace event injection
  tracing: Fix __print_hex_dump scope
2019-12-04 19:13:52 -08:00
Linus Torvalds
ef867c12f3 Additional power management updates for 5.5-rc1
- Avoid a race condition in the ACPI EC driver that may cause
    systems to be unable to leave suspend-to-idle (Rafael Wysocki).
 
  - Drop the "disabled" field, which is redundant, from struct
    cpuidle_state (Rafael Wysocki).
 
  - Reintroduce device PM QoS frequency constraints (temporarily
    introduced and than dropped during the 5.4 cycle) in preparation
    for adding QoS support to devfreq (Leonard Crestez).
 
  - Clean up indentation (in multiple places) and the cpuidle drivers
    help text in Kconfig (Krzysztof Kozlowski, Randy Dunlap).
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Merge tag 'pm-5.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull additional power management updates from Rafael Wysocki:
 "These fix an ACPI EC driver bug exposed by the recent rework of the
  suspend-to-idle code flow, reintroduce frequency constraints into
  device PM QoS (in preparation for adding QoS support to devfreq), drop
  a redundant field from struct cpuidle_state and clean up Kconfig in
  some places.

  Specifics:

   - Avoid a race condition in the ACPI EC driver that may cause systems
     to be unable to leave suspend-to-idle (Rafael Wysocki)

   - Drop the "disabled" field, which is redundant, from struct
     cpuidle_state (Rafael Wysocki)

   - Reintroduce device PM QoS frequency constraints (temporarily
     introduced and than dropped during the 5.4 cycle) in preparation
     for adding QoS support to devfreq (Leonard Crestez)

   - Clean up indentation (in multiple places) and the cpuidle drivers
     help text in Kconfig (Krzysztof Kozlowski, Randy Dunlap)"

* tag 'pm-5.5-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: PM: s2idle: Rework ACPI events synchronization
  ACPI: EC: Rework flushing of pending work
  PM / devfreq: Add missing locking while setting suspend_freq
  PM / QoS: Restore DEV_PM_QOS_MIN/MAX_FREQUENCY
  PM / QoS: Reorder pm_qos/freq_qos/dev_pm_qos structs
  PM / QoS: Initial kunit test
  PM / QoS: Redefine FREQ_QOS_MAX_DEFAULT_VALUE to S32_MAX
  power: avs: Fix Kconfig indentation
  cpufreq: Fix Kconfig indentation
  cpuidle: minor Kconfig help text fixes
  cpuidle: Drop disabled field from struct cpuidle_state
  cpuidle: Fix Kconfig indentation
2019-12-04 10:48:09 -08:00
Christian Brauner
0b8d616fb5
taskstats: fix data-race
When assiging and testing taskstats in taskstats_exit() there's a race
when setting up and reading sig->stats when a thread-group with more
than one thread exits:

write to 0xffff8881157bbe10 of 8 bytes by task 7951 on cpu 0:
 taskstats_tgid_alloc kernel/taskstats.c:567 [inline]
 taskstats_exit+0x6b7/0x717 kernel/taskstats.c:596
 do_exit+0x2c2/0x18e0 kernel/exit.c:864
 do_group_exit+0xb4/0x1c0 kernel/exit.c:983
 get_signal+0x2a2/0x1320 kernel/signal.c:2734
 do_signal+0x3b/0xc00 arch/x86/kernel/signal.c:815
 exit_to_usermode_loop+0x250/0x2c0 arch/x86/entry/common.c:159
 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x2d7/0x2f0 arch/x86/entry/common.c:299
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881157bbe10 of 8 bytes by task 7949 on cpu 1:
 taskstats_tgid_alloc kernel/taskstats.c:559 [inline]
 taskstats_exit+0xb2/0x717 kernel/taskstats.c:596
 do_exit+0x2c2/0x18e0 kernel/exit.c:864
 do_group_exit+0xb4/0x1c0 kernel/exit.c:983
 __do_sys_exit_group kernel/exit.c:994 [inline]
 __se_sys_exit_group kernel/exit.c:992 [inline]
 __x64_sys_exit_group+0x2e/0x30 kernel/exit.c:992
 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by using smp_load_acquire() and smp_store_release().

Reported-by: syzbot+c5d03165a1bd1dead0c1@syzkaller.appspotmail.com
Fixes: 34ec12349c ("taskstats: cleanup ->signal->stats allocation")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Marco Elver <elver@google.com>
Reviewed-by: Will Deacon <will@kernel.org>
Reviewed-by: Andrea Parri <parri.andrea@gmail.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://lore.kernel.org/r/20191009114809.8643-1-christian.brauner@ubuntu.com
2019-12-04 15:18:39 +01:00
Steven Rostedt (VMware)
a356646a56 tracing: Do not create directories if lockdown is in affect
If lockdown is disabling tracing on boot up, it prevents the tracing files
from even bering created. But when that happens, there's several places that
will give a warning that the files were not created as that is usually a
sign of a bug.

Add in strategic locations where a check is made to see if tracing is
disabled by lockdown, and if it is, do not go further, and fail silently
(but print that tracing is disabled by lockdown, without doing a WARN_ON()).

Cc: Matthew Garrett <mjg59@google.com>
Fixes: 17911ff38a ("tracing: Add locked_down checks to the open calls of files created for tracefs")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-12-04 08:27:15 -05:00
Linus Torvalds
043cf46825 Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Ingo Molnar:
 "The main changes in the timer code in this cycle were:

   - Clockevent updates:

      - timer-of framework cleanups. (Geert Uytterhoeven)

      - Use timer-of for the renesas-ostm and the device name to prevent
        name collision in case of multiple timers. (Geert Uytterhoeven)

      - Check if there is an error after calling of_clk_get in asm9260
        (Chuhong Yuan)

   - ABI fix: Zero out high order bits of nanoseconds on compat
     syscalls. This got broken a year ago, with apparently no side
     effects so far.

     Since the kernel would use random data otherwise I don't think we'd
     have other options but to fix the bug, even if there was a side
     effect to applications (Dmitry Safonov)

   - Optimize ns_to_timespec64() on 32-bit systems: move away from
     div_s64_rem() which can be slow, to div_u64_rem() which is faster
     (Arnd Bergmann)

   - Annotate KCSAN-reported false positive data races in
     hrtimer_is_queued() users by moving timer->state handling over to
     the READ_ONCE()/WRITE_ONCE() APIs. This documents these accesses
     (Eric Dumazet)

   - Misc cleanups and small fixes"

[ I undid the "ABI fix" and updated the comments instead. The reason
  there were apparently no side effects is that the fix was a no-op.

  The updated comment is to say _why_ it was a no-op.    - Linus ]

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  time: Zero the upper 32-bits in __kernel_timespec on 32-bit
  time: Rename tsk->real_start_time to ->start_boottime
  hrtimer: Remove the comment about not used HRTIMER_SOFTIRQ
  time: Fix spelling mistake in comment
  time: Optimize ns_to_timespec64()
  hrtimer: Annotate lockless access to timer->state
  clocksource/drivers/asm9260: Add a check for of_clk_get
  clocksource/drivers/renesas-ostm: Use unique device name instead of ostm
  clocksource/drivers/renesas-ostm: Convert to timer_of
  clocksource/drivers/timer-of: Use unique device name instead of timer
  clocksource/drivers/timer-of: Convert last full_name to %pOF
2019-12-03 12:20:25 -08:00
Linus Torvalds
b22bfea7f1 Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq updates from Ingo Molnar:
 "Most of the IRQ subsystem changes in this cycle were irq-chip driver
  updates:

   - Qualcomm PDC wakeup interrupt support

   - Layerscape external IRQ support

   - Broadcom bcm7038 PM and wakeup support

   - Ingenic driver cleanup and modernization

   - GICv3 ITS preparation for GICv4.1 updates

   - GICv4 fixes

  There's also the series from Frederic Weisbecker that fixes memory
  ordering bugs for the irq-work logic, whose primary fix is to turn
  work->irq_work.flags into an atomic variable and then convert the
  complex (and buggy) atomic_cmpxchg() loop in irq_work_claim() into a
  much simpler atomic_fetch_or() call.

  There are also various smaller cleanups"

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
  pinctrl/sdm845: Add PDC wakeup interrupt map for GPIOs
  pinctrl/msm: Setup GPIO chip in hierarchy
  irqchip/qcom-pdc: Add irqchip set/get state calls
  irqchip/qcom-pdc: Add irqdomain for wakeup capable GPIOs
  irqchip/qcom-pdc: Do not toggle IRQ_ENABLE during mask/unmask
  irqchip/qcom-pdc: Update max PDC interrupts
  of/irq: Document properties for wakeup interrupt parent
  genirq: Introduce irq_chip_get/set_parent_state calls
  irqdomain: Add bus token DOMAIN_BUS_WAKEUP
  genirq: Fix function documentation of __irq_alloc_descs()
  irq_work: Fix IRQ_WORK_BUSY bit clearing
  irqchip/ti-sci-inta: Use ERR_CAST inlined function instead of ERR_PTR(PTR_ERR(...))
  irq_work: Slightly simplify IRQ_WORK_PENDING clearing
  irq_work: Fix irq_work_claim() memory ordering
  irq_work: Convert flags to atomic_t
  irqchip: Ingenic: Add process for more than one irq at the same time.
  irqchip: ingenic: Alloc generic chips from IRQ domain
  irqchip: ingenic: Get virq number from IRQ domain
  irqchip: ingenic: Error out if IRQ domain creation failed
  irqchip: ingenic: Drop redundant irq_suspend / irq_resume functions
  ...
2019-12-03 09:29:50 -08:00
Linus Torvalds
76bb8b0596 Kbuild updates for v5.5
- remove unneeded asm headers from hexagon, ia64
 
  - add 'dir-pkg' target, which works like 'tar-pkg' but skips archiving
 
  - add 'helpnewconfig' target, which shows help for new CONFIG options
 
  - support 'make nsdeps' for external modules
 
  - make rebuilds faster by deleting $(wildcard $^) checks
 
  - remove compile tests for kernel-space headers
 
  - refactor modpost to simplify modversion handling
 
  - make single target builds faster
 
  - optimize and clean up scripts/kallsyms.c
 
  - refactor various Makefiles and scripts
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Merge tag 'kbuild-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - remove unneeded asm headers from hexagon, ia64

 - add 'dir-pkg' target, which works like 'tar-pkg' but skips archiving

 - add 'helpnewconfig' target, which shows help for new CONFIG options

 - support 'make nsdeps' for external modules

 - make rebuilds faster by deleting $(wildcard $^) checks

 - remove compile tests for kernel-space headers

 - refactor modpost to simplify modversion handling

 - make single target builds faster

 - optimize and clean up scripts/kallsyms.c

 - refactor various Makefiles and scripts

* tag 'kbuild-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (59 commits)
  MAINTAINERS: update Kbuild/Kconfig maintainer's email address
  scripts/kallsyms: remove redundant initializers
  scripts/kallsyms: put check_symbol_range() calls close together
  scripts/kallsyms: make check_symbol_range() void function
  scripts/kallsyms: move ignored symbol types to is_ignored_symbol()
  scripts/kallsyms: move more patterns to the ignored_prefixes array
  scripts/kallsyms: skip ignored symbols very early
  scripts/kallsyms: add const qualifiers where possible
  scripts/kallsyms: make find_token() return (unsigned char *)
  scripts/kallsyms: replace prefix_underscores_count() with strspn()
  scripts/kallsyms: add sym_name() to mitigate cast ugliness
  scripts/kallsyms: remove unneeded length check for prefix matching
  scripts/kallsyms: remove redundant is_arm_mapping_symbol()
  scripts/kallsyms: set relative_base more effectively
  scripts/kallsyms: shrink table before sorting it
  scripts/kallsyms: fix definitely-lost memory leak
  scripts/kallsyms: remove unneeded #ifndef ARRAY_SIZE
  kbuild: make single target builds even faster
  modpost: respect the previous export when 'exported twice' is warned
  modpost: do not set ->preloaded for symbols from Module.symvers
  ...
2019-12-02 17:35:04 -08:00
David S. Miller
734c7022ad Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:

====================
pull-request: bpf 2019-12-02

The following pull-request contains BPF updates for your *net* tree.

We've added 10 non-merge commits during the last 6 day(s) which contain
a total of 10 files changed, 60 insertions(+), 51 deletions(-).

The main changes are:

1) Fix vmlinux BTF generation for binutils pre v2.25, from Stanislav Fomichev.

2) Fix libbpf global variable relocation to take symbol's st_value offset
   into account, from Andrii Nakryiko.

3) Fix libbpf build on powerpc where check_abi target fails due to different
   readelf output format, from Aurelien Jarno.

4) Don't set BPF insns RO for the case when they are JITed in order to avoid
   fragmenting the direct map, from Daniel Borkmann.

5) Fix static checker warning in btf_distill_func_proto() as well as a build
   error due to empty enum when BPF is compiled out, from Alexei Starovoitov.

6) Fix up generation of bpf_helper_defs.h for perf, from Arnaldo Carvalho de Melo.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-02 10:50:29 -08:00
Cong Wang
6c3edaf9fd tracing: Introduce trace event injection
We have been trying to use rasdaemon to monitor hardware errors like
correctable memory errors. rasdaemon uses trace events to monitor
various hardware errors. In order to test it, we have to inject some
hardware errors, unfortunately not all of them provide error
injections. MCE does provide a way to inject MCE errors, but errors
like PCI error and devlink error don't, it is not easy to add error
injection to each of them. Instead, it is relatively easier to just
allow users to inject trace events in a generic way so that all trace
events can be injected.

This patch introduces trace event injection, where a new 'inject' is
added to each tracepoint directory. Users could write into this file
with key=value pairs to specify the value of each fields of the trace
event, all unspecified fields are set to zero values by default.

For example, for the net/net_dev_queue tracepoint, we can inject:

  INJECT=/sys/kernel/debug/tracing/events/net/net_dev_queue/inject
  echo "" > $INJECT
  echo "name='test'" > $INJECT
  echo "name='test' len=1024" > $INJECT
  cat /sys/kernel/debug/tracing/trace
  ...
   <...>-614   [000] ....    36.571483: net_dev_queue: dev= skbaddr=00000000fbf338c2 len=0
   <...>-614   [001] ....   136.588252: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=0
   <...>-614   [001] .N..   208.431878: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=1024

Triggers could be triggered as usual too:

  echo "stacktrace if len == 1025" > /sys/kernel/debug/tracing/events/net/net_dev_queue/trigger
  echo "len=1025" > $INJECT
  cat /sys/kernel/debug/tracing/trace
  ...
      bash-614   [000] ....    36.571483: net_dev_queue: dev= skbaddr=00000000fbf338c2 len=0
      bash-614   [001] ....   136.588252: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=0
      bash-614   [001] .N..   208.431878: net_dev_queue: dev=test skbaddr=00000000fbf338c2 len=1024
      bash-614   [001] .N.1   284.236349: <stack trace>
 => event_inject_write
 => vfs_write
 => ksys_write
 => do_syscall_64
 => entry_SYSCALL_64_after_hwframe

The only thing that can't be injected is string pointers as they
require constant string pointers, this can't be done at run time.

Link: http://lkml.kernel.org/r/20191130045218.18979-1-xiyou.wangcong@gmail.com

Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-12-02 11:07:00 -05:00