36302 Commits

Author SHA1 Message Date
Piotr Figiel
90f093fa8e rseq, ptrace: Add PTRACE_GET_RSEQ_CONFIGURATION request
For userspace checkpoint and restore (C/R) a way of getting process state
containing RSEQ configuration is needed.

There are two ways this information is going to be used:
 - to re-enable RSEQ for threads which had it enabled before C/R
 - to detect if a thread was in a critical section during C/R

Since C/R preserves TLS memory and addresses RSEQ ABI will be restored
using the address registered before C/R.

Detection whether the thread is in a critical section during C/R is needed
to enforce behavior of RSEQ abort during C/R. Attaching with ptrace()
before registers are dumped itself doesn't cause RSEQ abort.
Restoring the instruction pointer within the critical section is
problematic because rseq_cs may get cleared before the control is passed
to the migrated application code leading to RSEQ invariants not being
preserved. C/R code will use RSEQ ABI address to find the abort handler
to which the instruction pointer needs to be set.

To achieve above goals expose the RSEQ ABI address and the signature value
with the new ptrace request PTRACE_GET_RSEQ_CONFIGURATION.

This new ptrace request can also be used by debuggers so they are aware
of stops within restartable sequences in progress.

Signed-off-by: Piotr Figiel <figiel@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michal Miroslaw <emmir@google.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20210226135156.1081606-1-figiel@google.com
2021-03-17 16:15:39 +01:00
Sascha Hauer
fa8b90070a quota: wire up quotactl_path
Wire up the quotactl_path syscall added in the previous patch.

Link: https://lore.kernel.org/r/20210304123541.30749-3-s.hauer@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
2021-03-17 15:51:17 +01:00
Dirk Behme
6b2c339df9 softirq: s/BUG/WARN_ONCE/ on tasklet SCHED state not set
Replace BUG() with WARN_ONCE() on wrong tasklet state, in order to:

 - increase the verbosity / aid in debugging
 - avoid fatal/unrecoverable state

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210317102012.32399-1-erosca@de.adit-jv.com
2021-03-17 12:59:35 +01:00
Waiman Long
5de2055d31 locking/ww_mutex: Simplify use_ww_ctx & ww_ctx handling
The use_ww_ctx flag is passed to mutex_optimistic_spin(), but the
function doesn't use it. The frequent use of the (use_ww_ctx && ww_ctx)
combination is repetitive.

In fact, ww_ctx should not be used at all if !use_ww_ctx.  Simplify
ww_mutex code by dropping use_ww_ctx from mutex_optimistic_spin() an
clear ww_ctx if !use_ww_ctx. In this way, we can replace (use_ww_ctx &&
ww_ctx) by just (ww_ctx).

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210316153119.13802-2-longman@redhat.com
2021-03-17 09:56:44 +01:00
Bhaskar Chowdhury
4faf62b1ef locking/rwsem: Fix comment typo
s/folowing/following/

Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20210317041806.4096156-1-unixbhaskar@gmail.com
2021-03-17 09:34:39 +01:00
Christoph Hellwig
5d0538b2b8 swiotlb: lift the double initialization protection from xen-swiotlb
Lift the double initialization protection from xen-swiotlb to the core
code to avoid exposing too many swiotlb internals.  Also upgrade the
check to a warning as it should not happen.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2021-03-17 00:40:49 +00:00
Christoph Hellwig
80808d273a swiotlb: split swiotlb_tbl_sync_single
Split swiotlb_tbl_sync_single into two separate funtions for the to device
and to cpu synchronization.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2021-03-17 00:32:01 +00:00
Christoph Hellwig
2bdba622c3 swiotlb: move orig addr and size validation into swiotlb_bounce
Move the code to find and validate the original buffer address and size
from the callers into swiotlb_bounce.  This means a tiny bit of extra
work in the swiotlb_map path, but avoids code duplication and a leads to
a better code structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2021-03-17 00:29:41 +00:00
Christoph Hellwig
2973073a80 swiotlb: remove the alloc_size parameter to swiotlb_tbl_unmap_single
Now that swiotlb remembers the allocation size there is no need to pass
it back to swiotlb_tbl_unmap_single.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
2021-03-17 00:21:53 +00:00
Alexei Starovoitov
8a141dd7f7 ftrace: Fix modify_ftrace_direct.
The following sequence of commands:
  register_ftrace_direct(ip, addr1);
  modify_ftrace_direct(ip, addr1, addr2);
  unregister_ftrace_direct(ip, addr2);
will cause the kernel to warn:
[   30.179191] WARNING: CPU: 2 PID: 1961 at kernel/trace/ftrace.c:5223 unregister_ftrace_direct+0x130/0x150
[   30.180556] CPU: 2 PID: 1961 Comm: test_progs    W  O      5.12.0-rc2-00378-g86bc10a0a711-dirty #3246
[   30.182453] RIP: 0010:unregister_ftrace_direct+0x130/0x150

When modify_ftrace_direct() changes the addr from old to new it should update
the addr stored in ftrace_direct_funcs. Otherwise the final
unregister_ftrace_direct() won't find the address and will cause the splat.

Fixes: 0567d6809182 ("ftrace: Add modify_ftrace_direct()")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20210316195815.34714-1-alexei.starovoitov@gmail.com
2021-03-17 00:43:12 +01:00
Oleg Nesterov
5abbe51a52 kernel, fs: Introduce and use set_restart_fn() and arch_set_restart_data()
Preparation for fixing get_nr_restart_syscall() on X86 for COMPAT.

Add a new helper which sets restart_block->fn and calls a dummy
arch_set_restart_data() helper.

Fixes: 609c19a385c8 ("x86/ptrace: Stop setting TS_COMPAT in ptrace code")
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210201174641.GA17871@redhat.com
2021-03-16 22:13:10 +01:00
Ondrej Mosnacek
08ef1af4de perf/core: Fix unconditional security_locked_down() call
Currently, the lockdown state is queried unconditionally, even though
its result is used only if the PERF_SAMPLE_REGS_INTR bit is set in
attr.sample_type. While that doesn't matter in case of the Lockdown LSM,
it causes trouble with the SELinux's lockdown hook implementation.

SELinux implements the locked_down hook with a check whether the current
task's type has the corresponding "lockdown" class permission
("integrity" or "confidentiality") allowed in the policy. This means
that calling the hook when the access control decision would be ignored
generates a bogus permission check and audit record.

Fix this by checking sample_type first and only calling the hook when
its result would be honored.

Fixes: b0c8fdc7fdb7 ("lockdown: Lock down perf when in confidentiality mode")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Link: https://lkml.kernel.org/r/20210224215628.192519-1-omosnace@redhat.com
2021-03-16 21:44:43 +01:00
Namhyung Kim
ff65338e78 perf core: Allocate perf_event in the target node memory
For cpu events, it'd better allocating them in the corresponding node
memory as they would be mostly accessed by the target cpu.  Although
perf tools sets the cpu affinity before calling perf_event_open, there
are places it doesn't (notably perf record) and we should consider
other external users too.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210311115413.444407-2-namhyung@kernel.org
2021-03-16 21:44:43 +01:00
Namhyung Kim
bdacfaf26d perf core: Add a kmem_cache for struct perf_event
The kernel can allocate a lot of struct perf_event when profiling. For
example, 256 cpu x 8 events x 20 cgroups = 40K instances of the struct
would be allocated on a large system.

The size of struct perf_event in my setup is 1152 byte. As it's
allocated by kmalloc, the actual allocation size would be rounded up
to 2K.

Then there's 896 byte (~43%) of waste per instance resulting in total
~35MB with 40K instances. We can create a dedicated kmem_cache to
avoid such a big unnecessary memory consumption.

With this change, I can see below (note this machine has 112 cpus).

  # grep perf_event /proc/slabinfo
  perf_event    224    784   1152    7    2 : tunables   24   12    8 : slabdata    112    112      0

The sixth column is pages-per-slab which is 2, and the fifth column is
obj-per-slab which is 7.  Thus actually it can use 1152 x 7 = 8064
byte in the 8K, and wasted memory is (8192 - 8064) / 7 = ~18 byte per
instance.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210311115413.444407-1-namhyung@kernel.org
2021-03-16 21:44:42 +01:00
Namhyung Kim
9483409ab5 perf core: Allocate perf_buffer in the target node memory
I found the ring buffer pages are allocated in the node but the ring
buffer itself is not.  Let's convert it to use kzalloc_node() too.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210315033436.682438-1-namhyung@kernel.org
2021-03-16 21:44:42 +01:00
Wei Yongjun
4d0b93896f bpf: Make symbol 'bpf_task_storage_busy' static
The sparse tool complains as follows:

kernel/bpf/bpf_task_storage.c:23:1: warning:
 symbol '__pcpu_scope_bpf_task_storage_busy' was not declared. Should it be static?

This symbol is not used outside of bpf_task_storage.c, so this
commit marks it static.

Fixes: bc235cdb423a ("bpf: Prevent deadlock from recursive bpf_task_storage_[get|delete]")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20210311131505.1901509-1-weiyongjun1@huawei.com
2021-03-16 12:24:20 -07:00
Liu xuzhi
6bd45f2e78 kernel/bpf/: Fix misspellings using codespell tool
A typo is found out by codespell tool in 34th lines of hashtab.c:

$ codespell ./kernel/bpf/
./hashtab.c:34 : differrent ==> different

Fix a typo found by codespell.

Signed-off-by: Liu xuzhi <liu.xuzhi@zte.com.cn>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210311123103.323589-1-liu.xuzhi@zte.com.cn
2021-03-16 12:22:20 -07:00
Amir Goldstein
5b8fea65d1 fanotify: configurable limits via sysfs
fanotify has some hardcoded limits. The only APIs to escape those limits
are FAN_UNLIMITED_QUEUE and FAN_UNLIMITED_MARKS.

Allow finer grained tuning of the system limits via sysfs tunables under
/proc/sys/fs/fanotify, similar to tunables under /proc/sys/fs/inotify,
with some minor differences.

- max_queued_events - global system tunable for group queue size limit.
  Like the inotify tunable with the same name, it defaults to 16384 and
  applies on initialization of a new group.

- max_user_marks - user ns tunable for marks limit per user.
  Like the inotify tunable named max_user_watches, on a machine with
  sufficient RAM and it defaults to 1048576 in init userns and can be
  further limited per containing user ns.

- max_user_groups - user ns tunable for number of groups per user.
  Like the inotify tunable named max_user_instances, it defaults to 128
  in init userns and can be further limited per containing user ns.

The slightly different tunable names used for fanotify are derived from
the "group" and "mark" terminology used in the fanotify man pages and
throughout the code.

Considering the fact that the default value for max_user_instances was
increased in kernel v5.10 from 8192 to 1048576, leaving the legacy
fanotify limit of 8192 marks per group in addition to the max_user_marks
limit makes little sense, so the per group marks limit has been removed.

Note that when a group is initialized with FAN_UNLIMITED_MARKS, its own
marks are not accounted in the per user marks account, so in effect the
limit of max_user_marks is only for the collection of groups that are
not initialized with FAN_UNLIMITED_MARKS.

Link: https://lore.kernel.org/r/20210304112921.3996419-2-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2021-03-16 16:49:31 +01:00
Andy Shevchenko
ef4cb70a4c genirq/irq_sim: Fix typos in kernel doc (fnode -> fwnode)
Fix typos in kernel doc, otherwise validation script complains:

.../irq_sim.c:170: warning: Function parameter or member 'fwnode' not described in 'irq_domain_create_sim'
.../irq_sim.c:170: warning: Excess function parameter 'fnode' description in 'irq_domain_create_sim'
.../irq_sim.c:240: warning: Function parameter or member 'fwnode' not described in 'devm_irq_domain_create_sim'
.../irq_sim.c:240: warning: Excess function parameter 'fnode' description in 'devm_irq_domain_create_sim'

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210302161453.28540-1-andriy.shevchenko@linux.intel.com
2021-03-16 16:20:58 +01:00
Krzysztof Kozlowski
5c982c5875 genirq: Fix typos and misspellings in comments
No functional change.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210316100205.23492-1-krzysztof.kozlowski@canonical.com
2021-03-16 15:08:29 +01:00
Davidlohr Bueso
3a0ade0c52 tasklet: Remove tasklet_kill_immediate
Ever since RCU was converted to softirq, it has no users.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20210306213658.12862-1-dave@stgolabs.net
2021-03-16 15:06:31 +01:00
Frederic Weisbecker
e02691b7ef rcu/nocb: Move trace_rcu_nocb_wake() calls outside nocb_lock when possible
Those tracing calls don't need to be under ->nocb_lock.  This commit
therefore moves them outside of that lock.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-03-15 13:54:55 -07:00
Frederic Weisbecker
0efdf14a9f rcu/nocb: Remove stale comment above rcu_segcblist_offload()
This commit removes a stale comment claiming that the cblist must be
empty before changing the offloading state.  This claim was correct back
when the offloaded state was defined exclusively at boot.

Reported-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-03-15 13:54:54 -07:00
Frederic Weisbecker
76d00b494d rcu/nocb: Disable bypass when CPU isn't completely offloaded
Currently, the bypass is flushed at the very last moment in the
deoffloading procedure.  However, this approach leads to a larger state
space than would be preferred.  This commit therefore disables the
bypass at soon as the deoffloading procedure begins, then flushes it.
This guarantees that the bypass remains empty and thus out of the way
of the deoffloading procedure.

Symmetrically, this commit waits to enable the bypass until the offloading
procedure has completed.

Reported-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-03-15 13:54:54 -07:00
Frederic Weisbecker
b2fcf21020 rcu/nocb: Fix missed nocb_timer requeue
This sequence of events can lead to a failure to requeue a CPU's
->nocb_timer:

1.	There are no callbacks queued for any CPU covered by CPU 0-2's
	->nocb_gp_kthread.  Note that ->nocb_gp_kthread is associated
	with CPU 0.

2.	CPU 1 enqueues its first callback with interrupts disabled, and
	thus must defer awakening its ->nocb_gp_kthread.  It therefore
	queues its rcu_data structure's ->nocb_timer.  At this point,
	CPU 1's rdp->nocb_defer_wakeup is RCU_NOCB_WAKE.

3.	CPU 2, which shares the same ->nocb_gp_kthread, also enqueues a
	callback, but with interrupts enabled, allowing it to directly
	awaken the ->nocb_gp_kthread.

4.	The newly awakened ->nocb_gp_kthread associates both CPU 1's
	and CPU 2's callbacks with a future grace period and arranges
	for that grace period to be started.

5.	This ->nocb_gp_kthread goes to sleep waiting for the end of this
	future grace period.

6.	This grace period elapses before the CPU 1's timer fires.
	This is normally improbably given that the timer is set for only
	one jiffy, but timers can be delayed.  Besides, it is possible
	that kernel was built with CONFIG_RCU_STRICT_GRACE_PERIOD=y.

7.	The grace period ends, so rcu_gp_kthread awakens the
	->nocb_gp_kthread, which in turn awakens both CPU 1's and
	CPU 2's ->nocb_cb_kthread.  Then ->nocb_gb_kthread sleeps
	waiting for more newly queued callbacks.

8.	CPU 1's ->nocb_cb_kthread invokes its callback, then sleeps
	waiting for more invocable callbacks.

9.	Note that neither kthread updated any ->nocb_timer state,
	so CPU 1's ->nocb_defer_wakeup is still set to RCU_NOCB_WAKE.

10.	CPU 1 enqueues its second callback, this time with interrupts
 	enabled so it can wake directly	->nocb_gp_kthread.
	It does so with calling wake_nocb_gp() which also cancels the
	pending timer that got queued in step 2. But that doesn't reset
	CPU 1's ->nocb_defer_wakeup which is still set to RCU_NOCB_WAKE.
	So CPU 1's ->nocb_defer_wakeup and its ->nocb_timer are now
	desynchronized.

11.	->nocb_gp_kthread associates the callback queued in 10 with a new
	grace period, arranges for that grace period to start and sleeps
	waiting for it to complete.

12.	The grace period ends, rcu_gp_kthread awakens ->nocb_gp_kthread,
	which in turn wakes up CPU 1's ->nocb_cb_kthread which then
	invokes the callback queued in 10.

13.	CPU 1 enqueues its third callback, this time with interrupts
	disabled so it must queue a timer for a deferred wakeup. However
	the value of its ->nocb_defer_wakeup is RCU_NOCB_WAKE which
	incorrectly indicates that a timer is already queued.  Instead,
	CPU 1's ->nocb_timer was cancelled in 10.  CPU 1 therefore fails
	to queue the ->nocb_timer.

14.	CPU 1 has its pending callback and it may go unnoticed until
	some other CPU ever wakes up ->nocb_gp_kthread or CPU 1 ever
	calls an explicit deferred wakeup, for example, during idle entry.

This commit fixes this bug by resetting rdp->nocb_defer_wakeup everytime
we delete the ->nocb_timer.

It is quite possible that there is a similar scenario involving
->nocb_bypass_timer and ->nocb_defer_wakeup.  However, despite some
effort from several people, a failure scenario has not yet been located.
However, that by no means guarantees that no such scenario exists.
Finding a failure scenario is left as an exercise for the reader, and the
"Fixes:" tag below relates to ->nocb_bypass_timer instead of ->nocb_timer.

Fixes: d1b222c6be1f (rcu/nocb: Add bypass callback queueing)
Cc: <stable@vger.kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-03-15 13:54:54 -07:00
Jiapeng Chong
9640dcab97 rcu: Make nocb_nobypass_lim_per_jiffy static
RCU triggerse the following sparse warning:

kernel/rcu/tree_plugin.h:1497:5: warning: symbol
'nocb_nobypass_lim_per_jiffy' was not declared. Should it be static?

This commit therefore makes this variable static.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Reported-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-03-15 13:54:42 -07:00
Sangmoon Kim
565cfb9e64 rcu/tree: Add a trace event for RCU CPU stall warnings
This commit adds a trace event which allows tracing the beginnings of RCU
CPU stall warnings on systems where sysctl_panic_on_rcu_stall is disabled.

The first parameter is the name of RCU flavor like other trace events.
The second parameter indicates whether this is a stall of an expedited
grace period, a self-detected stall of a normal grace period, or a stall
of a normal grace period detected by some CPU other than the one that
is stalled.

RCU CPU stall warnings are often caused by external-to-RCU issues,
for example, in interrupt handling or task scheduling.  Therefore,
this event uses TRACE_EVENT, not TRACE_EVENT_RCU, to avoid requiring
those interested in tracing RCU CPU stalls to rebuild their kernels
with CONFIG_RCU_TRACE=y.

Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Sangmoon Kim <sangmoon.kim@samsung.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-03-15 13:53:24 -07:00
Paul E. McKenney
7e937220af rcu: Add explicit barrier() to __rcu_read_unlock()
Because preemptible RCU's __rcu_read_unlock() is an external function,
the rough equivalent of an implicit barrier() is inserted by the compiler.
Except that there is a direct call to __rcu_read_unlock() in that same
file, and compilers are getting to the point where they might choose to
inline the fastpath of the __rcu_read_unlock() function.

This commit therefore adds an explicit barrier() to the very beginning
of __rcu_read_unlock().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-03-15 13:53:24 -07:00
Paul E. McKenney
1c0c4bc1ce softirq: Don't try waking ksoftirqd before it has been spawned
If there is heavy softirq activity, the softirq system will attempt
to awaken ksoftirqd and will stop the traditional back-of-interrupt
softirq processing.  This is all well and good, but only if the
ksoftirqd kthreads already exist, which is not the case during early
boot, in which case the system hangs.

One reproducer is as follows:

tools/testing/selftests/rcutorture/bin/kvm.sh --allcpus --duration 2 --configs "TREE03" --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y CONFIG_NO_HZ_IDLE=y CONFIG_HZ_PERIODIC=n" --bootargs "threadirqs=1" --trust-make

This commit therefore adds a couple of existence checks for ksoftirqd
and forces back-of-interrupt softirq processing when ksoftirqd does not
yet exist.  With this change, the above test passes.

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Uladzislau Rezki <urezki@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
[ paulmck: Remove unneeded check per Sebastian Siewior feedback. ]
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-03-15 13:51:48 -07:00
Jianqun Xu
024c79520f kernel/irq: export irq_gc_set_wake
Module driver may use irq_gc_set_wake.

Signed-off-by: Jianqun Xu <jay.xu@rock-chips.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210305080658.2422114-1-jay.xu@rock-chips.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2021-03-15 16:36:44 +01:00
Christoph Hellwig
7d5b5738d1 dma-mapping: add a dma_alloc_noncontiguous API
Add a new API that returns a potentiall virtually non-contigous sg_table
and a DMA address.  This API is only properly implemented for dma-iommu
and will simply return a contigious chunk as a fallback.

The intent is that drivers can use this API if either:

 - no kernel mapping or only temporary kernel mappings are required.
   That is as a better replacement for DMA_ATTR_NO_KERNEL_MAPPING
 - a kernel mapping is required for cached and DMA mapped pages, but
   the driver also needs the pages to e.g. map them to userspace.
   In that sense it is a replacement for some aspects of the recently
   removed and never fully implemented DMA_ATTR_NON_CONSISTENT

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Tested-by: Ricardo Ribalda <ribalda@chromium.org>
2021-03-15 10:02:31 +01:00
Christoph Hellwig
198c50e2cc dma-mapping: refactor dma_{alloc,free}_pages
Factour out internal versions without the dma_debug calls in preparation
for callers that will need different dma_debug calls.

Note that this changes the dma_debug calls to get the not page aligned
size values, but as long as alloc and free agree on one variant we are
fine.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Tested-by: Ricardo Ribalda <ribalda@chromium.org>
2021-03-15 10:02:31 +01:00
Christoph Hellwig
eedb0b12d0 dma-mapping: add a dma_mmap_pages helper
Add a helper to map memory allocated using dma_alloc_pages into
a user address space, similar to the dma_alloc_attrs function for
coherent allocations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Tested-by: Ricardo Ribalda <ribalda@chromium.org>
2021-03-15 10:02:31 +01:00
Alexey Dobriyan
c995f12ad8 prctl: fix PR_SET_MM_AUXV kernel stack leak
Doing a

	prctl(PR_SET_MM, PR_SET_MM_AUXV, addr, 1);

will copy 1 byte from userspace to (quite big) on-stack array
and then stash everything to mm->saved_auxv.
AT_NULL terminator will be inserted at the very end.

/proc/*/auxv handler will find that AT_NULL terminator
and copy original stack contents to userspace.

This devious scheme requires CAP_SYS_RESOURCE.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-03-14 14:33:27 -07:00
Linus Torvalds
70404fe303 A set of irqchip updates:
- Make the GENERIC_IRQ_MULTI_HANDLER configuration correct
 
   - Add a missing DT compatible string fir tge Ingenic driver
 
   - Remove the pointless debugfs_file pointer from struct irqdomain
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Merge tag 'irq-urgent-2021-03-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fixes from Thomas Gleixner:
 "A set of irqchip updates:

   - Make the GENERIC_IRQ_MULTI_HANDLER configuration correct

   - Add a missing DT compatible string for the Ingenic driver

   - Remove the pointless debugfs_file pointer from struct irqdomain"

* tag 'irq-urgent-2021-03-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/ingenic: Add support for the JZ4760
  dt-bindings/irq: Add compatible string for the JZ4760B
  irqchip: Do not blindly select CONFIG_GENERIC_IRQ_MULTI_HANDLER
  ARM: ep93xx: Select GENERIC_IRQ_MULTI_HANDLER directly
  irqdomain: Remove debugfs_file from struct irq_domain
2021-03-14 13:33:33 -07:00
Linus Torvalds
802b31c0dd A single fix in for hrtimers to prevent an interrupt storm caused by the
lack of reevaluation of the timers which expire in softirq context under
 certain circumstances, e.g. when the clock was set.
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Merge tag 'timers-urgent-2021-03-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fix from Thomas Gleixner:
 "A single fix in for hrtimers to prevent an interrupt storm caused by
  the lack of reevaluation of the timers which expire in softirq context
  under certain circumstances, e.g. when the clock was set"

* tag 'timers-urgent-2021-03-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  hrtimer: Update softirq_expires_next correctly after __hrtimer_get_next_event()
2021-03-14 13:29:38 -07:00
Linus Torvalds
c72cbc9361 A set of scheduler updates:
- Prevent a NULL pointer dereference in the migration_stop_cpu()
     mechanims
 
   - Prevent self concurrency of affine_move_task()
 
   - Small fixes and cleanups related to task migration/affinity setting
 
   - Ensure that sync_runqueues_membarrier_state() is invoked on the current
     CPU when it is in the cpu mask
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Merge tag 'sched-urgent-2021-03-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Thomas Gleixner:
 "A set of scheduler updates:

   - Prevent a NULL pointer dereference in the migration_stop_cpu()
     mechanims

   - Prevent self concurrency of affine_move_task()

   - Small fixes and cleanups related to task migration/affinity setting

   - Ensure that sync_runqueues_membarrier_state() is invoked on the
     current CPU when it is in the cpu mask"

* tag 'sched-urgent-2021-03-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/membarrier: fix missing local execution of ipi_sync_rq_state()
  sched: Simplify set_affinity_pending refcounts
  sched: Fix affine_move_task() self-concurrency
  sched: Optimize migration_cpu_stop()
  sched: Collate affine_move_task() stoppers
  sched: Simplify migration_cpu_stop()
  sched: Fix migration_cpu_stop() requeueing
2021-03-14 13:27:06 -07:00
Linus Torvalds
fa509ff879 A couple of locking fixes:
- A fix for the static_call mechanism so it handles unaligned
    addresses correctly.
 
  - Make u64_stats_init() a macro so every instance gets a seperate lockdep
    key.
 
  - Make seqcount_latch_init() a macro as well to preserve the static
    variable which is used for the lockdep key.
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Merge tag 'locking-urgent-2021-03-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fixes from Thomas Gleixner:
 "A couple of locking fixes:

   - A fix for the static_call mechanism so it handles unaligned
     addresses correctly.

   - Make u64_stats_init() a macro so every instance gets a seperate
     lockdep key.

   - Make seqcount_latch_init() a macro as well to preserve the static
     variable which is used for the lockdep key"

* tag 'locking-urgent-2021-03-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  seqlock,lockdep: Fix seqcount_latch_init()
  u64_stats,lockdep: Fix u64_stats_init() vs lockdep
  static_call: Fix the module key fixup
2021-03-14 13:03:21 -07:00
Linus Torvalds
75013c6c52 - Make sure PMU internal buffers are flushed for per-CPU events too and
properly handle PID/TID for large PEBS.
 
 - Handle the case properly when there's no PMU and therefore return an
   empty list of perf MSRs for VMX to switch instead of reading random
   garbage from the stack.
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Merge tag 'perf_urgent_for_v5.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fixes from Borislav Petkov:

 - Make sure PMU internal buffers are flushed for per-CPU events too and
   properly handle PID/TID for large PEBS.

 - Handle the case properly when there's no PMU and therefore return an
   empty list of perf MSRs for VMX to switch instead of reading random
   garbage from the stack.

* tag 'perf_urgent_for_v5.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/perf: Use RET0 as default for guest_get_msrs to handle "no PMU" case
  perf/x86/intel: Set PERF_ATTACH_SCHED_CB for large PEBS and LBR
  perf/core: Flush PMU internal buffers for per-CPU events
2021-03-14 12:57:17 -07:00
Linus Torvalds
50eb842fe5 Merge branch 'akpm' (patches from Andrew)
Merge misc fixes from Andrew Morton:
 "28 patches.

  Subsystems affected by this series: mm (memblock, pagealloc, hugetlb,
  highmem, kfence, oom-kill, madvise, kasan, userfaultfd, memcg, and
  zram), core-kernel, kconfig, fork, binfmt, MAINTAINERS, kbuild, and
  ia64"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (28 commits)
  zram: fix broken page writeback
  zram: fix return value on writeback_store
  mm/memcg: set memcg when splitting page
  mm/memcg: rename mem_cgroup_split_huge_fixup to split_page_memcg and add nr_pages argument
  ia64: fix ptrace(PTRACE_SYSCALL_INFO_EXIT) sign
  ia64: fix ia64_syscall_get_set_arguments() for break-based syscalls
  mm/userfaultfd: fix memory corruption due to writeprotect
  kasan: fix KASAN_STACK dependency for HW_TAGS
  kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC
  mm/madvise: replace ptrace attach requirement for process_madvise
  include/linux/sched/mm.h: use rcu_dereference in in_vfork()
  kfence: fix reports if constant function prefixes exist
  kfence, slab: fix cache_alloc_debugcheck_after() for bulk allocations
  kfence: fix printk format for ptrdiff_t
  linux/compiler-clang.h: define HAVE_BUILTIN_BSWAP*
  MAINTAINERS: exclude uapi directories in API/ABI section
  binfmt_misc: fix possible deadlock in bm_register_write
  mm/highmem.c: fix zero_user_segments() with start > end
  hugetlb: do early cow when page pinned on src mm
  mm: use is_cow_mapping() across tree where proper
  ...
2021-03-14 12:23:34 -07:00
Fenghua Yu
82e69a121b mm/fork: clear PASID for new mm
When a new mm is created, its PASID should be cleared, i.e.  the PASID is
initialized to its init state 0 on both ARM and X86.

This patch was part of the series introducing mm->pasid, but got lost
along the way [1].  It still makes sense to have it, because each address
space has a different PASID.  And the IOMMU code in
iommu_sva_alloc_pasid() expects the pasid field of a new mm struct to be
cleared.

[1] https://lore.kernel.org/linux-iommu/YDgh53AcQHT+T3L0@otcwcpicx3.sc.intel.com/

Link: https://lkml.kernel.org/r/20210302103837.2562625-1-jean-philippe@linaro.org
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: Jacob Pan <jacob.jun.pan@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-03-13 11:27:30 -08:00
Jens Axboe
16efa4fce3 io_uring: allow IO worker threads to be frozen
With the freezer using the proper signaling to notify us of when it's
time to freeze a thread, we can re-enable normal freezer usage for the
IO threads. Ensure that SQPOLL, io-wq, and the io-wq manager call
try_to_freeze() appropriately, and remove the default setting of
PF_NOFREEZE from create_io_thread().

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-12 20:26:13 -07:00
Jens Axboe
15b2219fac kernel: freezer should treat PF_IO_WORKER like PF_KTHREAD for freezing
Don't send fake signals to PF_IO_WORKER threads, they don't accept
signals. Just treat them like kthreads in this regard, all they need
is a wakeup as no forced kernel/user transition is needed.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-03-12 20:20:42 -07:00
Richard Guy Briggs
5504a69a42 audit: further cleanup of AUDIT_FILTER_ENTRY deprecation
Remove the list parameter from the function call since the exit filter
list is the only remaining list used by this function.

This cleans up commit 5260ecc2e048
("audit: deprecate the AUDIT_FILTER_ENTRY filter")

Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-03-12 16:30:23 -05:00
Linus Torvalds
9278be92f2 io_uring-5.12-2021-03-12
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Merge tag 'io_uring-5.12-2021-03-12' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:
 "Not quite as small this week as I had hoped, but at least this should
  be the end of it. All the little known issues have been ironed out -
  most of it little stuff, but cancelations being the bigger part. Only
  minor tweaks and/or regular fixes expected beyond this point.

   - Fix the creds tracking for async (io-wq and SQPOLL)

   - Various SQPOLL fixes related to parking, sharing, forking, IOPOLL,
     completions, and life times. Much simpler now.

   - Make IO threads unfreezable by default, on account of a bug report
     that had them spinning on resume. Honestly not quite sure why
     thawing leaves us with a perpetual signal pending (causing the
     spin), but for now make them unfreezable like there were in 5.11
     and prior.

   - Move personality_idr to xarray, solving a use-after-free related to
     removing an entry from the iterator callback. Buffer idr needs the
     same treatment.

   - Re-org around and task vs context tracking, enabling the fixing of
     cancelations, and then cancelation fixes on top.

   - Various little bits of cleanups and hardening, and removal of now
     dead parts"

* tag 'io_uring-5.12-2021-03-12' of git://git.kernel.dk/linux-block: (34 commits)
  io_uring: fix OP_ASYNC_CANCEL across tasks
  io_uring: cancel sqpoll via task_work
  io_uring: prevent racy sqd->thread checks
  io_uring: remove useless ->startup completion
  io_uring: cancel deferred requests in try_cancel
  io_uring: perform IOPOLL reaping if canceler is thread itself
  io_uring: force creation of separate context for ATTACH_WQ and non-threads
  io_uring: remove indirect ctx into sqo injection
  io_uring: fix invalid ctx->sq_thread_idle
  kernel: make IO threads unfreezable by default
  io_uring: always wait for sqd exited when stopping SQPOLL thread
  io_uring: remove unneeded variable 'ret'
  io_uring: move all io_kiocb init early in io_init_req()
  io-wq: fix ref leak for req in case of exit cancelations
  io_uring: fix complete_post races for linked req
  io_uring: add io_disarm_next() helper
  io_uring: fix io_sq_offload_create error handling
  io-wq: remove unused 'user' member of io_wq
  io_uring: Convert personality_idr to XArray
  io_uring: clean R_DISABLED startup mess
  ...
2021-03-12 13:13:57 -08:00
Davidlohr Bueso
c2e4bfe0ee kernel/futex: Explicitly document pi_lock for pi_state owner fixup
This seems to belong in the serialization and lifetime rules section.
pi_state_update_owner() will take the pi_mutex's owner's pi_lock to
do whatever fixup, successful or not.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210226175029.50335-4-dave@stgolabs.net
2021-03-11 19:19:17 +01:00
Davidlohr Bueso
a3f2428d2b kernel/futex: Move hb unlock out of unqueue_me_pi()
This improves the code readability, and the locking more obvious
as it becomes symmetric for the caller.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210226175029.50335-3-dave@stgolabs.net
2021-03-11 19:19:17 +01:00
Davidlohr Bueso
a1565aa469 kernel/futex: Make futex_wait_requeue_pi() only call fixup_owner()
A small cleanup that allows for fixup_pi_state_owner() only to be called
from fixup_owner(), and make requeue_pi uniformly call fixup_owner()
regardless of the state in which the fixup is actually needed. Of course
this makes the caller's first pi_state->owner != current check redundant,
but that should't really matter.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210226175029.50335-2-dave@stgolabs.net
2021-03-11 19:19:17 +01:00
Davidlohr Bueso
9a4b99fce6 kernel/futex: Kill rt_mutex_next_owner()
Update wake_futex_pi() and kill the call altogether. This is possible because:

(i) The case of fixup_owner() in which the pi_mutex was stolen from the
signaled enqueued top-waiter which fails to trylock and doesn't see a
current owner of the rtmutex but needs to acknowledge an non-enqueued
higher priority waiter, which is the other alternative. This used to be
handled by rt_mutex_next_owner(), which guaranteed fixup_pi_state_owner('newowner')
never to be nil. Nowadays the logic is handled by an EAGAIN loop, without
the need of rt_mutex_next_owner(). Specifically:

    c1e2f0eaf015 (futex: Avoid violating the 10th rule of futex)
    9f5d1c336a10 (futex: Handle transient "ownerless" rtmutex state correctly)

(ii) rt_mutex_next_owner() and rt_mutex_top_waiter() are semantically
equivalent, as of:

    c28d62cf52d7 (locking/rtmutex: Handle non enqueued waiters gracefully in remove_waiter())

So instead of keeping the call around, just use the good ole rt_mutex_top_waiter().
No change in semantics.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210226175029.50335-1-dave@stgolabs.net
2021-03-11 19:19:17 +01:00
David S. Miller
547fd08377 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:

====================
pull-request: bpf 2021-03-10

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

We've added 8 non-merge commits during the last 5 day(s) which contain
a total of 11 files changed, 136 insertions(+), 17 deletions(-).

The main changes are:

1) Reject bogus use of vmlinux BTF as map/prog creation BTF, from Alexei Starovoitov.

2) Fix allocation failure splat in x86 JIT for large progs. Also fix overwriting
   percpu cgroup storage from tracing programs when nested, from Yonghong Song.

3) Fix rx queue retrieval in XDP for multi-queue veth, from Maciej Fijalkowski.

4) Fix bpf_check_mtu() helper API before freeze to have mtu_len as custom skb/xdp
   L3 input length, from Jesper Dangaard Brouer.

5) Fix inode_storage's lookup_elem return value upon having bad fd, from Tal Lossos.

6) Fix bpftool and libbpf cross-build on MacOS, from Georgi Valkov.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2021-03-10 15:14:56 -08:00