current->group_leader->exit_signal may change during copy_process() if
current->real_parent exits.

Move the assignment inside tasklist_lock to avoid the race.

Signed-off-by: Eddy Wu <eddy_wu@trendmicro.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull perf fix from Thomas Gleixner:
 "A single fix for the perf core plugging a memory leak in the address
  filter parser"

* tag 'perf-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix a memory leak in perf_event_parse_addr_filter()

Pull futex fix from Thomas Gleixner:
 "A single fix for the futex code where an intermediate state in the
  underlying RT mutex was not handled correctly and triggering a BUG()
  instead of treating it as another variant of retry condition"

* tag 'locking-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Handle transient "ownerless" rtmutex state correctly

Pull irq fixes from Thomas Gleixner:
 "A set of fixes for interrupt chip drivers:

   - Fix the fallout of the IPI as interrupt conversion in Kconfig and
     the BCM2836 interrupt chip driver

   - Fixes for interrupt affinity setting and the handling of
     hierarchical irq domains in the SiFive PLIC driver

   - Make the unmapped event handling in the TI SCI driver work
     correctly

   - A few minor fixes and cleanups in various chip drivers and Kconfig"

* tag 'irq-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  dt-bindings: irqchip: ti, sci-inta: Fix diagram indentation for unmapped events
  irqchip/ti-sci-inta: Add support for unmapped event handling
  dt-bindings: irqchip: ti, sci-inta: Update for unmapped event handling
  irqchip/renesas-intc-irqpin: Merge irlm_bit and needs_irlm
  irqchip/sifive-plic: Fix chip_data access within a hierarchy
  irqchip/sifive-plic: Fix broken irq_set_affinity() callback
  irqchip/stm32-exti: Add all LP timer exti direct events support
  irqchip/bcm2836: Fix missing __init annotation
  irqchip/mips: Drop selection of IRQ_DOMAIN_HIERARCHY
  irqchip/mst: Make mst_intc_of_init static
  irqchip/mst: MST_IRQ should depend on ARCH_MEDIATEK or ARCH_MSTARV7
  genirq: Let GENERIC_IRQ_IPI select IRQ_DOMAIN_HIERARCHY

Pull entry code fix from Thomas Gleixner:
 "A single fix for the generic entry code to correct the wrong
  assumption that the lockdep interrupt state needs not to be
  established before calling the RCU check"

* tag 'core-urgent-2020-11-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  entry: Fix the incorrect ordering of lockdep and RCU check

Gratian managed to trigger the BUG_ON(!newowner) in fixup_pi_state_owner().
This is one possible chain of events leading to this:

Task Prio       Operation
T1   120	lock(F)
T2   120	lock(F)   -> blocks (top waiter)
T3   50 (RT)	lock(F)   -> boosts T1 and blocks (new top waiter)
XX   		timeout/  -> wakes T2
		signal
T1   50		unlock(F) -> wakes T3 (rtmutex->owner == NULL, waiter bit is set)
T2   120	cleanup   -> try_to_take_mutex() fails because T3 is the top waiter
     			     and the lower priority T2 cannot steal the lock.
     			  -> fixup_pi_state_owner() sees newowner == NULL -> BUG_ON()

The comment states that this is invalid and rt_mutex_real_owner() must
return a non NULL owner when the trylock failed, but in case of a queued
and woken up waiter rt_mutex_real_owner() == NULL is a valid transient
state. The higher priority waiter has simply not yet managed to take over
the rtmutex.

The BUG_ON() is therefore wrong and this is just another retry condition in
fixup_pi_state_owner().

Drop the locks, so that T3 can make progress, and then try the fixup again.

Gratian provided a great analysis, traces and a reproducer. The analysis is
to the point, but it confused the hell out of that tglx dude who had to
page in all the futex horrors again. Condensed version is above.

[ tglx: Wrote comment and changelog ]

Fixes: c1e2f0eaf015 ("futex: Avoid violating the 10th rule of futex")
Reported-by: Gratian Crisan <gratian.crisan@ni.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87a6w6x7bb.fsf@ni.com
Link: https://lore.kernel.org/r/87sg9pkvf7.fsf@nanos.tec.linutronix.de

As shown through runtime testing, the "filename" allocation is not
always freed in perf_event_parse_addr_filter().

There are three possible ways that this could happen:

 - It could be allocated twice on subsequent iterations through the loop,
 - or leaked on the success path,
 - or on the failure path.

Clean up the code flow to make it obvious that 'filename' is always
freed in the reallocation path and in the two return paths as well.

We rely on the fact that kfree(NULL) is NOP and filename is initialized
with NULL.

This fixes the leak. No other side effects expected.

[ Dan Carpenter: cleaned up the code flow & added a changelog. ]
[ Ingo Molnar: updated the changelog some more. ]

Fixes: 375637bc5249 ("perf/core: Introduce address range filtering")
Signed-off-by: "kiyin(尹亮)" <kiyin@tencent.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: "Srivatsa S. Bhat" <srivatsa@csail.mit.edu>
Cc: Anthony Liguori <aliguori@amazon.com>
--
 kernel/events/core.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

Pull tracing fixes from Steven Rostedt:

 - Fix off-by-one error in retrieving the context buffer for
   trace_printk()

 - Fix off-by-one error in stack nesting limit

 - Fix recursion to not make all NMI code false positive as recursing

 - Stop losing events in function tracing when transitioning between irq
   context

 - Stop losing events in ring buffer when transitioning between irq
   context

 - Fix return code of error pointer in parse_synth_field() to prevent
   NULL pointer dereference.

 - Fix false positive of NMI recursion in kprobe event handling

* tag 'trace-v5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  kprobes: Tell lockdep about kprobe nesting
  tracing: Make -ENOMEM the default error for parse_synth_field()
  ring-buffer: Fix recursion protection transitions between interrupt context
  tracing: Fix the checking of stackidx in __ftrace_trace_stack
  ftrace: Handle tracing when switching between context
  ftrace: Fix recursion check for NMI test
  tracing: Fix out of bounds write in get_trace_buf

Pull power management fixes from Rafael Wysocki:
 "These fix the device links support in runtime PM, correct mistakes in
  the cpuidle documentation, fix the handling of policy limits changes
  in the schedutil cpufreq governor, fix assorted issues in the OPP
  (operating performance points) framework and make one janitorial
  change.

  Specifics:

   - Unify the handling of managed and stateless device links in the
     runtime PM framework and prevent runtime PM references to devices
     from being leaked after device link removal (Rafael Wysocki).

   - Fix two mistakes in the cpuidle documentation (Julia Lawall).

   - Prevent the schedutil cpufreq governor from missing policy limits
     updates in some cases (Viresh Kumar).

   - Prevent static OPPs from being dropped by mistake (Viresh Kumar).

   - Prevent helper function in the OPP framework from returning
     prematurely (Viresh Kumar).

   - Prevent opp_table_lock from being held too long during removal of
     OPP tables with no more active references (Viresh Kumar).

   - Drop redundant semicolon from the Intel RAPL power capping driver
     (Tom Rix)"

* tag 'pm-5.10-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM: runtime: Resume the device earlier in __device_release_driver()
  PM: runtime: Drop pm_runtime_clean_up_links()
  PM: runtime: Drop runtime PM references to supplier on link removal
  powercap/intel_rapl: remove unneeded semicolon
  Documentation: PM: cpuidle: correct path name
  Documentation: PM: cpuidle: correct typo
  cpufreq: schedutil: Don't skip freq update if need_freq_update is set
  opp: Reduce the size of critical section in _opp_table_kref_release()
  opp: Fix early exit from dev_pm_opp_register_set_opp_helper()
  opp: Don't always remove static OPPs in _of_add_opp_table_v1()

When an exception/interrupt hits kernel space and the kernel is not
currently in the idle task then RCU must be watching.

irqentry_enter() validates this via rcu_irq_enter_check_tick(), which in
turn invokes lockdep when taking a lock. But at that point lockdep does not
yet know about the fact that interrupts have been disabled by the CPU,
which triggers a lockdep splat complaining about inconsistent state.

Invoking trace_hardirqs_off() before rcu_irq_enter_check_tick() defeats the
point of rcu_irq_enter_check_tick() because trace_hardirqs_off() uses RCU.

So use the same sequence as for the idle case and tell lockdep about the
irq state change first, invoke the RCU check and then do the lockdep and
tracer update.

Fixes: a5497bab5f72 ("entry: Provide generic interrupt entry/exit code")
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87y2jhl19s.fsf@nanos.tec.linutronix.de