linux.git, branch v4.9.74

Linux 4.9.74

2018-01-02T19:35:18+00:00

mm/vmstat: Make NR_TLB_REMOTE_FLUSH_RECEIVED available even on UP

2018-01-02T19:35:18+00:00

commit 5dd0b16cdaff9b94da06074d5888b03235c0bf17 upstream.

This fixes CONFIG_SMP=n, CONFIG_DEBUG_TLBFLUSH=y without introducing
further #ifdef soup.  Caught by a Kbuild bot randconfig build.

Signed-off-by: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: ce4a4e565f52 ("x86/mm: Remove the UP asm/tlbflush.h code, always use the (formerly) SMP code")
Link: http://lkml.kernel.org/r/76da9a3cc4415996f2ad2c905b93414add322021.1496673616.git.luto@kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

tty: fix tty_ldisc_receive_buf() documentation

2018-01-02T19:35:17+00:00

commit e7e51dcf3b8a5f65c5653a054ad57eb2492a90d0 upstream.

The tty_ldisc_receive_buf() helper returns the number of bytes
processed so drop the bogus "not" from the kernel doc comment.

Fixes: 8d082cd300ab ("tty: Unify receive_buf() code paths")
Signed-off-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman

n_tty: fix EXTPROC vs ICANON interaction with TIOCINQ (aka FIONREAD)

2018-01-02T19:35:17+00:00

commit 966031f340185eddd05affcf72b740549f056348 upstream.

We added support for EXTPROC back in 2010 in commit 26df6d13406d ("tty:
Add EXTPROC support for LINEMODE") and the intent was to allow it to
override some (all?) ICANON behavior.  Quoting from that original commit
message:

         There is a new bit in the termios local flag word, EXTPROC.
         When this bit is set, several aspects of the terminal driver
         are disabled.  Input line editing, character echo, and mapping
         of signals are all disabled.  This allows the telnetd to turn
         off these functions when in linemode, but still keep track of
         what state the user wants the terminal to be in.

but the problem turns out that "several aspects of the terminal driver
are disabled" is a bit ambiguous, and you can really confuse the n_tty
layer by setting EXTPROC and then causing some of the ICANON invariants
to no longer be maintained.

This fixes at least one such case (TIOCINQ) becoming unhappy because of
the confusion over whether ICANON really means ICANON when EXTPROC is set.

This basically makes TIOCINQ match the case of read: if EXTPROC is set,
we ignore ICANON.  Also, make sure to reset the ICANON state ie EXTPROC
changes, not just if ICANON changes.

Fixes: 26df6d13406d ("tty: Add EXTPROC support for LINEMODE")
Reported-by: Tetsuo Handa 
Reported-by: syzkaller 
Cc: Jiri Slaby 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

x86/smpboot: Remove stale TLB flush invocations

2018-01-02T19:35:17+00:00

commit 322f8b8b340c824aef891342b0f5795d15e11562 upstream.

smpboot_setup_warm_reset_vector() and smpboot_restore_warm_reset_vector()
invoke local_flush_tlb() for no obvious reason.

Digging in history revealed that the original code in the 2.1 era added
those because the code manipulated a swapper_pg_dir pagetable entry. The
pagetable manipulation was removed long ago in the 2.3 timeframe, but the
TLB flush invocations stayed around forever.

Remove them along with the pointless pr_debug()s which come from the same 2.1
change.

Reported-by: Dominik Brodowski 
Signed-off-by: Thomas Gleixner 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Dave Hansen 
Cc: Linus Torvalds 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20171230211829.586548655@linutronix.de
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

nohz: Prevent a timer interrupt storm in tick_nohz_stop_sched_tick()

2018-01-02T19:35:17+00:00

commit 5d62c183f9e9df1deeea0906d099a94e8a43047a upstream.

The conditions in irq_exit() to invoke tick_nohz_irq_exit() which
subsequently invokes tick_nohz_stop_sched_tick() are:

  if ((idle_cpu(cpu) && !need_resched()) || tick_nohz_full_cpu(cpu))

If need_resched() is not set, but a timer softirq is pending then this is
an indication that the softirq code punted and delegated the execution to
softirqd. need_resched() is not true because the current interrupted task
takes precedence over softirqd.

Invoking tick_nohz_irq_exit() in this case can cause an endless loop of
timer interrupts because the timer wheel contains an expired timer, but
softirqs are not yet executed. So it returns an immediate expiry request,
which causes the timer to fire immediately again. Lather, rinse and
repeat....

Prevent that by adding a check for a pending timer soft interrupt to the
conditions in tick_nohz_stop_sched_tick() which avoid calling
get_next_timer_interrupt(). That keeps the tick sched timer on the tick and
prevents a repetitive programming of an already expired timer.

Reported-by: Sebastian Siewior 
Signed-off-by: Thomas Gleixner 
Acked-by: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Paul McKenney 
Cc: Anna-Maria Gleixner 
Cc: Sebastian Siewior 
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712272156050.2431@nanos
Signed-off-by: Greg Kroah-Hartman

timers: Reinitialize per cpu bases on hotplug

2018-01-02T19:35:17+00:00

commit 26456f87aca7157c057de65c9414b37f1ab881d1 upstream.

The timer wheel bases are not (re)initialized on CPU hotplug. That leaves
them with a potentially stale clk and next_expiry valuem, which can cause
trouble then the CPU is plugged.

Add a prepare callback which forwards the clock, sets next_expiry to far in
the future and reset the control flags to a known state.

Set base->must_forward_clk so the first timer which is queued will try to
forward the clock to current jiffies.

Fixes: 500462a9de65 ("timers: Switch to a non-cascading wheel")
Reported-by: Paul E. McKenney 
Signed-off-by: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Frederic Weisbecker 
Cc: Sebastian Siewior 
Cc: Anna-Maria Gleixner 
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1712272152200.2431@nanos
Signed-off-by: Greg Kroah-Hartman

timers: Invoke timer_start_debug() where it makes sense

2018-01-02T19:35:17+00:00

commit fd45bb77ad682be728d1002431d77b8c73342836 upstream.

The timer start debug function is called before the proper timer base is
set. As a consequence the trace data contains the stale CPU and flags
values.

Call the debug function after setting the new base and flags.

Fixes: 500462a9de65 ("timers: Switch to a non-cascading wheel")
Signed-off-by: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Frederic Weisbecker 
Cc: Sebastian Siewior 
Cc: rt@linutronix.de
Cc: Paul McKenney 
Cc: Anna-Maria Gleixner 
Link: https://lkml.kernel.org/r/20171222145337.792907137@linutronix.de
Signed-off-by: Greg Kroah-Hartman

timers: Use deferrable base independent of base::nohz_active

2018-01-02T19:35:17+00:00

commit ced6d5c11d3e7b342f1a80f908e6756ebd4b8ddd upstream.

During boot and before base::nohz_active is set in the timer bases, deferrable
timers are enqueued into the standard timer base. This works correctly as
long as base::nohz_active is false.

Once it base::nohz_active is set and a timer which was enqueued before that
is accessed the lock selector code choses the lock of the deferred
base. This causes unlocked access to the standard base and in case the
timer is removed it does not clear the pending flag in the standard base
bitmap which causes get_next_timer_interrupt() to return bogus values.

To prevent that, the deferrable timers must be enqueued in the deferrable
base, even when base::nohz_active is not set. Those deferrable timers also
need to be expired unconditional.

Fixes: 500462a9de65 ("timers: Switch to a non-cascading wheel")
Signed-off-by: Anna-Maria Gleixner 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Sebastian Siewior 
Cc: rt@linutronix.de
Cc: Paul McKenney 
Link: https://lkml.kernel.org/r/20171222145337.633328378@linutronix.de
Signed-off-by: Greg Kroah-Hartman

usb: xhci: Add XHCI_TRUST_TX_LENGTH for Renesas uPD720201

2018-01-02T19:35:16+00:00

commit da99706689481717998d1d48edd389f339eea979 upstream.

When plugging in a USB webcam I see the following message:
xhci_hcd 0000:04:00.0: WARN Successful completion on short TX: needs
XHCI_TRUST_TX_LENGTH quirk?
handle_tx_event: 913 callbacks suppressed

All is quiet again with this patch (and I've done a fair but of soak
testing with the camera since).

Signed-off-by: Daniel Thompson 
Acked-by: Ard Biesheuvel 
Signed-off-by: Mathias Nyman 
Signed-off-by: Greg Kroah-Hartman