linux-stable.git/Documentation/kernel-parameters.txt, branch v3.16.6

uas: Add no-report-opcodes quirk

2014-10-15T10:05:30+00:00

commit 734016b00b50a3c6a0e1fc1b7b217e783f5123a1 upstream.

Besides the ASM1051 (*) needing sdev->no_report_opcodes = 1, it turns out that
the JMicron JMS567 also needs it to work properly with uas (usb-storage always
sets it). Since some of the scsi devs were not to keen on the idea to
outrightly set sdev->no_report_opcodes = 1 for all uas devices, so add a quirk
for this, and set it for the JMS567.

*) Which has become a non-issue since we've completely blacklisted uas on
the ASM1051 for other reasons

Reported-and-tested-by: Claudio Bizzarri 
Signed-off-by: Hans de Goede 
Signed-off-by: Greg Kroah-Hartman

uas: Add a quirk for rejecting ATA_12 and ATA_16 commands

2014-10-15T10:05:30+00:00

commit 593078525c8b234a35a36ff551b8716464e86481 upstream.

And set this quirk for the Seagate Expansion Desk (0bc2:2312), as that one
seems to hang upon receiving an ATA_12 or ATA_16 command.

https://bugzilla.kernel.org/show_bug.cgi?id=79511
https://bbs.archlinux.org/viewtopic.php?id=183190

While at it also add missing documentation for the u value for usb-storage
quirks.

Signed-off-by: Hans de Goede 
Signed-off-by: Greg Kroah-Hartman

USB: document the 'u' flag for usb-storage quirks parameter

2014-10-05T20:40:58+00:00

commit b6089f19fe0cec625b5963a851a07c3e412c27c8 upstream.

Commit d24d481b7d36 (usb-storage: Modify and export adjust_quirks so
that it can be used by uas) added the 'u' flag to the quirks module
parameter for usb-storage, but neglected to update the
documentation.  This patch adds the documentation.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-07-19T16:23:27+00:00

Pull RCU fixes from Thomas Gleixner:
 "Two RCU patches:
   - Address a serious performance regression on open/close caused by
     commit ac1bea85781e ("Make cond_resched() report RCU quiescent
     states")
   - Export RCU debug functions.  Not a regression, but enablement to
     address a serious recursion bug in the sl*b allocators in 3.17"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  rcu: Reduce overhead of cond_resched() checks for RCU
  rcu: Export debug_init_rcu_head() and and debug_init_rcu_head()

Revert "ACPI / video: change acpi-video brightness_switch_enabled default to 0"

2014-07-14T18:10:27+00:00

This reverts commit 886129a8eebeb (ACPI / video: change acpi-video
brightness_switch_enabled default to 0) as it is reported to cause
problems to happen.

Fixes: 886129a8eebeb (ACPI / video: change acpi-video brightness_switch_enabled default to 0)
Link: http://marc.info/?l=linux-acpi&m=140534286826819&w=2
Reported by: Bjørn Mork 
Signed-off-by: Rafael J. Wysocki

Merge branch 'urgent.2014.06.23a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/urgent

2014-06-25T05:37:49+00:00

Pull RCU fixes from Paul E. McKenney:

" This series includes the following:

   1.    Export a pair of debug-object interfaces for RCU that will
         allow the slab allocators to avoid a recursion bug located
         by Sasha Levin.  Strictly speaking, this is not a regression,
         but it would be good to enable the fix.

   2.    Address a serious performance regression on an open/close
         micro-benchmark located by Dave Hansen.  The offending commit
         is ac1bea85781e (Make cond_resched() report RCU quiescent states).  "

Signed-off-by: Ingo Molnar

kernel/watchdog.c: print traces for all cpus on lockup detection

2014-06-23T23:47:44+00:00

A 'softlockup' is defined as a bug that causes the kernel to loop in
kernel mode for more than a predefined period to time, without giving
other tasks a chance to run.

Currently, upon detection of this condition by the per-cpu watchdog
task, debug information (including a stack trace) is sent to the system
log.

On some occasions, we have observed that the "victim" rather than the
actual "culprit" (i.e.  the owner/holder of the contended resource) is
reported to the user.  Often this information has proven to be
insufficient to assist debugging efforts.

To avoid loss of useful debug information, for architectures which
support NMI, this patch makes it possible to improve soft lockup
reporting.  This is accomplished by issuing an NMI to each cpu to obtain
a stack trace.

If NMI is not supported we just revert back to the old method.  A sysctl
and boot-time parameter is available to toggle this feature.

[dzickus@redhat.com: add CONFIG_SMP in certain areas]
[akpm@linux-foundation.org: additional CONFIG_SMP=n optimisations]
[mq@suse.cz: fix warning]
Signed-off-by: Aaron Tomlin 
Signed-off-by: Don Zickus 
Cc: David S. Miller 
Cc: Mateusz Guzik 
Cc: Oleg Nesterov 
Signed-off-by: Jan Moskyto Matejka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rcu: Reduce overhead of cond_resched() checks for RCU

2014-06-23T18:19:32+00:00

Commit ac1bea85781e (Make cond_resched() report RCU quiescent states)
fixed a problem where a CPU looping in the kernel with but one runnable
task would give RCU CPU stall warnings, even if the in-kernel loop
contained cond_resched() calls.  Unfortunately, in so doing, it introduced
performance regressions in Anton Blanchard's will-it-scale "open1" test.
The problem appears to be not so much the increased cond_resched() path
length as an increase in the rate at which grace periods complete, which
increased per-update grace-period overhead.

This commit takes a different approach to fixing this bug, mainly by
moving the RCU-visible quiescent state from cond_resched() to
rcu_note_context_switch(), and by further reducing the check to a
simple non-zero test of a single per-CPU variable.  However, this
approach requires that the force-quiescent-state processing send
resched IPIs to the offending CPUs.  These will be sent only once
the grace period has reached an age specified by the boot/sysfs
parameter rcutree.jiffies_till_sched_qs, or once the grace period
reaches an age halfway to the point at which RCU CPU stall warnings
will be emitted, whichever comes first.

Reported-by: Dave Hansen 
Signed-off-by: Paul E. McKenney 
Cc: Andi Kleen 
Cc: Christoph Lameter 
Cc: Mike Galbraith 
Cc: Eric Dumazet 
Reviewed-by: Josh Triplett 
[ paulmck: Made rcu_momentary_dyntick_idle() as suggested by the
  ktest build robot.  Also fixed smp_mb() comment as noted by
  Oleg Nesterov. ]

Merge with e552592e (Reduce overhead of cond_resched() checks for RCU)

Signed-off-by: Paul E. McKenney

x86, kaslr: boot-time selectable with hibernation

2014-06-16T21:30:44+00:00

Changes kASLR from being compile-time selectable (blocked by
CONFIG_HIBERNATION), to being boot-time selectable (with hibernation
available by default) via the "kaslr" kernel command line.

Signed-off-by: Kees Cook 
Acked-by: Pavel Machek 
Signed-off-by: Rafael J. Wysocki

PM / hibernate: introduce "nohibernate" boot parameter

2014-06-16T21:29:39+00:00

To support using kernel features that are not compatible with hibernation,
this creates the "nohibernate" kernel boot parameter to disable both
hibernation and resume. This allows hibernation support to be a boot-time
choice instead of only a compile-time choice.

Signed-off-by: Kees Cook 
Acked-by: Pavel Machek 
Signed-off-by: Rafael J. Wysocki