Commit Graph

23591 Commits

Author SHA1 Message Date
Linus Torvalds
e34bac726d Merge branch 'akpm' (patches from Andrew)
Merge updates from Andrew Morton:

 - various misc bits

 - most of MM (quite a lot of MM material is awaiting the merge of
   linux-next dependencies)

 - kasan

 - printk updates

 - procfs updates

 - MAINTAINERS

 - /lib updates

 - checkpatch updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (123 commits)
  init: reduce rootwait polling interval time to 5ms
  binfmt_elf: use vmalloc() for allocation of vma_filesz
  checkpatch: don't emit unified-diff error for rename-only patches
  checkpatch: don't check c99 types like uint8_t under tools
  checkpatch: avoid multiple line dereferences
  checkpatch: don't check .pl files, improve absolute path commit log test
  scripts/checkpatch.pl: fix spelling
  checkpatch: don't try to get maintained status when --no-tree is given
  lib/ida: document locking requirements a bit better
  lib/rbtree.c: fix typo in comment of ____rb_erase_color
  lib/Kconfig.debug: make CONFIG_STRICT_DEVMEM depend on CONFIG_DEVMEM
  MAINTAINERS: add drm and drm/i915 irc channels
  MAINTAINERS: add "C:" for URI for chat where developers hang out
  MAINTAINERS: add drm and drm/i915 bug filing info
  MAINTAINERS: add "B:" for URI where to file bugs
  get_maintainer: look for arbitrary letter prefixes in sections
  printk: add Kconfig option to set default console loglevel
  printk/sound: handle more message headers
  printk/btrfs: handle more message headers
  printk/kdb: handle more message headers
  ...
2016-12-12 20:50:02 -08:00
Linus Torvalds
f082f02c47 Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq updates from Thomas Gleixner:
 "The irq department provides:

   - a major update to the auto affinity management code, which is used
     by multi-queue devices

   - move of the microblaze irq chip driver into the common driver code
     so it can be shared between microblaze, powerpc and MIPS

   - a series of updates to the ARM GICV3 interrupt controller

   - the usual pile of fixes and small improvements all over the place"

* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  powerpc/virtex: Use generic xilinx irqchip driver
  irqchip/xilinx: Try to fall back if xlnx,kind-of-intr not provided
  irqchip/xilinx: Add support for parent intc
  irqchip/xilinx: Rename get_irq to xintc_get_irq
  irqchip/xilinx: Restructure and use jump label api
  irqchip/xilinx: Clean up print messages
  microblaze/irqchip: Move intc driver to irqchip
  ARM: virt: Select ARM_GIC_V3_ITS
  ARM: gic-v3-its: Add 32bit support to GICv3 ITS
  irqchip/gic-v3-its: Specialise readq and writeq accesses
  irqchip/gic-v3-its: Specialise flush_dcache operation
  irqchip/gic-v3-its: Narrow down Entry Size when used as a divider
  irqchip/gic-v3-its: Change unsigned types for AArch32 compatibility
  irqchip/gic-v3: Use nops macro for Cavium ThunderX erratum 23154
  irqchip/gic-v3: Convert arm64 GIC accessors to {read,write}_sysreg_s
  genirq/msi: Drop artificial PCI dependency
  irqchip/bcm7038-l1: Implement irq_cpu_offline() callback
  genirq/affinity: Use default affinity mask for reserved vectors
  genirq/affinity: Take reserved vectors into account when spreading irqs
  PCI: Remove the irq_affinity mask from struct pci_dev
  ...
2016-12-12 20:23:11 -08:00
Linus Torvalds
9465d9cc31 Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
 "The time/timekeeping/timer folks deliver with this update:

   - Fix a reintroduced signed/unsigned issue and cleanup the whole
     signed/unsigned mess in the timekeeping core so this wont happen
     accidentaly again.

   - Add a new trace clock based on boot time

   - Prevent injection of random sleep times when PM tracing abuses the
     RTC for storage

   - Make posix timers configurable for real tiny systems

   - Add tracepoints for the alarm timer subsystem so timer based
     suspend wakeups can be instrumented

   - The usual pile of fixes and updates to core and drivers"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  timekeeping: Use mul_u64_u32_shr() instead of open coding it
  timekeeping: Get rid of pointless typecasts
  timekeeping: Make the conversion call chain consistently unsigned
  timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion
  alarmtimer: Add tracepoints for alarm timers
  trace: Update documentation for mono, mono_raw and boot clock
  trace: Add an option for boot clock as trace clock
  timekeeping: Add a fast and NMI safe boot clock
  timekeeping/clocksource_cyc2ns: Document intended range limitation
  timekeeping: Ignore the bogus sleep time if pm_trace is enabled
  selftests/timers: Fix spelling mistake "Asyncrhonous" -> "Asynchronous"
  clocksource/drivers/bcm2835_timer: Unmap region obtained by of_iomap
  clocksource/drivers/arm_arch_timer: Map frame with of_io_request_and_map()
  arm64: dts: rockchip: Arch counter doesn't tick in system suspend
  clocksource/drivers/arm_arch_timer: Don't assume clock runs in suspend
  posix-timers: Make them configurable
  posix_cpu_timers: Move the add_device_randomness() call to a proper place
  timer: Move sys_alarm from timer.c to itimer.c
  ptp_clock: Allow for it to be optional
  Kconfig: Regenerate *.c_shipped files after previous changes
  ...
2016-12-12 19:56:15 -08:00
Linus Torvalds
e71c3978d6 Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull smp hotplug updates from Thomas Gleixner:
 "This is the final round of converting the notifier mess to the state
  machine. The removal of the notifiers and the related infrastructure
  will happen around rc1, as there are conversions outstanding in other
  trees.

  The whole exercise removed about 2000 lines of code in total and in
  course of the conversion several dozen bugs got fixed. The new
  mechanism allows to test almost every hotplug step standalone, so
  usage sites can exercise all transitions extensively.

  There is more room for improvement, like integrating all the
  pointlessly different architecture mechanisms of synchronizing,
  setting cpus online etc into the core code"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (60 commits)
  tracing/rb: Init the CPU mask on allocation
  soc/fsl/qbman: Convert to hotplug state machine
  soc/fsl/qbman: Convert to hotplug state machine
  zram: Convert to hotplug state machine
  KVM/PPC/Book3S HV: Convert to hotplug state machine
  arm64/cpuinfo: Convert to hotplug state machine
  arm64/cpuinfo: Make hotplug notifier symmetric
  mm/compaction: Convert to hotplug state machine
  iommu/vt-d: Convert to hotplug state machine
  mm/zswap: Convert pool to hotplug state machine
  mm/zswap: Convert dst-mem to hotplug state machine
  mm/zsmalloc: Convert to hotplug state machine
  mm/vmstat: Convert to hotplug state machine
  mm/vmstat: Avoid on each online CPU loops
  mm/vmstat: Drop get_online_cpus() from init_cpu_node_state/vmstat_cpu_dead()
  tracing/rb: Convert to hotplug state machine
  oprofile/nmi timer: Convert to hotplug state machine
  net/iucv: Use explicit clean up labels in iucv_init()
  x86/pci/amd-bus: Convert to hotplug state machine
  x86/oprofile/nmi: Convert to hotplug state machine
  ...
2016-12-12 19:25:04 -08:00
Petr Mladek
497957576c printk/kdb: handle more message headers
Commit 4bcc595ccd ("printk: reinstate KERN_CONT for printing
continuation lines") allows to define more message headers for a single
message.  The motivation is that continuous lines might get mixed.
Therefore it make sense to define the right log level for every piece of
a cont line.

This patch introduces printk_skip_headers() that will skip all headers
and uses it in the kdb code instead of printk_skip_level().

This approach helps to fix other printk_skip_level() users
independently.

Link: http://lkml.kernel.org/r/1478695291-12169-3-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12 18:55:09 -08:00
Petr Mladek
22c2c7b2ef printk/NMI: handle continuous lines and missing newline
Commit 4bcc595ccd ("printk: reinstate KERN_CONT for printing
continuation lines") added back KERN_CONT message header.  As a result
it might appear in the middle of the line when the parts are squashed
via the temporary NMI buffer.

A reasonable solution seems to be to split the text in the NNI temporary
not only by newlines but also by the message headers.

Another solution would be to filter out KERN_CONT when writing to the
temporary buffer.  But this would complicate the lockless handling.
Also it would not solve problems with a missing newline that was there
even before the KERN_CONT stuff.

This patch moves the temporary buffer handling into separate function.
I played with it and it seems that using the char pointers make the code
easier to read.

Also it prints the final newline as a continuous line.

Finally, it moves handling of the s->len overflow into the paranoid
check.  And allows to recover from the disaster.

Link: http://lkml.kernel.org/r/1478695291-12169-2-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: David Sterba <dsterba@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12 18:55:09 -08:00
Petr Mladek
4a998e322a printk/NMI: fix up handling of the full nmi log buffer
vsnprintf() adds the trailing '\0' but it does not count it into the
number of printed characters.  The result is that there is one byte less
space for the real characters in the buffer.

The broken check for the free space might cause that we will repeatedly
try to print 1 character into the buffer, never reach the full buffer,
and do not count the messages as missed.

Also vsnprintf() returns the number of characters that would be printed
if the buffer was big enough.  As a result, s->len might be bigger than
the size of the buffer[*].  And the printk() function might return
bigger len than it really printed.  Both problems are fixed by using
vscnprintf() instead.

Note that I though about increasing the number of missed messages even
when the message was shrunken.  But it made the code even more
complicated.  I think that it is not worth it.  Shrunken messages are
usually easy to recognize.  And it should be a corner case.

[*] The overflown s->len value is crazy and unexpected.  I "made a
mistake" and reported this situation as an internal error when fixed
handling of PR_CONT headers in some other patch.

Link: http://lkml.kernel.org/r/20161208174912.GA17042@linux.suse
Signed-off-by: Petr Mladek <pmladek@suse.com>
CcL Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Takashi Iwai <tiwai@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12 18:55:09 -08:00
Tetsuo Handa
4ca5ede07c hung_task: decrement sysctl_hung_task_warnings only if it is positive
Since sysctl_hung_task_warnings == -1 is allowed (infinite warnings),
commit 48a6d64eda ("hung_task: allow hung_task_panic when
hung_task_warnings is 0") should decrement it only when it is not -1.

This prevents the kernel from ceasing warnings after the first
4294967295 ;)

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: John Siddle <jsiddle@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12 18:55:09 -08:00
Andrey Ryabinin
0f110a9b95 kernel/fork: use vfree_atomic() to free thread stack
vfree() is going to use sleeping lock.  Thread stack freed in atomic
context, therefore we must use vfree_atomic() here.

Link: http://lkml.kernel.org/r/1479474236-4139-6-git-send-email-hch@lst.de
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Jisheng Zhang <jszhang@marvell.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: John Dias <joaodias@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12 18:55:08 -08:00
Stanislav Kinsburskiy
3fb4afd9a5 prctl: remove one-shot limitation for changing exe link
This limitation came with the reason to remove "another way for
malicious code to obscure a compromised program and masquerade as a
benign process" by allowing "security-concious program can use this
prctl once during its early initialization to ensure the prctl cannot
later be abused for this purpose":

    http://marc.info/?l=linux-kernel&m=133160684517468&w=2

This explanation doesn't look sufficient.  The only thing "exe" link is
indicating is the file, used to execve, which is basically nothing and
not reliable immediately after process has returned from execve system
call.

Moreover, to use this feture, all the mappings to previous exe file have
to be unmapped and all the new exe file permissions must be satisfied.

Which means, that changing exe link is very similar to calling execve on
the binary.

The need to remove this limitations comes from migration of NFS mount
point, which is not accessible during restore and replaced by other file
system.  Because of this exe link has to be changed twice.

[akpm@linux-foundation.org: fix up comment]
Link: http://lkml.kernel.org/r/20160927153755.9337.69650.stgit@localhost.localdomain
Signed-off-by: Stanislav Kinsburskiy <skinsbursky@virtuozzo.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12 18:55:06 -08:00
Nicolas Iooss
c0b942a763 kthread: add __printf attributes
When commit fbae2d44aa ("kthread: add kthread_create_worker*()")
introduced some kthread_create_...() functions which were taking
printf-like parametter, it introduced __printf attributes to some
functions (e.g.  kthread_create_worker()).  Nevertheless some new
functions were forgotten (they have been detected thanks to
-Wmissing-format-attribute warning flag).

Add the missing __printf attributes to the newly-introduced functions in
order to detect formatting issues at build-time with -Wformat flag.

Link: http://lkml.kernel.org/r/20161126193543.22672-1-nicolas.iooss_linux@m4x.org
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-12 18:55:06 -08:00
Linus Torvalds
5645688f9d Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 asm updates from Ingo Molnar:
 "The main changes in this development cycle were:

   - a large number of call stack dumping/printing improvements: higher
     robustness, better cross-context dumping, improved output, etc.
     (Josh Poimboeuf)

   - vDSO getcpu() performance improvement for future Intel CPUs with
     the RDPID instruction (Andy Lutomirski)

   - add two new Intel AVX512 features and the CPUID support
     infrastructure for it: AVX512IFMA and AVX512VBMI. (Gayatri Kammela,
     He Chen)

   - more copy-user unification (Borislav Petkov)

   - entry code assembly macro simplifications (Alexander Kuleshov)

   - vDSO C/R support improvements (Dmitry Safonov)

   - misc fixes and cleanups (Borislav Petkov, Paul Bolle)"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits)
  scripts/decode_stacktrace.sh: Fix address line detection on x86
  x86/boot/64: Use defines for page size
  x86/dumpstack: Make stack name tags more comprehensible
  selftests/x86: Add test_vdso to test getcpu()
  x86/vdso: Use RDPID in preference to LSL when available
  x86/dumpstack: Handle NULL stack pointer in show_trace_log_lvl()
  x86/cpufeatures: Enable new AVX512 cpu features
  x86/cpuid: Provide get_scattered_cpuid_leaf()
  x86/cpuid: Cleanup cpuid_regs definitions
  x86/copy_user: Unify the code by removing the 64-bit asm _copy_*_user() variants
  x86/unwind: Ensure stack grows down
  x86/vdso: Set vDSO pointer only after success
  x86/prctl/uapi: Remove #ifdef for CHECKPOINT_RESTORE
  x86/unwind: Detect bad stack return address
  x86/dumpstack: Warn on stack recursion
  x86/unwind: Warn on bad frame pointer
  x86/decoder: Use stderr if insn sanity test fails
  x86/decoder: Use stdout if insn decoder test is successful
  mm/page_alloc: Remove kernel address exposure in free_reserved_area()
  x86/dumpstack: Remove raw stack dump
  ...
2016-12-12 13:49:57 -08:00
Linus Torvalds
cbaa1576c4 Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull hotplug API fix from Ingo Molnar:
 "Late breaking fix from the v4.9 cycle: fix a hotplug register/
  unregister notifier API asymmetry bug that can cause kernel warnings
  (and worse) with certain Kconfig combinations"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  hotplug: Make register and unregister notifier API symmetric
2016-12-12 12:53:54 -08:00
Linus Torvalds
92c020d08d Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
 "The main scheduler changes in this cycle were:

   - support Intel Turbo Boost Max Technology 3.0 (TBM3) by introducig a
     notion of 'better cores', which the scheduler will prefer to
     schedule single threaded workloads on. (Tim Chen, Srinivas
     Pandruvada)

   - enhance the handling of asymmetric capacity CPUs further (Morten
     Rasmussen)

   - improve/fix load handling when moving tasks between task groups
     (Vincent Guittot)

   - simplify and clean up the cputime code (Stanislaw Gruszka)

   - improve mass fork()ed task spread a.k.a. hackbench speedup (Vincent
     Guittot)

   - make struct kthread kmalloc()ed and related fixes (Oleg Nesterov)

   - add uaccess atomicity debugging (when using access_ok() in the
     wrong context), under CONFIG_DEBUG_ATOMIC_SLEEP=y (Peter Zijlstra)

   - implement various fixes, cleanups and other enhancements (Daniel
     Bristot de Oliveira, Martin Schwidefsky, Rafael J. Wysocki)"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
  sched/core: Use load_avg for selecting idlest group
  sched/core: Fix find_idlest_group() for fork
  kthread: Don't abuse kthread_create_on_cpu() in __kthread_create_worker()
  kthread: Don't use to_live_kthread() in kthread_[un]park()
  kthread: Don't use to_live_kthread() in kthread_stop()
  Revert "kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function"
  kthread: Make struct kthread kmalloc'ed
  x86/uaccess, sched/preempt: Verify access_ok() context
  sched/x86: Make CONFIG_SCHED_MC_PRIO=y easier to enable
  sched/x86: Change CONFIG_SCHED_ITMT to CONFIG_SCHED_MC_PRIO
  x86/sched: Use #include <linux/mutex.h> instead of #include <asm/mutex.h>
  cpufreq/intel_pstate: Use CPPC to get max performance
  acpi/bus: Set _OSC for diverse core support
  acpi/bus: Enable HWP CPPC objects
  x86/sched: Add SD_ASYM_PACKING flags to x86 ITMT CPU
  x86/sysctl: Add sysctl for ITMT scheduling feature
  x86: Enable Intel Turbo Boost Max Technology 3.0
  x86/topology: Define x86's arch_update_cpu_topology
  sched: Extend scheduler's asym packing
  sched/fair: Clean up the tunable parameter definitions
  ...
2016-12-12 12:15:10 -08:00
Linus Torvalds
6cdf89b1ca Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "The tree got pretty big in this development cycle, but the net effect
  is pretty good:

    115 files changed, 673 insertions(+), 1522 deletions(-)

  The main changes were:

   - Rework and generalize the mutex code to remove per arch mutex
     primitives. (Peter Zijlstra)

   - Add vCPU preemption support: add an interface to query the
     preemption status of vCPUs and use it in locking primitives - this
     optimizes paravirt performance. (Pan Xinhui, Juergen Gross,
     Christian Borntraeger)

   - Introduce cpu_relax_yield() and remov cpu_relax_lowlatency() to
     clean up and improve the s390 lock yielding machinery and its core
     kernel impact. (Christian Borntraeger)

   - Micro-optimize mutexes some more. (Waiman Long)

   - Reluctantly add the to-be-deprecated mutex_trylock_recursive()
     interface on a temporary basis, to give the DRM code more time to
     get rid of its locking hacks. Any other users will be NAK-ed on
     sight. (We turned off the deprecation warning for the time being to
     not pollute the build log.) (Peter Zijlstra)

   - Improve the rtmutex code a bit, in light of recent long lived
     bugs/races. (Thomas Gleixner)

   - Misc fixes, cleanups"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
  x86/paravirt: Fix bool return type for PVOP_CALL()
  x86/paravirt: Fix native_patch()
  locking/ww_mutex: Use relaxed atomics
  locking/rtmutex: Explain locking rules for rt_mutex_proxy_unlock()/init_proxy_locked()
  locking/rtmutex: Get rid of RT_MUTEX_OWNER_MASKALL
  x86/paravirt: Optimize native pv_lock_ops.vcpu_is_preempted()
  locking/mutex: Break out of expensive busy-loop on {mutex,rwsem}_spin_on_owner() when owner vCPU is preempted
  locking/osq: Break out of spin-wait busy waiting loop for a preempted vCPU in osq_lock()
  Documentation/virtual/kvm: Support the vCPU preemption check
  x86/xen: Support the vCPU preemption check
  x86/kvm: Support the vCPU preemption check
  x86/kvm: Support the vCPU preemption check
  kvm: Introduce kvm_write_guest_offset_cached()
  locking/core, x86/paravirt: Implement vcpu_is_preempted(cpu) for KVM and Xen guests
  locking/spinlocks, s390: Implement vcpu_is_preempted(cpu)
  locking/core, powerpc: Implement vcpu_is_preempted(cpu)
  sched/core: Introduce the vcpu_is_preempted(cpu) interface
  sched/wake_q: Rename WAKE_Q to DEFINE_WAKE_Q
  locking/core: Provide common cpu_relax_yield() definition
  locking/mutex: Don't mark mutex_trylock_recursive() as deprecated, temporarily
  ...
2016-12-12 10:48:02 -08:00
Linus Torvalds
9ad1aeecdb Merge branch 'core-smp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull SMP bootup updates from Ingo Molnar:
 "Three changes to unify/standardize some of the bootup message printing
  in kernel/smp.c between architectures"

* 'core-smp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kernel/smp: Tell the user we're bringing up secondary CPUs
  kernel/smp: Make the SMP boot message common on all arches
  kernel/smp: Define pr_fmt() for smp.c
2016-12-12 10:02:01 -08:00
Linus Torvalds
718c0ddd6a Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
 "The main RCU changes in this development cycle were:

   - Miscellaneous fixes, including a change to call_rcu()'s rcu_head
     alignment check.

   - Security-motivated list consistency checks, which are disabled by
     default behind DEBUG_LIST.

   - Torture-test updates.

   - Documentation updates, yet again just simple changes"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  torture: Prevent jitter from delaying build-only runs
  torture: Remove obsolete files from rcutorture .gitignore
  rcu: Don't kick unless grace period or request
  rcu: Make expedited grace periods recheck dyntick idle state
  torture: Trace long read-side delays
  rcu: RCU_TRACE enables event tracing as well as debugfs
  rcu: Remove obsolete comment from __call_rcu()
  rcu: Remove obsolete rcu_check_callbacks() header comment
  rcu: Tighten up __call_rcu() rcu_head alignment check
  Documentation/RCU: Fix minor typo
  documentation: Present updated RCU guarantee
  bug: Avoid Kconfig warning for BUG_ON_DATA_CORRUPTION
  lib/Kconfig.debug: Fix typo in select statement
  lkdtm: Add tests for struct list corruption
  bug: Provide toggle for BUG on data corruption
  list: Split list_del() debug checking into separate function
  rculist: Consolidate DEBUG_LIST for list_add_rcu()
  list: Split list_add() debug checking into separate function
2016-12-12 09:09:54 -08:00
Vincent Guittot
6b94780e45 sched/core: Use load_avg for selecting idlest group
find_idlest_group() only compares the runnable_load_avg when looking
for the least loaded group. But on fork intensive use case like
hackbench where tasks blocked quickly after the fork, this can lead to
selecting the same CPU instead of other CPUs, which have similar
runnable load but a lower load_avg.

When the runnable_load_avg of 2 CPUs are close, we now take into
account the amount of blocked load as a 2nd selection factor. There is
now 3 zones for the runnable_load of the rq:

 - [0 .. (runnable_load - imbalance)]:
	Select the new rq which has significantly less runnable_load

 - [(runnable_load - imbalance) .. (runnable_load + imbalance)]:
	The runnable loads are close so we use load_avg to chose
	between the 2 rq

 - [(runnable_load + imbalance) .. ULONG_MAX]:
	Keep the current rq which has significantly less runnable_load

The scale factor that is currently used for comparing runnable_load,
doesn't work well with small value. As an example, the use of a
scaling factor fails as soon as this_runnable_load == 0 because we
always select local rq even if min_runnable_load is only 1, which
doesn't really make sense because they are just the same. So instead
of scaling factor, we use an absolute margin for runnable_load to
detect CPUs with similar runnable_load and we keep using scaling
factor for blocked load.

For use case like hackbench, this enable the scheduler to select
different CPUs during the fork sequence and to spread tasks across the
system.

Tests have been done on a Hikey board (ARM based octo cores) for
several kernel. The result below gives min, max, avg and stdev values
of 18 runs with each configuration.

The patches depend on the "no missing update_rq_clock()" work.

hackbench -P -g 1

         ea86cb4b76  7dc603c902  v4.8        v4.8+patches
  min    0.049         0.050         0.051       0,048
  avg    0.057         0.057(0%)     0.057(0%)   0,055(+5%)
  max    0.066         0.068         0.070       0,063
  stdev  +/-9%         +/-9%         +/-8%       +/-9%

More performance numbers here:

  https://lkml.kernel.org/r/20161203214707.GI20785@codeblueprint.co.uk

Tested-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Morten.Rasmussen@arm.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: kernellwp@gmail.com
Cc: umgwanakikbuti@gmail.com
Cc: yuyang.du@intel.comc
Link: http://lkml.kernel.org/r/1481216215-24651-3-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-11 13:10:57 +01:00
Vincent Guittot
f519a3f1c6 sched/core: Fix find_idlest_group() for fork
During fork, the utilization of a task is init once the rq has been
selected because the current utilization level of the rq is used to
set the utilization of the fork task. As the task's utilization is
still 0 at this step of the fork sequence, it doesn't make sense to
look for some spare capacity that can fit the task's utilization.
Furthermore, I can see perf regressions for the test:

   hackbench -P -g 1

because the least loaded policy is always bypassed and tasks are not
spread during fork.

With this patch and the fix below, we are back to same performances as
for v4.8. The fix below is only a temporary one used for the test
until a smarter solution is found because we can't simply remove the
test which is useful for others benchmarks

| @@ -5708,13 +5708,6 @@ static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int t
|
|	avg_cost = this_sd->avg_scan_cost;
|
| -	/*
| -	 * Due to large variance we need a large fuzz factor; hackbench in
| -	 * particularly is sensitive here.
| -	 */
| -	if ((avg_idle / 512) < avg_cost)
| -		return -1;
| -
|	time = local_clock();
|
|	for_each_cpu_wrap(cpu, sched_domain_span(sd), target, wrap) {

Tested-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dietmar.eggemann@arm.com
Cc: kernellwp@gmail.com
Cc: umgwanakikbuti@gmail.com
Cc: yuyang.du@intel.comc
Link: http://lkml.kernel.org/r/1481216215-24651-2-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-11 13:10:56 +01:00
Ingo Molnar
6643aab30f Merge branch 'linus' into sched/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-11 13:10:40 +01:00
Ingo Molnar
6f38751510 Merge branch 'linus' into locking/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-11 13:07:13 +01:00
David S. Miller
821781a9f4 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-12-10 16:21:55 -05:00
Thomas Gleixner
c029a2bec6 timekeeping: Use mul_u64_u32_shr() instead of open coding it
The resume code must deal with a clocksource delta which is potentially big
enough to overflow the 64bit mult.

Replace the open coded handling with the proper function.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Parit Bhargava <prarit@redhat.com>
Cc: Laurent Vivier <lvivier@redhat.com>
Cc: "Christopher S. Hall" <christopher.s.hall@intel.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Liav Rehana <liavr@mellanox.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20161208204228.921674404@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-09 12:06:42 +01:00
Thomas Gleixner
cbd99e3b28 timekeeping: Get rid of pointless typecasts
cycle_t is defined as u64, so casting it to u64 is a pointless and
confusing exercise. cycle_t should simply go away and be replaced with a
plain u64 to avoid further confusion.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Parit Bhargava <prarit@redhat.com>
Cc: Laurent Vivier <lvivier@redhat.com>
Cc: "Christopher S. Hall" <christopher.s.hall@intel.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Liav Rehana <liavr@mellanox.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20161208204228.844699737@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-09 12:06:42 +01:00
Thomas Gleixner
acc89612a7 timekeeping: Make the conversion call chain consistently unsigned
Propagating a unsigned value through signed variables and functions makes
absolutely no sense and is just prone to (re)introduce subtle signed
vs. unsigned issues as happened recently.

Clean it up.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Parit Bhargava <prarit@redhat.com>
Cc: Laurent Vivier <lvivier@redhat.com>
Cc: "Christopher S. Hall" <christopher.s.hall@intel.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Liav Rehana <liavr@mellanox.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20161208204228.765843099@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-09 12:06:41 +01:00
Thomas Gleixner
9c1645727b timekeeping_Force_unsigned_clocksource_to_nanoseconds_conversion
The clocksource delta to nanoseconds conversion is using signed math, but
the delta is unsigned. This makes the conversion space smaller than
necessary and in case of a multiplication overflow the conversion can
become negative. The conversion is done with scaled math:

    s64 nsec_delta = ((s64)clkdelta * clk->mult) >> clk->shift;

Shifting a signed integer right obvioulsy preserves the sign, which has
interesting consequences:
 
 - Time jumps backwards
 
 - __iter_div_u64_rem() which is used in one of the calling code pathes
   will take forever to piecewise calculate the seconds/nanoseconds part.

This has been reported by several people with different scenarios:

David observed that when stopping a VM with a debugger:

 "It was essentially the stopped by debugger case.  I forget exactly why,
  but the guest was being explicitly stopped from outside, it wasn't just
  scheduling lag.  I think it was something in the vicinity of 10 minutes
  stopped."

 When lifting the stop the machine went dead.

The stopped by debugger case is not really interesting, but nevertheless it
would be a good thing not to die completely.

But this was also observed on a live system by Liav:

 "When the OS is too overloaded, delta will get a high enough value for the
  msb of the sum delta * tkr->mult + tkr->xtime_nsec to be set, and so
  after the shift the nsec variable will gain a value similar to
  0xffffffffff000000."

Unfortunately this has been reintroduced recently with commit 6bd58f09e1
("time: Add cycles to nanoseconds translation"). It had been fixed a year
ago already in commit 35a4933a89 ("time: Avoid signed overflow in
timekeeping_get_ns()").

Though it's not surprising that the issue has been reintroduced because the
function itself and the whole call chain uses s64 for the result and the
propagation of it. The change in this recent commit is subtle:

   s64 nsec;

-  nsec = (d * m + n) >> s:
+  nsec = d * m + n;
+  nsec >>= s;

d being type of cycle_t adds another level of obfuscation.

This wouldn't have happened if the previous change to unsigned computation
would have made the 'nsec' variable u64 right away and a follow up patch
had cleaned up the whole call chain.

There have been patches submitted which basically did a revert of the above
patch leaving everything else unchanged as signed. Back to square one. This
spawned a admittedly pointless discussion about potential users which rely
on the unsigned behaviour until someone pointed out that it had been fixed
before. The changelogs of said patches added further confusion as they made
finally false claims about the consequences for eventual users which expect
signed results.

Despite delta being cycle_t, aka. u64, it's very well possible to hand in
a signed negative value and the signed computation will happily return the
correct result. But nobody actually sat down and analyzed the code which
was added as user after the propably unintended signed conversion.

Though in sensitive code like this it's better to analyze it proper and
make sure that nothing relies on this than hunting the subtle wreckage half
a year later. After analyzing all call chains it stands that no caller can
hand in a negative value (which actually would work due to the s64 cast)
and rely on the signed math to do the right thing.

Change the conversion function to unsigned math. The conversion of all call
chains is done in a follow up patch.

This solves the starvation issue, which was caused by the negative result,
but it does not solve the underlying problem. It merily procrastinates
it. When the timekeeper update is deferred long enough that the unsigned
multiplication overflows, then time going backwards is observable again.

It does neither solve the issue of clocksources with a small counter width
which will wrap around possibly several times and cause random time stamps
to be generated. But those are usually not found on systems used for
virtualization, so this is likely a non issue.

I took the liberty to claim authorship for this simply because
analyzing all callsites and writing the changelog took substantially
more time than just making the simple s/s64/u64/ change and ignore the
rest.

Fixes: 6bd58f09e1 ("time: Add cycles to nanoseconds translation")
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Reported-by: Liav Rehana <liavr@mellanox.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Parit Bhargava <prarit@redhat.com>
Cc: Laurent Vivier <lvivier@redhat.com>
Cc: "Christopher S. Hall" <christopher.s.hall@intel.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20161208204228.688545601@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-09 12:06:41 +01:00
Martin KaFai Lau
17bedab272 bpf: xdp: Allow head adjustment in XDP prog
This patch allows XDP prog to extend/remove the packet
data at the head (like adding or removing header).  It is
done by adding a new XDP helper bpf_xdp_adjust_head().

It also renames bpf_helper_changes_skb_data() to
bpf_helper_changes_pkt_data() to better reflect
that XDP prog does not work on skb.

This patch adds one "xdp_adjust_head" bit to bpf_prog for the
XDP-capable driver to check if the XDP prog requires
bpf_xdp_adjust_head() support.  The driver can then decide
to error out during XDP_SETUP_PROG.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-08 14:25:13 -05:00
Alexei Starovoitov
d2a4dd37f6 bpf: fix state equivalence
Commmits 57a09bf0a4 ("bpf: Detect identical PTR_TO_MAP_VALUE_OR_NULL registers")
and 484611357c ("bpf: allow access into map value arrays") by themselves
are correct, but in combination they make state equivalence ignore 'id' field
of the register state which can lead to accepting invalid program.

Fixes: 57a09bf0a4 ("bpf: Detect identical PTR_TO_MAP_VALUE_OR_NULL registers")
Fixes: 484611357c ("bpf: allow access into map value arrays")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-08 13:31:11 -05:00
Oleg Nesterov
8fb9dcbdc3 kthread: Don't abuse kthread_create_on_cpu() in __kthread_create_worker()
kthread_create_on_cpu() sets KTHREAD_IS_PER_CPU and kthread->cpu, this
only makes sense if this kthread can be parked/unparked by cpuhp code.
kthread workers never call kthread_parkme() so this has no effect.

Change __kthread_create_worker() to simply call kthread_bind(task, cpu).
The very fact that kthread_create_on_cpu() doesn't accept a generic fmt
shows that it should not be used outside of smpboot.c.

Now, the only reason we can not unexport this helper and move it into
smpboot.c is that it sets kthread->cpu and struct kthread is not exported.
And the only reason we can not kill kthread->cpu is that kthread_unpark()
is used by drivers/gpu/drm/amd/scheduler/gpu_scheduler.c and thus we can
not turn _unpark into kthread_unpark(struct smp_hotplug_thread *, cpu).

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Chunming Zhou <David1.Zhou@amd.com>
Cc: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20161129175110.GA5342@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-08 14:36:20 +01:00
Oleg Nesterov
cf380a4a96 kthread: Don't use to_live_kthread() in kthread_[un]park()
Now that to_kthread() is always validm change kthread_park() and
kthread_unpark() to use it and kill to_live_kthread().

The conversion of kthread_unpark() is trivial. If KTHREAD_IS_PARKED is set
then the task has called complete(&self->parked) and there the function
cannot race against a concurrent kthread_stop() and exit.

kthread_park() is more tricky, because its semantics are not well
defined. It returns -ENOSYS if the thread exited but this can never happen
and as Roman pointed out kthread_park() can obviously block forever if it
would race with the exiting kthread.

The usage of kthread_park() in cpuhp code (cpu.c, smpboot.c, stop_machine.c)
is fine. It can never see an exiting/exited kthread, smpboot_destroy_threads()
clears *ht->store, smpboot_park_thread() checks it is not NULL under the same
smpboot_threads_lock. cpuhp_threads and cpu_stop_threads never exit, so other
callers are fine too.

But it has two more users:

- watchdog_park_threads():

  The code is actually correct, get_online_cpus() ensures that
  kthread_park() can't race with itself (note that kthread_park() can't
  handle this race correctly), but it should not use kthread_park()
  directly.

- drivers/gpu/drm/amd/scheduler/gpu_scheduler.c should not use
  kthread_park() either.

  kthread_park() must not be called after amd_sched_fini() which does
  kthread_stop(), otherwise even to_live_kthread() is not safe because
  task_struct can be already freed and sched->thread can point to nowhere.

The usage of kthread_park/unpark should either be restricted to core code
which is properly protected against the exit race or made more robust so it
is safe to use it in drivers.

To catch eventual exit issues, add a WARN_ON(PF_EXITING) for now.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Chunming Zhou <David1.Zhou@amd.com>
Cc: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20161129175107.GA5339@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-08 14:36:19 +01:00
Oleg Nesterov
efb29fbfa5 kthread: Don't use to_live_kthread() in kthread_stop()
kthread_stop() had to use to_live_kthread() simply because it was not
possible to access kthread->exited after the exiting task clears
task_struct->vfork_done. Now that to_kthread() is always valid,
wake_up_process() + wait_for_completion() can be done
ununconditionally. It's not an issue anymore if the task has already issued
complete_vfork_done() or died.

The exiting task can get the spurious wakeup after mm_release() but this is
possible without this change too and is fine; do_task_dead() ensures that
this can't make any harm.

As a further enhancement this could be converted to task_work_add() later,
so ->vfork_done can be avoided completely.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Chunming Zhou <David1.Zhou@amd.com>
Cc: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20161129175103.GA5336@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-08 14:36:19 +01:00
Oleg Nesterov
eff9662547 Revert "kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function"
This reverts commit 23196f2e5f.

Now that struct kthread is kmalloc'ed and not longer on the task stack
there is no need anymore to pin the stack.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Chunming Zhou <David1.Zhou@amd.com>
Cc: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20161129175100.GA5333@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-08 14:36:18 +01:00
Oleg Nesterov
1da5c46fa9 kthread: Make struct kthread kmalloc'ed
commit 23196f2e5f "kthread: Pin the stack via try_get_task_stack() /
put_task_stack() in to_live_kthread() function" is a workaround for the
fragile design of struct kthread being allocated on the task stack.

struct kthread in its current form should be removed, but this needs
cleanups outside of kthread.c.

As a first step move struct kthread away from the task stack by making it
kmalloc'ed. This allows to access kthread.exited without the magic of
trying to pin task stack and the try logic in to_live_kthread().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Chunming Zhou <David1.Zhou@amd.com>
Cc: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20161129175057.GA5330@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-08 14:36:18 +01:00
Michal Hocko
777c6e0dae hotplug: Make register and unregister notifier API symmetric
Yu Zhao has noticed that __unregister_cpu_notifier only unregisters its
notifiers when HOTPLUG_CPU=y while the registration might succeed even
when HOTPLUG_CPU=n if MODULE is enabled. This means that e.g. zswap
might keep a stale notifier on the list on the manual clean up during
the pool tear down and thus corrupt the list. Resulting in the following

[  144.964346] BUG: unable to handle kernel paging request at ffff880658a2be78
[  144.971337] IP: [<ffffffffa290b00b>] raw_notifier_chain_register+0x1b/0x40
<snipped>
[  145.122628] Call Trace:
[  145.125086]  [<ffffffffa28e5cf8>] __register_cpu_notifier+0x18/0x20
[  145.131350]  [<ffffffffa2a5dd73>] zswap_pool_create+0x273/0x400
[  145.137268]  [<ffffffffa2a5e0fc>] __zswap_param_set+0x1fc/0x300
[  145.143188]  [<ffffffffa2944c1d>] ? trace_hardirqs_on+0xd/0x10
[  145.149018]  [<ffffffffa2908798>] ? kernel_param_lock+0x28/0x30
[  145.154940]  [<ffffffffa2a3e8cf>] ? __might_fault+0x4f/0xa0
[  145.160511]  [<ffffffffa2a5e237>] zswap_compressor_param_set+0x17/0x20
[  145.167035]  [<ffffffffa2908d3c>] param_attr_store+0x5c/0xb0
[  145.172694]  [<ffffffffa290848d>] module_attr_store+0x1d/0x30
[  145.178443]  [<ffffffffa2b2b41f>] sysfs_kf_write+0x4f/0x70
[  145.183925]  [<ffffffffa2b2a5b9>] kernfs_fop_write+0x149/0x180
[  145.189761]  [<ffffffffa2a99248>] __vfs_write+0x18/0x40
[  145.194982]  [<ffffffffa2a9a412>] vfs_write+0xb2/0x1a0
[  145.200122]  [<ffffffffa2a9a732>] SyS_write+0x52/0xa0
[  145.205177]  [<ffffffffa2ff4d97>] entry_SYSCALL_64_fastpath+0x12/0x17

This can be even triggered manually by changing
/sys/module/zswap/parameters/compressor multiple times.

Fix this issue by making unregister APIs symmetric to the register so
there are no surprises.

Fixes: 47e627bc8c ("[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU")
Reported-and-tested-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Link: http://lkml.kernel.org/r/20161207135438.4310-1-mhocko@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-08 10:08:41 +01:00
Kefeng Wang
166ad0e1e2 kcov: add missing #include <linux/sched.h>
In __sanitizer_cov_trace_pc we use task_struct and fields within it, but
as we haven't included <linux/sched.h>, it is not guaranteed to be
defined.  While we usually happen to acquire the definition through a
transitive include, this is fragile (and hasn't been true in the past,
causing issues with backports).

Include <linux/sched.h> to avoid any fragility.

[mark.rutland@arm.com: rewrote changelog]
Link: http://lkml.kernel.org/r/1481007384-27529-1-git-send-email-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-07 17:10:00 -08:00
Linus Torvalds
68f5503bdc Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar:
 "An autogroup nice level adjustment bug fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/autogroup: Fix 64-bit kernel nice level adjustment
2016-12-07 11:35:55 -08:00
Linus Torvalds
bf7f1c7e2f Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "A bogus warning fix, a counter width handling fix affecting certain
  machines, plus a oneliner hw-enablement patch for Knights Mill CPUs"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Remove invalid warning from list_update_cgroup_even()t
  perf/x86: Fix full width counter, counter overflow
  perf/x86/intel: Enable C-state residency events for Knights Mill
2016-12-07 11:32:19 -08:00
Linus Torvalds
5b43f97f3f Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
 "Two rtmutex race fixes (which miraculously never triggered, that we
  know of), plus two lockdep printk formatting regression fixes"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  lockdep: Fix report formatting
  locking/rtmutex: Use READ_ONCE() in rt_mutex_owner()
  locking/rtmutex: Prevent dequeue vs. unlock race
  locking/selftest: Fix output since KERN_CONT changes
2016-12-07 11:27:33 -08:00
Daniel Borkmann
ef0915cacd bpf: fix loading of BPF_MAXINSNS sized programs
General assumption is that single program can hold up to BPF_MAXINSNS,
that is, 4096 number of instructions. It is the case with cBPF and
that limit was carried over to eBPF. When recently testing digest, I
noticed that it's actually not possible to feed 4096 instructions
via bpf(2).

The check for > BPF_MAXINSNS was added back then to bpf_check() in
cbd3570086 ("bpf: verifier (add ability to receive verification log)").
However, 09756af468 ("bpf: expand BPF syscall with program load/unload")
added yet another check that comes before that into bpf_prog_load(),
but this time bails out already in case of >= BPF_MAXINSNS.

Fix it up and perform the check early in bpf_prog_load(), so we can drop
the second one in bpf_check(). It makes sense, because also a 0 insn
program is useless and we don't want to waste any resources doing work
up to bpf_check() point. The existing bpf(2) man page documents E2BIG
as the official error for such cases, so just stick with it as well.

Fixes: 09756af468 ("bpf: expand BPF syscall with program load/unload")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-07 13:16:04 -05:00
Murali Karicheri
5304121ada clocksource: export the clocks_calc_mult_shift to use by timestamp code
The CPSW CPTS driver is capable of doing timestamping on tx/rx packets and
requires to know mult and shift factors for timestamp conversion from raw
value to nanoseconds (ptp clock). Now these mult and shift factors are
calculated manually and provided through DT, which makes very hard to
support of a lot number of platforms, especially if CPTS refclk is not the
same for some kind of boards and depends on efuse settings (Keystone 2
platforms). Hence, export clocks_calc_mult_shift() to allow drivers like
CPSW CPTS (and other ptp drivesr) to benefit from automaitc calculation of
mult and shift factors.

Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-07 11:13:48 -05:00
Sebastian Andrzej Siewior
b18cc3de00 tracing/rb: Init the CPU mask on allocation
Before commit b32614c034 ("tracing/rb: Convert to hotplug state machine")
the allocated cpumask was initialized to the mask of online or possible
CPUs. After the CPU hotplug changes the buffer initialization moved to
trace_rb_cpu_prepare() but the cpumask is allocated with alloc_cpumask()
and therefor has random content. As a consequence the cpu buffers are not
initialized and a later access dereferences a NULL pointer.

Use zalloc_cpumask() instead so trace_rb_cpu_prepare() initializes the
buffers properly.

Fixes: b32614c034 ("tracing/rb: Convert to hotplug state machine")
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/20161207133133.hzkcqfllxcdi3joz@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-07 14:36:21 +01:00
Dmitry Vyukov
f943fe0faf lockdep: Fix report formatting
Since commit:

  4bcc595ccd ("printk: reinstate KERN_CONT for printing continuation lines")

printk() requires KERN_CONT to continue log messages. Lots of printk()
in lockdep.c and print_ip_sym() don't have it. As the result lockdep
reports are completely messed up.

Add missing KERN_CONT and inline print_ip_sym() where necessary.

Example of a messed up report:

  0-rc5+ #41 Not tainted
  -------------------------------------------------------
  syz-executor0/5036 is trying to acquire lock:
   (
  rtnl_mutex
  ){+.+.+.}
  , at:
  [<ffffffff86b3d6ac>] rtnl_lock+0x1c/0x20
  but task is already holding lock:
   (
  &net->packet.sklist_lock
  ){+.+...}
  , at:
  [<ffffffff873541a6>] packet_diag_dump+0x1a6/0x1920
  which lock already depends on the new lock.
  the existing dependency chain (in reverse order) is:
  -> #3
   (
  &net->packet.sklist_lock
  +.+...}
  ...

Without this patch all scripts that parse kernel bug reports are broken.

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andreyknvl@google.com
Cc: aryabinin@virtuozzo.com
Cc: joe@perches.com
Cc: syzkaller@googlegroups.com
Link: http://lkml.kernel.org/r/1480343083-48731-1-git-send-email-dvyukov@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-06 10:40:08 +01:00
David Carrillo-Cisneros
8fc31ce889 perf/core: Remove invalid warning from list_update_cgroup_even()t
The warning introduced in commit:

  864c2357ca ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups")

assumed that a cgroup switch always precedes list_del_event. This is
not the case. Remove warning.

Make sure that cpuctx->cgrp is NULL until a cgroup event is sched in
or ctx->nr_cgroups == 0.

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1480841177-27299-1-git-send-email-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-12-06 09:44:29 +01:00
Daniel Borkmann
7bd509e311 bpf: add prog_digest and expose it via fdinfo/netlink
When loading a BPF program via bpf(2), calculate the digest over
the program's instruction stream and store it in struct bpf_prog's
digest member. This is done at a point in time before any instructions
are rewritten by the verifier. Any unstable map file descriptor
number part of the imm field will be zeroed for the hash.

fdinfo example output for progs:

  # cat /proc/1590/fdinfo/5
  pos:          0
  flags:        02000002
  mnt_id:       11
  prog_type:    1
  prog_jited:   1
  prog_digest:  b27e8b06da22707513aa97363dfb11c7c3675d28
  memlock:      4096

When programs are pinned and retrieved by an ELF loader, the loader
can check the program's digest through fdinfo and compare it against
one that was generated over the ELF file's program section to see
if the program needs to be reloaded. Furthermore, this can also be
exposed through other means such as netlink in case of a tc cls/act
dump (or xdp in future), but also through tracepoints or other
facilities to identify the program. Other than that, the digest can
also serve as a base name for the work in progress kallsyms support
of programs. The digest doesn't depend/select the crypto layer, since
we need to keep dependencies to a minimum. iproute2 will get support
for this facility.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-05 15:33:11 -05:00
Gianluca Borello
3c839744b3 bpf: Preserve const register type on const OR alu ops
Occasionally, clang (e.g. version 3.8.1) translates a sum between two
constant operands using a BPF_OR instead of a BPF_ADD. The verifier is
currently not handling this scenario, and the destination register type
becomes UNKNOWN_VALUE even if it's still storing a constant. As a result,
the destination register cannot be used as argument to a helper function
expecting a ARG_CONST_STACK_*, limiting some use cases.

Modify the verifier to handle this case, and add a few tests to make sure
all combinations are supported, and stack boundaries are still verified
even with BPF_OR.

Signed-off-by: Gianluca Borello <g.borello@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-05 13:40:05 -05:00
David S. Miller
2745529ac7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Couple conflicts resolved here:

1) In the MACB driver, a bug fix to properly initialize the
   RX tail pointer properly overlapped with some changes
   to support variable sized rings.

2) In XGBE we had a "CONFIG_PM" --> "CONFIG_PM_SLEEP" fix
   overlapping with a reorganization of the driver to support
   ACPI, OF, as well as PCI variants of the chip.

3) In 'net' we had several probe error path bug fixes to the
   stmmac driver, meanwhile a lot of this code was cleaned up
   and reorganized in 'net-next'.

4) The cls_flower classifier obtained a helper function in
   'net-next' called __fl_delete() and this overlapped with
   Daniel Borkamann's bug fix to use RCU for object destruction
   in 'net'.  It also overlapped with Jiri's change to guard
   the rhashtable_remove_fast() call with a check against
   tc_skip_sw().

5) In mlx4, a revert bug fix in 'net' overlapped with some
   unrelated changes in 'net-next'.

6) In geneve, a stale header pointer after pskb_expand_head()
   bug fix in 'net' overlapped with a large reorganization of
   the same code in 'net-next'.  Since the 'net-next' code no
   longer had the bug in question, there was nothing to do
   other than to simply take the 'net-next' hunks.

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-03 12:29:53 -05:00
Linus Torvalds
8bca927f13 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) Lots more phydev and probe error path leaks in various drivers by
    Johan Hovold.

 2) Fix race in packet_set_ring(), from Philip Pettersson.

 3) Use after free in dccp_invalid_packet(), from Eric Dumazet.

 4) Signnedness overflow in SO_{SND,RCV}BUFFORCE, also from Eric
    Dumazet.

 5) When tunneling between ipv4 and ipv6 we can be left with the wrong
    skb->protocol value as we enter the IPSEC engine and this causes all
    kinds of problems. Set it before the output path does any
    dst_output() calls, from Eli Cooper.

 6) bcmgenet uses wrong device struct pointer in DMA API calls, fix from
    Florian Fainelli.

 7) Various netfilter nat bug fixes from FLorian Westphal.

 8) Fix memory leak in ipvlan_link_new(), from Gao Feng.

 9) Locking fixes, particularly wrt. socket lookups, in l2tp from
    Guillaume Nault.

10) Avoid invoking rhash teardowns in atomic context by moving netlink
    cb->done() dump completion from a worker thread. Fix from Herbert
    Xu.

11) Buffer refcount problems in tun and macvtap on errors, from Jason
    Wang.

12) We don't set Kconfig symbol DEFAULT_TCP_CONG properly when the user
    selects BBR. Fix from Julian Wollrath.

13) Fix deadlock in transmit path on altera TSE driver, from Lino
    Sanfilippo.

14) Fix unbalanced reference counting in dsa_switch_tree, from Nikita
    Yushchenko.

15) tc_tunnel_key needs to be properly exported to userspace via uapi,
    fix from Roi Dayan.

16) rds_tcp_init_net() doesn't unregister notifier in error path, fix
    from Sowmini Varadhan.

17) Stale packet header pointer access after pskb_expand_head() in
    genenve driver, fix from Sabrina Dubroca.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (103 commits)
  net: avoid signed overflows for SO_{SND|RCV}BUFFORCE
  geneve: avoid use-after-free of skb->data
  tipc: check minimum bearer MTU
  net: renesas: ravb: unintialized return value
  sh_eth: remove unchecked interrupts for RZ/A1
  net: bcmgenet: Utilize correct struct device for all DMA operations
  NET: usb: qmi_wwan: add support for Telit LE922A PID 0x1040
  cdc_ether: Fix handling connection notification
  ip6_offload: check segs for NULL in ipv6_gso_segment.
  RDS: TCP: unregister_netdevice_notifier() in error path of rds_tcp_init_net
  Revert: "ip6_tunnel: Update skb->protocol to ETH_P_IPV6 in ip6_tnl_xmit()"
  ipv6: Set skb->protocol properly for local output
  ipv4: Set skb->protocol properly for local output
  packet: fix race condition in packet_set_ring
  net: ethernet: altera: TSE: do not use tx queue lock in tx completion handler
  net: ethernet: altera: TSE: Remove unneeded dma sync for tx buffers
  net: ethernet: stmmac: fix of-node and fixed-link-phydev leaks
  net: ethernet: stmmac: platform: fix outdated function header
  net: ethernet: stmmac: dwmac-meson8b: fix probe error path
  net: ethernet: stmmac: dwmac-generic: fix probe error path
  ...
2016-12-02 11:45:27 -08:00
David Ahern
6102365876 bpf: Add new cgroup attach type to enable sock modifications
Add new cgroup based program type, BPF_PROG_TYPE_CGROUP_SOCK. Similar to
BPF_PROG_TYPE_CGROUP_SKB programs can be attached to a cgroup and run
any time a process in the cgroup opens an AF_INET or AF_INET6 socket.
Currently only sk_bound_dev_if is exported to userspace for modification
by a bpf program.

This allows a cgroup to be configured such that AF_INET{6} sockets opened
by processes are automatically bound to a specific device. In turn, this
enables the running of programs that do not support SO_BINDTODEVICE in a
specific VRF context / L3 domain.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-02 13:46:08 -05:00
David Ahern
b2cd12574a bpf: Refactor cgroups code in prep for new type
Code move and rename only; no functional change intended.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-02 13:44:56 -05:00
Thomas Graf
3a0af8fd61 bpf: BPF for lightweight tunnel infrastructure
Registers new BPF program types which correspond to the LWT hooks:
  - BPF_PROG_TYPE_LWT_IN   => dst_input()
  - BPF_PROG_TYPE_LWT_OUT  => dst_output()
  - BPF_PROG_TYPE_LWT_XMIT => lwtunnel_xmit()

The separate program types are required to differentiate between the
capabilities each LWT hook allows:

 * Programs attached to dst_input() or dst_output() are restricted and
   may only read the data of an skb. This prevent modification and
   possible invalidation of already validated packet headers on receive
   and the construction of illegal headers while the IP headers are
   still being assembled.

 * Programs attached to lwtunnel_xmit() are allowed to modify packet
   content as well as prepending an L2 header via a newly introduced
   helper bpf_skb_change_head(). This is safe as lwtunnel_xmit() is
   invoked after the IP header has been assembled completely.

All BPF programs receive an skb with L3 headers attached and may return
one of the following error codes:

 BPF_OK - Continue routing as per nexthop
 BPF_DROP - Drop skb and return EPERM
 BPF_REDIRECT - Redirect skb to device as per redirect() helper.
                (Only valid in lwtunnel_xmit() context)

The return codes are binary compatible with their TC_ACT_
relatives to ease compatibility.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-12-02 10:51:49 -05:00