The BPF JIT uses a 'b <disp>(%r<x>)' instruction in the definition
of the sk_load_word and sk_load_half functions.

Add support for branch-on-condition instructions contained in the
thunk code of an expoline.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The inline assembly to call __do_softirq on the irq stack uses
an indirect branch. This can be replaced with a normal relative
branch.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5e ("s390: introduce execute-trampolines for branches")
Reviewed-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The nospec-branch.c file is compiled without the gcc options to
generate expoline thunks. The return branch of the sysfs show
functions cpu_show_spectre_v1 and cpu_show_spectre_v2 is an indirect
branch as well. These need to be compiled with expolines.

Move the sysfs functions for spectre reporting to a separate file
and loose an '.' for one of the messages.

Cc: stable@vger.kernel.org # 4.16
Fixes: d424986f ("s390: add sysfs attributes for spectre")
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The assember code in arch/s390/kernel uses a few more indirect branches
which need to be done with execute trampolines for CONFIG_EXPOLINE=y.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5e ("s390: introduce execute-trampolines for branches")
Reviewed-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The return from the ftrace_stub, _mcount, ftrace_caller and
return_to_handler functions is done with "br %r14" and "br %r1".
These are indirect branches as well and need to use execute
trampolines for CONFIG_EXPOLINE=y.

The ftrace_caller function is a special case as it returns to the
start of a function and may only use %r0 and %r1. For a pre z10
machine the standard execute trampoline uses a LARL + EX to do
this, but this requires *two* registers in the range %r1..%r15.
To get around this the 'br %r1' located in the lowcore is used,
then the EX instruction does not need an address register.
But the lowcore trick may only be used for pre z14 machines,
with noexec=on the mapping for the first page may not contain
instructions. The solution for that is an ALTERNATIVE in the
expoline THUNK generated by 'GEN_BR_THUNK %r1' to switch to
EXRL, this relies on the fact that a machine that supports
noexec=on has EXRL as well.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5e ("s390: introduce execute-trampolines for branches")
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The return from the memmove, memset, memcpy, __memset16, __memset32 and
__memset64 functions are done with "br %r14". These are indirect branches
as well and need to use execute trampolines for CONFIG_EXPOLINE=y.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5e ("s390: introduce execute-trampolines for branches")
Reviewed-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The return from the crc32_le_vgfm_16/crc32c_le_vgfm_16 and the
crc32_be_vgfm_16 functions are done with "br %r14". These are indirect
branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5e ("s390: introduce execute-trampolines for branches")
Reviewed-by: NHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

To be able to use the expoline branches in different assembler
files move the associated macros from entry.S to a new header
nospec-insn.h.

While we are at it make the macros a bit nicer to use.

Cc: stable@vger.kernel.org # 4.16
Fixes: f19fbd5e ("s390: introduce execute-trampolines for branches")
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

If the translation of a channel program fails, we may end up attempting
to clean up (free, unpin) stuff that never got translated (and allocated,
pinned) in the first place.

By adjusting the lengths of the chains accordingly (so the element that
failed, and all subsequent elements are excluded) cleanup activities
based on false assumptions can be avoided.

Let's make sure cp_free works properly after cp_prefetch returns with an
error by setting ch_len of a ccw chain to the number of the translated
CCWs on that chain.

Cc: stable@vger.kernel.org #v4.12+
Acked-by: NPierre Morel <pmorel@linux.vnet.ibm.com>
Reviewed-by: NDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: NHalil Pasic <pasic@linux.vnet.ibm.com>
Signed-off-by: NDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Message-Id: <20180423110113.59385-2-bjsdjshi@linux.vnet.ibm.com>
[CH: fixed typos]
Signed-off-by: NCornelia Huck <cohuck@redhat.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Fix the following sparse complaints:

arch/s390/purgatory/purgatory.c:18:5: warning: symbol 'kernel_entry' was not declared. Should it be static?
arch/s390/purgatory/purgatory.c:19:5: warning: symbol 'kernel_type' was not declared. Should it be static?
arch/s390/purgatory/purgatory.c:21:5: warning: symbol 'crash_start' was not declared. Should it be static?
arch/s390/purgatory/purgatory.c:22:5: warning: symbol 'crash_size' was not declared. Should it be static?
Signed-off-by: NSebastian Ott <sebott@linux.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Change the following to y:

arch/s390/configs/performance_defconfig:262:warning: symbol value 'm' invalid for NF_TABLES_IPV4
arch/s390/configs/performance_defconfig:264:warning: symbol value 'm' invalid for NF_TABLES_ARP
arch/s390/configs/performance_defconfig:285:warning: symbol value 'm' invalid for NF_TABLES_IPV6
arch/s390/configs/performance_defconfig:306:warning: symbol value 'm' invalid for NF_TABLES_BRIDGE
Signed-off-by: NSebastian Ott <sebott@linux.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Signed-off-by: NHarald Freudenberger <freude@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Pull virtio fixups from Michael Tsirkin:

 - Latest header update will break QEMU (if it's rebuilt with the new
   header) - and it seems that the code there is so fragile that any
   change in this header will break it. Add a better interface so users
   do not need to change their code every time that header changes.

 - Fix virtio console for spec compliance.

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_console: reset on out of memory
  virtio_console: move removal code
  virtio_console: drop custom control queue cleanup
  virtio_console: free buffers after reset
  virtio: add ability to iterate over vqs
  virtio_console: don't tie bufs to a vq
  virtio_balloon: add array of stat names

Merge tag 'hwmon-for-linus-v4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:

 - Add support for new Ryzen chips to k10temp driver
   ... making Phoronix happy

 - Fix inconsistent chip access in nct6683 driver

 - Handle absence of few types of sensors in scmi driver

* tag 'hwmon-for-linus-v4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (k10temp) Add support for AMD Ryzen w/ Vega graphics
  hwmon: (k10temp) Add temperature offset for Ryzen 2700X
  hwmon: (nct6683) Enable EC access if disabled at boot
  hwmon: (scmi) handle absence of few types of sensors

Pull PCI fixes from Bjorn Helgaas:

 - fix Aardvark MRRS setting (Evan Wang)

 - clarify "bandwidth available" link status message (Jakub Kicinski)

 - update Kirin GPIO name to fix probe failure (Loic Poulain)

 - fix Aardvark IRQ usage (Victor Gu)

 - fix Aardvark config accessor issues (Victor Gu)

* tag 'pci-v4.17-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI: Add "PCIe" to pcie_print_link_status() messages
  PCI: kirin: Fix reset gpio name
  PCI: aardvark: Fix PCIe Max Read Request Size setting
  PCI: aardvark: Use ISR1 instead of ISR0 interrupt in legacy irq mode
  PCI: aardvark: Set PIO_ADDR_LS correctly in advk_pcie_rd_conf()
  PCI: aardvark: Fix logic in advk_pcie_{rd,wr}_conf()

Pull tracing fixes from Steven Rostedt:

 - Add workqueue forward declaration (for new work, but a nice clean up)

 - seftest fixes for the new histogram code

 - Print output fix for hwlat tracer

 - Fix missing system call events - due to change in x86 syscall naming

 - Fix kprobe address being used by perf being hashed

* tag 'trace-v4.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix missing tab for hwlat_detector print format
  selftests: ftrace: Add a testcase for multiple actions on trigger
  selftests: ftrace: Fix trigger extended error testcase
  kprobes: Fix random address output of blacklist file
  tracing: Fix kernel crash while using empty filter with perf
  tracing/x86: Update syscall trace events to handle new prefixed syscall func names
  tracing: Add missing forward declaration

Pull ACPI fixes from Rafael Wysocki:
 "These are two watchdog-related fixes, fix for a backlight regression
  from the 4.16 cycle that unfortunately was propagated to -stable and a
  button module modification to prevent graphics driver modules from
  failing to load due to unmet dependencies if ACPI is disabled from the
  kernel command line.

  Specifics:

   - Change the ACPI subsystem initialization ordering to initialize the
     WDAT watchodg before reserving PNP motherboard resources so as to
     allow the watchdog to allocate its resources before the PNP code
     gets to them and prevents it from working correctly (Mika
     Westerberg).

   - Add a quirk for Lenovo Z50-70 to use the iTCO watchdog instead of
     the WDAT one which conflicts with the RTC on that platform (Mika
     Westerberg).

   - Avoid breaking backlight handling on Dell XPS 13 2013 model by
     allowing laptops to use the ACPI backlight by default even if they
     are Windows 8-ready in principle (Hans de Goede)"

* tag 'acpi-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / video: Only default only_lcd to true on Win8-ready _desktops_
  ACPI / button: make module loadable when booted in non-ACPI mode
  ACPI / watchdog: Prefer iTCO_wdt on Lenovo Z50-70
  ACPI / scan: Initialize watchdog before PNP

Pull power management fixes from Rafael Wysocki:
 "These are a Low Power S0 Idle quirk, a hibernation handling fix for
  the PCI bus type and a brcmstb-avs-cpufreq driver fixup removing
  development debug code from it.

  Specifics:

   - Blacklist the Low Power S0 Idle _DSM on ThinkPad X1 Tablet(2016)
     where it causes issues and make it use ACPI S3 which works instead
     of the non-working suspend-to-idle by default (Chen Yu).

   - Fix the handling of hibernation in the PCI core for devices with
     the DPM_FLAG_SMART_SUSPEND flag set to fix a regression affecting
     intel-lpss I2C devices (Mika Westerberg).

   - Drop development debug code from the brcmstb-avs-cpufreq driver
     (Markus Mayer)"

* tag 'pm-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: brcmstb-avs-cpufreq: remove development debug support
  PCI / PM: Do not clear state_saved in pci_pm_freeze() when smart suspend is set
  ACPI / PM: Blacklist Low Power S0 Idle _DSM for ThinkPad X1 Tablet(2016)

Pull /dev/random fixes from Ted Ts'o:
 "Fix a regression on NUMA kernels and suppress excess unseeded entropy
  pool warnings"

* tag 'random_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
  random: rate limit unseeded randomness warnings
  random: fix possible sleeping allocation from irq context

Pull s390 fixes from Martin Schwidefsky:
 "A couple of bug fixes:

   - correct some CPU-MF counter names for z13 and z14

   - correct locking in the vfio-ccw fsm_io_helper function

   - provide arch_uretprobe_is_alive to avoid sigsegv with uretprobes

   - fix a corner case with CPU-MF sampling in regard to execve

   - fix expoline code revert for loadable modules

   - update chpid descriptor for resource accessibility events

   - fix dasd I/O errors due to outdated device alias infomation"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390: correct module section names for expoline code revert
  vfio: ccw: process ssch with interrupts disabled
  s390: update sampling tag after task pid change
  s390/cpum_cf: rename IBM z13/z14 counter names
  s390/dasd: fix IO error for newly defined devices
  s390/uprobes: implement arch_uretprobe_is_alive()
  s390/cio: update chpid descriptor after resource accessibility event

* acpi-watchdog:
  ACPI / watchdog: Prefer iTCO_wdt on Lenovo Z50-70

* acpi-button:
  ACPI / button: make module loadable when booted in non-ACPI mode

* acpi-video:
  ACPI / video: Only default only_lcd to true on Win8-ready _desktops_

* acpi-pm:
  ACPI / PM: Blacklist Low Power S0 Idle _DSM for ThinkPad X1 Tablet(2016)

* pm-cpufreq:
  cpufreq: brcmstb-avs-cpufreq: remove development debug support

Pull fsnotify fix from Jan Kara:
 "A fix of a fsnotify race causing panics / softlockups"

* tag 'for_v4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fsnotify: Fix fsnotify_mark_connector race

Pull SCSI fixes from James Bottomley:
 "Eight bug fixes, one spelling update and one tracepoint addition.

  The most serious is probably the mptsas write same fix because it
  means anyone using these controllers sees errors when modern
  filesystems try to issue discards"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: target: fix crash with iscsi target and dvd
  scsi: sd_zbc: Avoid that resetting a zone fails sporadically
  scsi: sd: Defer spinning up drive while SANITIZE is in progress
  scsi: megaraid_sas: Do not log an error if FW successfully initializes.
  scsi: ufs: add trace event for ufs upiu
  scsi: core: remove reference to scsi_show_extd_sense()
  scsi: mptsas: Disable WRITE SAME
  scsi: fnic: fix spelling mistake in fnic stats "Abord" -> "Abort"
  scsi: scsi_debug: IMMED related delay adjustments
  scsi: iscsi: respond to netlink with unicast when appropriate

Pull block updates from Jens Axboe:
 "I ended up sitting on this about a week longer than I wanted to, since
  we were hashing out details with a timeout change. I've now killed
  that patch, so we can flush the existing queue in due time.

  This contains:

   - Fix for an old regression, where entering the queue can be
     disturbed by a signal to the process. This can cause spurious EIO.
     Fix from Alan Jenkins.

   - cdrom information leak fix from Dan.

   - Trivial helper for testing queue FUA from Dave Chinner, part of his
     O_DIRECT FUA series.

   - Series of swim fixes from Finn that actually makes it work again.

   - Loop O_DIRECT corruption fix, which caused data corruption in
     production for us. From me.

   - BFQ crash fix from me.

   - bcache maintainer update. Michael no longer has the time to do it,
     Coly has stepped up to serve as the new maintainer.

   - blkcg locking fixes from Jiang Biao.

   - Revert of a change from this merge window from Ming, that causes an
     issue on some hardware.

   - Minor clarification doc addition from Linus Walleij"

* tag 'for-linus-20180425' of git://git.kernel.dk/linux-block: (22 commits)
  Revert "blk-mq: remove code for dealing with remapping queue"
  block: mq: Add some minor doc for core structs
  bcache: mark Coly Li as bcache maintainer
  MAINTAINERS: Remove me as maintainer of bcache
  blkcg: init root blkcg_gq under lock
  blkcg: small fix on comment in blkcg_init_queue
  blkcg: don't hold blkcg lock when deactivating policy
  block: add blk_queue_fua() helper function
  cdrom: information leak in cdrom_ioctl_media_changed()
  bfq-iosched: ensure to clear bic/bfqq pointers when preparing request
  blk-mq: start request gstate with gen 1
  block/swim: Select appropriate drive on device open
  block/swim: Fix IO error at end of medium
  block/swim: Check drive type
  block/swim: Rename macros to avoid inconsistent inverted logic
  block/swim: Don't log an error message for an invalid ioctl
  block/swim: Remove extra put_disk() call from error path
  block/swim: Fix array bounds check
  m68k/mac: Don't remap SWIM MMIO region
  loop: handle short DIO reads
  ...

Merge tag 'riscv-for-linus-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux

Pull RISC-V fixes from Palmer Dabbelt:
 "This contains three small fixes related to the RISC-V port that I'd
  like to target for 4.17-rc3:

   - a Kconfig cleanup to select DMA_DIRECT_OPS instead of redefining it
     in arch/riscv

   - the removal of asm/handle_irq.h, which doesn't exist, from our arch
     header list

   - the addition of "-no-pie" the link rules for our VDSO-related
     files, which fixes the build on systems where PIE is enabled by
     default"

* tag 'riscv-for-linus-4.17-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux:
  RISC-V: build vdso-dummy.o with -no-pie
  riscv: there is no <asm/handle_irq.h>
  riscv: select DMA_DIRECT_OPS instead of redefining it

Pull dma-mapping fixes from Christoph Hellwig:
 "A few small dma-mapping fixes for Linux 4.17-rc3:

   - don't loop to try GFP_DMA allocations if ZONE_DMA is not actually
     enabled (regression in 4.16)

   - don't try to do virt_to_page before we know we actuall have a valid
     page in dma_common_mmap

   - a comment fixup related to the above fix"

* tag 'dma-mapping-4.17-3' of git://git.infradead.org/users/hch/dma-mapping:
  dma-mapping: postpone cpu addr translation on mmap
  dma-coherent: clarify dma_mmap_from_dev_coherent documentation
  dma-direct: don't retry allocation for no-op GFP_DMA

When out of memory and we can't add ctrl vq buffers,
probe fails. Unfortunately the error handling is
out of spec: it calls del_vqs without bothering
to reset the device first.

To fix, call the full cleanup function in this case.

Cc: stable@vger.kernel.org
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Will make it reusable for error handling.

Cc: stable@vger.kernel.org
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

We now cleanup all VQs on device removal - no need
to handle the control VQ specially.

Cc: stable@vger.kernel.org
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Console driver is out of spec. The spec says:
	A driver MUST NOT decrement the available idx on a live
	virtqueue (ie. there is no way to “unexpose” buffers).
and it does exactly that by trying to detach unused buffers
without doing a device reset first.

Defer detaching the buffers until device unplug.

Of course this means we might get an interrupt for
a vq without an attached port now. Handle that by
discarding the consumed buffer.
Reported-by: NTiwei Bie <tiwei.bie@intel.com>
Fixes: b3258ff1 ("virtio: Decrement avail idx on buffer detach")
Cc: stable@vger.kernel.org
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

For cleanup it's helpful to be able to simply scan all vqs and discard
all data. Add an iterator to do that.

Cc: stable@vger.kernel.org
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

an allocated buffer doesn't need to be tied to a vq -
only vq->vdev is ever used. Pass the function the
just what it needs - the vdev.

Cc: stable@vger.kernel.org
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

This reverts commit 37c7c6c7.

Turns out some drivers(most are FC drivers) may not use managed
IRQ affinity, and has their customized .map_queues meantime, so
still keep this code for avoiding regression.
Reported-by: NLaurence Oberman <loberman@redhat.com>
Tested-by: NLaurence Oberman <loberman@redhat.com>
Tested-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Tested-by: NStefan Haberland <sth@linux.vnet.ibm.com>
Cc: Ewan Milne <emilne@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

It's been missing for a while but no one is touching that up.  Fix it.

Link: http://lkml.kernel.org/r/20180315060639.9578-1-peterx@redhat.com

CC: Ingo Molnar <mingo@kernel.org>
Cc:stable@vger.kernel.org
Fixes: 7b2c8625 ("tracing: Add NMI tracing in hwlat detector")
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Add a testcase for multiple actions with different
parameters on an event trigger, which has been fixed
by commit 192c283e93bd ("tracing: Add action comparisons
 when testing matching hist triggers").

Link: http://lkml.kernel.org/r/152292055227.15769.6327959816123227152.stgit@devboxReviewed-by: NTom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: NTom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Previous testcase redirects echo-out into /dev/null
using "&>" as below

echo "trigger-command" >> trigger &> /dev/null

But this means redirecting both stdout and stderr into
/dev/null because it is same as below

echo "trigger-command" >> trigger > /dev/null 2>&1

So ">> trigger" redirects stdout to trigger file, but
next "> /dev/null" redirects stdout to /dev/null again
and the last "2>/&1" redirects stderr to stdout (/dev/null)

This fixes it by "2> /dev/null". And also, since it
must fail, add "!" to echo command.

Link: http://lkml.kernel.org/r/152292052250.15769.12565292689264162435.stgit@devbox

Fixes: f06eec4d ("selftests: ftrace: Add inter-event hist triggers testcases")
Reviewed-by: NTom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: NTom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

File /sys/kernel/debug/kprobes/blacklist displays random addresses:

[root@s8360046 linux]# cat /sys/kernel/debug/kprobes/blacklist
0x0000000047149a90-0x00000000bfcb099a	print_type_x8
....

This breaks 'perf probe' which uses the blacklist file to prohibit
probes on certain functions by checking the address range.

Fix this by printing the correct (unhashed) address.

The file mode is read all but this is not an issue as the file
hierarchy points out:
 # ls -ld /sys/ /sys/kernel/ /sys/kernel/debug/ /sys/kernel/debug/kprobes/
	/sys/kernel/debug/kprobes/blacklist
dr-xr-xr-x 12 root root 0 Apr 19 07:56 /sys/
drwxr-xr-x  8 root root 0 Apr 19 07:56 /sys/kernel/
drwx------ 16 root root 0 Apr 19 06:56 /sys/kernel/debug/
drwxr-xr-x  2 root root 0 Apr 19 06:56 /sys/kernel/debug/kprobes/
-r--r--r--  1 root root 0 Apr 19 06:56 /sys/kernel/debug/kprobes/blacklist

Everything in and below /sys/kernel/debug is rwx to root only,
no group or others have access.

Background:
Directory /sys/kernel/debug/kprobes is created by debugfs_create_dir()
which sets the mode bits to rwxr-xr-x. Maybe change that to use the
parent's directory mode bits instead?

Link: http://lkml.kernel.org/r/20180419105556.86664-1-tmricht@linux.ibm.com

Fixes: ad67b74d ("printk: hash addresses printed with %p")
Cc: stable@vger.kernel.org
Cc: <stable@vger.kernel.org> # v4.15+
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S Miller <davem@davemloft.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: acme@kernel.org
Signed-off-by: NThomas Richter <tmricht@linux.ibm.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Kernel is crashing when user tries to record 'ftrace:function' event
with empty filter:

  # perf record -e ftrace:function --filter="" ls

  # dmesg
  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  Oops: 0000 [#1] SMP PTI
  ...
  RIP: 0010:ftrace_profile_set_filter+0x14b/0x2d0
  RSP: 0018:ffffa4a7c0da7d20 EFLAGS: 00010246
  RAX: ffffa4a7c0da7d64 RBX: 0000000000000000 RCX: 0000000000000006
  RDX: 0000000000000000 RSI: 0000000000000092 RDI: ffff8c48ffc968f0
  ...
  Call Trace:
   _perf_ioctl+0x54a/0x6b0
   ? rcu_all_qs+0x5/0x30
  ...

After patch:
  # perf record -e ftrace:function --filter="" ls
  failed to set filter "" on event ftrace:function with 22 (Invalid argument)

Also, if user tries to echo "" > filter, it used to throw an error.
This behavior got changed by commit 80765597 ("tracing: Rewrite
filter logic to be simpler and faster"). This patch restores the
behavior as a side effect:

Before patch:
  # echo "" > filter
  #

After patch:
  # echo "" > filter
  bash: echo: write error: Invalid argument
  #

Link: http://lkml.kernel.org/r/20180420150758.19787-1-ravi.bangoria@linux.ibm.com

Fixes: 80765597 ("tracing: Rewrite filter logic to be simpler and faster")
Signed-off-by: NRavi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

Arnaldo noticed that the latest kernel is missing the syscall event system
directory in x86. I bisected it down to d5a00528 ("syscalls/core,
syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()").

The system call trace events are special, as there is only one trace event
for all system calls (the raw_syscalls). But a macro that wraps the system
calls creates meta data for them that copies the name to find the system
call that maps to the system call table (the number). At boot up, it does a
kallsyms lookup of the system call table to find the function that maps to
the meta data of the system call. If it does not find a function, then that
system call is ignored.

Because the x86 system calls had "__x64_", or "__ia32_" prefixed to the
"sys" for the names, they do not match the default compare algorithm. As
this was a problem for power pc, the algorithm can be overwritten by the
architecture. The solution is to have x86 have its own algorithm to do the
compare and this brings back the system call trace events.

Link: http://lkml.kernel.org/r/20180417174128.0f3457f0@gandalf.local.homeReported-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: NDominik Brodowski <linux@dominikbrodowski.net>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Fixes: d5a00528 ("syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()")
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>