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Filename Latest commit message Latest commit date
Alistair Popple 2b74e2a9b3 powerpc/powernv/npu: Fix deadlock in mmio_invalidate()
When sending TLB invalidates to the NPU we need to send extra flushes due
to a hardware issue. The original implementation would lock the all the
ATSD MMIO registers sequentially before unlocking and relocking each of
them sequentially to do the extra flush.

This introduced a deadlock as it is possible for one thread to hold one
ATSD register whilst waiting for another register to be freed while the
other thread is holding that register waiting for the one in the first
thread to be freed.

For example if there are two threads and two ATSD registers:

  Thread A	Thread B
  ----------------------
  Acquire 1
  Acquire 2
  Release 1	Acquire 1
  Wait 1	Wait 2

Both threads will be stuck waiting to acquire a register resulting in an
RCU stall warning or soft lockup.

This patch solves the deadlock by refactoring the code to ensure registers
are not released between flushes and to ensure all registers are either
acquired or released together and in order.

Fixes: bbd5ff50af ("powerpc/powernv/npu-dma: Add explicit flush when sending an ATSD")
Signed-off-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2018-03-13 15:50:29 +11:00
arch powerpc/powernv/npu: Fix deadlock in mmio_invalidate() 2018-03-13 15:50:29 +11:00
block for-linus-20180302 2018-03-02 09:35:36 -08:00
certs
crypto
Documentation Merge branch 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-03-04 12:12:48 -08:00
drivers cxl: Check if PSL data-cache is available before issue flush request 2018-03-13 15:50:26 +11:00
firmware
fs for-4.16-rc3-tag 2018-03-04 11:04:27 -08:00
include Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 2018-03-03 14:32:00 -08:00
init
ipc
kernel Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-03-04 11:34:49 -08:00
lib A single fix for a memory leak regression in the dma-debug code. 2018-02-28 11:13:08 -08:00
LICENSES
mm
net libceph, ceph: avoid memory leak when specifying same option several times 2018-02-26 16:19:30 +01:00
samples - do not build samples when cross compiling (Michal Hocko) 2018-02-27 10:39:29 -08:00
scripts Kbuild fixes for v4.16 2018-03-03 10:37:01 -08:00
security integrity/security: fix digsig.c build error with header file 2018-02-22 20:09:08 -08:00
sound ALSA: x86: Fix potential crash at error path 2018-02-28 08:46:00 +01:00
tools selftests/powerpc: Skip tm-unavailable if TM is not enabled 2018-03-13 15:10:15 +11:00
usr
virt KVM: mmu: Fix overlap between public and private memslots 2018-02-24 01:43:36 +01:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Kbuild fixes for v4.16 2018-03-03 10:37:01 -08:00
Makefile Linux 4.16-rc4 2018-03-04 14:54:11 -08:00
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.