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Rik van Riel 2ff6ddf19c x86/mm/tlb: Leave lazy TLB mode at page table free time
Andy discovered that speculative memory accesses while in lazy
TLB mode can crash a system, when a CPU tries to dereference a
speculative access using memory contents that used to be valid
page table memory, but have since been reused for something else
and point into la-la land.

The latter problem can be prevented in two ways. The first is to
always send a TLB shootdown IPI to CPUs in lazy TLB mode, while
the second one is to only send the TLB shootdown at page table
freeing time.

The second should result in fewer IPIs, since operationgs like
mprotect and madvise are very common with some workloads, but
do not involve page table freeing. Also, on munmap, batching
of page table freeing covers much larger ranges of virtual
memory than the batching of unmapped user pages.

Tested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Rik van Riel <riel@surriel.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: efault@gmx.de
Cc: kernel-team@fb.com
Cc: luto@kernel.org
Link: http://lkml.kernel.org/r/20180716190337.26133-3-riel@surriel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-07-17 09:35:31 +02:00
arch x86/mm/tlb: Leave lazy TLB mode at page table free time 2018-07-17 09:35:31 +02:00
block for-linus-20180713 2018-07-14 12:28:00 -07:00
certs
crypto
Documentation Kbuild fixes for v4.18 (2nd) 2018-07-13 12:15:12 -07:00
drivers mm: Allocate the mm_cpumask (mm->cpu_bitmap[]) dynamically based on nr_cpu_ids 2018-07-17 09:35:30 +02:00
firmware
fs reiserfs: fix buffer overflow with long warning messages 2018-07-14 11:11:10 -07:00
include x86/mm/tlb: Leave lazy TLB mode at page table free time 2018-07-17 09:35:31 +02:00
init
ipc
kernel mm: Allocate the mm_cpumask (mm->cpu_bitmap[]) dynamically based on nr_cpu_ids 2018-07-17 09:35:30 +02:00
lib Linux 4.18-rc5 2018-07-17 09:31:30 +02:00
LICENSES
mm x86/mm/tlb: Leave lazy TLB mode at page table free time 2018-07-17 09:35:31 +02:00
net net/9p/client.c: put refcount of trans_mod in error case in parse_opts() 2018-07-14 11:11:09 -07:00
samples sample: vfio-mdev: avoid deadlock in mdev_access() 2018-07-11 13:22:41 -06:00
scripts checkpatch: fix duplicate invalid vsprintf pointer extension '%p<foo>' messages 2018-07-14 11:11:10 -07:00
security
sound ALSA: hda/ca0132: Update a pci quirk device name 2018-07-12 09:18:31 +02:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-07-13 13:33:09 -07:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Char/Misc fixes for 4.18-rc5 2018-07-11 10:10:50 -07:00
Makefile Linux 4.18-rc5 2018-07-15 12:49:31 -07:00
README

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

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

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.