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Filename Latest commit message Latest commit date
Thomas Gleixner 2d1e38f566 kprobes: Cure hotplug lock ordering issues
Converting the cpu hotplug locking to a percpu rwsem unearthed hidden lock
ordering problems.

There is a wide range of locks involved in this: kprobe_mutex,
jump_label_mutex, ftrace_lock, text_mutex, event_mutex, module_mutex,
func_hash->regex_lock and a gazillion of lock order permutations with
nested get_online_cpus() calls.

Some of those permutations are potential deadlocks even with the current
nesting hotplug locking scheme, but they can't be discovered by lockdep.

The conversion of the hotplug locking to a percpu rwsem requires to prevent
nested locking, so it's required to take the hotplug rwsem early in the
call chain and establish a proper lock order.

After quite some analysis and going down the wrong road severa times the
following lock order has been chosen:

kprobe_mutex -> cpus_rwsem -> jump_label_mutex -> text_mutex

For kprobes which hook on an ftrace function trace point, it's required to
drop cpus_rwsem before calling into the ftrace code to avoid a deadlock on
the func_hash->regex_lock.

[ Steven: Ftrace interaction fixes ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Link: http://lkml.kernel.org/r/20170524081549.104864779@linutronix.de
2017-05-26 10:10:45 +02:00
arch jump_label: Reorder hotplug lock and jump_label_lock 2017-05-26 10:10:45 +02:00
block Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 2017-05-12 15:43:10 -07:00
certs
crypto
Documentation Staging driver fixes for 4.12-rc2 2017-05-20 09:02:27 -07:00
drivers ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus() 2017-05-26 10:10:44 +02:00
firmware
fs Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-05-20 16:12:30 -07:00
include perf/tracing/cpuhotplug: Fix locking order 2017-05-26 10:10:44 +02:00
init
ipc
kernel kprobes: Cure hotplug lock ordering issues 2017-05-26 10:10:45 +02:00
lib
mm mm: vmscan: scan until it finds eligible pages 2017-05-12 15:57:16 -07:00
net xen: fixes for 4.12 rc2 2017-05-19 15:06:48 -07:00
samples samples/bpf: run cleanup routines when receiving SIGTERM 2017-05-11 21:43:30 -04:00
scripts DeviceTree fixes for 4.12-rc: 2017-05-19 15:03:24 -07:00
security
sound drm/i915: Fix runtime PM for LPE audio 2017-05-15 14:44:11 +03:00
tools This fixes a bug caused by not cleaning up the new instance unique triggers 2017-05-20 23:39:03 -07:00
usr
virt KVM: arm/arm64: Hold slots_lock when unregistering kvm io bus devices 2017-05-18 11:18:16 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Staging driver fixes for 4.12-rc2 2017-05-20 09:02:27 -07:00
Makefile Linux 4.12-rc2 2017-05-21 19:30:23 -07:00
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.