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Ville Syrjälä ef2b11c0a3 ACPI / PM: Fix acpi_pm_notifier_lock vs flush_workqueue() deadlock commit `ff1656790b` upstream. acpi_remove_pm_notifier() ends up calling flush_workqueue() while holding acpi_pm_notifier_lock, and that same lock is taken by by the work via acpi_pm_notify_handler(). This can deadlock. To fix the problem let's split the single lock into two: one to protect the dev->wakeup between the work vs. add/remove, and another one to handle notifier installation vs. removal. After commit `a1d14934ea` "workqueue/lockdep: 'Fix' flush_work() annotation" I was able to kill the machine (Intel Braswell) very easily with 'powertop --auto-tune', runtime suspending i915, and trying to wake it up via the USB keyboard. The cases when it didn't die are presumably explained by lockdep getting disabled by something else (cpu hotplug locking issues usually). Fortunately I still got a lockdep report over netconsole (trickling in very slowly), even though the machine was otherwise practically dead: [ 112.179806] ====================================================== [ 114.670858] WARNING: possible circular locking dependency detected [ 117.155663] 4.13.0-rc6-bsw-bisect-00169-ga1d14934ea4b #119 Not tainted [ 119.658101] ------------------------------------------------------ [ 121.310242] xhci_hcd 0000:00:14.0: xHCI host not responding to stop endpoint command. [ 121.313294] xhci_hcd 0000:00:14.0: xHCI host controller not responding, assume dead [ 121.313346] xhci_hcd 0000:00:14.0: HC died; cleaning up [ 121.313485] usb 1-6: USB disconnect, device number 3 [ 121.313501] usb 1-6.2: USB disconnect, device number 4 [ 134.747383] kworker/0:2/47 is trying to acquire lock: [ 137.220790] (acpi_pm_notifier_lock){+.+.}, at: [<ffffffff813cafdf>] acpi_pm_notify_handler+0x2f/0x80 [ 139.721524] [ 139.721524] but task is already holding lock: [ 144.672922] ((&dpc->work)){+.+.}, at: [<ffffffff8109ce90>] process_one_work+0x160/0x720 [ 147.184450] [ 147.184450] which lock already depends on the new lock. [ 147.184450] [ 154.604711] [ 154.604711] the existing dependency chain (in reverse order) is: [ 159.447888] [ 159.447888] -> #2 ((&dpc->work)){+.+.}: [ 164.183486] __lock_acquire+0x1255/0x13f0 [ 166.504313] lock_acquire+0xb5/0x210 [ 168.778973] process_one_work+0x1b9/0x720 [ 171.030316] worker_thread+0x4c/0x440 [ 173.257184] kthread+0x154/0x190 [ 175.456143] ret_from_fork+0x27/0x40 [ 177.624348] [ 177.624348] -> #1 ("kacpi_notify"){+.+.}: [ 181.850351] __lock_acquire+0x1255/0x13f0 [ 183.941695] lock_acquire+0xb5/0x210 [ 186.046115] flush_workqueue+0xdd/0x510 [ 190.408153] acpi_os_wait_events_complete+0x31/0x40 [ 192.625303] acpi_remove_notify_handler+0x133/0x188 [ 194.820829] acpi_remove_pm_notifier+0x56/0x90 [ 196.989068] acpi_dev_pm_detach+0x5f/0xa0 [ 199.145866] dev_pm_domain_detach+0x27/0x30 [ 201.285614] i2c_device_probe+0x100/0x210 [ 203.411118] driver_probe_device+0x23e/0x310 [ 205.522425] __driver_attach+0xa3/0xb0 [ 207.634268] bus_for_each_dev+0x69/0xa0 [ 209.714797] driver_attach+0x1e/0x20 [ 211.778258] bus_add_driver+0x1bc/0x230 [ 213.837162] driver_register+0x60/0xe0 [ 215.868162] i2c_register_driver+0x42/0x70 [ 217.869551] 0xffffffffa0172017 [ 219.863009] do_one_initcall+0x45/0x170 [ 221.843863] do_init_module+0x5f/0x204 [ 223.817915] load_module+0x225b/0x29b0 [ 225.757234] SyS_finit_module+0xc6/0xd0 [ 227.661851] do_syscall_64+0x5c/0x120 [ 229.536819] return_from_SYSCALL_64+0x0/0x7a [ 231.392444] [ 231.392444] -> #0 (acpi_pm_notifier_lock){+.+.}: [ 235.124914] check_prev_add+0x44e/0x8a0 [ 237.024795] __lock_acquire+0x1255/0x13f0 [ 238.937351] lock_acquire+0xb5/0x210 [ 240.840799] __mutex_lock+0x75/0x940 [ 242.709517] mutex_lock_nested+0x1c/0x20 [ 244.551478] acpi_pm_notify_handler+0x2f/0x80 [ 246.382052] acpi_ev_notify_dispatch+0x44/0x5c [ 248.194412] acpi_os_execute_deferred+0x14/0x30 [ 250.003925] process_one_work+0x1ec/0x720 [ 251.803191] worker_thread+0x4c/0x440 [ 253.605307] kthread+0x154/0x190 [ 255.387498] ret_from_fork+0x27/0x40 [ 257.153175] [ 257.153175] other info that might help us debug this: [ 257.153175] [ 262.324392] Chain exists of: [ 262.324392] acpi_pm_notifier_lock --> "kacpi_notify" --> (&dpc->work) [ 262.324392] [ 267.391997] Possible unsafe locking scenario: [ 267.391997] [ 270.758262] CPU0 CPU1 [ 272.431713] ---- ---- [ 274.060756] lock((&dpc->work)); [ 275.646532] lock("kacpi_notify"); [ 277.260772] lock((&dpc->work)); [ 278.839146] lock(acpi_pm_notifier_lock); [ 280.391902] [ 280.391902] * DEADLOCK * [ 280.391902] [ 284.986385] 2 locks held by kworker/0:2/47: [ 286.524895] #0: ("kacpi_notify"){+.+.}, at: [<ffffffff8109ce90>] process_one_work+0x160/0x720 [ 288.112927] #1: ((&dpc->work)){+.+.}, at: [<ffffffff8109ce90>] process_one_work+0x160/0x720 [ 289.727725] Fixes: `c072530f39` (ACPI / PM: Revork the handling of ACPI device wakeup notifications) Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		History 2017-11-30 08:40:38 +00:00
arch	s390/disassembler: increase show_code buffer size	2017-11-30 08:40:38 +00:00
block	bio: ensure __bio_clone_fast copies bi_partno	2017-11-24 08:37:03 +01:00
certs	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
crypto	crypto: dh - Don't permit 'key' or 'g' size longer than 'p'	2017-11-21 09:49:21 +01:00
Documentation	Documentation: enforcement-statement: name updates	2017-11-05 10:21:06 -08:00
drivers	ACPI / PM: Fix acpi_pm_notifier_lock vs flush_workqueue() deadlock	2017-11-30 08:40:38 +00:00
firmware	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
fs	coda: fix 'kernel memory exposure attempt' in fsync	2017-11-24 08:37:05 +01:00
include	mm/page_alloc.c: broken deferred calculation	2017-11-24 08:37:05 +01:00
init	License cleanup: add SPDX license identifiers to some files	2017-11-02 10:04:46 -07:00
ipc	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
kernel	rcu: Fix up pending cbs check in rcu_prepare_for_idle	2017-11-24 08:37:04 +01:00
lib	KEYS: fix NULL pointer dereference during ASN.1 parsing [ver #2 ]	2017-11-09 00:38:21 +11:00
mm	mm/page_ext.c: check if page_ext is not prepared	2017-11-24 08:37:05 +01:00
net	net/sctp: Always set scope_id in sctp_inet6_skb_msgname	2017-11-24 08:37:03 +01:00
samples	License cleanup: add SPDX license identifiers to some files	2017-11-02 10:04:46 -07:00
scripts	scripts: add leaking_addresses.pl	2017-11-06 11:46:42 -08:00
security	ima: do not update security.ima if appraisal status is not INTEGRITY_PASS	2017-11-24 08:37:03 +01:00
sound	sound fixes for 4.14	2017-11-09 09:58:11 -08:00
tools	selftests/x86/protection_keys: Fix syscall NR redefinition warnings	2017-11-21 09:49:22 +01:00
usr	initramfs: fix initramfs rebuilds w/ compression after disabling	2017-11-03 07:39:19 -07:00
virt	Fixes for interrupt controller emulation in ARM/ARM64 and x86, plus a one-liner	2017-11-04 11:44:55 -07:00
.cocciconfig	scripts: add Linux .cocciconfig for coccinelle	2016-07-22 12:13:39 +02:00
.get_maintainer.ignore	Add hch to .get_maintainer.ignore	2015-08-21 14:30:10 -07:00
.gitattributes	.gitattributes: set git diff driver for C source code files	2016-10-07 18:46:30 -07:00
.gitignore	kbuild: Add support to generate LLVM assembly files	2017-04-25 08:13:52 +09:00
.mailmap	.mailmap: Add Maciej W. Rozycki's Imagination e-mail address	2017-11-10 12:16:15 -08:00
COPYING	[PATCH] update FSF address in COPYING	2005-09-10 10:06:29 -07:00
CREDITS	MAINTAINERS: update TPM driver infrastructure changes	2017-11-09 17:58:40 -08:00
Kbuild	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
Kconfig	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
MAINTAINERS	Merge branch 'akpm' (patches from Andrew)	2017-11-09 18:26:51 -08:00
Makefile	Linux 4.14.2	2017-11-24 08:37:05 +01:00
README	README: add a new README file, pointing to the Documentation/	2016-10-24 08:12:35 -02:00

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.