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Stephen Boyd 6ec9351809 drm/msm/kms: Make a lock_class_key for each crtc mutex 
Lockdep complains about an AA deadlock when rebooting the device.

base-commit: 19c329f680

============================================
WARNING: possible recursive locking detected
5.4.91 #1 Not tainted
--------------------------------------------
reboot/5213 is trying to acquire lock:
ffffff80d13391b0 (&kms->commit_lock[i]){+.+.}, at: lock_crtcs+0x60/0xa4

but task is already holding lock:
ffffff80d1339110 (&kms->commit_lock[i]){+.+.}, at: lock_crtcs+0x60/0xa4

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(&kms->commit_lock[i]);
lock(&kms->commit_lock[i]);

*** DEADLOCK ***

May be due to missing lock nesting notation

6 locks held by reboot/5213:
__arm64_sys_reboot+0x148/0x2a0
device_shutdown+0x10c/0x2c4
drm_atomic_helper_shutdown+0x48/0xfc
modeset_lock+0x120/0x24c
lock_crtcs+0x60/0xa4

stack backtrace:
CPU: 4 PID: 5213 Comm: reboot Not tainted 5.4.91 #1
Hardware name: Google Pompom (rev1) with LTE (DT)
Call trace:
dump_backtrace+0x0/0x1dc
show_stack+0x24/0x30
dump_stack+0xfc/0x1a8
__lock_acquire+0xcd0/0x22b8
lock_acquire+0x1ec/0x240
__mutex_lock_common+0xe0/0xc84
mutex_lock_nested+0x48/0x58
lock_crtcs+0x60/0xa4
msm_atomic_commit_tail+0x348/0x570
commit_tail+0xdc/0x178
drm_atomic_helper_commit+0x160/0x168
drm_atomic_commit+0x68/0x80

This is because lockdep thinks all the locks taken in lock_crtcs() are
the same lock, when they actually aren't. That's because we call
mutex_init() in msm_kms_init() and that assigns one static key for every
lock initialized in this loop. Let's allocate a dynamic number of
lock_class_keys and assign them to each lock so that lockdep can figure
out an AA deadlock isn't possible here.

Fixes: b3d91800d9 ("drm/msm: Fix race condition in msm driver with async layer updates")
Cc: Krishna Manikandan <mkrishn@codeaurora.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
 		2021-01-31 11:34:36 -08:00
Documentation Merge branch 'akpm' (patches from Andrew) 2021-01-24 12:16:34 -08:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
arch Cleanup and warning fixes. 2021-01-24 13:52:02 -08:00
block block-5.11-2021-01-10 2021-01-10 12:53:08 -08:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto X.509: Fix crash caused by NULL pointer 2021-01-20 11:33:51 -08:00
drivers drm/msm/kms: Make a lock_class_key for each crtc mutex 2021-01-31 11:34:36 -08:00
fs io_uring-5.11-2021-01-24 2021-01-24 12:30:14 -08:00
include block-5.11-2021-01-24 2021-01-24 12:24:35 -08:00
init Revert "init/console: Use ttynull as a fallback when there is no console" 2021-01-08 11:02:18 -08:00
ipc Merge branch 'akpm' (patches from Andrew) 2020-12-15 12:53:37 -08:00
kernel - Fix a kernel panic in mips-cpu due to invalid irq domain hierarchy. 2021-01-24 10:24:20 -08:00
lib ubsan: disable unsigned-overflow check for i386 2021-01-24 10:34:52 -08:00
mm mm/highmem: prepare for overriding set_pte_at() 2021-01-24 10:34:52 -08:00
net A patch to zero out sensitive cryptographic data and two minor cleanups 2021-01-22 13:47:25 -08:00
samples ARM: SoC drivers for v5.11 2020-12-16 16:38:41 -08:00
scripts Kbuild fixes for v5.11 2021-01-10 13:24:55 -08:00
security dump_common_audit_data(): fix racy accesses to ->d_name 2021-01-16 15:11:35 -05:00
sound ALSA: usb-audio: Fix hw constraints dependencies 2021-01-20 21:46:45 +01:00
tools - Adjust objtool to handle a recent binutils change to not generate unused 2021-01-24 10:17:03 -08:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt x86: 2021-01-08 15:06:02 -08:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap MAINTAINERS: Update my email address 2021-01-15 23:55:16 +01:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: dccp: move Gerrit Renker to CREDITS 2021-01-14 10:53:49 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2021-01-24 12:16:34 -08:00
Makefile Linux 5.11-rc5 2021-01-24 16:47:14 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.

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.