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Srinivas Pandruvada 79175b6ee6 platform/x86: ISST: Fix possible circular locking dependency detected [ Upstream commit `17da2d5f93` ] As reported: [ 256.104522] ====================================================== [ 256.113783] WARNING: possible circular locking dependency detected [ 256.120093] 5.16.0-rc6-yocto-standard+ #99 Not tainted [ 256.125362] ------------------------------------------------------ [ 256.131673] intel-speed-sel/844 is trying to acquire lock: [ 256.137290] ffffffffc036f0d0 (punit_misc_dev_lock){+.+.}-{3:3}, at: isst_if_open+0x18/0x90 [isst_if_common] [ 256.147171] [ 256.147171] but task is already holding lock: [ 256.153135] ffffffff8ee7cb50 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x2a/0x170 [ 256.160407] [ 256.160407] which lock already depends on the new lock. [ 256.160407] [ 256.168712] [ 256.168712] the existing dependency chain (in reverse order) is: [ 256.176327] [ 256.176327] -> #1 (misc_mtx){+.+.}-{3:3}: [ 256.181946] lock_acquire+0x1e6/0x330 [ 256.186265] __mutex_lock+0x9b/0x9b0 [ 256.190497] mutex_lock_nested+0x1b/0x20 [ 256.195075] misc_register+0x32/0x1a0 [ 256.199390] isst_if_cdev_register+0x65/0x180 [isst_if_common] [ 256.205878] isst_if_probe+0x144/0x16e [isst_if_mmio] ... [ 256.241976] [ 256.241976] -> #0 (punit_misc_dev_lock){+.+.}-{3:3}: [ 256.248552] validate_chain+0xbc6/0x1750 [ 256.253131] __lock_acquire+0x88c/0xc10 [ 256.257618] lock_acquire+0x1e6/0x330 [ 256.261933] __mutex_lock+0x9b/0x9b0 [ 256.266165] mutex_lock_nested+0x1b/0x20 [ 256.270739] isst_if_open+0x18/0x90 [isst_if_common] [ 256.276356] misc_open+0x100/0x170 [ 256.280409] chrdev_open+0xa5/0x1e0 ... The call sequence suggested that misc_device /dev file can be opened before misc device is yet to be registered, which is done only once. Here punit_misc_dev_lock was used as common lock, to protect the registration by multiple ISST HW drivers, one time setup, prevent duplicate registry of misc device and prevent load/unload when device is open. We can split into locks: - One which just prevent duplicate call to misc_register() and one time setup. Also never call again if the misc_register() failed or required one time setup is failed. This lock is not shared with any misc device callbacks. - The other lock protects registry, load and unload of HW drivers. Sequence in isst_if_cdev_register() - Register callbacks under punit_misc_dev_open_lock - Call isst_misc_reg() which registers misc_device on the first registry which is under punit_misc_dev_reg_lock, which is not shared with callbacks. Sequence in isst_if_cdev_unregister Just opposite of isst_if_cdev_register Reported-and-tested-by: Liwei Song <liwei.song@windriver.com> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Link: https://lore.kernel.org/r/20220112022521.54669-1-srinivas.pandruvada@linux.intel.com Reviewed-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-02-23 12:00:58 +01:00
arch	parisc: Add ioread64_lo_hi() and iowrite64_lo_hi()	2022-02-23 12:00:58 +01:00
block	block: bio-integrity: Advance seed correctly for larger interval sizes	2022-02-08 18:30:35 +01:00
certs	certs: Trigger creation of RSA module signing key if it's not an RSA key	2021-09-15 09:50:29 +02:00
crypto	crypto: api - Move cryptomgr soft dependency into algapi	2022-02-11 09:09:03 +01:00
Documentation	ARM: dts: Fix timer regression for beagleboard revision c	2022-02-16 12:54:22 +01:00
drivers	platform/x86: ISST: Fix possible circular locking dependency detected	2022-02-23 12:00:58 +01:00
fs	btrfs: send: in case of IO error log it	2022-02-23 12:00:58 +01:00
include	can: isotp: add SF_BROADCAST support for functional addressing	2022-02-23 12:00:56 +01:00
init	bpf: Add kconfig knob for disabling unpriv bpf by default	2022-01-05 12:40:34 +01:00
ipc	shm: extend forced shm destroy to support objects from several IPC nses	2021-12-01 09:19:10 +01:00
kernel	rcu: Do not report strict GPs for outgoing CPUs	2022-02-23 12:00:56 +01:00
lib	lib/test_meminit: destroy cache in kmem_cache_alloc_bulk() test	2022-01-27 10:54:36 +01:00
LICENSES	LICENSES/deprecated: add Zlib license text	2020-09-16 14:33:49 +02:00
mm	mm: don't try to NUMA-migrate COW pages that have other uses	2022-02-23 12:00:57 +01:00
net	can: isotp: add SF_BROADCAST support for functional addressing	2022-02-23 12:00:56 +01:00
samples	ftrace/samples: Add missing prototypes direct functions	2022-01-11 15:25:00 +01:00
scripts	Makefile.extrawarn: Move -Wunaligned-access to W=1	2022-02-16 12:54:30 +01:00
security	ima: Do not print policy rule with inactive LSM labels	2022-02-16 12:54:16 +01:00
sound	ASoC: max9759: fix underflow in speaker_gain_control_put()	2022-02-08 18:30:38 +01:00
tools	selftests: nft_concat_range: add test for reload with no element add/del	2022-02-08 18:30:41 +01:00
usr	usr/include/Makefile: add linux/nfc.h to the compile-test coverage	2022-02-01 17:25:48 +01:00
virt	KVM: eventfd: Fix false positive RCU usage warning	2022-02-16 12:54:20 +01:00
.clang-format	RDMA 5.10 pull request	2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore	kbuild: generate Module.symvers only when vmlinux exists	2021-05-19 10:12:59 +02:00
.mailmap	mailmap: add two more addresses of Uwe Kleine-König	2020-12-06 10:19:07 -08:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: Move Jason Cooper to CREDITS	2020-11-30 10:20:34 +01:00
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	MAINTAINERS: adjust GCC PLUGINS after gcc-plugin.sh removal	2021-12-14 11:32:46 +01:00
Makefile	Linux 5.10.101	2022-02-16 12:54:31 +01:00
README

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.