forge/linux-uconsole: Linux kernel for uConsole

Linux kernel for uConsole

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Hans de Goede 70bb4bf9fd i2c-cht-wc: Fix lockdep warning [ Upstream commit `232219b9a4` ] When the kernel is build with lockdep support and the i2c-cht-wc driver is used, the following warning is shown: [ 66.674334] ====================================================== [ 66.674337] WARNING: possible circular locking dependency detected [ 66.674340] 5.3.0-rc4+ #83 Not tainted [ 66.674342] ------------------------------------------------------ [ 66.674345] systemd-udevd/1232 is trying to acquire lock: [ 66.674349] 00000000a74dab07 (intel_soc_pmic_chtwc:167:(&cht_wc_regmap_cfg)->lock){+.+.}, at: regmap_write+0x31/0x70 [ 66.674360] but task is already holding lock: [ 66.674362] 00000000d44a85b7 (i2c_register_adapter){+.+.}, at: i2c_smbus_xfer+0x49/0xf0 [ 66.674370] which lock already depends on the new lock. [ 66.674371] the existing dependency chain (in reverse order) is: [ 66.674374] -> #1 (i2c_register_adapter){+.+.}: [ 66.674381] rt_mutex_lock_nested+0x46/0x60 [ 66.674384] i2c_smbus_xfer+0x49/0xf0 [ 66.674387] i2c_smbus_read_byte_data+0x45/0x70 [ 66.674391] cht_wc_byte_reg_read+0x35/0x50 [ 66.674394] _regmap_read+0x63/0x1a0 [ 66.674396] _regmap_update_bits+0xa8/0xe0 [ 66.674399] regmap_update_bits_base+0x63/0xa0 [ 66.674403] regmap_irq_update_bits.isra.0+0x3b/0x50 [ 66.674406] regmap_add_irq_chip+0x592/0x7a0 [ 66.674409] devm_regmap_add_irq_chip+0x89/0xed [ 66.674412] cht_wc_probe+0x102/0x158 [ 66.674415] i2c_device_probe+0x95/0x250 [ 66.674419] really_probe+0xf3/0x380 [ 66.674422] driver_probe_device+0x59/0xd0 [ 66.674425] device_driver_attach+0x53/0x60 [ 66.674428] __driver_attach+0x92/0x150 [ 66.674431] bus_for_each_dev+0x7d/0xc0 [ 66.674434] bus_add_driver+0x14d/0x1f0 [ 66.674437] driver_register+0x6d/0xb0 [ 66.674440] i2c_register_driver+0x45/0x80 [ 66.674445] do_one_initcall+0x60/0x2f4 [ 66.674450] kernel_init_freeable+0x20d/0x2b4 [ 66.674453] kernel_init+0xa/0x10c [ 66.674457] ret_from_fork+0x3a/0x50 [ 66.674459] -> #0 (intel_soc_pmic_chtwc:167:(&cht_wc_regmap_cfg)->lock){+.+.}: [ 66.674465] __lock_acquire+0xe07/0x1930 [ 66.674468] lock_acquire+0x9d/0x1a0 [ 66.674472] __mutex_lock+0xa8/0x9a0 [ 66.674474] regmap_write+0x31/0x70 [ 66.674480] cht_wc_i2c_adap_smbus_xfer+0x72/0x240 [i2c_cht_wc] [ 66.674483] __i2c_smbus_xfer+0x1a3/0x640 [ 66.674486] i2c_smbus_xfer+0x67/0xf0 [ 66.674489] i2c_smbus_read_byte_data+0x45/0x70 [ 66.674494] bq24190_probe+0x26b/0x410 [bq24190_charger] [ 66.674497] i2c_device_probe+0x189/0x250 [ 66.674500] really_probe+0xf3/0x380 [ 66.674503] driver_probe_device+0x59/0xd0 [ 66.674506] device_driver_attach+0x53/0x60 [ 66.674509] __driver_attach+0x92/0x150 [ 66.674512] bus_for_each_dev+0x7d/0xc0 [ 66.674515] bus_add_driver+0x14d/0x1f0 [ 66.674518] driver_register+0x6d/0xb0 [ 66.674521] i2c_register_driver+0x45/0x80 [ 66.674524] do_one_initcall+0x60/0x2f4 [ 66.674528] do_init_module+0x5c/0x230 [ 66.674531] load_module+0x2707/0x2a20 [ 66.674534] __do_sys_init_module+0x188/0x1b0 [ 66.674537] do_syscall_64+0x5c/0xb0 [ 66.674541] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.674543] other info that might help us debug this: [ 66.674545] Possible unsafe locking scenario: [ 66.674547] CPU0 CPU1 [ 66.674548] ---- ---- [ 66.674550] lock(i2c_register_adapter); [ 66.674553] lock(intel_soc_pmic_chtwc:167:(&cht_wc_regmap_cfg)->lock); [ 66.674556] lock(i2c_register_adapter); [ 66.674559] lock(intel_soc_pmic_chtwc:167:(&cht_wc_regmap_cfg)->lock); [ 66.674561] * DEADLOCK * The problem is that the CHT Whiskey Cove PMIC's builtin i2c-adapter is itself a part of an i2c-client (the PMIC). This means that transfers done through it take adapter->bus_lock twice, once for the parent i2c-adapter and once for its own bus_lock. Lockdep does not like this nested locking. To make lockdep happy in the case of busses with muxes, the i2c-core's i2c_adapter_lock_bus function calls: rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter)); But i2c_adapter_depth only works when the direct parent of the adapter is another adapter, as it is only meant for muxes. In this case there is an i2c-client and MFD instantiated platform_device in the parent->child chain between the 2 devices. This commit overrides the default i2c_lock_operations, passing a hardcoded depth of 1 to rt_mutex_lock_nested, making lockdep happy. Note that if there were to be a mux attached to the i2c-wc-cht adapter, this would break things again since the i2c-mux code expects the root-adapter to have a locking depth of 0. But the i2c-wc-cht adapter always has only 1 client directly attached in the form of the charger IC paired with the CHT Whiskey Cove PMIC. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Sasha Levin <sashal@kernel.org>		2019-10-07 18:57:08 +02:00
arch	MIPS: tlbex: Explicitly cast _PAGE_NO_EXEC to a boolean	2019-10-07 18:57:07 +02:00
block	block: fix null pointer dereference in blk_mq_rq_timed_out()	2019-10-05 13:10:08 +02:00
certs	export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR()	2018-08-22 23:21:44 +09:00
crypto	crypto: chacha20poly1305 - fix atomic sleep when using async algorithm	2019-07-26 09:14:19 +02:00
Documentation	ovl: fix regression caused by overlapping layers detection	2019-09-21 07:17:14 +02:00
drivers	i2c-cht-wc: Fix lockdep warning	2019-10-07 18:57:08 +02:00
firmware	kbuild: remove all dummy assignments to obj-	2017-11-18 11:46:06 +09:00
fs	ext4: fix potential use after free after remounting with noblock_validity	2019-10-07 18:57:05 +02:00
include	scsi: core: Reduce memory required for SCSI logging	2019-10-07 18:57:04 +02:00
init	initramfs: don't free a non-existent initrd	2019-10-01 08:26:09 +02:00
ipc	ipc/mqueue.c: only perform resource calculation if user valid	2019-08-06 19:06:52 +02:00
kernel	alarmtimer: Use EOPNOTSUPP instead of ENOTSUPP	2019-10-05 13:10:07 +02:00
lib	lib: logic_pio: Add logic_pio_unregister_range()	2019-09-06 10:22:19 +02:00
LICENSES	LICENSES: Remove CC-BY-SA-4.0 license text	2018-10-18 11:28:50 +02:00
mm	mm/compaction.c: clear total_{migrate,free}_scanned before scanning a new zone	2019-10-05 13:10:13 +02:00
net	cfg80211: Purge frame registrations on iftype change	2019-10-05 13:10:10 +02:00
samples	samples, bpf: suppress compiler warning	2019-07-14 08:11:04 +02:00
scripts	randstruct: Check member structs in is_pure_ops_struct()	2019-10-05 13:10:02 +02:00
security	keys: Fix missing null pointer check in request_key_auth_describe()	2019-09-21 07:17:13 +02:00
sound	ASoC: Intel: Fix use of potentially uninitialized variable	2019-10-05 13:10:06 +02:00
tools	libtraceevent: Change users plugin directory	2019-10-05 13:09:53 +02:00
usr	initramfs: move gen_initramfs_list.sh from scripts/ to usr/	2018-08-22 23:21:44 +09:00
virt	KVM: coalesced_mmio: add bounds checking	2019-09-21 07:16:44 +02:00
.clang-format	clang-format: Set IndentWrappedFunctionNames false	2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes	.gitattributes: set git diff driver for C source code files	2016-10-07 18:46:30 -07:00
.gitignore	Kbuild updates for v4.17 (2nd)	2018-04-15 17:21:30 -07:00
.mailmap	libnvdimm-for-4.19_misc	2018-08-25 18:13:10 -07:00
COPYING	COPYING: use the new text with points to the license files	2018-03-23 12:41:45 -06:00
CREDITS	9p: remove Ron Minnich from MAINTAINERS	2018-08-17 16:20:26 -07:00
Kbuild	Kbuild updates for v4.15	2017-11-17 17:45:29 -08:00
Kconfig	kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt	2018-08-02 08:06:55 +09:00
MAINTAINERS	platform/x86: Add Intel AtomISP2 dummy / power-management driver	2019-04-20 09:16:02 +02:00
Makefile	Linux 4.19.77	2019-10-05 13:10:13 +02:00
README	Docs: Added a pointer to the formatted docs to README	2018-03-21 09:02:53 -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.
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.