linux

mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-10-09 18:15:49 +00:00

No description

C 96.9%
Assembly 0.9%
Rust 0.6%
Shell 0.6%
Python 0.5%
Other 0.3%

Find a file

Alexander Sverdlin 105d29fa8d net: dsa: lan9303: consequently nested-lock physical MDIO commit `5a22fbcc10` upstream. When LAN9303 is MDIO-connected two callchains exist into mdio->bus->write(): 1. switch ports 1&2 ("physical" PHYs): virtual (switch-internal) MDIO bus (lan9303_switch_ops->phy_{read\|write})-> lan9303_mdio_phy_{read\|write} -> mdiobus_{read\|write}_nested 2. LAN9303 virtual PHY: virtual MDIO bus (lan9303_phy_{read\|write}) -> lan9303_virt_phy_reg_{read\|write} -> regmap -> lan9303_mdio_{read\|write} If the latter functions just take mutex_lock(&sw_dev->device->bus->mdio_lock) it triggers a LOCKDEP false-positive splat. It's false-positive because the first mdio_lock in the second callchain above belongs to virtual MDIO bus, the second mdio_lock belongs to physical MDIO bus. Consequent annotation in lan9303_mdio_{read\|write} as nested lock (similar to lan9303_mdio_phy_{read\|write}, it's the same physical MDIO bus) prevents the following splat: WARNING: possible circular locking dependency detected 5.15.71 #1 Not tainted ------------------------------------------------------ kworker/u4:3/609 is trying to acquire lock: ffff000011531c68 (lan9303_mdio:131:(&lan9303_mdio_regmap_config)->lock){+.+.}-{3:3}, at: regmap_lock_mutex but task is already holding lock: ffff0000114c44d8 (&bus->mdio_lock){+.+.}-{3:3}, at: mdiobus_read which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&bus->mdio_lock){+.+.}-{3:3}: lock_acquire __mutex_lock mutex_lock_nested lan9303_mdio_read _regmap_read regmap_read lan9303_probe lan9303_mdio_probe mdio_probe really_probe __driver_probe_device driver_probe_device __device_attach_driver bus_for_each_drv __device_attach device_initial_probe bus_probe_device deferred_probe_work_func process_one_work worker_thread kthread ret_from_fork -> #0 (lan9303_mdio:131:(&lan9303_mdio_regmap_config)->lock){+.+.}-{3:3}: __lock_acquire lock_acquire.part.0 lock_acquire __mutex_lock mutex_lock_nested regmap_lock_mutex regmap_read lan9303_phy_read dsa_slave_phy_read __mdiobus_read mdiobus_read get_phy_device mdiobus_scan __mdiobus_register dsa_register_switch lan9303_probe lan9303_mdio_probe mdio_probe really_probe __driver_probe_device driver_probe_device __device_attach_driver bus_for_each_drv __device_attach device_initial_probe bus_probe_device deferred_probe_work_func process_one_work worker_thread kthread ret_from_fork other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&bus->mdio_lock); lock(lan9303_mdio:131:(&lan9303_mdio_regmap_config)->lock); lock(&bus->mdio_lock); lock(lan9303_mdio:131:(&lan9303_mdio_regmap_config)->lock); * DEADLOCK * 5 locks held by kworker/u4:3/609: #0: ffff000002842938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work #1: ffff80000bacbd60 (deferred_probe_work){+.+.}-{0:0}, at: process_one_work #2: ffff000007645178 (&dev->mutex){....}-{3:3}, at: __device_attach #3: ffff8000096e6e78 (dsa2_mutex){+.+.}-{3:3}, at: dsa_register_switch #4: ffff0000114c44d8 (&bus->mdio_lock){+.+.}-{3:3}, at: mdiobus_read stack backtrace: CPU: 1 PID: 609 Comm: kworker/u4:3 Not tainted 5.15.71 #1 Workqueue: events_unbound deferred_probe_work_func Call trace: dump_backtrace show_stack dump_stack_lvl dump_stack print_circular_bug check_noncircular __lock_acquire lock_acquire.part.0 lock_acquire __mutex_lock mutex_lock_nested regmap_lock_mutex regmap_read lan9303_phy_read dsa_slave_phy_read __mdiobus_read mdiobus_read get_phy_device mdiobus_scan __mdiobus_register dsa_register_switch lan9303_probe lan9303_mdio_probe ... Cc: stable@vger.kernel.org Fixes: `dc70058315` ("net: dsa: LAN9303: add MDIO managed mode support") Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://lore.kernel.org/r/20231027065741.534971-1-alexander.sverdlin@siemens.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		History 2023-11-28 17:07:18 +00:00
arch	parisc/pgtable: Do not drop upper 5 address bits of physical address	2023-11-28 17:07:14 +00:00
block	blk-core: use pr_warn_ratelimited() in bio_check_ro()	2023-11-20 11:52:17 +01:00
certs	certs: Fix build error when PKCS#11 URI contains semicolon	2023-02-09 11:28:11 +01:00
crypto	crypto: pcrypt - Fix hungtask for PADATA_RESET	2023-11-28 17:06:58 +00:00
Documentation	smp,csd: Throw an error if a CSD lock is stuck for too long	2023-11-28 17:06:55 +00:00
drivers	net: dsa: lan9303: consequently nested-lock physical MDIO	2023-11-28 17:07:18 +00:00
fs	btrfs: zoned: wait for data BG to be finished on direct IO allocation	2023-11-28 17:07:15 +00:00
include	net: ethtool: Fix documentation of ethtool_sprintf()	2023-11-28 17:07:18 +00:00
init	proc: sysctl: prevent aliased sysctls from getting passed to init	2023-11-28 17:07:08 +00:00
io_uring	io_uring/net: ensure socket is marked connected on connect retry	2023-11-20 11:52:18 +01:00
ipc	ipc: fix memory leak in init_mqueue_fs()	2022-12-31 13:32:01 +01:00
kernel	tracing: Have the user copy of synthetic event address use correct context	2023-11-28 17:07:13 +00:00
lib	lib/generic-radix-tree.c: Don't overflow in peek()	2023-11-28 17:06:54 +00:00
LICENSES	LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers	2021-12-16 14:33:10 +01:00
mm	mm/memory_hotplug: use pfn math in place of direct struct page manipulation	2023-11-28 17:07:14 +00:00
net	Revert ncsi: Propagate carrier gain/loss events to the NCSI controller	2023-11-28 17:07:18 +00:00
rust	rust: allocator: Prevent mis-aligned allocation	2023-08-11 12:08:18 +02:00
samples	fprobe: Pass entry_data to handlers	2023-10-25 12:03:12 +02:00
scripts	randstruct: Fix gcc-plugin performance mode to stay in group	2023-11-28 17:07:07 +00:00
security	ima: detect changes to the backing overlay file	2023-11-28 17:07:12 +00:00
sound	ALSA: hda/realtek: Add quirks for HP Laptops	2023-11-28 17:07:16 +00:00
tools	cxl/region: Fix x1 root-decoder granularity calculations	2023-11-28 17:07:18 +00:00
usr	usr/gen_init_cpio.c: remove unnecessary -1 values from int file	2022-10-03 14:21:44 -07:00
virt	kvm/vfio: ensure kvg instance stays around in kvm_vfio_group_add()	2023-09-13 09:42:46 +02:00
.clang-format	inet: ping: use hlist_nulls rcu iterator during lookup	2022-12-01 12:42:46 +01:00
.cocciconfig	scripts: add Linux .cocciconfig for coccinelle	2016-07-22 12:13:39 +02:00
.get_maintainer.ignore	get_maintainer: add Alan to .get_maintainer.ignore	2022-08-20 15:17:44 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	Kbuild: add Rust support	2022-09-28 09:02:20 +02:00
.mailmap	9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address	2022-12-10 17:10:52 -08:00
.rustfmt.toml	rust: add `.rustfmt.toml`	2022-09-28 09:02:20 +02:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: Remove Michal Marek from Kbuild maintainers	2022-11-16 14:53:00 +09:00
Kbuild	Kbuild updates for v6.1	2022-10-10 12:00:45 -07:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	devlink: move code to a dedicated directory	2023-08-30 16:11:00 +02:00
Makefile	Linux 6.1.63	2023-11-20 11:52:19 +01:00
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.