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Russell King (Oracle) 291016c5bd net: phylib: get rid of unnecessary locking 
[ Upstream commit f4b47a2e94 ]

The locking in phy_probe() and phy_remove() does very little to prevent
any races with e.g. phy_attach_direct(), but instead causes lockdep ABBA
warnings. Remove it.

======================================================
WARNING: possible circular locking dependency detected
6.2.0-dirty #1108 Tainted: G        W   E
------------------------------------------------------
ip/415 is trying to acquire lock:
ffff5c268f81ef50 (&dev->lock){+.+.}-{3:3}, at: phy_attach_direct+0x17c/0x3a0 [libphy]

but task is already holding lock:
ffffaef6496cb518 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x154/0x560

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (rtnl_mutex){+.+.}-{3:3}:
       __lock_acquire+0x35c/0x6c0
       lock_acquire.part.0+0xcc/0x220
       lock_acquire+0x68/0x84
       __mutex_lock+0x8c/0x414
       mutex_lock_nested+0x34/0x40
       rtnl_lock+0x24/0x30
       sfp_bus_add_upstream+0x34/0x150
       phy_sfp_probe+0x4c/0x94 [libphy]
       mv3310_probe+0x148/0x184 [marvell10g]
       phy_probe+0x8c/0x200 [libphy]
       call_driver_probe+0xbc/0x15c
       really_probe+0xc0/0x320
       __driver_probe_device+0x84/0x120
       driver_probe_device+0x44/0x120
       __device_attach_driver+0xc4/0x160
       bus_for_each_drv+0x80/0xe0
       __device_attach+0xb0/0x1f0
       device_initial_probe+0x1c/0x2c
       bus_probe_device+0xa4/0xb0
       device_add+0x360/0x53c
       phy_device_register+0x60/0xa4 [libphy]
       fwnode_mdiobus_phy_device_register+0xc0/0x190 [fwnode_mdio]
       fwnode_mdiobus_register_phy+0x160/0xd80 [fwnode_mdio]
       of_mdiobus_register+0x140/0x340 [of_mdio]
       orion_mdio_probe+0x298/0x3c0 [mvmdio]
       platform_probe+0x70/0xe0
       call_driver_probe+0x34/0x15c
       really_probe+0xc0/0x320
       __driver_probe_device+0x84/0x120
       driver_probe_device+0x44/0x120
       __driver_attach+0x104/0x210
       bus_for_each_dev+0x78/0xdc
       driver_attach+0x2c/0x3c
       bus_add_driver+0x184/0x240
       driver_register+0x80/0x13c
       __platform_driver_register+0x30/0x3c
       xt_compat_calc_jump+0x28/0xa4 [x_tables]
       do_one_initcall+0x50/0x1b0
       do_init_module+0x50/0x1fc
       load_module+0x684/0x744
       __do_sys_finit_module+0xc4/0x140
       __arm64_sys_finit_module+0x28/0x34
       invoke_syscall+0x50/0x120
       el0_svc_common.constprop.0+0x6c/0x1b0
       do_el0_svc+0x34/0x44
       el0_svc+0x48/0xf0
       el0t_64_sync_handler+0xb8/0xc0
       el0t_64_sync+0x1a0/0x1a4

-> #0 (&dev->lock){+.+.}-{3:3}:
       check_prev_add+0xb4/0xc80
       validate_chain+0x414/0x47c
       __lock_acquire+0x35c/0x6c0
       lock_acquire.part.0+0xcc/0x220
       lock_acquire+0x68/0x84
       __mutex_lock+0x8c/0x414
       mutex_lock_nested+0x34/0x40
       phy_attach_direct+0x17c/0x3a0 [libphy]
       phylink_fwnode_phy_connect.part.0+0x70/0xe4 [phylink]
       phylink_fwnode_phy_connect+0x48/0x60 [phylink]
       mvpp2_open+0xec/0x2e0 [mvpp2]
       __dev_open+0x104/0x214
       __dev_change_flags+0x1d4/0x254
       dev_change_flags+0x2c/0x7c
       do_setlink+0x254/0xa50
       __rtnl_newlink+0x430/0x514
       rtnl_newlink+0x58/0x8c
       rtnetlink_rcv_msg+0x17c/0x560
       netlink_rcv_skb+0x64/0x150
       rtnetlink_rcv+0x20/0x30
       netlink_unicast+0x1d4/0x2b4
       netlink_sendmsg+0x1a4/0x400
       ____sys_sendmsg+0x228/0x290
       ___sys_sendmsg+0x88/0xec
       __sys_sendmsg+0x70/0xd0
       __arm64_sys_sendmsg+0x2c/0x40
       invoke_syscall+0x50/0x120
       el0_svc_common.constprop.0+0x6c/0x1b0
       do_el0_svc+0x34/0x44
       el0_svc+0x48/0xf0
       el0t_64_sync_handler+0xb8/0xc0
       el0t_64_sync+0x1a0/0x1a4

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(rtnl_mutex);
                               lock(&dev->lock);
                               lock(rtnl_mutex);
  lock(&dev->lock);

 *** DEADLOCK ***

Fixes: 298e54fa81 ("net: phy: add core phylib sfp support")
Reported-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-03-17 08:57:56 +01:00
arch powerpc: dts: t1040rdb: fix compatible string for Rev A boards 2023-03-17 08:57:52 +01:00
block block: fix scan partition for exclusively open device again 2023-03-17 08:57:50 +01:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-01-31 17:53:01 +09:00
crypto crypto: rsa-pkcs1pad - Use akcipher_request_complete 2023-03-10 09:28:18 +01:00
Documentation usb: gadget: uvc: Make bSourceID read/write 2023-03-11 13:50:44 +01:00
drivers net: phylib: get rid of unnecessary locking 2023-03-17 08:57:56 +01:00
fs ext4: Fix possible corruption when moving a directory 2023-03-17 08:57:51 +01:00
include bus: mhi: ep: Change state_lock to mutex 2023-03-17 08:57:49 +01:00
init Kbuild fixes for v6.2 (3rd) 2023-01-21 10:56:37 -08:00
io_uring io_uring/uring_cmd: ensure that device supports IOPOLL 2023-03-17 08:57:45 +01:00
ipc Non-MM patches for 6.2-rc1. 2022-12-12 17:28:58 -08:00
kernel fork: allow CLONE_NEWTIME in clone3 flags 2023-03-17 08:57:46 +01:00
lib cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG 2023-03-10 09:29:06 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm memory tier: release the new_memtier in find_create_memory_tier() 2023-03-10 09:29:50 +01:00
net bpf, sockmap: Fix an infinite loop error when len is 0 in tcp_bpf_recvmsg_parser() 2023-03-17 08:57:54 +01:00
rust rust: print: avoid evaluating arguments in pr_* macros in unsafe blocks 2023-01-16 00:54:35 +01:00
samples ftrace: Export ftrace_free_filter() to modules 2023-01-24 11:20:58 -05:00
scripts gcc-plugins: drop -std=gnu++11 to fix GCC 13 build 2023-03-10 09:29:11 +01:00
security ima: Align ima_file_mmap() parameters with mmap_file LSM hook 2023-03-10 09:29:36 +01:00
sound ASoC: mediatek: mt8195: add missing initialization 2023-03-11 13:50:37 +01:00
tools perf stat: Fix counting when initial delay configured 2023-03-17 08:57:53 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt KVM: Register /dev/kvm as the _very_ last thing during initialization 2023-03-10 09:29:33 +01:00
.clang-format iommufd for 6.2 2022-12-14 09:15:43 -08:00
.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 .gitignore: ignore *.rpm 2022-12-30 17:22:14 +09:00
.mailmap 12 hotfixes, mostly against mm/. Five of these fixes are cc:stable. 2023-02-13 14:09:20 -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: update SCTP maintainers 2023-02-02 11:35:33 -08:00
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 audit: update the mailing list in MAINTAINERS 2023-02-25 11:13:29 +01:00
Makefile Linux 6.2.6 2023-03-13 10:26:43 +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.