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Ahmed Zaki 63d14a4312 iavf: fix a deadlock caused by rtnl and driver's lock circular dependencies 
[ Upstream commit d1639a1731 ]

A driver's lock (crit_lock) is used to serialize all the driver's tasks.
Lockdep, however, shows a circular dependency between rtnl and
crit_lock. This happens when an ndo that already holds the rtnl requests
the driver to reset, since the reset task (in some paths) tries to grab
rtnl to either change real number of queues of update netdev features.

  [566.241851] ======================================================
  [566.241893] WARNING: possible circular locking dependency detected
  [566.241936] 6.2.14-100.fc36.x86_64+debug #1 Tainted: G           OE
  [566.241984] ------------------------------------------------------
  [566.242025] repro.sh/2604 is trying to acquire lock:
  [566.242061] ffff9280fc5ceee8 (&adapter->crit_lock){+.+.}-{3:3}, at: iavf_close+0x3c/0x240 [iavf]
  [566.242167]
               but task is already holding lock:
  [566.242209] ffffffff9976d350 (rtnl_mutex){+.+.}-{3:3}, at: iavf_remove+0x6b5/0x730 [iavf]
  [566.242300]
               which lock already depends on the new lock.

  [566.242353]
               the existing dependency chain (in reverse order) is:
  [566.242401]
               -> #1 (rtnl_mutex){+.+.}-{3:3}:
  [566.242451]        __mutex_lock+0xc1/0xbb0
  [566.242489]        iavf_init_interrupt_scheme+0x179/0x440 [iavf]
  [566.242560]        iavf_watchdog_task+0x80b/0x1400 [iavf]
  [566.242627]        process_one_work+0x2b3/0x560
  [566.242663]        worker_thread+0x4f/0x3a0
  [566.242696]        kthread+0xf2/0x120
  [566.242730]        ret_from_fork+0x29/0x50
  [566.242763]
               -> #0 (&adapter->crit_lock){+.+.}-{3:3}:
  [566.242815]        __lock_acquire+0x15ff/0x22b0
  [566.242869]        lock_acquire+0xd2/0x2c0
  [566.242901]        __mutex_lock+0xc1/0xbb0
  [566.242934]        iavf_close+0x3c/0x240 [iavf]
  [566.242997]        __dev_close_many+0xac/0x120
  [566.243036]        dev_close_many+0x8b/0x140
  [566.243071]        unregister_netdevice_many_notify+0x165/0x7c0
  [566.243116]        unregister_netdevice_queue+0xd3/0x110
  [566.243157]        iavf_remove+0x6c1/0x730 [iavf]
  [566.243217]        pci_device_remove+0x33/0xa0
  [566.243257]        device_release_driver_internal+0x1bc/0x240
  [566.243299]        pci_stop_bus_device+0x6c/0x90
  [566.243338]        pci_stop_and_remove_bus_device+0xe/0x20
  [566.243380]        pci_iov_remove_virtfn+0xd1/0x130
  [566.243417]        sriov_disable+0x34/0xe0
  [566.243448]        ice_free_vfs+0x2da/0x330 [ice]
  [566.244383]        ice_sriov_configure+0x88/0xad0 [ice]
  [566.245353]        sriov_numvfs_store+0xde/0x1d0
  [566.246156]        kernfs_fop_write_iter+0x15e/0x210
  [566.246921]        vfs_write+0x288/0x530
  [566.247671]        ksys_write+0x74/0xf0
  [566.248408]        do_syscall_64+0x58/0x80
  [566.249145]        entry_SYSCALL_64_after_hwframe+0x72/0xdc
  [566.249886]
                 other info that might help us debug this:

  [566.252014]  Possible unsafe locking scenario:

  [566.253432]        CPU0                    CPU1
  [566.254118]        ----                    ----
  [566.254800]   lock(rtnl_mutex);
  [566.255514]                                lock(&adapter->crit_lock);
  [566.256233]                                lock(rtnl_mutex);
  [566.256897]   lock(&adapter->crit_lock);
  [566.257388]
                  *** DEADLOCK ***

The deadlock can be triggered by a script that is continuously resetting
the VF adapter while doing other operations requiring RTNL, e.g:

	while :; do
		ip link set $VF up
		ethtool --set-channels $VF combined 2
		ip link set $VF down
		ip link set $VF up
		ethtool --set-channels $VF combined 4
		ip link set $VF down
	done

Any operation that triggers a reset can substitute "ethtool --set-channles"

As a fix, add a new task "finish_config" that do all the work which
needs rtnl lock. With the exception of iavf_remove(), all work that
require rtnl should be called from this task.

As for iavf_remove(), at the point where we need to call
unregister_netdevice() (and grab rtnl_lock), we make sure the finish_config
task is not running (cancel_work_sync()) to safely grab rtnl. Subsequent
finish_config work cannot restart after that since the task is guarded
by the __IAVF_IN_REMOVE_TASK bit in iavf_schedule_finish_config().

Fixes: 5ac49f3c27 ("iavf: use mutexes for locking of critical sections")
Signed-off-by: Ahmed Zaki <ahmed.zaki@intel.com>
Signed-off-by: Mateusz Palczewski <mateusz.palczewski@intel.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-07-27 08:56:58 +02:00
arch arm64: Fix HFGxTR_EL2 field naming 2023-07-27 08:56:55 +02:00
block blk-mq: fix NULL dereference on q->elevator in blk_mq_elv_switch_none 2023-07-27 08:56:45 +02:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto crypto: jitter - correct health test during initialization 2023-07-19 16:36:19 +02:00
Documentation media: uapi: Fix [GS]_ROUTING ACTIVE flag value 2023-07-23 13:54:08 +02:00
drivers iavf: fix a deadlock caused by rtnl and driver's lock circular dependencies 2023-07-27 08:56:58 +02:00
fs cifs: fix mid leak during reconnection after timeout threshold 2023-07-27 08:56:56 +02:00
include sched/psi: use kernfs polling functions for PSI trigger polling 2023-07-27 08:56:53 +02:00
init kbuild: Fix CFI failures with GCOV 2023-07-19 16:36:23 +02:00
io_uring io_uring: Fix io_uring mmap() by using architecture-provided get_unmapped_area() 2023-07-27 08:56:31 +02:00
ipc Merge branch 'work.namespace' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2023-02-24 19:20:07 -08:00
kernel kallsyms: strip LTO-only suffixes from promoted global functions 2023-07-27 08:56:54 +02:00
lib iov_iter: Mark copy_iovec_from_user() noclone 2023-07-27 08:56:53 +02:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/mlock: fix vma iterator conversion of apply_vma_lock_flags() 2023-07-27 08:56:32 +02:00
net net: sched: cls_bpf: Undo tcf_bind_filter in case of an error 2023-07-27 08:56:57 +02:00
rust Rust changes for v6.4 2023-04-30 11:20:22 -07:00
samples samples: ftrace: Save required argument registers in sample trampolines 2023-07-23 13:54:09 +02:00
scripts kallsyms: strip LTO-only suffixes from promoted global functions 2023-07-27 08:56:54 +02:00
security keys: Fix linking a duplicate key to a keyring's assoc_array 2023-07-27 08:56:32 +02:00
sound ASoC: SOF: ipc3-dtrace: uninitialized data in dfsentry_trace_filter_write() 2023-07-27 08:56:56 +02:00
tools perf build: Fix library not found error when using CSLIBS 2023-07-27 08:56:54 +02:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: Avoid illegal stage2 mapping on invalid memory slot 2023-06-22 15:14:57 -04:00
.clang-format cxl for v6.4 2023-04-30 11:51:51 -07:00
.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 *.dtso files 2023-02-26 15:28:23 +09:00
.gitignore linux-kselftest-kunit-6.4-rc1 2023-04-24 12:31:32 -07:00
.mailmap mailmap: add entries for Ben Dooks 2023-06-19 13:19:35 -07:00
.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: sctp: move Neil to CREDITS 2023-05-12 08:51:32 +01:00
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 Networking fixes for 6.4-rc8, including fixes from ipsec, bpf, 2023-06-22 17:59:51 -07:00
Makefile Linux 6.4.6 2023-07-24 18:56:41 +02:00
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.