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Cristian Marussi 5362263b0c firmware: arm_scmi: Fix virtio channels cleanup on shutdown 
[ Upstream commit e325285de2 ]

When unloading the SCMI core stack module, configured to use the virtio
SCMI transport, LOCKDEP reports the splat down below about unsafe locks
dependencies.

In order to avoid this possible unsafe locking scenario call upfront
virtio_break_device() before getting hold of vioch->lock.

=====================================================
 WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
 6.1.0-00067-g6b934395ba07-dirty #4 Not tainted
 -----------------------------------------------------
 rmmod/307 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
 ffff000080c510e0 (&dev->vqs_list_lock){+.+.}-{3:3}, at: virtio_break_device+0x28/0x68

 and this task is already holding:
 ffff00008288ada0 (&channels[i].lock){-.-.}-{3:3}, at: virtio_chan_free+0x60/0x168 [scmi_module]

 which would create a new lock dependency:
  (&channels[i].lock){-.-.}-{3:3} -> (&dev->vqs_list_lock){+.+.}-{3:3}

 but this new dependency connects a HARDIRQ-irq-safe lock:
  (&channels[i].lock){-.-.}-{3:3}

 ... which became HARDIRQ-irq-safe at:
   lock_acquire+0x128/0x398
   _raw_spin_lock_irqsave+0x78/0x140
   scmi_vio_complete_cb+0xb4/0x3b8 [scmi_module]
   vring_interrupt+0x84/0x120
   vm_interrupt+0x94/0xe8
   __handle_irq_event_percpu+0xb4/0x3d8
   handle_irq_event_percpu+0x20/0x68
   handle_irq_event+0x50/0xb0
   handle_fasteoi_irq+0xac/0x138
   generic_handle_domain_irq+0x34/0x50
   gic_handle_irq+0xa0/0xd8
   call_on_irq_stack+0x2c/0x54
   do_interrupt_handler+0x8c/0x90
   el1_interrupt+0x40/0x78
   el1h_64_irq_handler+0x18/0x28
   el1h_64_irq+0x64/0x68
   _raw_write_unlock_irq+0x48/0x80
   ep_start_scan+0xf0/0x128
   do_epoll_wait+0x390/0x858
   do_compat_epoll_pwait.part.34+0x1c/0xb8
   __arm64_sys_epoll_pwait+0x80/0xd0
   invoke_syscall+0x4c/0x110
   el0_svc_common.constprop.3+0x98/0x120
   do_el0_svc+0x34/0xd0
   el0_svc+0x40/0x98
   el0t_64_sync_handler+0x98/0xc0
   el0t_64_sync+0x170/0x174

 to a HARDIRQ-irq-unsafe lock:
  (&dev->vqs_list_lock){+.+.}-{3:3}

 ... which became HARDIRQ-irq-unsafe at:
 ...
   lock_acquire+0x128/0x398
   _raw_spin_lock+0x58/0x70
   __vring_new_virtqueue+0x130/0x1c0
   vring_create_virtqueue+0xc4/0x2b8
   vm_find_vqs+0x20c/0x430
   init_vq+0x308/0x390
   virtblk_probe+0x114/0x9b0
   virtio_dev_probe+0x1a4/0x248
   really_probe+0xc8/0x3a8
   __driver_probe_device+0x84/0x190
   driver_probe_device+0x44/0x110
   __driver_attach+0x104/0x1e8
   bus_for_each_dev+0x7c/0xd0
   driver_attach+0x2c/0x38
   bus_add_driver+0x1e4/0x258
   driver_register+0x6c/0x128
   register_virtio_driver+0x2c/0x48
   virtio_blk_init+0x70/0xac
   do_one_initcall+0x84/0x420
   kernel_init_freeable+0x2d0/0x340
   kernel_init+0x2c/0x138
   ret_from_fork+0x10/0x20

 other info that might help us debug this:

  Possible interrupt unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&dev->vqs_list_lock);
                                local_irq_disable();
                                lock(&channels[i].lock);
                                lock(&dev->vqs_list_lock);
   <Interrupt>
     lock(&channels[i].lock);

  *** DEADLOCK ***
================

Fixes: 42e90eb53b ("firmware: arm_scmi: Add a virtio channel refcount")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Link: https://lore.kernel.org/r/20221222183823.518856-6-cristian.marussi@arm.com
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-02-01 08:34:06 +01:00
arch arm64: dts: imx8mm-venice-gw7901: fix USB2 controller OC polarity 2023-02-01 08:34:05 +01:00
block block: mq-deadline: Rename deadline_is_seq_writes() 2023-01-24 07:24:44 +01:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2022-12-31 13:32:34 +01:00
Documentation docs: Fix path paste-o for /sys/kernel/warn_count 2023-01-24 07:24:41 +01:00
drivers firmware: arm_scmi: Fix virtio channels cleanup on shutdown 2023-02-01 08:34:06 +01:00
fs fs/ntfs3: Fix attr_punch_hole() null pointer derenference 2023-01-24 07:24:41 +01:00
include panic: Consolidate open-coded panic_on_warn checks 2023-01-24 07:24:41 +01:00
init gcc: disable -Warray-bounds for gcc-11 too 2023-01-14 10:33:43 +01:00
io_uring io_uring/poll: don't reissue in case of poll race on multishot request 2023-01-24 07:24:37 +01:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel exit: Use READ_ONCE() for all oops/warn limit reads 2023-01-24 07:24:41 +01:00
lib panic: Consolidate open-coded panic_on_warn checks 2023-01-24 07:24:41 +01:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm panic: Consolidate open-coded panic_on_warn checks 2023-01-24 07:24:41 +01:00
net Revert "wifi: mac80211: fix memory leak in ieee80211_if_add()" 2023-01-24 07:24:44 +01:00
rust Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2022-12-31 13:32:42 +01:00
scripts - Handle different output of readelf on different distros running 2022-11-27 12:08:17 -08:00
security device_cgroup: Roll back to original exceptions after copy failure 2023-01-07 11:11:56 +01:00
sound ALSA: usb-audio: Fix possible NULL pointer dereference in snd_usb_pcm_has_fixed_rate() 2023-01-18 11:58:32 +01:00
tools selftests: mptcp: userspace: validate v4-v6 subflows mix 2023-01-24 07:24:37 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt Merge branch 'kvm-dwmw2-fixes' into HEAD 2022-11-23 18:59:45 -05:00
.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 panic: Expose "warn_count" to sysfs 2023-01-24 07:24:41 +01:00
Makefile Linux 6.1.8 2023-01-24 07:24:44 +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.