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Filename Latest commit message Latest commit date
Vishal Verma ae03fa7ad3 ACPI: NFIT: fix a potential deadlock during NFIT teardown
[ Upstream commit fb6df4366f86dd252bfa3049edffa52d17e7b895 ]

Lockdep reports that acpi_nfit_shutdown() may deadlock against an
opportune acpi_nfit_scrub(). acpi_nfit_scrub () is run from inside a
'work' and therefore has already acquired workqueue-internal locks. It
also acquiires acpi_desc->init_mutex. acpi_nfit_shutdown() first
acquires init_mutex, and was subsequently attempting to cancel any
pending workqueue items. This reversed locking order causes a potential
deadlock:

    ======================================================
    WARNING: possible circular locking dependency detected
    6.2.0-rc3 #116 Tainted: G           O     N
    ------------------------------------------------------
    libndctl/1958 is trying to acquire lock:
    ffff888129b461c0 ((work_completion)(&(&acpi_desc->dwork)->work)){+.+.}-{0:0}, at: __flush_work+0x43/0x450

    but task is already holding lock:
    ffff888129b460e8 (&acpi_desc->init_mutex){+.+.}-{3:3}, at: acpi_nfit_shutdown+0x87/0xd0 [nfit]

    which lock already depends on the new lock.

    ...

    Possible unsafe locking scenario:

          CPU0                    CPU1
          ----                    ----
     lock(&acpi_desc->init_mutex);
                                  lock((work_completion)(&(&acpi_desc->dwork)->work));
                                  lock(&acpi_desc->init_mutex);
     lock((work_completion)(&(&acpi_desc->dwork)->work));

    *** DEADLOCK ***

Since the workqueue manipulation is protected by its own internal locking,
the cancellation of pending work doesn't need to be done under
acpi_desc->init_mutex. Move cancel_delayed_work_sync() outside the
init_mutex to fix the deadlock. Any work that starts after
acpi_nfit_shutdown() drops the lock will see ARS_CANCEL, and the
cancel_delayed_work_sync() will safely flush it out.

Reported-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Link: https://lore.kernel.org/r/20230112-acpi_nfit_lockdep-v1-1-660be4dd10be@intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-03 11:41:47 +01:00
arch ARM: dts: rockchip: add power-domains property to dp node on rk3288 2023-03-03 11:41:47 +01:00
block blk-cgroup: fix missing pd_online_fn() while activating policy 2023-02-06 07:52:48 +01:00
certs
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2023-01-18 11:41:19 +01:00
Documentation docs: Fix path paste-o for /sys/kernel/warn_count 2023-02-06 07:52:50 +01:00
drivers ACPI: NFIT: fix a potential deadlock during NFIT teardown 2023-03-03 11:41:47 +01:00
fs ext4: Fix function prototype mismatch for ext4_feat_ktype 2023-02-25 11:53:27 +01:00
include uaccess: Add speculation barrier to copy_from_user() 2023-02-25 11:53:26 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel bpf: add missing header file include 2023-02-25 11:53:27 +01:00
lib uaccess: Add speculation barrier to copy_from_user() 2023-02-25 11:53:26 +01:00
LICENSES
mm Revert "mm: Always release pages to the buddy allocator in memblock_free_late()." 2023-02-22 12:50:39 +01:00
net Revert "net/sched: taprio: make qdisc_leaf() see the per-netdev-queue pfifo child qdiscs" 2023-02-25 11:53:27 +01:00
samples samples: vfio-mdev: Fix missing pci_disable_device() in mdpy_fb_probe() 2023-01-18 11:41:26 +01:00
scripts ftrace/scripts: Update the instructions for ftrace-bisect.sh 2023-02-06 07:52:44 +01:00
security tomoyo: fix broken dependency on *.conf.default 2023-02-06 07:52:35 +01:00
sound ASoC: SOF: Intel: hda-dai: fix possible stream_tag leak 2023-02-22 12:50:42 +01:00
tools Revert "ipv4: Fix incorrect route flushing when source address is deleted" 2023-02-22 12:50:38 +01:00
usr
virt KVM: arm64: vgic: Fix exit condition in scan_its_table() 2022-10-29 10:20:35 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS net/phy/mdio-i2c: Move header file to include/linux/mdio 2023-02-06 07:52:46 +01:00
Makefile Linux 5.4.233 2023-02-25 11:53:27 +01:00
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.