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641649f31e
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Dan Williams 641649f31e nvdimm: Fix firmware activation deadlock scenarios 
[ Upstream commit e6829d1bd3 ]

Lockdep reports the following deadlock scenarios for CXL root device
power-management, device_prepare(), operations, and device_shutdown()
operations for 'nd_region' devices:

 Chain exists of:
   &nvdimm_region_key --> &nvdimm_bus->reconfig_mutex --> system_transition_mutex

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(system_transition_mutex);
                                lock(&nvdimm_bus->reconfig_mutex);
                                lock(system_transition_mutex);
   lock(&nvdimm_region_key);

 Chain exists of:
   &cxl_nvdimm_bridge_key --> acpi_scan_lock --> &cxl_root_key

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&cxl_root_key);
                                lock(acpi_scan_lock);
                                lock(&cxl_root_key);
   lock(&cxl_nvdimm_bridge_key);

These stem from holding nvdimm_bus_lock() over hibernate_quiet_exec()
which walks the entire system device topology taking device_lock() along
the way. The nvdimm_bus_lock() is protecting against unregistration,
multiple simultaneous ops callers, and preventing activate_show() from
racing activate_store(). For the first 2, the lock is redundant.
Unregistration already flushes all ops users, and sysfs already prevents
multiple threads to be active in an ops handler at the same time. For
the last userspace should already be waiting for its last
activate_store() to complete, and does not need activate_show() to flush
the write side, so this lock usage can be deleted in these attributes.

Fixes: 48001ea50d ("PM, libnvdimm: Add runtime firmware activation support")
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/165074883800.4116052.10737040861825806582.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-09 10:21:15 +02:00
arch powerpc/fadump: fix PT_LOAD segment for boot memory area 2022-06-09 10:21:15 +02:00
block block-map: add __GFP_ZERO flag for alloc_page in function bio_copy_kern 2022-05-12 12:25:45 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:50:29 +02:00
crypto crypto: ecrdsa - Fix incorrect use of vli_cmp 2022-06-06 08:42:43 +02:00
Documentation spi: qcom-qspi: Add minItems to interconnect-names 2022-06-09 10:20:59 +02:00
drivers nvdimm: Fix firmware activation deadlock scenarios 2022-06-09 10:21:15 +02:00
fs ext4: reject the 'commit' option on ext2 filesystems 2022-06-09 10:21:10 +02:00
include scsi: fcoe: Fix Wstringop-overflow warnings in fcoe_wwn_from_mac() 2022-06-09 10:21:15 +02:00
init random: handle latent entropy and command line from random_init() 2022-05-30 09:33:44 +02:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:19:10 +01:00
kernel sched/fair: Fix cfs_rq_clock_pelt() for throttled cfs_rq 2022-06-09 10:21:02 +02:00
lib lib/crypto: add prompts back to crypto libraries 2022-06-06 08:42:42 +02:00
LICENSES
mm zsmalloc: fix races between asynchronous zspage free and page migration 2022-06-06 08:42:43 +02:00
net net/smc: postpone sk_refcnt increment in connect() 2022-06-09 10:21:12 +02:00
samples samples/bpf, xdpsock: Fix race when running for fix duration of time 2022-04-08 14:40:21 +02:00
scripts scripts/faddr2line: Fix overlapping text section failures 2022-06-09 10:21:08 +02:00
security lsm,selinux: pass flowi_common instead of flowi to the LSM hooks 2022-06-09 10:21:09 +02:00
sound ASoC: max98090: Move check for invalid values before casting in max98090_put_enab_tlv() 2022-06-09 10:21:11 +02:00
tools kselftest/cgroup: fix test_stress.sh to use OUTPUT dir 2022-06-09 10:21:07 +02:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2022-02-01 17:25:48 +01:00
virt KVM: Prevent module exit until all VMs are freed 2022-04-08 14:40:38 +02:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore kbuild: generate Module.symvers only when vmlinux exists 2021-05-19 10:12:59 +02:00
.mailmap mailmap: add two more addresses of Uwe Kleine-König 2020-12-06 10:19:07 -08:00
COPYING
CREDITS MAINTAINERS: Move Jason Cooper to CREDITS 2020-11-30 10:20:34 +01:00
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: add git tree for random.c 2022-05-30 09:33:24 +02:00
Makefile Linux 5.10.120 2022-06-06 08:42:45 +02:00
README

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.