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James Clark c45b2835e7 coresight: Fix loss of connection info when a module is unloaded
child_fwnode should be a read only property based on the DT or ACPI. If
it's cleared on the parent device when a child is unloaded, then when
the child is loaded again the connection won't be remade.

child_dev should be cleared instead which signifies that the connection
should be remade when the child_fwnode registers a new coresight_device.

Similarly the reference count shouldn't be decremented as long as the
parent device exists. The correct place to drop the reference is in
coresight_release_platform_data() which is already done.

Reproducible on Juno with the following steps:

  # load all coresight modules.
  $ cd /sys/bus/coresight/devices/
  $ echo 1 > tmc_etr0/enable_sink
  $ echo 1 > etm0/enable_source
  # Works fine ^

  $ echo 0 > etm0/enable_source
  $ rmmod coresight-funnel
  $ modprobe coresight-funnel
  $ echo 1 > etm0/enable_source
  -bash: echo: write error: Invalid argument

Fixes: 37ea1ffddf ("coresight: Use fwnode handle instead of device names")
Fixes: 2af89ebacf ("coresight: Clear the connection field properly")
Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230425143542.2305069-2-james.clark@arm.com
2023-06-05 15:46:45 +01:00
arch A single fix for x86: 2023-05-28 07:42:05 -04:00
block block: make bio_check_eod work for zero sized devices 2023-05-24 08:19:26 -06:00
certs KEYS: Add missing function documentation 2023-04-24 16:15:52 +03:00
crypto This push fixes the following problems: 2023-05-07 10:57:14 -07:00
Documentation devres: Provide krealloc_array 2023-05-30 21:07:15 +01:00
drivers coresight: Fix loss of connection info when a module is unloaded 2023-06-05 15:46:45 +01:00
fs for-6.4-rc3-tag 2023-05-26 13:21:38 -07:00
include devres: Provide krealloc_array 2023-05-30 21:07:15 +01:00
init Objtool changes for v6.4: 2023-04-28 14:02:54 -07:00
io_uring io_uring: unlock sqd->lock before sq thread release CPU 2023-05-25 09:30:13 -06:00
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 Two fixes for debugobjects: 2023-05-28 07:15:33 -04:00
lib Two fixes for debugobjects: 2023-05-28 07:15:33 -04:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: fix zswap writeback race condition 2023-05-17 15:24:33 -07:00
net Networking fixes for 6.4-rc4, including fixes from bluetooth and bpf 2023-05-25 10:55:26 -07:00
rust Rust changes for v6.4 2023-04-30 11:20:22 -07:00
samples samples/bpf: Drop unnecessary fallthrough 2023-05-16 19:44:05 +02:00
scripts Locking changes in v6.4: 2023-05-05 12:56:55 -07:00
security integrity-v6.4 2023-04-29 10:11:32 -07:00
sound ALSA: hda/realtek: Enable headset onLenovo M70/M90 2023-05-24 14:18:59 +02:00
tools cxl fixes for v6.4-rc4 2023-05-26 17:45:24 -07:00
usr initramfs: Check negative timestamp to prevent broken cpio archive 2023-04-16 17:37:01 +09:00
virt KVM: Fix vcpu_array[0] races 2023-05-19 13:56:26 -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 Nikolay Aleksandrov 2023-05-17 09:35:05 +01:00
.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 ARM: SoC fixes for 6.4 2023-05-26 16:17:56 -07:00
Makefile Linux 6.4-rc4 2023-05-28 07:49:00 -04:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.