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Padmanabha Srinivasaiah 993db6da4a staging: vc04_services: Fix RCU dereference check [ Upstream commit `0cea730cac` ] In service_callback path RCU dereferenced pointer struct vchiq_service need to be accessed inside rcu read-critical section. Also userdata/user_service part of vchiq_service is accessed around different synchronization mechanism, getting an extra reference to a pointer keeps sematics simpler and avoids prolonged graceperiod. Accessing vchiq_service with rcu_read_[lock/unlock] fixes below issue. [ 32.201659] ============================= [ 32.201664] WARNING: suspicious RCU usage [ 32.201670] 5.15.11-rt24-v8+ #3 Not tainted [ 32.201680] ----------------------------- [ 32.201685] drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h:529 suspicious rcu_dereference_check() usage! [ 32.201695] [ 32.201695] other info that might help us debug this: [ 32.201695] [ 32.201700] [ 32.201700] rcu_scheduler_active = 2, debug_locks = 1 [ 32.201708] no locks held by vchiq-slot/0/98. [ 32.201715] [ 32.201715] stack backtrace: [ 32.201723] CPU: 1 PID: 98 Comm: vchiq-slot/0 Not tainted 5.15.11-rt24-v8+ #3 [ 32.201733] Hardware name: Raspberry Pi 4 Model B Rev 1.4 (DT) [ 32.201739] Call trace: [ 32.201742] dump_backtrace+0x0/0x1b8 [ 32.201772] show_stack+0x20/0x30 [ 32.201784] dump_stack_lvl+0x8c/0xb8 [ 32.201799] dump_stack+0x18/0x34 [ 32.201808] lockdep_rcu_suspicious+0xe4/0xf8 [ 32.201817] service_callback+0x124/0x400 [ 32.201830] slot_handler_func+0xf60/0x1e20 [ 32.201839] kthread+0x19c/0x1a8 [ 32.201849] ret_from_fork+0x10/0x20 Tested-by: Stefan Wahren <stefan.wahren@i2se.com> Signed-off-by: Padmanabha Srinivasaiah <treasure4paddy@gmail.com> Link: https://lore.kernel.org/r/20211231195406.5479-1-treasure4paddy@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2022-02-23 12:03:17 +01:00
arch	ARM: OMAP2+: adjust the location of put_device() call in omapdss_init_of	2022-02-23 12:03:17 +01:00
block	block: fix surprise removal for drivers calling blk_set_queue_dying	2022-02-23 12:03:15 +01:00
certs	certs: Add support for using elliptic curve keys for signing modules	2021-08-23 19:55:42 +03:00
crypto	crypto: api - Move cryptomgr soft dependency into algapi	2022-02-11 09:10:26 +01:00
Documentation	ARM: dts: Fix timer regression for beagleboard revision c	2022-02-16 12:56:21 +01:00
drivers	staging: vc04_services: Fix RCU dereference check	2022-02-23 12:03:17 +01:00
fs	NFS: Do not report writeback errors in nfs_getattr()	2022-02-23 12:03:15 +01:00
include	block: fix surprise removal for drivers calling blk_set_queue_dying	2022-02-23 12:03:15 +01:00
init	init: make unknown command line param message clearer	2021-11-18 19:17:11 +01:00
ipc	ipc/sem: do not sleep with a spin lock held	2022-02-08 18:34:03 +01:00
kernel	gcc-plugins/stackleak: Use noinstr in favor of notrace	2022-02-23 12:03:07 +01:00
lib	lib/test_meminit: destroy cache in kmem_cache_alloc_bulk() test	2022-01-27 11:05:44 +01:00
LICENSES	LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes"	2021-07-15 06:31:24 -06:00
mm	mm: don't try to NUMA-migrate COW pages that have other uses	2022-02-23 12:03:03 +01:00
net	tipc: fix wrong notification node addresses	2022-02-23 12:03:14 +01:00
samples	samples: bpf: Fix 'unknown warning group' build warning on Clang	2022-01-27 11:03:29 +01:00
scripts	Makefile.extrawarn: Move -Wunaligned-access to W=1	2022-02-16 12:56:39 +01:00
security	ima: Do not print policy rule with inactive LSM labels	2022-02-16 12:56:04 +01:00
sound	ASoC: qcom: Actually clear DMA interrupt register for HDMI	2022-02-23 12:03:15 +01:00
tools	selftests/exec: Add non-regular to TEST_GEN_PROGS	2022-02-23 12:03:13 +01:00
usr	usr/include/Makefile: add linux/nfc.h to the compile-test coverage	2022-02-01 17:27:15 +01:00
virt	KVM: eventfd: Fix false positive RCU usage warning	2022-02-16 12:56:16 +01:00
.clang-format	clang-format: Update with the latest for_each macro list	2021-05-12 23:32:39 +02:00
.cocciconfig	scripts: add Linux .cocciconfig for coccinelle	2016-07-22 12:13:39 +02:00
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes	.gitattributes: use 'dts' diff driver for dts files	2019-12-04 19:44:11 -08:00
.gitignore	.gitignore: ignore only top-level modules.builtin	2021-05-02 00:43:35 +09:00
.mailmap	mailmap: add Andrej Shadura	2021-10-18 20:22:03 -10:00
COPYING	COPYING: state that all contributions really are covered by this file	2020-02-10 13:32:20 -08:00
CREDITS	MAINTAINERS: Move Daniel Drake to credits	2021-09-21 08:34:58 +03:00
Kbuild	kbuild: rename hostprogs-y/always to hostprogs/always-y	2020-02-04 01:53:07 +09:00
Kconfig	kbuild: ensure full rebuild when the compiler is updated	2020-05-12 13:28:33 +09:00
MAINTAINERS	drm fixes for 5.15 final	2021-10-28 12:17:01 -07:00
Makefile	Linux 5.15.24	2022-02-16 12:56:41 +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.