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13 August 2024, 17:29:01 UTC
Revision e2c631ba75a7e727e8db0a9d30a06bfd434adb3a authored by Peter Zijlstra on 05 September 2018, 08:41:58 UTC, committed by Thomas Gleixner on 06 September 2018, 21:38:35 UTC 
clocksource: Revert "Remove kthread"
 
I turns out that the silly spawn kthread from worker was actually needed.

clocksource_watchdog_kthread() cannot be called directly from
clocksource_watchdog_work(), because clocksource_select() calls
timekeeping_notify() which uses stop_machine(). One cannot use
stop_machine() from a workqueue() due lock inversions wrt CPU hotplug.

Revert the patch but add a comment that explain why we jump through such
apparently silly hoops.

Fixes: 7197e77abcb6 ("clocksource: Remove kthread")
Reported-by: Siegfried Metz <frame@mailbox.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Tested-by: Kevin Shanahan <kevin@shanahan.id.au>
Tested-by: viktor_jaegerskuepper@freenet.de
Tested-by: Siegfried Metz <frame@mailbox.org>
Cc: rafael.j.wysocki@intel.com
Cc: len.brown@intel.com
Cc: diego.viola@gmail.com
Cc: rui.zhang@intel.com
Cc: bjorn.andersson@linaro.org
Link: https://lkml.kernel.org/r/20180905084158.GR24124@hirez.programming.kicks-ass.net
1 parent c43c5e9
Raw File
Tip revision: e2c631ba75a7e727e8db0a9d30a06bfd434adb3a authored by Peter Zijlstra on 05 September 2018, 08:41:58 UTC
clocksource: Revert "Remove kthread"
Tip revision: e2c631b
Kconfig 
# SPDX-License-Identifier: GPL-2.0
#
# For a description of the syntax of this configuration file,
# see Documentation/kbuild/kconfig-language.txt.
#
mainmenu "Linux/$(ARCH) $(KERNELVERSION) Kernel Configuration"

comment "Compiler: $(CC_VERSION_TEXT)"

source "scripts/Kconfig.include"

source "init/Kconfig"

source "kernel/Kconfig.freezer"

source "fs/Kconfig.binfmt"

source "mm/Kconfig"

source "net/Kconfig"

source "drivers/Kconfig"

source "fs/Kconfig"

source "security/Kconfig"

source "crypto/Kconfig"

source "lib/Kconfig"

source "lib/Kconfig.debug"
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