kernel_optimize_test/arch/powerpc
Valentin Schneider bdf4d33e83 powerpc/preempt: Don't touch the idle task's preempt_count during hotplug
commit 2c669ef6979c370f98d4b876e54f19613c81e075 upstream.

Powerpc currently resets a CPU's idle task preempt_count to 0 before
said task starts executing the secondary startup routine (and becomes an
idle task proper).

This conflicts with commit f1a0a376ca0c ("sched/core: Initialize the
idle task with preemption disabled").

which initializes all of the idle tasks' preempt_count to
PREEMPT_DISABLED during smp_init(). Note that this was superfluous
before said commit, as back then the hotplug machinery would invoke
init_idle() via idle_thread_get(), which would have already reset the
CPU's idle task's preempt_count to PREEMPT_ENABLED.

Get rid of this preempt_count write.

Fixes: f1a0a376ca0c ("sched/core: Initialize the idle task with preemption disabled")
Reported-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Bharata B Rao <bharata@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210707183831.2106509-1-valentin.schneider@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-14 16:56:55 +02:00
..
boot powerpc/fsl: set fsl,i2c-erratum-a004447 flag for P1010 i2c controllers 2021-06-16 12:01:38 +02:00
configs
crypto
include KVM: PPC: Book3S HV: Fix TLB management on SMT8 POWER9 and POWER10 processors 2021-07-14 16:55:55 +02:00
kernel powerpc/64s: Fix copy-paste data exposure into newly created tasks 2021-07-14 16:56:49 +02:00
kexec
kvm KVM: PPC: Book3S HV: Fix TLB management on SMT8 POWER9 and POWER10 processors 2021-07-14 16:55:55 +02:00
lib
math-emu
mm
net
oprofile
perf
platforms powerpc/preempt: Don't touch the idle task's preempt_count during hotplug 2021-07-14 16:56:55 +02:00
purgatory
sysdev
tools
xmon
Kbuild
Kconfig
Kconfig.debug
Makefile
Makefile.postlink