From: Mukesh Ojha <mojha@codeaurora.org>
To: Neeraj Upadhyay <neeraju@codeaurora.org>,
tglx@linutronix.de, josh@joshtriplett.org, peterz@infradead.org,
mingo@kernel.org, jiangshanlai@gmail.com, dzickus@redhat.com,
brendan.jackman@arm.com, malat@debian.org
Cc: linux-kernel@vger.kernel.org, sramana@codeaurora.org,
linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH] cpu/hotplug: Fix rollback during error-out in takedown_cpu()
Date: Tue, 4 Sep 2018 17:42:28 +0530 [thread overview]
Message-ID: <26a4e734-088c-dbd7-30d2-34065787e925@codeaurora.org> (raw)
In-Reply-To: <1536042803-6152-1-git-send-email-neeraju@codeaurora.org>
On 9/4/2018 12:03 PM, Neeraj Upadhyay wrote:
> If takedown_cpu() fails during _cpu_down(), st->state is reset,
> by calling cpuhp_reset_state(). This results in an additional
> increment of st->state, which results in CPUHP_AP_SMPBOOT_THREADS
> state being skipped during rollback. Fix this by not calling
> cpuhp_reset_state() and doing the state reset directly in
> _cpu_down().
>
> Fixes: 4dddfb5faa61 ("smp/hotplug: Rewrite AP state machine core")
> Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
> ---
> kernel/cpu.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index aa7fe85..9f49edb 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -970,7 +970,14 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
> */
> ret = cpuhp_down_callbacks(cpu, st, target);
> if (ret && st->state > CPUHP_TEARDOWN_CPU && st->state < prev_state) {
> - cpuhp_reset_state(st, prev_state);
> + /*
> + * As st->last is not set, cpuhp_reset_state() increments
> + * st->state, which results in CPUHP_AP_SMPBOOT_THREADS being
> + * skipped during rollback. So, don't use it here.
> + */
> + st->rollback = true;
> + st->target = prev_state;
> + st->bringup = !st->bringup;
Acked-by: Mukesh Ojha <mojha@codeaurora.org>
looks valid for this case.
> __cpuhp_kick_ap(st);
> }
>
next prev parent reply other threads:[~2018-09-04 12:12 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-04 6:33 [PATCH] cpu/hotplug: Fix rollback during error-out in takedown_cpu() Neeraj Upadhyay
2018-09-04 12:12 ` Mukesh Ojha [this message]
2018-09-05 11:33 ` Thomas Gleixner
2018-09-05 12:09 ` Mukesh Ojha
2018-09-05 13:14 ` Thomas Gleixner
2018-09-05 12:23 ` Thomas Gleixner
2018-09-05 12:51 ` Neeraj Upadhyay
2018-09-05 13:17 ` Thomas Gleixner
2018-09-06 2:56 ` Neeraj Upadhyay
2018-09-06 8:18 ` Thomas Gleixner
2018-09-06 9:00 ` Neeraj Upadhyay
2018-09-05 14:53 ` Sudeep Holla
2018-09-05 15:19 ` Geert Uytterhoeven
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