From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neeraj Upadhyay Subject: [PATCH] cpu/hotplug: Fix rollback during error-out in takedown_cpu() Date: Tue, 4 Sep 2018 12:03:23 +0530 Message-ID: <1536042803-6152-1-git-send-email-neeraju@codeaurora.org> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: 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, Neeraj Upadhyay List-Id: linux-arm-msm@vger.kernel.org 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 --- 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; __cpuhp_kick_ap(st); } -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation