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From:   Vineeth Remanan Pillai <vpillai@digitalocean.com>
To:     Aubrey Li <aubrey.intel@gmail.com>
Cc:     Vineeth Remanan Pillai <vpillai@digitalocean.com>,
        Nishanth Aravamudan <naravamudan@digitalocean.com>,
        Julien Desfossez <jdesfossez@digitalocean.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Tim Chen <tim.c.chen@linux.intel.com>, mingo@kernel.org,
        tglx@linutronix.de, pjt@google.com, torvalds@linux-foundation.org,
        linux-kernel@vger.kernel.org, subhra.mazumdar@oracle.com,
        fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com,
        Aaron Lu <aaron.lwe@gmail.com>,
        Valentin Schneider <valentin.schneider@arm.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Phil Auld <pauld@redhat.com>
Subject: Re: [RFC PATCH v2 00/17] Core scheduling v2
Date:   Wed, 24 Apr 2019 11:19:13 +0000
Message-Id: <20190424111913.1386-1-vpillai@digitalocean.com>
In-Reply-To: <CAERHkrtcW8L0duMTzkt-eDnesiG6sEO=zfswZcoM+n3TMxrG_w@mail.gmail.com>
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> Is this one missed? Or fixed with a better impl?
>
> The boot up CPUs don't match the possible cpu map, so the not onlined
> CPU rq->core are not initialized, which causes NULL pointer dereference
> panic in online_fair_sched_group():
>
Thanks for pointing this out. I think the ideal fix would be to
correctly initialize/cleanup the coresched attributes in the cpu
hotplug code path so that lock could be taken successfully if the
sibling is offlined/onlined after coresched was enabled. We are
working on another bug related to hotplugpath and shall introduce
the fix in v3.

Thanks