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Date: Mon, 8 Oct 2012 13:19:56 -0700
From: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
To: David Ahern <dsahern@gmail.com>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org,
        fweisbec@gmail.com, Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>,
        Dong Hao <haodong@linux.vnet.ibm.com>
Subject: Re: [PATCH 07/12] perf kvm: handle realloc failures
Message-ID: <20121008201956.GE2631@ghostprotocols.net>
References: <1349716656-48165-1-git-send-email-dsahern@gmail.com>
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Em Mon, Oct 08, 2012 at 11:17:31AM -0600, David Ahern escreveu:
> Save previous pointer and free on failure.

<SNIP>
 
> +	prev = event->vcpu;
>  	event->vcpu = realloc(event->vcpu,
>  			      event->max_vcpu * sizeof(*event->vcpu));
>  	if (!event->vcpu) {
> +		free(prev);
>  		pr_err("Not enough memory\n");

Unfamiliar way of doing it, usually we do it like:

  	vcpu = realloc(event->vcpu, event->max_vcpu * sizeof(*event->vcpu));

	if (!vcpu) {
  		pr_err("Not enough memory\n");
		return -1;
	}

	event->vcpu = vcpu;

I.e. we don't trow away the old value of event->vcpu.

- Arnaldo