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Date: Tue, 28 Apr 2026 07:33:49 +0100
From: Leo Yan <leo.yan@arm.com>
To: "Yingchao Deng (Consultant)" <quic_yingdeng@quicinc.com>
Cc: Yingchao Deng <yingchao.deng@oss.qualcomm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@arm.com>,
	James Clark <james.clark@linaro.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	Jinlong Mao <jinlong.mao@oss.qualcomm.com>,
	Tingwei Zhang <tingwei.zhang@oss.qualcomm.com>,
	Jie Gan <jie.gan@oss.qualcomm.com>
Subject: Re: [PATCH v8 1/4] coresight: cti: Convert trigger usage fields to
 dynamic bitmaps and arrays
Message-ID: <20260428063349.GD16537@e132581.arm.com>
References: <20260426-extended-cti-v8-0-23b900a4902f@oss.qualcomm.com>
 <20260426-extended-cti-v8-1-23b900a4902f@oss.qualcomm.com>
 <20260427165913.GA16537@e132581.arm.com>
 <b20a2f7c-4838-408f-94ed-ee9656d451c4@quicinc.com>
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On Tue, Apr 28, 2026 at 10:25:11AM +0800, Yingchao Deng (Consultant) wrote:

[...]

> >    tg->used_mask = bitmap_zalloc(nr_filter_sigs, GFP_KERNEL);

> "nr_filter_sigs" is the count of entries in the DT property array, if the DT
> property is:
>     arm,trig-filters = <22 23>;
> Here nr_filter_sigs=2, so bitmap_zalloc(2) allocates only 1 unsigned long
> (64 bits). set_bit(22/23, used_mask) still fits, but it's logically an OOB,
> and any index >=64 would
> write past the end.

Thanks for explanation. It is correct for me.