linux-kernel - Re: [PATCH 1/2] scsi: qedf: Replace kmalloc

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Message-ID: <2025020626-purist-chrome-0dd6@gregkh>
Date: Thu, 6 Feb 2025 06:36:58 +0100
From: Greg KH <gregkh@...uxfoundation.org>
To: Jiasheng Jiang <jiashengjiangcool@...il.com>
Cc: markus.elfring@....de, GR-QLogic-Storage-Upstream@...vell.com,
	James.Bottomley@...senpartnership.com, arun.easi@...ium.com,
	bvanassche@....org, jhasan@...vell.com,
	linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
	manish.rangankar@...ium.com, martin.petersen@...cle.com,
	nilesh.javali@...ium.com, skashyap@...vell.com,
	stable@...r.kernel.org
Subject: Re: [PATCH 1/2] scsi: qedf: Replace kmalloc_array() with kcalloc()

On Thu, Feb 06, 2025 at 05:25:22AM +0000, Jiasheng Jiang wrote:
> Replace kmalloc_array() with kcalloc() to avoid old (dirty) data being
> used/freed.

Used/freed where?

> 
> Fixes: 61d8658b4a43 ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.")
> Cc: <stable@...r.kernel.org> # v5.10+
> Signed-off-by: Jiasheng Jiang <jiashengjiangcool@...il.com>
> ---
>  drivers/scsi/qedf/qedf_io.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/scsi/qedf/qedf_io.c b/drivers/scsi/qedf/qedf_io.c
> index fcfc3bed02c6..d52057b97a4f 100644
> --- a/drivers/scsi/qedf/qedf_io.c
> +++ b/drivers/scsi/qedf/qedf_io.c
> @@ -254,9 +254,7 @@ struct qedf_cmd_mgr *qedf_cmd_mgr_alloc(struct qedf_ctx *qedf)
>  	}
>  
>  	/* Allocate pool of io_bdts - one for each qedf_ioreq */
> -	cmgr->io_bdt_pool = kmalloc_array(num_ios, sizeof(struct io_bdt *),
> -	    GFP_KERNEL);
> -
> +	cmgr->io_bdt_pool = kcalloc(num_ios, sizeof(*cmgr->io_bdt_pool), GFP_KERNEL);

This is just an array that is then properly all initialized a few lines
below this.

So why does this need to be zeroed out at all?

thanks,

greg k-h