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From: Bjorn Helgaas <helgaas@kernel.org>
To: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, tristmd@gmail.com,
	stable@vger.kernel.org
Subject: Re: [PATCH] blktrace: Protect q->blk_trace with RCU
Date: Mon, 2 Mar 2020 14:40:57 -0600	[thread overview]
Message-ID: <20200302204057.GA128531@google.com> (raw)
In-Reply-To: <20200206142812.25989-1-jack@suse.cz>

On Thu, Feb 06, 2020 at 03:28:12PM +0100, Jan Kara wrote:

> @@ -1844,18 +1896,18 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
>  	}
>  
>  	ret = 0;
> -	if (q->blk_trace == NULL)
> +	if (bt == NULL)
>  		ret = blk_trace_setup_queue(q, bdev);
>  
>  	if (ret == 0) {
>  		if (attr == &dev_attr_act_mask)
> -			q->blk_trace->act_mask = value;
> +			bt->act_mask = value;

You've likely seen this already, but Coverity complains that "bt" may
be a NULL pointer here, since we checked it for NULL above.

  CID 1460458:  Null pointer dereferences  (FORWARD_NULL)

>  		else if (attr == &dev_attr_pid)
> -			q->blk_trace->pid = value;
> +			bt->pid = value;
>  		else if (attr == &dev_attr_start_lba)
> -			q->blk_trace->start_lba = value;
> +			bt->start_lba = value;
>  		else if (attr == &dev_attr_end_lba)
> -			q->blk_trace->end_lba = value;
> +			bt->end_lba = value;
>  	}
>  
>  out_unlock_bdev:
> 

  parent reply	other threads:[~2020-03-02 20:41 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-06 14:28 [PATCH] blktrace: Protect q->blk_trace with RCU Jan Kara
2020-02-06 18:46 ` Chaitanya Kulkarni
2020-02-06 18:49   ` Jens Axboe
2020-02-06 19:37     ` Chaitanya Kulkarni
2020-02-10  0:38 ` Chaitanya Kulkarni
2020-02-10  2:19 ` Ming Lei
2020-02-10  3:54 ` Bart Van Assche
2020-02-19 12:59 ` Jan Kara
2020-02-25 10:20   ` Ming Lei
2020-02-25 15:40     ` Jens Axboe
2020-03-02 20:40 ` Bjorn Helgaas [this message]
2020-03-02 21:19   ` Chaitanya Kulkarni
2020-03-02 21:59     ` Bjorn Helgaas
2020-03-02 22:06     ` Keith Busch
2020-03-03 11:07       ` Cengiz Can
2020-03-03 12:17         ` Greg KH
2020-03-05  1:51         ` Ming Lei
2020-03-05  4:27           ` Cengiz Can

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