linux-kernel - Re: [PATCH] dmatest: properly handle duplicate DMA channels

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20080919163145.de9866ac.akpm@linux-foundation.org>
Date:	Fri, 19 Sep 2008 16:31:45 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Timur Tabi <timur@...escale.com>
Cc:	dan.j.williams@...el.com, haavard.skinnemoen@...el.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] dmatest: properly handle duplicate DMA channels

On Thu, 18 Sep 2008 10:21:19 -0500
Timur Tabi <timur@...escale.com> wrote:

> --- a/drivers/dma/dmatest.c
> +++ b/drivers/dma/dmatest.c
> @@ -321,10 +321,15 @@ static void dmatest_cleanup_channel(struct dmatest_chan *dtc)
>  
>  static enum dma_state_client dmatest_add_channel(struct dma_chan *chan)
>  {
> -	struct dmatest_chan	*dtc;
> +	struct dmatest_chan	*dtc, *_dtc;
>  	struct dmatest_thread	*thread;
>  	unsigned int		i;
>  
> +	/* Have we already been told about this channel? */
> +	list_for_each_entry_safe(dtc, _dtc, &dmatest_channels, node)
> +		if (dtc->chan == chan)
> +			return DMA_DUP;
> +
>  	dtc = kmalloc(sizeof(struct dmatest_chan), GFP_ATOMIC);
>  	if (!dtc) {
>  		pr_warning("dmatest: No memory for %s\n", chan->dev.bus_id);

hm.  A few lines after that GFP_ATOMIC the driver does a GFP_KERNEL
allocation.

One of them is incorrect.  The interface is undocumented (natch), but I
assume that GFP_KERNEL is the one to use here.

--- a/drivers/dma/dmatest.c~a
+++ a/drivers/dma/dmatest.c
@@ -330,7 +330,7 @@ static enum dma_state_client dmatest_add
 		if (dtc->chan == chan)
 			return DMA_DUP;
 
-	dtc = kmalloc(sizeof(struct dmatest_chan), GFP_ATOMIC);
+	dtc = kmalloc(sizeof(struct dmatest_chan), GFP_KERNEL);
 	if (!dtc) {
 		pr_warning("dmatest: No memory for %s\n", chan->dev.bus_id);
 		return DMA_NAK;
_

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/