github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-09-23 22:14:03 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel()

Browse Source 
When dma_device_put() drops the last reference on chan->device->ref,
dma_device_release() runs and may free the dma_device along with its
channels.

dma_chan_put() then still reads chan->device->owner via
dma_chan_to_owner() for the trailing module_put(). KASAN catches it:

	slab-use-after-free in dma_chan_put+0x3e6/0x4c0
	Read of size 8 by task insmod/6319
	Freed by task 6319:
	  kfree+0x225/0x470
	  dma_chan_put+0x395/0x4c0
	  dmaengine_put+0xf8/0x160

Cache the module owner in dma_chan_put() before the put so the trailing
module_put() does not need chan->device.

Fixes: 8ad342a863 ("dmaengine: Add reference counting to dma_device struct")
Suggested-by: Sashiko <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Shivank Garg 2026-08-22 19:22:05 +00:00 committed by Vinod Koul
parent 44dab65906
commit e873c74132
1 changed files with 4 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/dma/dmaengine.c
View File

@ -500,10 +500,13 @@ static int dma_chan_get(struct dma_chan *chan)
*/
static void dma_chan_put(struct dma_chan *chan)
{
struct module *owner;
/* This channel is not in use, bail out */
if (!chan->client_count)
return;
owner = dma_chan_to_owner(chan);
chan->client_count--;
/* This channel is not in use anymore, free it */
@ -523,7 +526,7 @@ static void dma_chan_put(struct dma_chan *chan)
/* This channel is not in use anymore, drop the device ref */
if (!chan->client_count)
dma_device_put(chan->device);
module_put(dma_chan_to_owner(chan));
module_put(owner);
}
enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)