Commit 7b221c5f authored by Tudor Ambarus's avatar Tudor Ambarus Committed by sanglipeng
Browse files

dmaengine: at_hdmac: Fix concurrency over the active list 

stable inclusion
from stable-v5.10.155
commit a35dd5dd98b67b98f57e55efb4374e55c2cb680f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7M5F4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a35dd5dd98b67b98f57e55efb4374e55c2cb680f



--------------------------------

commit 03ed9ba3 upstream.

The tasklet (atc_advance_work()) did not held the channel lock when
retrieving the first active descriptor, causing concurrency problems if
issue_pending() was called in between. If issue_pending() was called
exactly after the lock was released in the tasklet (atc_advance_work()),
atc_chain_complete() could complete a descriptor for which the controller
has not yet raised an interrupt.

Fixes: dc78baa2 ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller")
Reported-by: default avatarPeter Rosin <peda@axentia.se>
Signed-off-by: default avatarTudor Ambarus <tudor.ambarus@microchip.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/


Acked-by: default avatarNicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com
Link: https://lore.kernel.org/r/20221025090306.297886-11-tudor.ambarus@microchip.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarsanglipeng <sanglipeng1@jd.com>
parent 2bfd3358

drivers/dma/at_hdmac.c

+6 −4
Original line number Diff line number Diff line
@@ -443,8 +443,6 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) 
	if (!atc_chan_is_cyclic(atchan))

		dma_cookie_complete(txd);



	/* Remove transfer node from the active list. */

	list_del_init(&desc->desc_node);

	spin_unlock_irqrestore(&atchan->lock, flags);



	dma_descriptor_unmap(txd);
@@ -476,6 +474,7 @@ atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc) 
 */

static void atc_advance_work(struct at_dma_chan *atchan)

{

	struct at_desc *desc;

	unsigned long flags;



	dev_vdbg(chan2dev(&atchan->chan_common), "advance_work\n");
@@ -483,9 +482,12 @@ static void atc_advance_work(struct at_dma_chan *atchan) 
	spin_lock_irqsave(&atchan->lock, flags);

	if (atc_chan_is_enabled(atchan) || list_empty(&atchan->active_list))

		return spin_unlock_irqrestore(&atchan->lock, flags);

	spin_unlock_irqrestore(&atchan->lock, flags);



	atc_chain_complete(atchan, atc_first_active(atchan));

	desc = atc_first_active(atchan);

	/* Remove the transfer node from the active list. */

	list_del_init(&desc->desc_node);

	spin_unlock_irqrestore(&atchan->lock, flags);

	atc_chain_complete(atchan, desc);



	/* advance work */

	spin_lock_irqsave(&atchan->lock, flags);