* FAILED: patch "[PATCH] dmaengine: at_hdmac: Fix concurrency over the active list" failed to apply to 4.9-stable tree
@ 2022-11-14 11:09 gregkh
0 siblings, 0 replies; only message in thread
From: gregkh @ 2022-11-14 11:09 UTC (permalink / raw)
To: tudor.ambarus, nicolas.ferre, peda, vkoul; +Cc: stable
The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
Possible dependencies:
03ed9ba357cc ("dmaengine: at_hdmac: Fix concurrency over the active list")
6ba826cbb57d ("dmaengine: at_hdmac: Free the memset buf without holding the chan lock")
06988949df8c ("dmaengine: at_hdmac: Fix concurrency over descriptor")
c6babed879fb ("dmaengine: at_hdmac: Fix concurrency problems by removing atc_complete_all()")
078a6506141a ("dmaengine: at_hdmac: Fix deadlocks")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 03ed9ba357cc78116164b90b87f45eacab60b561 Mon Sep 17 00:00:00 2001
From: Tudor Ambarus <tudor.ambarus@microchip.com>
Date: Tue, 25 Oct 2022 12:02:44 +0300
Subject: [PATCH] dmaengine: at_hdmac: Fix concurrency over the active list
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: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller")
Reported-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Tudor 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: Nicolas 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: Vinod Koul <vkoul@kernel.org>
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 0fb44f622d35..b53a9fc15dd9 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -462,8 +462,6 @@ 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);
@@ -495,6 +493,7 @@ 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");
@@ -502,9 +501,12 @@ 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);
^ permalink raw reply related [flat|nested] only message in thread
only message in thread, other threads:[~2022-11-14 11:15 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-11-14 11:09 FAILED: patch "[PATCH] dmaengine: at_hdmac: Fix concurrency over the active list" failed to apply to 4.9-stable tree gregkh
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).