diff options
| author |   Tudor Ambarus <tudor.ambarus@microchip.com> | 2022-10-25 12:02:44 +0300 |
|---|---|---|
| committer |   Vinod Koul <vkoul@kernel.org> | 2022-11-08 10:43:57 +0530 |
| commit | 03ed9ba357cc78116164b90b87f45eacab60b561 (patch) | |
| tree | 210dedb5c5baeda627711aca508e97417300566a /drivers | |
| parent | dmaengine: at_hdmac: Free the memset buf without holding the chan lock (diff) | |
| download | linux-dev-03ed9ba357cc78116164b90b87f45eacab60b561.tar.xz linux-dev-03ed9ba357cc78116164b90b87f45eacab60b561.zip | |
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>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/dma/at_hdmac.c | 10 |
1 files changed, 6 insertions, 4 deletions
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); |