The patch titled dmaengine: fix broken device refcounting has been removed from the -mm tree. Its filename was dmaengine-fix-broken-device-refcounting.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ Subject: dmaengine: fix broken device refcounting From: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx> When a DMA device is unregistered, its reference count is decremented twice for each channel: Once dma_class_dev_release() and once in dma_chan_cleanup(). This may result in the DMA device driver's remove() function completing before all channels have been cleaned up, causing lots of use-after-free fun. Fix it by incrementing the device's reference count twice for each channel during registration. [dan.j.williams@xxxxxxxxx: kill unnecessary client refcounting] Signed-off-by: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> Signed-off-by: Shannon Nelson <shannon.nelson@xxxxxxxxx> Cc: <stable@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/dma/dmaengine.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff -puN drivers/dma/dmaengine.c~dmaengine-fix-broken-device-refcounting drivers/dma/dmaengine.c --- a/drivers/dma/dmaengine.c~dmaengine-fix-broken-device-refcounting +++ a/drivers/dma/dmaengine.c @@ -182,10 +182,9 @@ static void dma_client_chan_alloc(struct /* we are done once this client rejects * an available resource */ - if (ack == DMA_ACK) { + if (ack == DMA_ACK) dma_chan_get(chan); - kref_get(&device->refcount); - } else if (ack == DMA_NAK) + else if (ack == DMA_NAK) return; } } @@ -272,11 +271,8 @@ static void dma_clients_notify_removed(s /* client was holding resources for this channel so * free it */ - if (ack == DMA_ACK) { + if (ack == DMA_ACK) dma_chan_put(chan); - kref_put(&chan->device->refcount, - dma_async_device_cleanup); - } } mutex_unlock(&dma_list_mutex); @@ -316,11 +312,8 @@ void dma_async_client_unregister(struct ack = client->event_callback(client, chan, DMA_RESOURCE_REMOVED); - if (ack == DMA_ACK) { + if (ack == DMA_ACK) dma_chan_put(chan); - kref_put(&chan->device->refcount, - dma_async_device_cleanup); - } } list_del(&client->global_node); @@ -397,6 +390,8 @@ int dma_async_device_register(struct dma goto err_out; } + /* One for the channel, one of the class device */ + kref_get(&device->refcount); kref_get(&device->refcount); kref_init(&chan->refcount); chan->slow_ref = 0; _ Patches currently in -mm which might be from hskinnemoen@xxxxxxxxx are origin.patch git-avr32.patch git-mtd.patch read_current_time-cleanups.patch generic-gpio-gpio_chip-support.patch avr32-uses-gpio_chip.patch mcp23s08-spi-gpio-expander.patch mcp23s08-spi-gpio-expander-checkpatch-fixes.patch sanitize-the-type-of-struct-useru_ar0.patch add-cmpxchg_local-to-avr32.patch - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html