On 7/17/20 12:08 PM, Philippe Mathieu-Daudé wrote:
> On 7/17/20 9:53 AM, Philippe Mathieu-Daudé wrote:
>> libFuzzer found a case where requests are queued for later in the
>> AIO context, but a command set the bus inactive, then when finally
>> the requests are processed by the DMA it aborts because it is
>> inactive:
>>
>> include/hw/ide/pci.h:59: IDEState *bmdma_active_if(BMDMAState *): Assertion
>> `bmdma->bus->retry_unit != (uint8_t)-1' failed.
>>
>> Reproducer available on the BugLink.
>>
>> Fix by draining the pending DMA requests before inactivating the bus.
>>
>
Sorry I also forgot:
Reported-by: Alexander Bulekov <alx...@bu.edu>
> Fixes: 8ccad811e6 ("use AIO for DMA transfers - enabled DMA for CDROMs")
>
>> BugLink: https://bugs.launchpad.net/qemu/+bug/1887303
>> Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org>
>> ---
>> RFC because I don't have much clue about block drive and IDE,
>> so block-team please be very careful while reviewing this bug.
>> ---
>> hw/ide/core.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/hw/ide/core.c b/hw/ide/core.c
>> index d997a78e47..f7affafb0c 100644
>> --- a/hw/ide/core.c
>> +++ b/hw/ide/core.c
>> @@ -804,7 +804,7 @@ void dma_buf_commit(IDEState *s, uint32_t tx_bytes)
>>
>> void ide_set_inactive(IDEState *s, bool more)
>> {
>> - s->bus->dma->aiocb = NULL;
>> + ide_cancel_dma_sync(s);
>> ide_clear_retry(s);
>> if (s->bus->dma->ops->set_inactive) {
>> s->bus->dma->ops->set_inactive(s->bus->dma, more);
>>
>
