Le jeu. 27 août 2020 13:47, P J P <ppan...@redhat.com> a écrit :
> From: Prasad J Pandit <p...@fedoraproject.org>
>
> While cancelling an i/o operation via ide_cancel_dma_sync(),
> check for null block pointer before calling blk_drain(). Avoid
> null pointer dereference.
>
> ->
> https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Fide_nullptr1
> ==1803100==Hint: address points to the zero page.
> #0 blk_bs ../block/block-backend.c:714
> #1 blk_drain ../block/block-backend.c:1715
> #2 ide_cancel_dma_sync ../hw/ide/core.c:723
> #3 bmdma_cmd_writeb ../hw/ide/pci.c:298
> #4 bmdma_write ../hw/ide/piix.c:75
> #5 memory_region_write_accessor ../softmmu/memory.c:483
> #6 access_with_adjusted_size ../softmmu/memory.c:544
> #7 memory_region_dispatch_write ../softmmu/memory.c:1465
> #8 flatview_write_continue ../exec.c:3176
> ...
>
> Reported-by: Ruhr-University <bugs-sys...@rub.de>
> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org>
> ---
> 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..038af1cd6b 100644
> --- a/hw/ide/core.c
> +++ b/hw/ide/core.c
> @@ -718,7 +718,7 @@ void ide_cancel_dma_sync(IDEState *s)
> * whole DMA operation will be submitted to disk with a single
> * aio operation with preadv/pwritev.
> */
> - if (s->bus->dma->aiocb) {
> + if (s->blk && s->bus->dma->aiocb) {
>
But s->blk mustn't be null here... IMHO we should assert() here and add a
check earlier.
Don't we already have a Launchpad bug for this BTW?
trace_ide_cancel_dma_sync_remaining();
> blk_drain(s->blk);
> assert(s->bus->dma->aiocb == NULL);
> --
> 2.26.2
>
>
>
