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) { trace_ide_cancel_dma_sync_remaining(); blk_drain(s->blk); assert(s->bus->dma->aiocb == NULL); -- 2.26.2