From: Prasad J Pandit <p...@fedoraproject.org> When IDE AHCI emulation uses Frame Information Structures(FIS) engine for data transfer, the mapped FIS buffer address is stored in a static 'bounce.buffer'. When a request is made to map another memory region, address_space_map() returns NULL because 'bounce.buffer' is in_use. It leads to a null pointer dereference error while doing 'dma_memory_unmap'. Add a check to avoid it.
Reported-by: Zuozhi fzz <zuozhi....@alibaba-inc.com> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- hw/ide/ahci.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) Update as per review -> https://lists.gnu.org/archive/html/qemu-devel/2016-01/msg05715.html diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c index 17f1cbd..f413a59 100644 --- a/hw/ide/ahci.c +++ b/hw/ide/ahci.c @@ -661,9 +661,11 @@ static bool ahci_map_fis_address(AHCIDevice *ad) static void ahci_unmap_fis_address(AHCIDevice *ad) { - dma_memory_unmap(ad->hba->as, ad->res_fis, 256, - DMA_DIRECTION_FROM_DEVICE, 256); - ad->res_fis = NULL; + if (ad->res_fis) { + dma_memory_unmap(ad->hba->as, ad->res_fis, 256, + DMA_DIRECTION_FROM_DEVICE, 256); + ad->res_fis = NULL; + } } static bool ahci_map_clb_address(AHCIDevice *ad) @@ -677,9 +679,11 @@ static bool ahci_map_clb_address(AHCIDevice *ad) static void ahci_unmap_clb_address(AHCIDevice *ad) { - dma_memory_unmap(ad->hba->as, ad->lst, 1024, - DMA_DIRECTION_FROM_DEVICE, 1024); - ad->lst = NULL; + if (ad->lst) { + dma_memory_unmap(ad->hba->as, ad->lst, 1024, + DMA_DIRECTION_FROM_DEVICE, 1024); + ad->lst = NULL; + } } static void ahci_write_fis_sdb(AHCIState *s, NCQTransferState *ncq_tfs) -- 2.5.0
