On 8/27/20 7:38 AM, P J P wrote:
From: Prasad J Pandit <p...@fedoraproject.org>
While transferring data via fdctrl_write_data(), check that
current drive does not have a null block pointer. Avoid
null pointer dereference.
Hi PJP. I assume this patch actually covers the exact same thing that
the other if cur_drv->blk patch we have been discussing recently does.
You may want to combine the Reported-By lines for both.
I am dropping this patch from my queue in favor of pursuing our other,
more recent and active thread, which I am also now tracking via this
gitlab issue:
https://gitlab.com/qemu-project/qemu/-/issues/338
-> https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Ffdc_nullptr1
==1658854==Hint: address points to the zero page.
#0 blk_inc_in_flight block/block-backend.c:1327
#1 blk_prw block/block-backend.c:1299
#2 blk_pwrite block/block-backend.c:1464
#3 fdctrl_write_data hw/block/fdc.c:2418
#4 fdctrl_write hw/block/fdc.c:962
#5 portio_write ioport.c:205
#6 memory_region_write_accessor memory.c:483
#7 access_with_adjusted_size memory.c:544
#8 memory_region_dispatch_write memory.c:1476
Reported-by: Ruhr-University <bugs-sys...@rub.de>
Signed-off-by: Prasad J Pandit <p...@fedoraproject.org>
---
hw/block/fdc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/hw/block/fdc.c b/hw/block/fdc.c
index e9ed3eef45..dedadac68a 100644
--- a/hw/block/fdc.c
+++ b/hw/block/fdc.c
@@ -2419,7 +2419,8 @@ static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t
value)
if (pos == FD_SECTOR_LEN - 1 ||
fdctrl->data_pos == fdctrl->data_len) {
cur_drv = get_cur_drv(fdctrl);
- if (blk_pwrite(cur_drv->blk, fd_offset(cur_drv), fdctrl->fifo,
+ if (cur_drv->blk
+ && blk_pwrite(cur_drv->blk, fd_offset(cur_drv), fdctrl->fifo,
BDRV_SECTOR_SIZE, 0) < 0) {
FLOPPY_DPRINTF("error writing sector %d\n",
fd_sector(cur_drv));
