diff options
| author | Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> | 2018-11-11 09:40:23 +0000 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2018-11-19 12:51:22 +0100 |
| commit | 441f6692ecc14859b77af2ac6d8f55e6f1354d3b (patch) | |
| tree | b85ca63dbe2421608c99188560f23dcdfa5bdfaa /hw | |
| parent | 5e3c0220d7e4f0361c4d36c697a8842f2b583402 (diff) | |
fdc: fix segfault in fdctrl_stop_transfer() when DMA is disabled
Commit c8a35f1cf0f "fdc: use IsaDma interface instead of global DMA_*
functions" accidentally introduced a segfault in fdctrl_stop_transfer() for
non-DMA transfers.
If fdctrl->dma_chann has not been configured then the fdctrl->dma interface
reference isn't initialised during isabus_fdc_realize(). Unfortunately
fdctrl_stop_transfer() unconditionally references the DMA interface when
finishing the transfer causing a NULL pointer dereference.
Fix the issue by adding a check in fdctrl_stop_transfer() so that the DMA
interface reference and release method is only invoked if fdctrl->dma_chann
has been set.
(This issue was discovered by Martin testing a recent change in the NetBSD
installer under qemu-system-sparc)
Cc: qemu-stable@nongnu.org
Reported-by: Martin Husemann <martin@duskware.de>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Hervé Poussineau <hpoussin@reactos.org>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'hw')
| -rw-r--r-- | hw/block/fdc.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/block/fdc.c b/hw/block/fdc.c index 2e9c1e1e2f..6f19f127a5 100644 --- a/hw/block/fdc.c +++ b/hw/block/fdc.c @@ -1617,7 +1617,7 @@ static void fdctrl_stop_transfer(FDCtrl *fdctrl, uint8_t status0, fdctrl->fifo[5] = cur_drv->sect; fdctrl->fifo[6] = FD_SECTOR_SC; fdctrl->data_dir = FD_DIR_READ; - if (!(fdctrl->msr & FD_MSR_NONDMA)) { + if (fdctrl->dma_chann != -1 && !(fdctrl->msr & FD_MSR_NONDMA)) { IsaDmaClass *k = ISADMA_GET_CLASS(fdctrl->dma); k->release_DREQ(fdctrl->dma, fdctrl->dma_chann); } |