fdc: fix segfault in fdctrl_stop_transfer() when DMA is disabled
Commit c8a35f1cf0
"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>
This commit is contained in:
parent
5e3c0220d7
commit
441f6692ec
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@ -1617,7 +1617,7 @@ static void fdctrl_stop_transfer(FDCtrl *fdctrl, uint8_t status0,
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fdctrl->fifo[5] = cur_drv->sect;
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fdctrl->fifo[5] = cur_drv->sect;
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fdctrl->fifo[6] = FD_SECTOR_SC;
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fdctrl->fifo[6] = FD_SECTOR_SC;
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fdctrl->data_dir = FD_DIR_READ;
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fdctrl->data_dir = FD_DIR_READ;
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if (!(fdctrl->msr & FD_MSR_NONDMA)) {
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if (fdctrl->dma_chann != -1 && !(fdctrl->msr & FD_MSR_NONDMA)) {
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IsaDmaClass *k = ISADMA_GET_CLASS(fdctrl->dma);
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IsaDmaClass *k = ISADMA_GET_CLASS(fdctrl->dma);
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k->release_DREQ(fdctrl->dma, fdctrl->dma_chann);
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k->release_DREQ(fdctrl->dma, fdctrl->dma_chann);
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}
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}
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