megasas: avoid NULL pointer dereference

While in megasas_handle_frame(), megasas_enqueue_frame() may
set a NULL frame into MegasasCmd object for a given 'frame_addr'
address. Add check to avoid a NULL pointer dereference issue.

Reported-by: Alexander Bulekov <alxndr@bu.edu>
Fixes: https://bugs.launchpad.net/qemu/+bug/1878259
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Acked-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Message-Id: <20200513192540.1583887-3-ppandit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Prasad J Pandit 2020-05-14 00:55:39 +05:30 committed by Paolo Bonzini
parent f50ab86a26
commit fd69185567

View File

@ -504,7 +504,7 @@ static MegasasCmd *megasas_enqueue_frame(MegasasState *s,
cmd->pa = frame; cmd->pa = frame;
/* Map all possible frames */ /* Map all possible frames */
cmd->frame = pci_dma_map(pcid, frame, &frame_size_p, 0); cmd->frame = pci_dma_map(pcid, frame, &frame_size_p, 0);
if (frame_size_p != frame_size) { if (!cmd->frame || frame_size_p != frame_size) {
trace_megasas_qf_map_failed(cmd->index, (unsigned long)frame); trace_megasas_qf_map_failed(cmd->index, (unsigned long)frame);
if (cmd->frame) { if (cmd->frame) {
megasas_unmap_frame(s, cmd); megasas_unmap_frame(s, cmd);