On 08/29/2017 07:15 PM, Philippe Mathieu-Daudé wrote:
Hi Seeteena,
On 08/29/2017 02:45 AM, Seeteena Thoufeek wrote:
---Steps to Reproduce---
When passed a negative number to 'maxcpus' parameter, Qemu aborts
with a core dump.
Run the following command with maxcpus argument as negative number
ppc64-softmmu/qemu-system-ppc64 --nographic -vga none -machine
pseries,accel=kvm,kvm-type=HV -m size=200g -device virtio-blk-pci,
drive=rootdisk -drive file=/home/images/pegas-1.0-ppc64le.qcow2,
if=none,cache=none,id=rootdisk,format=qcow2 -monitor telnet
:127.0.0.1:1234,server,nowait -net nic,model=virtio -net
user -redir tcp:2000::22 -device nec-usb-xhci -smp 8,cores=1,
threads=1,maxcpus=-12
(process:12149): GLib-ERROR **: gmem.c:130: failed to allocate
18446744073709550568 bytes
Trace/breakpoint trap
Reported-by: R.Nageswara Sastry <rnsas...@linux.vnet.ibm.com>
Signed-off-by: Seeteena Thoufeek <s1see...@linux.vnet.ibm.com>
---
v1 -> v2:
- Fix the error check in vl.c to make it generic.
v2 -> v3:
- Fix coding style pointed out by patchew.
- Fix check for "<= 0" instead of just "< 0".
v3 -> v4:
- Fix subject line.
- Removed space before ":" from vl.c:1248
- Removed Reviewed-by: flag.
---
vl.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/vl.c b/vl.c
index 8e247cc..2d9e73d 100644
--- a/vl.c
+++ b/vl.c
@@ -1244,7 +1244,10 @@ static void smp_parse(QemuOpts *opts)
}
max_cpus = qemu_opt_get_number(opts, "maxcpus", cpus);
-
+ if (max_cpus <= 0) {
+ error_report("Invalid max_cpus: %d", max_cpus);
I disagree with this patch, I think the correct fix is to declare
max_cpus as unsigned.
Looking at the codebase I can't find any signed use of it.
if I declare max_cpus as unsigned, the error check is no more valid
as the value max_cpus fetches is of unsigned type and hence we cannot do
this below check.
if (max_cpus <= 0) {
error_report("Invalid max_cpus: %d", max_cpus);
When I remove the error check with max_cpus defined as unsigned, the
code behaves as follows when negetive value is passed for maxcpus
ppc64-softmmu/qemu-system-ppc64 --nographic -vga none -machine
pseries,accel=kvm,kvm-type=HV -m size=20g -device
virtio-blk-pci,drive=rootdisk -drive
file=/var/lib/libvirt/images/avocado-fvt-wrapper/data/avocado-vt/images/ubuntu-17.10-ppc64le.qcow2,if=none,cache=none,id=rootdisk,format=qcow2
-monitor telnet:127.0.0.1:1234,server,nowait -net nic,model=virtio -net
user -device nec-usb-xhci -smp 8,cores=1,threads=1,maxcpus=-12
SLOF **********************************************************************
QEMU Starting
Build Date = Jan 4 2017 05:15:48
FW Version = buildd@ release 20161019
Press "s" to enter Open Firmware.
+ exit(1);
+ }
if (max_cpus < cpus) {
error_report("maxcpus must be equal to or greater than
smp");
exit(1);
Regards,
Phil.
