From commit e19afd56, we know target-arm restricts the list of
queryable cpu models to 'max', 'host', and the current type when
KVM is in use. The logic works well until using machine type none.

For machine type none, cpu_type will be null, and strlen(cpu_type)
will terminate process. So I add a check above it.

This won't affect i386 and s390x, because they are not invovled
current_cpu.

Signed-off-by: Liang Yan <lyan@suse.com>
---
 target/arm/monitor.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/target/arm/monitor.c b/target/arm/monitor.c
index 9725dfff16..0c0130c1af 100644
--- a/target/arm/monitor.c
+++ b/target/arm/monitor.c
@@ -137,17 +137,19 @@ CpuModelExpansionInfo *qmp_query_cpu_model_expansion(CpuModelExpansionType type,
     }
 
     if (kvm_enabled()) {
-        const char *cpu_type = current_machine->cpu_type;
-        int len = strlen(cpu_type) - strlen(ARM_CPU_TYPE_SUFFIX);
         bool supported = false;
 
         if (!strcmp(model->name, "host") || !strcmp(model->name, "max")) {
             /* These are kvmarm's recommended cpu types */
             supported = true;
-        } else if (strlen(model->name) == len &&
-                   !strncmp(model->name, cpu_type, len)) {
-            /* KVM is enabled and we're using this type, so it works. */
-            supported = true;
+        } else if (current_machine->cpu_type) {
+            const char *cpu_type = current_machine->cpu_type;
+            int len = strlen(cpu_type) - strlen(ARM_CPU_TYPE_SUFFIX);
+            if (strlen(model->name) == len &&
+			    !strncmp(model->name, cpu_type, len)) {
+		    /* KVM is enabled and we're using this type, so it works. */
+		    supported = true;
+            }
         }
         if (!supported) {
             error_setg(errp, "We cannot guarantee the CPU type '%s' works "
-- 
2.25.0

Patchew URL: https://patchew.org/QEMU/20200131212742.18579-1-lyan@suse.com/



Hi,

This series seems to have some coding style problems. See output below for
more information:

Subject: [PATCH] target/arm/monitor: query-cpu-model-expansion crashed qemu when using machine type none
Message-id: 20200131212742.18579-1-lyan@suse.com
Type: series

=== TEST SCRIPT BEGIN ===
#!/bin/bash
git rev-parse base > /dev/null || exit 0
git config --local diff.renamelimit 0
git config --local diff.renames True
git config --local diff.algorithm histogram
./scripts/checkpatch.pl --mailback base..
=== TEST SCRIPT END ===

From https://github.com/patchew-project/qemu
   aeab8e5..28db64f  master     -> master
From https://github.com/patchew-project/qemu
 * [new tag]         patchew/20200131212742.18579-1-lyan@suse.com -> patchew/20200131212742.18579-1-lyan@suse.com
Switched to a new branch 'test'
54bd33b target/arm/monitor: query-cpu-model-expansion crashed qemu when using machine type none

=== OUTPUT BEGIN ===
ERROR: code indent should never use tabs
#43: FILE: target/arm/monitor.c:149:
+^I^I^I    !strncmp(model->name, cpu_type, len)) {$

ERROR: code indent should never use tabs
#44: FILE: target/arm/monitor.c:150:
+^I^I    /* KVM is enabled and we're using this type, so it works. */$

ERROR: code indent should never use tabs
#45: FILE: target/arm/monitor.c:151:
+^I^I    supported = true;$

total: 3 errors, 0 warnings, 25 lines checked

Commit 54bd33b5bf01 (target/arm/monitor: query-cpu-model-expansion crashed qemu when using machine type none) has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.
=== OUTPUT END ===

Test command exited with code: 1


The full log is available at
http://patchew.org/logs/20200131212742.18579-1-lyan@suse.com/testing.checkpatch/?type=message.
---
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