From 823a62ec8aac4fb75e6e281164f3eb56ae47597c Mon Sep 17 00:00:00 2001
From: Boris Fiuczynski <fiuczy@linux.ibm.com>
Date: Tue, 1 Mar 2022 18:47:59 +0100
Subject: [PATCH] qemu: segmentation fault in virtqemud executing
 qemuDomainUndefineFlags

Commit 5adfb3472342741c443ac91dee0abb18b5a3d038 causes a segmentation fault.

Stack trace of thread 664419:
 #0  0x000003ff62ec553c in qemuDomainUndefineFlags (dom=0x3ff6c002810, flags=<optimized out>) at ../src/qemu/qemu_driver.c:6618
 #1  0x000003ff876a7e5c in virDomainUndefineFlags (domain=domain@entry=0x3ff6c002810, flags=<optimized out>) at ../src/libvirt-domain.c:6519
 #2  0x000002aa2b64a808 in remoteDispatchDomainUndefineFlags (server=0x2aa2c3d7880, msg=0x2aa2c3d2770, args=<optimized out>, rerr=0x3ff8287b950, client=<optimized out>)
        at src/remote/remote_daemon_dispatch_stubs.h:13080
 #3  remoteDispatchDomainUndefineFlagsHelper (server=0x2aa2c3d7880, client=<optimized out>, msg=0x2aa2c3d2770, rerr=0x3ff8287b950, args=<optimized out>, ret=0x0)
        at src/remote/remote_daemon_dispatch_stubs.h:13059
 #4  0x000003ff8758bbf4 in virNetServerProgramDispatchCall (msg=0x2aa2c3d2770, client=0x2aa2c3e3050, server=0x2aa2c3d7880, prog=0x2aa2c3d8010)
        at ../src/rpc/virnetserverprogram.c:428
 #5  virNetServerProgramDispatch (prog=0x2aa2c3d8010, server=server@entry=0x2aa2c3d7880, client=0x2aa2c3e3050, msg=0x2aa2c3d2770) at ../src/rpc/virnetserverprogram.c:302
 #6  0x000003ff8758c260 in virNetServerProcessMsg (msg=<optimized out>, prog=<optimized out>, client=<optimized out>, srv=0x2aa2c3d7880) at ../src/rpc/virnetserver.c:140
 #7  virNetServerHandleJob (jobOpaque=0x2aa2c3e2d30, opaque=0x2aa2c3d7880) at ../src/rpc/virnetserver.c:160
 #8  0x000003ff874c49aa in virThreadPoolWorker (opaque=<optimized out>) at ../src/util/virthreadpool.c:164
 #9  0x000003ff874c3f62 in virThreadHelper (data=<optimized out>) at ../src/util/virthread.c:256
 #10 0x000003ff86c1cf8c in start_thread () from /lib64/libc.so.6
 #11 0x000003ff86c9650e in thread_start () from /lib64/libc.so.6

Signed-off-by: Boris Fiuczynski <fiuczy@linux.ibm.com>
Reviewed-by: Jim Fehlig <jfehlig@suse.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>
---
 src/qemu/qemu_driver.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index bcd9bdb436..8337eed510 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -6615,7 +6615,7 @@ qemuDomainUndefineFlags(virDomainPtr dom,
         }
     }
 
-    if (vm->def->os.loader->nvram) {
+    if (vm->def->os.loader && vm->def->os.loader->nvram) {
         nvram_path = g_strdup(vm->def->os.loader->nvram);
     } else if (vm->def->os.firmware == VIR_DOMAIN_OS_DEF_FIRMWARE_EFI) {
         qemuDomainNVRAMPathFormat(cfg, vm->def, &nvram_path);
-- 
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