[Qemu-devel] [PATCH v4 08/38] 9pfs: Fix CLI parsing crash on error

[Markus Armbruster <armbru@redhat.com>]

Calling error_report() in a function that takes an Error ** argument
is suspicious.  9p-handle.c's handle_parse_opts() does that, and then
fails without setting an error.  Wrong.  Its caller crashes when it
tries to report the error:

    $ qemu-system-x86_64 -nodefaults -fsdev id=foo,fsdriver=handle
    qemu-system-x86_64: -fsdev id=foo,fsdriver=handle: warning: handle backend is deprecated
    qemu-system-x86_64: -fsdev id=foo,fsdriver=handle: fsdev: No path specified
    Segmentation fault (core dumped)

Screwed up when commit 91cda4e8f37 (v2.12.0) converted the function to
Error.  Fix by calling error_setg() instead of error_report().

Fixes: 91cda4e8f372602795e3a2f4bd2e3adaf9f82255
Cc: Greg Kurz <groug@kaod.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 hw/9pfs/9p-handle.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/9pfs/9p-handle.c b/hw/9pfs/9p-handle.c
index f3641dbe4a..3465b1ef30 100644
--- a/hw/9pfs/9p-handle.c
+++ b/hw/9pfs/9p-handle.c
@@ -19,6 +19,7 @@
 #include <grp.h>
 #include <sys/socket.h>
 #include <sys/un.h>
+#include "qapi/error.h"
 #include "qemu/xattr.h"
 #include "qemu/cutils.h"
 #include "qemu/error-report.h"
@@ -655,12 +656,13 @@ static int handle_parse_opts(QemuOpts *opts, FsDriverEntry *fse, Error **errp)
     warn_report("handle backend is deprecated");
 
     if (sec_model) {
-        error_report("Invalid argument security_model specified with handle fsdriver");
+        error_setg(errp,
+                   "Invalid argument security_model specified with handle fsdriver");
         return -1;
     }
 
     if (!path) {
-        error_report("fsdev: No path specified");
+        error_setg(errp, "fsdev: No path specified");
         return -1;
     }
     fse->path = g_strdup(path);
-- 
2.17.1