diff mbox series

system/qdev: Remove pointless NULL check in qdev_device_add_from_qdict

Message ID 20250210121045.38908-1-philmd@linaro.org
State New
Headers show
Series system/qdev: Remove pointless NULL check in qdev_device_add_from_qdict | expand

Commit Message

Philippe Mathieu-Daudé Feb. 10, 2025, 12:10 p.m. UTC 
Coverity reported a unnecessary NULL check:

  qemu/system/qdev-monitor.c: 720 in qdev_device_add_from_qdict()
  683     /* create device */
  684     dev = qdev_new(driver);
  ...
  719     err_del_dev:
  >>>     CID 1590192:  Null pointer dereferences  (REVERSE_INULL)
  >>>     Null-checking "dev" suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
  720         if (dev) {
  721             object_unparent(OBJECT(dev));
  722             object_unref(OBJECT(dev));
  723         }
  724         return NULL;
  725     }

Indeed, unlike qdev_try_new() which can return NULL,
qdev_new() always returns a heap pointer (or aborts).

Remove the unnecessary assignment and check.

Fixes: f3a85056569 ("qdev/qbus: add hidden device support")
Resolves: Coverity CID 1590192 (Null pointer dereferences)
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 system/qdev-monitor.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

Comments

Richard Henderson Feb. 10, 2025, 5:07 p.m. UTC | #1 
On 2/10/25 04:10, Philippe Mathieu-Daudé wrote:
> Coverity reported a unnecessary NULL check:
> 
>    qemu/system/qdev-monitor.c: 720 in qdev_device_add_from_qdict()
>    683     /* create device */
>    684     dev = qdev_new(driver);
>    ...
>    719     err_del_dev:
>    >>>     CID 1590192:  Null pointer dereferences  (REVERSE_INULL)
>    >>>     Null-checking "dev" suggests that it may be null, but it has already been dereferenced on all paths leading to the check.
>    720         if (dev) {
>    721             object_unparent(OBJECT(dev));
>    722             object_unref(OBJECT(dev));
>    723         }
>    724         return NULL;
>    725     }
> 
> Indeed, unlike qdev_try_new() which can return NULL,
> qdev_new() always returns a heap pointer (or aborts).
> 
> Remove the unnecessary assignment and check.
> 
> Fixes: f3a85056569 ("qdev/qbus: add hidden device support")
> Resolves: Coverity CID 1590192 (Null pointer dereferences)
> Suggested-by: Peter Maydell<peter.maydell@linaro.org>
> Signed-off-by: Philippe Mathieu-Daudé<philmd@linaro.org>
> ---
>   system/qdev-monitor.c | 9 ++++-----
>   1 file changed, 4 insertions(+), 5 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~
diff mbox series

Patch

diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c
index 861c25c855f..01d4b007322 100644
--- a/system/qdev-monitor.c
+++ b/system/qdev-monitor.c
@@ -628,7 +628,7 @@  DeviceState *qdev_device_add_from_qdict(const QDict *opts,
     DeviceClass *dc;
     const char *driver, *path;
     char *id;
-    DeviceState *dev = NULL;
+    DeviceState *dev;
     BusState *bus = NULL;
     QDict *properties;
 
@@ -717,10 +717,9 @@  DeviceState *qdev_device_add_from_qdict(const QDict *opts,
     return dev;
 
 err_del_dev:
-    if (dev) {
-        object_unparent(OBJECT(dev));
-        object_unref(OBJECT(dev));
-    }
+    object_unparent(OBJECT(dev));
+    object_unref(OBJECT(dev));
+
     return NULL;
 }