[Qemu-trivial] [PATCH] syscall: fix compiler warnings (clang 5)

[Philippe Mathieu-Daudé]

static code analyzer complain:

linux-user/syscall.c:5575:9: warning: Dereference of undefined pointer value
    if (*host_rt_dev_ptr != 0) {
        ^~~~~~~~~~~~~~~~

Reported-by: Clang Static Analyzer
Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
---
 linux-user/syscall.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index cec8428589..c541e22693 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -5526,7 +5526,7 @@ static abi_long do_ioctl_rt(const IOCTLEntry *ie, uint8_t 
*buf_temp,
     int target_size;
     void *argptr;
     abi_ulong *target_rt_dev_ptr;
-    unsigned long *host_rt_dev_ptr;
+    unsigned long *host_rt_dev_ptr = NULL;
     abi_long ret;
     int i;
 
@@ -5572,7 +5572,7 @@ static abi_long do_ioctl_rt(const IOCTLEntry *ie, uint8_t 
*buf_temp,
     unlock_user(argptr, arg, 0);
 
     ret = get_errno(safe_ioctl(fd, ie->host_cmd, buf_temp));
-    if (*host_rt_dev_ptr != 0) {
+    if (host_rt_dev_ptr != NULL && *host_rt_dev_ptr != 0) {
         unlock_user((void *)*host_rt_dev_ptr,
                     *target_rt_dev_ptr, 0);
     }
-- 
2.11.0