@@ -45,10 +45,11 @@ static int pcidev_struct_fill(libxl_device_pci *pcidev, unsigned int domain,
#define STATE_TYPE 9
#define STATE_RDM_STRATEGY 10
#define STATE_RESERVE_POLICY 11
+#define INVALID 0xffffffff
int xlu_pci_parse_bdf(XLU_Config *cfg, libxl_device_pci *pcidev, const char *str)
{
unsigned state = STATE_DOMAIN;
- unsigned dom, bus, dev, func, vslot = 0;
+ unsigned dom = INVALID, bus = INVALID, dev = INVALID, func = INVALID, vslot = 0;
char *buf2, *tok, *ptr, *end, *optkey = NULL;
if ( NULL == (buf2 = ptr = strdup(str)) )
@@ -170,6 +171,8 @@ int xlu_pci_parse_bdf(XLU_Config *cfg, libxl_device_pci *pcidev, const char *str
if ( tok != ptr || state != STATE_TERMINAL )
goto parse_error;
+ assert(dom != INVALID && bus != INVALID && dev != INVALID && func != INVALID);
+
/* Just a pretty way to fill in the values */
pcidev_struct_fill(pcidev, dom, bus, dev, func, vslot << 3);
It seems xlu_pci_parse_bdf has a state machine that is too complex for gcc to understand. The build fails with: libxlu_pci.c: In function 'xlu_pci_parse_bdf': libxlu_pci.c:32:18: error: 'func' may be used uninitialized in this function [-Werror=maybe-uninitialized] 32 | pcidev->func = func; | ~~~~~~~~~~~~~^~~~~~ libxlu_pci.c:51:29: note: 'func' was declared here 51 | unsigned dom, bus, dev, func, vslot = 0; | ^~~~ libxlu_pci.c:31:17: error: 'dev' may be used uninitialized in this function [-Werror=maybe-uninitialized] 31 | pcidev->dev = dev; | ~~~~~~~~~~~~^~~~~ libxlu_pci.c:51:24: note: 'dev' was declared here 51 | unsigned dom, bus, dev, func, vslot = 0; | ^~~ libxlu_pci.c:30:17: error: 'bus' may be used uninitialized in this function [-Werror=maybe-uninitialized] 30 | pcidev->bus = bus; | ~~~~~~~~~~~~^~~~~ libxlu_pci.c:51:19: note: 'bus' was declared here 51 | unsigned dom, bus, dev, func, vslot = 0; | ^~~ libxlu_pci.c:29:20: error: 'dom' may be used uninitialized in this function [-Werror=maybe-uninitialized] 29 | pcidev->domain = domain; | ~~~~~~~~~~~~~~~^~~~~~~~ libxlu_pci.c:51:14: note: 'dom' was declared here 51 | unsigned dom, bus, dev, func, vslot = 0; | ^~~ cc1: all warnings being treated as errors Workaround it by setting the initial value to invalid value (0xffffffff) and then assert on each value being set. This way we mute the gcc warning, while still detecting bugs in the parse code. Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> --- tools/libxl/libxlu_pci.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)