Quoting Nathan Chancellor <natechancellor@xxxxxxxxx>:
When building with -Wsometimes-uninitialized, clang warns:
drivers/pci/hotplug/rpaphp_core.c:243:14: warning: variable 'fndit' is
used uninitialized whenever 'for' loop exits because its condition is
false [-Wsometimes-uninitialized]
for (j = 0; j < entries; j++) {
^~~~~~~~~~~
drivers/pci/hotplug/rpaphp_core.c:256:6: note: uninitialized use occurs
here
if (fndit)
^~~~~
drivers/pci/hotplug/rpaphp_core.c:243:14: note: remove the condition if
it is always true
for (j = 0; j < entries; j++) {
^~~~~~~~~~~
drivers/pci/hotplug/rpaphp_core.c:233:14: note: initialize the variable
'fndit' to silence this warning
int j, fndit;
^
= 0
Looking at the loop in a vacuum as clang would, fndit could be
uninitialized if entries was ever zero or the if statement was
always true within the loop. Regardless of whether or not this
warning is a problem in practice, "found" variables should always
be initialized to false so that there is no possibility of
undefined behavior.
Link: https://github.com/ClangBuiltLinux/linux/issues/504
Fixes: 2fcf3ae508c2 ("hotplug/drc-info: Add code to search
ibm,drc-info property")
Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
---
drivers/pci/hotplug/rpaphp_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/hotplug/rpaphp_core.c
b/drivers/pci/hotplug/rpaphp_core.c
index bcd5d357ca23..07b56bf2886f 100644
--- a/drivers/pci/hotplug/rpaphp_core.c
+++ b/drivers/pci/hotplug/rpaphp_core.c
@@ -230,7 +230,7 @@ static int rpaphp_check_drc_props_v2(struct
device_node *dn, char *drc_name,
struct of_drc_info drc;
const __be32 *value;
char cell_drc_name[MAX_DRC_NAME_LEN];
- int j, fndit;
+ int j, fndit = 0;
Not sure fndit is needed at all. Looking into the full function code,
fndit only serves as doing a single action. That action could be done
in the loop directly, see below
And while you are at it, I guess you should also handle the
initialisation of cell_drc_name.
In the current code, it looks like content of cell_drc_name is
undefined when doing the strcmp when fndit is not 1.
info = of_find_property(dn->parent, "ibm,drc-info", NULL);
if (info == NULL)
--
2.22.0.rc2
diff --git a/drivers/pci/hotplug/rpaphp_core.c
b/drivers/pci/hotplug/rpaphp_core.c
index bcd5d357ca23..87113419a44f 100644
--- a/drivers/pci/hotplug/rpaphp_core.c
+++ b/drivers/pci/hotplug/rpaphp_core.c
@@ -230,7 +230,7 @@ static int rpaphp_check_drc_props_v2(struct
device_node *dn, char *drc_name,
struct of_drc_info drc;
const __be32 *value;
char cell_drc_name[MAX_DRC_NAME_LEN];
- int j, fndit;
+ int j;
info = of_find_property(dn->parent, "ibm,drc-info", NULL);
if (info == NULL)
@@ -248,14 +248,10 @@ static int rpaphp_check_drc_props_v2(struct
device_node *dn, char *drc_name,
if (my_index > drc.last_drc_index)
continue;
- fndit = 1;
+ /* Found it */
+ sprintf(cell_drc_name, "%s%d", drc.drc_name_prefix, my_index);
break;
}
- /* Found it */
-
- if (fndit)
- sprintf(cell_drc_name, "%s%d", drc.drc_name_prefix,
- my_index);
if (((drc_name == NULL) ||
(drc_name && !strcmp(drc_name, cell_drc_name))) &&
Christophe
