* [PATCH] fix infinite loop when expanding __builtin_object_size() with self-init vars
@ 2022-05-21 9:49 Luc Van Oostenryck
0 siblings, 0 replies; only message in thread
From: Luc Van Oostenryck @ 2022-05-21 9:49 UTC (permalink / raw)
To: linux-sparse; +Cc: Luc Van Oostenryck
From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
expand_object_size(), used to expand __builtin_object_size(),
recursively try to get the parent initializer. This fails miserably
by looping endlessly when the object is a self-initialized variable.
For the moment, fix this in the most obvious way: stop the recursion
and do not expand such variables.
Note: I wouldn't be surprised if these self-initialized variables create
other problems elsewhere. Maybe we should remove their initializer
and somehow mark them as "do not warn about -Wuninitialized"
(well, there is no such warnings *yet*).
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
builtin.c | 8 ++++++++
validation/builtin-objsize-self-init.c | 11 +++++++++++
2 files changed, 19 insertions(+)
create mode 100644 validation/builtin-objsize-self-init.c
diff --git a/builtin.c b/builtin.c
index 8e1d2d7e9386..3a29c3aec8a6 100644
--- a/builtin.c
+++ b/builtin.c
@@ -546,11 +546,19 @@ static int expand_object_size(struct expression *expr, int cost)
// a deref is just intermediate variable
// and so the offset needs to be zeroed.
if (arg->op == '*') {
+ struct expression *parent = arg;
arg = arg->unop;
off = 0;
switch (arg->type) {
case EXPR_SYMBOL:
arg = arg->symbol->initializer;
+ if (arg == parent) {
+ // stop at self-initialized vars
+ // and do not expand them.
+ arg = NULL;
+ val = -1;
+ break;
+ }
continue;
default:
break;
diff --git a/validation/builtin-objsize-self-init.c b/validation/builtin-objsize-self-init.c
new file mode 100644
index 000000000000..77e3da43e6d2
--- /dev/null
+++ b/validation/builtin-objsize-self-init.c
@@ -0,0 +1,11 @@
+static void f(void)
+{
+ void *param = param;
+ __builtin_object_size(param, 0);
+}
+
+/*
+ * check-name: builtin-objsize-self-init
+ * check-timeout:
+ * check-error-end
+ */
--
2.36.1
^ permalink raw reply related [flat|nested] only message in thread
only message in thread, other threads:[~2022-05-21 9:50 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-21 9:49 [PATCH] fix infinite loop when expanding __builtin_object_size() with self-init vars Luc Van Oostenryck
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).