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Fix #15217 (gtk.cfg: g_idle_add and g_timeout_add take the data pointer) #9008

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Merged
danmar merged 3 commits into from
Nov 13, 2026
Merged

Fix #15217 (gtk.cfg: g_idle_add and g_timeout_add take the data pointer) #9008

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46f1427
gtk.cfg: g_idle_add and g_timeout_add take the data pointer
pduchi Oct 21, 2026
fb46279
gtk.cfg: the data of g_idle_add and g_timeout_add is not const
pduchi Nov 13, 2026
c10a655
test/cfg/gtk.c: g_idle_add of freed data is not reported
pduchi Nov 13, 2026
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16 changes: 9 additions & 7 deletions cfg/gtk.cfg
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Original file line number Diff line number Diff line change
Expand Up @@ -717,6 +717,12 @@
<alloc init="true" no-fail="true">g_variant_type_dup_string</alloc>
<alloc init="true" no-fail="true">g_value_dup_string</alloc>
<use>g_register_data</use>
<use>g_idle_add</use>

@dmcppcheck dmcppcheck Nov 11, 2026

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AI review

Taking these functions off <leak-ignore/> also turns off the use-after-free check for their arguments. CheckLeakAutoVarImpl::functionCall calls checkTokenInsideExpression only for leak-ignore functions; a <use> function only gets changeAllocStatus. As a result:

void b(void){ gchar *p=g_strdup("x"); g_free(p); g_idle_add(cb,p); }

Base reports deallocuse: Dereferencing 'p' after it is deallocated / released. With this PR nothing is reported. This is how <use> works in general, so it may be acceptable, but it is a new false negative for these six functions.

<use>g_idle_add_full</use>
<use>g_timeout_add</use>
<use>g_timeout_add_full</use>
<use>g_timeout_add_seconds</use>
<use>g_timeout_add_seconds_full</use>
<dealloc>g_free</dealloc>
</memory>
<memory>
Expand Down Expand Up @@ -4237,19 +4243,17 @@
</function>
<!--guint g_idle_add (GSourceFunc function, gpointer data); -->
<function name="g_idle_add">
<leak-ignore/>
<noreturn>false</noreturn>
<returnValue type="guint"/>
<arg nr="1" direction="in">
<not-null/>
</arg>
<arg nr="2" direction="in">
<arg nr="2">
<not-uninit/>
</arg>
</function>
<!--guint g_idle_add_full (gint priority, GSourceFunc function, gpointer data, GDestroyNotify notify); -->
<function name="g_idle_add_full">
<leak-ignore/>
<noreturn>false</noreturn>
<returnValue type="guint"/>
<arg nr="1">
Expand Down Expand Up @@ -5652,7 +5656,6 @@
<!-- guint g_timeout_add ( guint interval, GSourceFunc function, gpointer data) -->
<!-- guint g_timeout_add_seconds ( guint interval, GSourceFunc function, gpointer data) -->
<function name="g_timeout_add,g_timeout_add_seconds">
<leak-ignore/>
<noreturn>false</noreturn>
<returnValue type="guint"/>
<arg nr="1" direction="in">
Expand All @@ -5663,13 +5666,12 @@
<not-uninit/>
<not-null/>
</arg>
<arg nr="3" direction="in">
<arg nr="3">
<not-uninit/>
</arg>
</function>
<!-- guint g_timeout_add_full (gint priority, guint interval, GSourceFunc function, gpointer data, GDestroyNotify notify) -->
<function name="g_timeout_add_full,g_timeout_add_seconds_full">
<leak-ignore/>
<noreturn>false</noreturn>
<returnValue type="guint"/>
<arg nr="1" direction="in">
Expand All @@ -5684,7 +5686,7 @@
<not-uninit/>
<not-null/>
</arg>
<arg nr="4" direction="in">
<arg nr="4">
<not-uninit/>
</arg>
<arg nr="5" direction="in">
Expand Down
47 changes: 47 additions & 0 deletions test/cfg/gtk.c
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Original file line number Diff line number Diff line change
Expand Up @@ -730,3 +730,50 @@ int g_define_enum_and_flags_type_test(void) {
return e + f;
}
#endif

static gboolean source_func_frees_data(gpointer data)
{
g_free(data);
return FALSE;
}

static void destroy_notify_frees_data(gpointer data)
{
g_free(data);
}

// The data passed to a GSource is owned by the callback or the destroy notify
// from then on, so it does not leak.
void g_idle_add_takes_data_test(void)
{
gchar *data = g_strdup("data");
g_idle_add(source_func_frees_data, data);

gchar *data_full = g_strdup("data");
g_idle_add_full(200, source_func_frees_data, data_full, NULL);
}

void g_timeout_add_takes_data_test(void)
{
gchar *data = g_strdup("data");
g_timeout_add(10, source_func_frees_data, data);

gchar *data_seconds = g_strdup("data");
g_timeout_add_seconds(1, source_func_frees_data, data_seconds);

gchar *data_full = g_strdup("data");
g_timeout_add_full(0, 10, source_func_frees_data, data_full, destroy_notify_frees_data);

gchar *data_seconds_full = g_strdup("data");
g_timeout_add_seconds_full(0, 1, source_func_frees_data, data_seconds_full, destroy_notify_frees_data);
}

// Handing over data that is already freed is a use after free.
// TODO: <use> functions don't get the deallocuse check yet.
void g_idle_add_freed_data_test(void)
{
gchar *data = g_strdup("data");
g_free(data);
// TODO cppcheck-suppress deallocuse
g_idle_add(source_func_frees_data, data);
}
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