From: Arnd Bergmann <arnd@xxxxxxxx>
Subject: mm/vmalloc.c: avoid bogus -Wmaybe-uninitialized warning
gcc gets confused in pcpu_get_vm_areas() because there are too many
branches that affect whether 'lva' was initialized before it gets used:
mm/vmalloc.c: In function 'pcpu_get_vm_areas':
mm/vmalloc.c:991:4: error: 'lva' may be used uninitialized in this function [-Werror=maybe-uninitialized]
insert_vmap_area_augment(lva, &va->rb_node,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
&free_vmap_area_root, &free_vmap_area_list);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/vmalloc.c:916:20: note: 'lva' was declared here
struct vmap_area *lva;
^~~
Add an intialization to NULL, and check whether this has changed
before the first use.
[akpm@xxxxxxxxxxxxxxxxxxxx: tweak comments]
Link: http://lkml.kernel.org/r/20190618092650.2943749-1-arnd@xxxxxxxx
Fixes: 68ad4a330433 ("mm/vmalloc.c: keep track of free blocks for vmap allocation")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Cc: Joel Fernandes <joelaf@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmalloc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/mm/vmalloc.c~mm-vmalloc-avoid-bogus-wmaybe-uninitialized-warning
+++ a/mm/vmalloc.c
@@ -913,7 +913,7 @@ adjust_va_to_fit_type(struct vmap_area *
unsigned long nva_start_addr, unsigned long size,
enum fit_type type)
{
- struct vmap_area *lva;
+ struct vmap_area *lva = NULL;
if (type == FL_FIT_TYPE) {
/*
@@ -972,7 +972,7 @@ adjust_va_to_fit_type(struct vmap_area *
if (type != FL_FIT_TYPE) {
augment_tree_propagate_from(va);
- if (type == NE_FIT_TYPE)
+ if (lva) /* type == NE_FIT_TYPE */
insert_vmap_area_augment(lva, &va->rb_node,
&free_vmap_area_root, &free_vmap_area_list);
}
_
