From: Arnd Bergmann arnd@arndb.de
mainline inclusion from mainline-5.2-rc7 commit 2c9292336a09f7bf019689580ceea9a2d116b999 category: bugfix bugzilla: 15766, https://bugzilla.openeuler.org/show_bug.cgi?id=25 CVE: NA
------------------------------------------------- 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@linux-foundation.org: tweak comments] Link: http://lkml.kernel.org/r/20190618092650.2943749-1-arnd@arndb.de Fixes: 68ad4a330433 ("mm/vmalloc.c: keep track of free blocks for vmap allocation") Signed-off-by: Arnd Bergmann arnd@arndb.de Reviewed-by: Uladzislau Rezki (Sony) urezki@gmail.com Cc: Joel Fernandes joelaf@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org (cherry picked from commit 2c9292336a09f7bf019689580ceea9a2d116b999) Signed-off-by: Kefeng Wang wangkefeng.wang@huawei.com Reviewed-by: Hanjun Guo guohanjun@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/vmalloc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index b246ebe224c4..1e459e02b6af 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -912,7 +912,7 @@ adjust_va_to_fit_type(struct vmap_area *va, 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) { /* @@ -971,7 +971,7 @@ adjust_va_to_fit_type(struct vmap_area *va, 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); }