From: Arnd Bergmann <arnd@arndb.de> mainline inclusion from mainline-5.2-rc7 commit 2c9292336a09f7bf019689580ceea9a2d116b999 category: bugfix bugzilla: 15766 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> --- mm/vmalloc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 0e86f5d..491e76c 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -911,7 +911,7 @@ classify_va_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) { /* @@ -970,7 +970,7 @@ classify_va_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); } -- 1.8.3