From: Miaohe Lin <linmiaohe@xxxxxxxxxx> Subject: mm, slub: fix two bugs in slab_debug_trace_open() Patch series "Fixups for slub". This series contains various bug fixes for slub. We fix memoryleak, use-afer-free, NULL pointer dereferencing and so on in slub. More details can be found in the respective changelogs. This patch (of 5): It's possible that __seq_open_private() will return NULL. So we should check it before using lest dereferencing NULL pointer. And in error paths, we forgot to release private buffer via seq_release_private(). Memory will leak in these paths. Link: https://lkml.kernel.org/r/20210916123920.48704-1-linmiaohe@xxxxxxxxxx Link: https://lkml.kernel.org/r/20210916123920.48704-2-linmiaohe@xxxxxxxxxx Fixes: 64dd68497be7 ("mm: slub: move sysfs slab alloc/free interfaces to debugfs") Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx> Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Faiyaz Mohammed <faiyazm@xxxxxxxxxxxxxx> Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx> Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Bharata B Rao <bharata@xxxxxxxxxxxxx> Cc: Roman Gushchin <guro@xxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/slub.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/mm/slub.c~mm-slub-fix-two-bugs-in-slab_debug_trace_open +++ a/mm/slub.c @@ -6108,9 +6108,14 @@ static int slab_debug_trace_open(struct struct kmem_cache *s = file_inode(filep)->i_private; unsigned long *obj_map; + if (!t) + return -ENOMEM; + obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL); - if (!obj_map) + if (!obj_map) { + seq_release_private(inode, filep); return -ENOMEM; + } if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0) alloc = TRACK_ALLOC; @@ -6119,6 +6124,7 @@ static int slab_debug_trace_open(struct if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) { bitmap_free(obj_map); + seq_release_private(inode, filep); return -ENOMEM; } _
