The patch below does not apply to the 5.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 2127d22509aec3a83dffb2a3c736df7ba747a7ce Mon Sep 17 00:00:00 2001

From: Miaohe Lin linmiaohe@huawei.com Date: Mon, 18 Oct 2021 15:15:52 -0700 Subject: [PATCH] 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@huawei.com Link: https://lkml.kernel.org/r/20210916123920.48704-2-linmiaohe@huawei.com Fixes: 64dd68497be7 ("mm: slub: move sysfs slab alloc/free interfaces to debugfs") Signed-off-by: Miaohe Lin linmiaohe@huawei.com Reviewed-by: Vlastimil Babka vbabka@suse.cz Cc: Christoph Lameter cl@linux.com Cc: Pekka Enberg penberg@kernel.org Cc: David Rientjes rientjes@google.com Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Faiyaz Mohammed faiyazm@codeaurora.org Cc: Andrey Konovalov andreyknvl@gmail.com Cc: Andrey Ryabinin ryabinin.a.a@gmail.com Cc: Kees Cook keescook@chromium.org Cc: Bharata B Rao bharata@linux.ibm.com Cc: Roman Gushchin guro@fb.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org

diff --git a/mm/slub.c b/mm/slub.c index 3d2025f7163b..ed160b6c54f8 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -6108,9 +6108,14 @@ static int slab_debug_trace_open(struct inode *inode, struct file *filep) 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 inode *inode, struct file *filep)

if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) { bitmap_free(obj_map); + seq_release_private(inode, filep); return -ENOMEM; }