From b007e43692c462a4df72f8c86e37c15828ad96ba Mon Sep 17 00:00:00 2001 From: Faiyaz Mohammed Date: Wed, 23 Jun 2021 10:50:06 +0530 Subject: [PATCH] FROMGIT: mm: slub: fix the leak of alloc/free traces debugfs interface Fix the leak of alloc/free traces debugfs interface, reported by kmemleak like below, unreferenced object 0xffff00091ae1b540 (size 64): comm "lsbug", pid 1607, jiffies 4294958291 (age 1476.340s) hex dump (first 32 bytes): 02 00 00 00 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b ........kkkkkkkk 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk backtrace: [] slab_post_alloc_hook+0xa0/0x418 [] kmem_cache_alloc_trace+0x1e4/0x378 [] slab_debugfs_start+0x30/0x50 slab_debugfs_start at mm/slub.c:5831 [] seq_read_iter+0x214/0xd50 [] seq_read+0x28c/0x418 [] full_proxy_read+0xdc/0x148 [] vfs_read+0x104/0x340 [] ksys_read+0xf8/0x1e0 [] __arm64_sys_read+0x74/0xa8 Link: https://lkml.kernel.org/r/1624248060-30286-1-git-send-email-faiyazm@codeaurora.org Fixes: 3589836402ca ("mm: slub: move sysfs slab alloc/free interfaces to debugfs") Link: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/mm/slub.c?h=next-20210617&id=84a2bdb1b458fc968d6d9e07dab388dc679bd747 Signed-off-by: Faiyaz Mohammed Cc: Vlastimil Babka Cc: Greg Kroah-Hartman Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton BUG: 176858818 (cherry picked from commit 29d055e7966b5beae75db7980df78f99344f74ae https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/mm/slub.c?h=next-20210624&id=29d055e7966b5beae75db7980df78f99344f74ae) Change-Id: I26fd4285b3e8f2a48f7c1320adceb0208e0fbc45 Signed-off-by: Faiyaz Mohammed --- mm/slub.c | 20 ++++++-------------- 1 file changed, 6 insertions(+), 14 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 46d14749cfba..9dde49d6deb9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -5749,31 +5749,23 @@ static int slab_debugfs_show(struct seq_file *seq, void *v) static void slab_debugfs_stop(struct seq_file *seq, void *v) { - kfree(v); } static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos) { - loff_t *spos = v; struct loc_track *t = seq->private; - if (*ppos < t->count) { - *ppos = ++*spos; - return spos; - } - *ppos = ++*spos; + v = ppos; + ++*ppos; + if (*ppos <= t->count) + return v; + return NULL; } static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos) { - loff_t *spos = kmalloc(sizeof(loff_t), GFP_KERNEL); - - if (!spos) - return NULL; - - *spos = *ppos; - return spos; + return ppos; } static const struct seq_operations slab_debugfs_sops = {