From 3510955b327176fd4cbab5baa75b449f077722a2 Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Thu, 13 Jun 2019 15:55:49 -0700 Subject: [PATCH] mm/list_lru.c: fix memory leak in __memcg_init_list_lru_node Syzbot reported following memory leak: ffffffffda RBX: 0000000000000003 RCX: 0000000000441f79 BUG: memory leak unreferenced object 0xffff888114f26040 (size 32): comm "syz-executor626", pid 7056, jiffies 4294948701 (age 39.410s) hex dump (first 32 bytes): 40 60 f2 14 81 88 ff ff 40 60 f2 14 81 88 ff ff @`......@`...... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: slab_post_alloc_hook mm/slab.h:439 [inline] slab_alloc mm/slab.c:3326 [inline] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553 kmalloc include/linux/slab.h:547 [inline] __memcg_init_list_lru_node+0x58/0xf0 mm/list_lru.c:352 memcg_init_list_lru_node mm/list_lru.c:375 [inline] memcg_init_list_lru mm/list_lru.c:459 [inline] __list_lru_init+0x193/0x2a0 mm/list_lru.c:626 alloc_super+0x2e0/0x310 fs/super.c:269 sget_userns+0x94/0x2a0 fs/super.c:609 sget+0x8d/0xb0 fs/super.c:660 mount_nodev+0x31/0xb0 fs/super.c:1387 fuse_mount+0x2d/0x40 fs/fuse/inode.c:1236 legacy_get_tree+0x27/0x80 fs/fs_context.c:661 vfs_get_tree+0x2e/0x120 fs/super.c:1476 do_new_mount fs/namespace.c:2790 [inline] do_mount+0x932/0xc50 fs/namespace.c:3110 ksys_mount+0xab/0x120 fs/namespace.c:3319 __do_sys_mount fs/namespace.c:3333 [inline] __se_sys_mount fs/namespace.c:3330 [inline] __x64_sys_mount+0x26/0x30 fs/namespace.c:3330 do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This is a simple off by one bug on the error path. Link: http://lkml.kernel.org/r/20190528043202.99980-1-shakeelb@google.com Fixes: 60d3fd32a7a9 ("list_lru: introduce per-memcg lists") Reported-by: syzbot+f90a420dfe2b1b03cb2c@syzkaller.appspotmail.com Signed-off-by: Shakeel Butt Acked-by: Michal Hocko Reviewed-by: Kirill Tkhai Cc: [4.0+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/list_lru.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/list_lru.c b/mm/list_lru.c index e4709fdaa8e6..927d85be32f6 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -354,7 +354,7 @@ static int __memcg_init_list_lru_node(struct list_lru_memcg *memcg_lrus, } return 0; fail: - __memcg_destroy_list_lru_node(memcg_lrus, begin, i - 1); + __memcg_destroy_list_lru_node(memcg_lrus, begin, i); return -ENOMEM; } -- 2.30.2