RDX: 0492492492492642 RSI: 0000000020000180 RDI: 0000000000000007
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fabb720c6d4
R13: 00000000004c9b18 R14: 00000000004e2b10 R15: 0000000000000008
==================================================================
BUG: KASAN: use-after-free in __list_del_entry_valid+0xd0/0xf3 lib/list_debug.c:42
Read of size 8 at addr ffff8880873c8210 by task kworker/u4:1/21

CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.0.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x113/0x167 lib/dump_stack.c:113
 print_address_description.cold.5+0x9/0x1ff mm/kasan/report.c:187
 kasan_report.cold.6+0x1b/0x39 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 __list_del_entry_valid+0xd0/0xf3 lib/list_debug.c:42
 __list_del_entry include/linux/list.h:117 [inline]
 list_del_rcu include/linux/rculist.h:130 [inline]
 cleanup_net+0xd9/0x840 net/core/net_namespace.c:523
 process_one_work+0x830/0x16a0 kernel/workqueue.c:2173
 worker_thread+0x85/0xb60 kernel/workqueue.c:2319
 kthread+0x324/0x3e0 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 7194:
 save_stack+0x43/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc.constprop.13+0xcb/0xd0 mm/kasan/common.c:496
 kasan_kmalloc mm/kasan/common.c:504 [inline]
 kasan_slab_alloc+0x12/0x20 mm/kasan/common.c:411
 kmem_cache_alloc+0x130/0x730 mm/slab.c:3543
 kmem_cache_zalloc include/linux/slab.h:730 [inline]
 net_alloc net/core/net_namespace.c:384 [inline]
 copy_net_ns+0xc6/0x2a0 net/core/net_namespace.c:424
 create_new_namespaces+0x483/0x750 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0x87/0x1a0 kernel/nsproxy.c:206
 ksys_unshare+0x31b/0x710 kernel/fork.c:2550
 __do_sys_unshare kernel/fork.c:2618 [inline]
 __se_sys_unshare kernel/fork.c:2616 [inline]
 __x64_sys_unshare+0x2c/0x40 kernel/fork.c:2616
 do_syscall_64+0xd0/0x4d0 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 21:
 save_stack+0x43/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466
 __cache_free mm/slab.c:3487 [inline]
 kmem_cache_free+0x83/0x290 mm/slab.c:3749
 net_free net/core/net_namespace.c:400 [inline]
 net_drop_ns+0x54/0x60 net/core/net_namespace.c:407
 cleanup_net+0x550/0x840 net/core/net_namespace.c:569
 process_one_work+0x830/0x16a0 kernel/workqueue.c:2173
 worker_thread+0x85/0xb60 kernel/workqueue.c:2319
 kthread+0x324/0x3e0 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8880873c81c0
 which belongs to the cache net_namespace of size 8512
The buggy address is located 80 bytes inside of
 8512-byte region [ffff8880873c81c0, ffff8880873ca300)
The buggy address belongs to the page:
page:ffffea00021cf200 count:1 mapcount:0 mapping:ffff88821b71c0c0 index:0x0 compound_mapcount: 0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00023a0008 ffffea000254a908 ffff88821b71c0c0
raw: 0000000000000000 ffff8880873c81c0 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880873c8100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880873c8180: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8880873c8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff8880873c8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880873c8300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================