syzbot

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BUG: KASAN: use-after-free in __list_del_entry_valid+0xe6/0xf5 lib/list_debug.c:51
Read of size 8 at addr ffff88808a5bd128 by task syz-executor.2/12471

CPU: 0 PID: 12471 Comm: syz-executor.2 Not tainted 5.2.0-rc3-next-20190605 #9
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0xd4/0x306 mm/kasan/report.c:351
 __kasan_report.cold+0x1b/0x36 mm/kasan/report.c:482
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 __list_del_entry_valid+0xe6/0xf5 lib/list_debug.c:51
 __list_del_entry include/linux/list.h:117 [inline]
 list_del include/linux/list.h:125 [inline]
 unregister_shrinker+0xb2/0x2e0 mm/vmscan.c:443
 nfsd_reply_cache_shutdown+0x26/0x360 fs/nfsd/nfscache.c:194
 nfsd_exit_net+0x170/0x4b0 fs/nfsd/nfsctl.c:1272
 ops_exit_list.isra.0+0xaa/0x150 net/core/net_namespace.c:154
 setup_net+0x400/0x740 net/core/net_namespace.c:333
 copy_net_ns+0x1df/0x340 net/core/net_namespace.c:439
 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206
 ksys_unshare+0x444/0x980 kernel/fork.c:2718
 __do_sys_unshare kernel/fork.c:2786 [inline]
 __se_sys_unshare kernel/fork.c:2784 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:2784
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459279
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f7ae73e1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000459279
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 000000000075bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7ae73e26d4
R13: 00000000004c84ef R14: 00000000004decb0 R15: 00000000ffffffff

Allocated by task 12460:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503
 __do_kmalloc mm/slab.c:3654 [inline]
 __kmalloc+0x15c/0x740 mm/slab.c:3663
 kmalloc include/linux/slab.h:552 [inline]
 kzalloc include/linux/slab.h:742 [inline]
 ops_init+0xff/0x410 net/core/net_namespace.c:120
 setup_net+0x2d3/0x740 net/core/net_namespace.c:316
 copy_net_ns+0x1df/0x340 net/core/net_namespace.c:439
 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206
 ksys_unshare+0x444/0x980 kernel/fork.c:2718
 __do_sys_unshare kernel/fork.c:2786 [inline]
 __se_sys_unshare kernel/fork.c:2784 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:2784
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 12460:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x106/0x2a0 mm/slab.c:3753
 ops_init+0xd1/0x410 net/core/net_namespace.c:135
 setup_net+0x2d3/0x740 net/core/net_namespace.c:316
 copy_net_ns+0x1df/0x340 net/core/net_namespace.c:439
 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206
 ksys_unshare+0x444/0x980 kernel/fork.c:2718
 __do_sys_unshare kernel/fork.c:2786 [inline]
 __se_sys_unshare kernel/fork.c:2784 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:2784
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88808a5bcdc0
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 872 bytes inside of
 1024-byte region [ffff88808a5bcdc0, ffff88808a5bd1c0)
The buggy address belongs to the page:
page:ffffea0002296f00 refcount:1 mapcount:0 mapping:ffff8880aa400ac0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea000249ea08 ffffea000235a588 ffff8880aa400ac0
raw: 0000000000000000 ffff88808a5bc040 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808a5bd000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88808a5bd080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88808a5bd100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff88808a5bd180: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88808a5bd200: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
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