================================================================== BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x91/0x2e0 lib/refcount.c:120 Read of size 4 at addr ffff888066be84c0 by task syz-executor0/10197 CPU: 0 PID: 10197 Comm: syz-executor0 Not tainted 4.20.0+ #8 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+0x1db/0x2d0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 check_memory_region_inline mm/kasan/generic.c:185 [inline] check_memory_region+0x123/0x190 mm/kasan/generic.c:191 kasan_check_read+0x11/0x20 mm/kasan/common.c:100 atomic_read include/asm-generic/atomic-instrumented.h:21 [inline] refcount_inc_not_zero_checked+0x91/0x2e0 lib/refcount.c:120 refcount_inc_checked+0x17/0x70 lib/refcount.c:153 sock_hold include/net/sock.h:643 [inline] nr_release+0x62/0x3c0 net/netrom/af_netrom.c:523 __sock_release+0xd3/0x250 net/socket.c:579 sock_close+0x1b/0x30 net/socket.c:1141 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x19d6/0x2650 kernel/exit.c:867 do_group_exit+0x177/0x430 kernel/exit.c:970 get_signal+0x8b4/0x19b0 kernel/signal.c:2517 do_signal+0x91/0x1e80 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2f7/0x3b0 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: Bad RIP value. RSP: 002b:00007f0cd242dcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000073c048 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000073c048 RBP: 000000000073c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000073c04c R13: 00007fff2056159f R14: 00007f0cd242e9c0 R15: 000000000073c04c Allocated by task 14381: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] kasan_kmalloc mm/kasan/common.c:482 [inline] kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455 __do_kmalloc mm/slab.c:3709 [inline] __kmalloc+0x15c/0x740 mm/slab.c:3718 kmalloc include/linux/slab.h:550 [inline] kzalloc include/linux/slab.h:740 [inline] __register_sysctl_table+0xc7/0xff0 fs/proc/proc_sysctl.c:1306 register_net_sysctl+0x29/0x30 net/sysctl_net.c:120 __addrconf_sysctl_register+0x221/0x430 net/ipv6/addrconf.c:6747 addrconf_init_net+0x1f5/0x2f0 net/ipv6/addrconf.c:6836 ops_init+0x109/0x5d0 net/core/net_namespace.c:129 setup_net+0x326/0x8c0 net/core/net_namespace.c:314 copy_net_ns+0x2ae/0x4b0 net/core/net_namespace.c:437 create_new_namespaces+0x4ce/0x930 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206 ksys_unshare+0x6d7/0xfb0 kernel/fork.c:2545 __do_sys_unshare kernel/fork.c:2613 [inline] __se_sys_unshare kernel/fork.c:2611 [inline] __x64_sys_unshare+0x31/0x40 kernel/fork.c:2611 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452 __cache_free mm/slab.c:3485 [inline] kfree+0xcf/0x230 mm/slab.c:3804 __rcu_reclaim kernel/rcu/rcu.h:233 [inline] rcu_do_batch kernel/rcu/tree.c:2452 [inline] invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline] rcu_process_callbacks+0xd76/0x1680 kernel/rcu/tree.c:2754 __do_softirq+0x30b/0xb11 kernel/softirq.c:292 The buggy address belongs to the object at ffff888066be8440 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 128 bytes inside of 2048-byte region [ffff888066be8440, ffff888066be8c40) The buggy address belongs to the page: page:ffffea00019afa00 count:1 mapcount:0 mapping:ffff88812c3f0c40 index:0xffff888066be9540 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea00025b0088 ffffea000169f688 ffff88812c3f0c40 raw: ffff888066be9540 ffff888066be8440 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888066be8380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888066be8400: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff888066be8480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888066be8500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888066be8580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================