================================================================== 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 ffff888099292640 by task syz-executor4/19925 CPU: 1 PID: 19925 Comm: syz-executor4 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:647 [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:00007ffdf77c72d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 0000000000000016 RCX: 0000000000457ec9 RDX: 0000000000000000 RSI: 0000000000000081 RDI: 000000000073bfa8 RBP: 000000000073bfa0 R08: 0000000000741ae8 R09: 0000000000000000 R10: 00007ffdf77c7390 R11: 0000000000000246 R12: 0000000000000003 R13: 00000000000009d9 R14: 000000000073bfac R15: 000000000073bfac Allocated by task 19935: 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] sk_prot_alloc+0x19c/0x2e0 net/core/sock.c:1477 sk_alloc+0xd7/0x1690 net/core/sock.c:1531 nr_create+0xb9/0x5e0 net/netrom/af_netrom.c:436 __sock_create+0x532/0x930 net/socket.c:1277 sock_create net/socket.c:1317 [inline] __sys_socket+0x106/0x260 net/socket.c:1347 __do_sys_socket net/socket.c:1356 [inline] __se_sys_socket net/socket.c:1354 [inline] __x64_sys_socket+0x73/0xb0 net/socket.c:1354 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 19925: 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 sk_prot_free net/core/sock.c:1514 [inline] __sk_destruct+0x76d/0xa60 net/core/sock.c:1596 sk_destruct+0x7b/0x90 net/core/sock.c:1604 __sk_free+0xce/0x300 net/core/sock.c:1615 sk_free+0x42/0x50 net/core/sock.c:1626 sock_put include/net/sock.h:1707 [inline] nr_release+0x337/0x3c0 net/netrom/af_netrom.c:557 __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 The buggy address belongs to the object at ffff8880992925c0 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 128 bytes inside of 2048-byte region [ffff8880992925c0, ffff888099292dc0) The buggy address belongs to the page: page:ffffea000264a480 count:1 mapcount:0 mapping:ffff88812c3f0c40 index:0xffff888099292e40 compound_mapcount: 0 flags: 0x1fffc0000010200(slab|head) raw: 01fffc0000010200 ffffea00015fa188 ffffea00019c2c88 ffff88812c3f0c40 raw: ffff888099292e40 ffff8880992925c0 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888099292500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888099292580: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb >ffff888099292600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888099292680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888099292700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================