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BUG: KASAN: use-after-free in __lock_acquire+0x2c57/0x3f20 kernel/locking/lockdep.c:3369
Read of size 8 at addr ffff888097255360 by task syz-executor.2/10735

CPU: 0 PID: 10735 Comm: syz-executor.2 Not tainted 4.14.259-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
 __lock_acquire+0x2c57/0x3f20 kernel/locking/lockdep.c:3369
 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
 _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:176
 spin_lock_bh include/linux/spinlock.h:322 [inline]
 lock_sock_nested+0x39/0x100 net/core/sock.c:2808
 lock_sock include/net/sock.h:1473 [inline]
 nr_accept+0x1a5/0x5c0 net/netrom/af_netrom.c:808
 SYSC_accept4 net/socket.c:1587 [inline]
 SyS_accept4+0x2dc/0x580 net/socket.c:1537
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7ff7a63ade99
RSP: 002b:00007ff7a4d02168 EFLAGS: 00000246 ORIG_RAX: 000000000000002b
RAX: ffffffffffffffda RBX: 00007ff7a64c1030 RCX: 00007ff7a63ade99
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007ff7a6407ff1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd4d5c481f R14: 00007ff7a4d02300 R15: 0000000000022000

Allocated by task 10722:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15a/0x400 mm/slab.c:3729
 kmalloc include/linux/slab.h:493 [inline]
 sk_prot_alloc+0x1ba/0x290 net/core/sock.c:1484
 sk_alloc+0x36/0xcd0 net/core/sock.c:1538
 nr_create+0x99/0x5c0 net/netrom/af_netrom.c:436
 __sock_create+0x303/0x620 net/socket.c:1275
 sock_create net/socket.c:1315 [inline]
 SYSC_socket net/socket.c:1345 [inline]
 SyS_socket+0xd1/0x1b0 net/socket.c:1325
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 10754:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 sk_prot_free net/core/sock.c:1521 [inline]
 __sk_destruct+0x5e3/0x760 net/core/sock.c:1600
 sk_destruct net/core/sock.c:1615 [inline]
 __sk_free+0xd9/0x2d0 net/core/sock.c:1623
 sk_free+0x2b/0x40 net/core/sock.c:1634
 sock_put include/net/sock.h:1664 [inline]
 nr_heartbeat_expiry+0x2ba/0x310 net/netrom/nr_timer.c:152
 call_timer_fn+0x14a/0x650 kernel/time/timer.c:1280
 expire_timers+0x232/0x4d0 kernel/time/timer.c:1319
 __run_timers kernel/time/timer.c:1637 [inline]
 run_timer_softirq+0x1d5/0x5a0 kernel/time/timer.c:1650
 __do_softirq+0x24d/0x9ff kernel/softirq.c:288

The buggy address belongs to the object at ffff8880972552c0
 which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 160 bytes inside of
 2048-byte region [ffff8880972552c0, ffff888097255ac0)
The buggy address belongs to the page:
page:ffffea00025c9500 count:1 mapcount:0 mapping:ffff8880972541c0 index:0x0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffff8880972541c0 0000000000000000 0000000100000003
raw: ffffea00024e72a0 ffffea0002ade0a0 ffff88813fe74c40 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888097255200: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888097255280: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff888097255300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff888097255380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888097255400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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