------------[ cut here ]------------ refcount_t: increment on 0; use-after-free. WARNING: CPU: 1 PID: 4913 at lib/refcount.c:156 refcount_inc_checked+0x4b/0x50 /lib/refcount.c:156 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 4913 Comm: syz-executor.5 Not tainted 5.2.0+ #34 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+0x1d8/0x2f8 /lib/dump_stack.c:113 panic+0x29b/0x7d9 /kernel/panic.c:219 __warn+0x22f/0x230 /kernel/panic.c:576 report_bug+0x190/0x290 /lib/bug.c:186 fixup_bug /arch/x86/kernel/traps.c:179 [inline] do_error_trap+0xd7/0x440 /arch/x86/kernel/traps.c:272 do_invalid_op+0x36/0x40 /arch/x86/kernel/traps.c:291 invalid_op+0x14/0x20 /arch/x86/entry/entry_64.S:1008 RIP: 0010:refcount_inc_checked+0x4b/0x50 /lib/refcount.c:156 Code: 3d 98 dd 93 05 01 75 08 e8 b2 50 11 fe 5b 5d c3 e8 aa 50 11 fe c6 05 82 dd 93 05 01 48 c7 c7 09 ce 87 88 31 c0 e8 85 79 e2 fd <0f> 0b eb df 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 RSP: 0018:ffff8880aeb09b40 EFLAGS: 00010246 RAX: 76020461f62c1600 RBX: ffff88805a06f500 RCX: ffff88805c7aa380 RDX: 0000000000000301 RSI: 0000000000000301 RDI: 0000000000000000 RBP: ffff8880aeb09b48 R08: ffffffff816046b4 R09: fffffbfff13bb2c1 R10: fffffbfff13bb2c1 R11: 0000000000000000 R12: ffff8880620de3c0 R13: dffffc0000000000 R14: 0000000000000004 R15: ffff88805a06f480 sock_hold /./include/net/sock.h:649 [inline] sk_add_node /./include/net/sock.h:701 [inline] nr_insert_socket /net/netrom/af_netrom.c:137 [inline] nr_rx_frame+0x17bc/0x1e40 /net/netrom/af_netrom.c:1023 nr_loopback_timer+0x6a/0x140 /net/netrom/nr_loopback.c:59 call_timer_fn+0xec/0x200 /kernel/time/timer.c:1322 expire_timers /kernel/time/timer.c:1366 [inline] __run_timers+0x7cd/0x9c0 /kernel/time/timer.c:1685 run_timer_softirq+0x4a/0x90 /kernel/time/timer.c:1698 __do_softirq+0x333/0x7c4 /./arch/x86/include/asm/paravirt.h:777 invoke_softirq /kernel/softirq.c:373 [inline] irq_exit+0x227/0x230 /kernel/softirq.c:413 exiting_irq /./arch/x86/include/asm/apic.h:537 [inline] smp_apic_timer_interrupt+0x113/0x280 /arch/x86/kernel/apic/apic.c:1095 apic_timer_interrupt+0xf/0x20 /arch/x86/entry/entry_64.S:828 RIP: 0010:unwind_next_frame+0x6ed/0x870 /arch/x86/kernel/unwind_frame.c:363 Code: 48 8b 44 24 78 42 8a 04 20 84 c0 0f 85 ed 00 00 00 48 8b 44 24 18 c7 00 00 00 00 00 31 c0 48 c7 84 24 80 00 00 00 0e 36 e0 45 <4b> c7 04 2c 00 00 00 00 65 48 8b 0c 25 28 00 00 00 48 3b 8c 24 c0 RSP: 0018:ffff88805952ef80 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13 RAX: 0000000081662e01 RBX: ffff88805952f1b0 RCX: 0000000081662e01 RDX: 1ffff1100b2a5e26 RSI: ffff88805952f1b0 RDI: ffff88805952f120 RBP: ffff88805952f088 R08: dffffc0000000000 R09: ffff88805952f120 R10: ffffed100b2a5e30 R11: 0000000000000000 R12: dffffc0000000000 R13: 1ffff1100b2a5e00 R14: ffff88805952f120 R15: ffff88805952f178 __unwind_start+0x36a/0x440 /arch/x86/kernel/unwind_frame.c:410 unwind_start /./arch/x86/include/asm/unwind.h:60 [inline] arch_stack_walk+0x78/0xe0 /arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x111/0x1e0 /kernel/stacktrace.c:123 save_stack /mm/kasan/common.c:69 [inline] set_track /mm/kasan/common.c:77 [inline] __kasan_kmalloc+0x11c/0x1b0 /mm/kasan/common.c:487 kasan_slab_alloc+0xf/0x20 /mm/kasan/common.c:495 slab_post_alloc_hook /mm/slab.h:520 [inline] slab_alloc /mm/slab.c:3319 [inline] kmem_cache_alloc+0x1f5/0x2e0 /mm/slab.c:3483 kmem_cache_zalloc /./include/linux/slab.h:738 [inline] alloc_buffer_head+0x26/0xf0 /fs/buffer.c:3368 alloc_page_buffers+0x11a/0x510 /fs/buffer.c:831 create_empty_buffers+0x2f/0x5a0 /fs/buffer.c:1518 ext4_block_write_begin+0x2d1/0x1330 /fs/ext4/inode.c:1183 ext4_da_write_begin+0x759/0xd50 /fs/ext4/inode.c:3122 generic_perform_write+0x2c3/0x560 /mm/filemap.c:3327 __generic_file_write_iter+0x24b/0x520 /mm/filemap.c:3456 ext4_file_write_iter+0x926/0x16a0 /fs/ext4/file.c:270 call_write_iter /./include/linux/fs.h:1870 [inline] new_sync_write /fs/read_write.c:483 [inline] __vfs_write+0x617/0x7d0 /fs/read_write.c:496 vfs_write+0x227/0x510 /fs/read_write.c:558 ksys_write+0x16b/0x2a0 /fs/read_write.c:611 __do_sys_write /fs/read_write.c:623 [inline] __se_sys_write /fs/read_write.c:620 [inline] __x64_sys_write+0x7b/0x90 /fs/read_write.c:620 do_syscall_64+0xfe/0x140 /arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459819 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:00007f6cd89d6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459819 RDX: 000000001802a140 RSI: 00000000200000c0 RDI: 0000000000000004 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6cd89d76d4 R13: 00000000004c9774 R14: 00000000004e0b70 R15: 00000000ffffffff Kernel Offset: disabled Rebooting in 86400 seconds..