------------[ cut here ]------------ refcount_t: increment on 0; use-after-free. WARNING: CPU: 1 PID: 5962 at lib/refcount.c:156 refcount_inc_checked lib/refcount.c:156 [inline] WARNING: CPU: 1 PID: 5962 at lib/refcount.c:156 refcount_inc_checked+0x61/0x70 lib/refcount.c:154 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 5962 Comm: syz-executor.3 Not tainted 5.4.0-syzkaller #0 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+0x197/0x210 lib/dump_stack.c:118 panic+0x2e3/0x75c kernel/panic.c:221 __warn.cold+0x2f/0x35 kernel/panic.c:582 report_bug+0x289/0x300 lib/bug.c:195 fixup_bug arch/x86/kernel/traps.c:179 [inline] fixup_bug arch/x86/kernel/traps.c:174 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028 RIP: 0010:refcount_inc_checked lib/refcount.c:156 [inline] RIP: 0010:refcount_inc_checked+0x61/0x70 lib/refcount.c:154 Code: 1d 11 7e 7c 06 31 ff 89 de e8 2b 0e 2d fe 84 db 75 dd e8 e2 0c 2d fe 48 c7 c7 e0 01 e7 87 c6 05 f1 7d 7c 06 01 e8 17 3f fe fd <0f> 0b eb c1 90 90 90 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 RSP: 0018:ffff88807d18fce8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000011d9d RSI: ffffffff815db046 RDI: ffffed100fa31f8f RBP: ffff88807d18fcf8 R08: ffff88806e918300 R09: ffffed1015d241b9 R10: ffffed1015d241b8 R11: ffff8880ae920dc7 R12: ffff8880822010f0 R13: ffff88807d18fe00 R14: ffff88806350f500 R15: 0000000000000118 kref_get include/linux/kref.h:45 [inline] j1939_netdev_start+0x53/0x550 net/can/j1939/main.c:256 j1939_sk_bind+0x640/0x8f0 net/can/j1939/socket.c:465 __sys_bind+0x239/0x290 net/socket.c:1648 __do_sys_bind net/socket.c:1659 [inline] __se_sys_bind net/socket.c:1657 [inline] __x64_sys_bind+0x73/0xb0 net/socket.c:1657 do_syscall_64+0xfa/0x760 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a649 Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f5fd186ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000031 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a649 RDX: 0000000000000018 RSI: 0000000020000240 RDI: 0000000000000004 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5fd186f6d4 R13: 00000000004c09c9 R14: 00000000004d3330 R15: 00000000ffffffff Kernel Offset: disabled Rebooting in 86400 seconds..