------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 11508 at lib/refcount.c:25 refcount_warn_saturate+0x108/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 1 PID: 11508 Comm: syz-executor.1 Not tainted 5.11.0-syzkaller-11482-g8b83369ddcb3 #0
Hardware name: linux,dummy-virt (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--)
pc : refcount_warn_saturate+0x108/0x1a0 lib/refcount.c:25
lr : refcount_warn_saturate+0x108/0x1a0 lib/refcount.c:25
sp : ffff000032abfb70
x29: ffff000032abfb70 x28: ffff000032abfd34 
x27: ffff00003375c000 x26: 1fffe00006557fa6 
x25: 1fffe000033632a3 x24: ffff000032abfd40 
x23: 1fffe00006557fa8 x22: 0000000000000004 
x21: ffff80001acea740 x20: ffff00003375d108 
x19: 0000000000000002 x18: ffff00006a377b48 
x17: 0000000000000000 x16: 0000000000000000 
x15: ffff80001b0d8010 x14: 1fffe00006557ea6 
x13: 0000000000000000 x12: ffff60000d470e97 
x11: 1fffe0000d470e96 x10: ffff60000d470e96 
x9 : dfff800000000000 x8 : ffff00006a3874b7 
x7 : 0000000000000001 x6 : 00009ffff2b8f16a 
x5 : ffff00006a3874b0 x4 : 1fffe00001fa4001 
x3 : dfff800000000000 x2 : 0000000000000000 
x1 : 0000000000000000 x0 : ffff00000fd20000 
Call trace:
 refcount_warn_saturate+0x108/0x1a0 lib/refcount.c:25
 __refcount_add include/linux/refcount.h:199 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 kref_get include/linux/kref.h:45 [inline]
 j1939_netdev_start+0x5fc/0x900 net/can/j1939/main.c:250
 j1939_sk_bind+0x2c8/0xd30 net/can/j1939/socket.c:479
 __sys_bind+0x16c/0x1d0 net/socket.c:1637
 __do_sys_bind net/socket.c:1648 [inline]
 __se_sys_bind net/socket.c:1646 [inline]
 __arm64_sys_bind+0x6c/0xa0 net/socket.c:1646
 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline]
 invoke_syscall arch/arm64/kernel/syscall.c:49 [inline]
 el0_svc_common.constprop.0+0xf0/0x2c0 arch/arm64/kernel/syscall.c:129
 do_el0_svc+0xa4/0xd0 arch/arm64/kernel/syscall.c:168
 el0_svc+0x24/0x34 arch/arm64/kernel/entry-common.c:416
 el0_sync_handler+0x1a4/0x1b0 arch/arm64/kernel/entry-common.c:432
 el0_sync+0x170/0x180 arch/arm64/kernel/entry.S:699