------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 17128 at lib/refcount.c:25 refcount_warn_saturate+0x108/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 1 PID: 17128 Comm: syz-executor.0 Not tainted 5.12.0-rc4-syzkaller-00007-g7acac4b3196c #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 : ffff000028fe7b70
x29: ffff000028fe7b70 x28: ffff80001712ec80 
x27: ffff000017388000 x26: ffff000009250568 
x25: 1fffe0000124a0ad x24: 1fffe00002e7180a 
x23: ffff000017388000 x22: ffff800014fa7760 
x21: ffff00000b340000 x20: ffff000017389108 
x19: 0000000000000002 x18: ffff00006ab3db48 
x17: 0000000000000000 x16: 0000000000000000 
x15: ffff8000172c8010 x14: 1fffe000051fcea6 
x13: 0000000000000001 x12: ffff60000d569a97 
x11: 1fffe0000d569a96 x10: ffff60000d569a96 
x9 : dfff800000000000 x8 : ffff00006ab4d4b7 
x7 : 0000000000000001 x6 : 00009ffff2a9656a 
x5 : ffff00006ab4d4b0 x4 : 1fffe00001668001 
x3 : dfff800000000000 x2 : 0000000000000000 
x1 : 0000000000000000 x0 : ffff00000b340000 
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+0x7bc/0x900 net/can/j1939/main.c:271
 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_compat+0x40/0x70 arch/arm64/kernel/syscall.c:174
 el0_svc_compat+0x24/0x3c arch/arm64/kernel/entry-common.c:494
 el0_sync_compat_handler+0x90/0x140 arch/arm64/kernel/entry-common.c:503
 el0_sync_compat+0x174/0x180 arch/arm64/kernel/entry.S:708
irq event stamp: 2780
hardirqs last  enabled at (2779): [<ffff80001440009c>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
hardirqs last  enabled at (2779): [<ffff80001440009c>] _raw_spin_unlock_irq+0x78/0x15c kernel/locking/spinlock.c:199
hardirqs last disabled at (2780): [<ffff8000143e2e34>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:237
softirqs last  enabled at (2772): [<ffff8000100109e0>] _stext+0x9e0/0x1084
softirqs last disabled at (2755): [<ffff80001015a04c>] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline]
softirqs last disabled at (2755): [<ffff80001015a04c>] invoke_softirq kernel/softirq.c:228 [inline]
softirqs last disabled at (2755): [<ffff80001015a04c>] __irq_exit_rcu+0x46c/0x510 kernel/softirq.c:422
---[ end trace b0d20f2a44dc2ffd ]---