------------[ cut here ]------------
WARNING: CPU: 0 PID: 12375 at lib/refcount.c:25 refcount_warn_saturate+0x108/0x174 lib/refcount.c:25
refcount_t: addition on 0; use-after-free.
Modules linked in:
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 12375 Comm: syz-executor.0 Not tainted 5.12.0-rc3-syzkaller #0
Hardware name: ARM-Versatile Express
Backtrace: 
[<81802550>] (dump_backtrace) from [<818027c4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:252)
 r7:00000080 r6:60000093 r5:00000000 r4:82b58344
[<818027ac>] (show_stack) from [<81809e98>] (__dump_stack lib/dump_stack.c:79 [inline])
[<818027ac>] (show_stack) from [<81809e98>] (dump_stack+0xb8/0xe8 lib/dump_stack.c:120)
[<81809de0>] (dump_stack) from [<81803358>] (panic+0x130/0x378 kernel/panic.c:231)
 r7:81f48198 r6:82a390a4 r5:00000000 r4:82c6b0d0
[<81803228>] (panic) from [<802446f4>] (__warn+0xb0/0x164 kernel/panic.c:605)
 r3:82a2248c r2:00000000 r1:00000000 r0:81f48198
 r7:00000019
[<80244644>] (__warn) from [<8180363c>] (warn_slowpath_fmt+0x9c/0xd4 kernel/panic.c:635)
 r7:807f727c r6:00000019 r5:81fa03ec r4:81fa03fc
[<818035a4>] (warn_slowpath_fmt) from [<807f727c>] (refcount_warn_saturate+0x108/0x174 lib/refcount.c:25)
 r8:864b4000 r7:0000011a r6:864b4000 r5:8613ba80 r4:86d3d000
[<807f7174>] (refcount_warn_saturate) from [<816d2270>] (__refcount_add include/linux/refcount.h:199 [inline])
[<807f7174>] (refcount_warn_saturate) from [<816d2270>] (__refcount_inc include/linux/refcount.h:250 [inline])
[<807f7174>] (refcount_warn_saturate) from [<816d2270>] (refcount_inc include/linux/refcount.h:267 [inline])
[<807f7174>] (refcount_warn_saturate) from [<816d2270>] (kref_get include/linux/kref.h:45 [inline])
[<807f7174>] (refcount_warn_saturate) from [<816d2270>] (j1939_netdev_start+0x280/0x388 net/can/j1939/main.c:250)
[<816d1ff0>] (j1939_netdev_start) from [<816d3c7c>] (j1939_sk_bind+0xf0/0x304 net/can/j1939/socket.c:479)
 r8:864b4000 r7:0000011a r6:846af800 r5:8613ba80 r4:86d1fef4
[<816d3b8c>] (j1939_sk_bind) from [<81324080>] (__sys_bind+0xc8/0xd8 net/socket.c:1637)
 r10:0000011a r9:86d1e000 r8:80200224 r7:0000011a r6:00000018 r5:8613ba80
 r4:20000040
[<81323fb8>] (__sys_bind) from [<813240a0>] (__do_sys_bind net/socket.c:1648 [inline])
[<81323fb8>] (__sys_bind) from [<813240a0>] (sys_bind+0x10/0x14 net/socket.c:1646)
 r6:00000000 r5:00000000 r4:00000000
[<81324090>] (sys_bind) from [<80200060>] (ret_fast_syscall+0x0/0x2c arch/arm/mm/proc-v7.S:64)
Exception stack(0x86d1ffa8 to 0x86d1fff0)
ffa0:                   00000000 00000000 00000003 20000040 00000018 00000000
ffc0: 00000000 00000000 00000000 0000011a 7ebf3332 76f116d0 7ebf34ac 76f1120c
ffe0: 76f11048 76f11038 00018d78 0004b600
Rebooting in 86400 seconds..