refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 14533 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 14533 Comm: syz-executor.1 Not tainted 5.12.0-rc3-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014
RIP: 0010:refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25
Code: 09 31 ff 89 de e8 57 e2 aa fd 84 db 0f 85 36 ff ff ff e8 3a da aa fd 48 c7 c7 a0 44 c1 89 c6 05 5a 6c e9 09 01 e8 7d 8a fc 04 <0f> 0b e9 17 ff ff ff e8 1b da aa fd 0f b6 1d 3f 6c e9 09 31 ff 89
RSP: 0018:ffffc90001ec7d28 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000040000 RSI: ffffffff815b8095 RDI: fffff520003d8f97
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815b0dfe R11: 0000000000000000 R12: ffff88805ec04000
R13: ffff88805ec04000 R14: ffff88806da60568 R15: ffff88806985c050
FS:  00007f00c280c700(0000) GS:ffff88802cc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff76fa0c000 CR3: 000000006b07c000 CR4: 0000000000150ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __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+0x777/0x890 net/can/j1939/main.c:271
 j1939_sk_bind+0x9b8/0xe20 net/can/j1939/socket.c:479
 __sys_bind+0x1e9/0x250 net/socket.c:1637
 __do_sys_bind net/socket.c:1648 [inline]
 __se_sys_bind net/socket.c:1646 [inline]
 __x64_sys_bind+0x6f/0xb0 net/socket.c:1646
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x466459
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f00c280c188 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459
RDX: 0000000000000018 RSI: 0000000020000200 RDI: 0000000000000003
RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007fffdfa93e9f R14: 00007f00c280c300 R15: 0000000000022000