------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 5321 at lib/refcount.c:28 refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 5321 Comm: syz.0.0 Not tainted 6.13.0-rc1-syzkaller-00025-gfeffde684ac2 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x15a/0x1d0 lib/refcount.c:28
Code: e0 1e 5f 8c e8 87 c5 95 fc 90 0f 0b 90 90 eb 99 e8 2b 1e d5 fc c6 05 6d 2c 39 0b 01 90 48 c7 c7 40 1f 5f 8c e8 67 c5 95 fc 90 <0f> 0b 90 90 e9 76 ff ff ff e8 08 1e d5 fc c6 05 47 2c 39 0b 01 90
RSP: 0018:ffffc9000d3d7870 EFLAGS: 00010246
RAX: 6610c3ec309e7600 RBX: ffff888033c1bc24 RCX: 0000000000100000
RDX: ffffc9000e882000 RSI: 0000000000002f49 RDI: 0000000000002f4a
RBP: 0000000000000003 R08: ffffffff81601c02 R09: 1ffff11003f8519a
R10: dffffc0000000000 R11: ffffed1003f8519b R12: ffff888043ee1068
R13: ffff888033c1bc24 R14: 1ffff110087dc218 R15: ffff888043ee1000
FS:  00007f6b330d96c0(0000) GS:ffff88801fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001200 CR3: 0000000042d60000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kfree_skb_reason include/linux/skbuff.h:1263 [inline]
 kfree_skb include/linux/skbuff.h:1272 [inline]
 j1939_session_destroy net/can/j1939/transport.c:282 [inline]
 __j1939_session_release net/can/j1939/transport.c:294 [inline]
 kref_put include/linux/kref.h:65 [inline]
 j1939_session_put+0x1ed/0x440 net/can/j1939/transport.c:299
 j1939_sk_queue_drop_all+0x191/0x240 net/can/j1939/socket.c:144
 j1939_sk_netdev_event_netdown+0xed/0x160 net/can/j1939/socket.c:1296
 j1939_netdev_notify+0xe2/0x140 net/can/j1939/main.c:377
 notifier_call_chain+0x1a5/0x3f0 kernel/notifier.c:85
 __dev_notify_flags+0x207/0x400
 dev_change_flags+0xf0/0x1a0 net/core/dev.c:9020
 dev_ifsioc+0x7c8/0xe70 net/core/dev_ioctl.c:526
 dev_ioctl+0x719/0x1340 net/core/dev_ioctl.c:783
 sock_do_ioctl+0x240/0x460 net/socket.c:1223
 sock_ioctl+0x626/0x8e0 net/socket.c:1328
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xf5/0x170 fs/ioctl.c:892
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6b3237ff19
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6b330d9058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6b32545fa0 RCX: 00007f6b3237ff19
RDX: 0000000020000080 RSI: 0000000000008914 RDI: 000000000000000a
RBP: 00007f6b323f3986 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f6b32545fa0 R15: 00007ffe259e6e18
 </TASK>