------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 2 PID: 6617 at lib/refcount.c:28 refcount_warn_saturate+0x14a/0x210 lib/refcount.c:28
Modules linked in:
CPU: 2 UID: 0 PID: 6617 Comm: syz.0.205 Not tainted 6.13.0-rc1-syzkaller-00036-g5076001689e4 #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+0x14a/0x210 lib/refcount.c:28
Code: ff 89 de e8 98 23 f9 fc 84 db 0f 85 66 ff ff ff e8 ab 21 f9 fc c6 05 77 cf a6 0b 01 90 48 c7 c7 a0 61 d1 8b e8 47 6b b9 fc 90 <0f> 0b 90 90 e9 43 ff ff ff e8 88 21 f9 fc 0f b6 1d 52 cf a6 0b 31
RSP: 0018:ffffc90006ddf930 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000cc04000
RDX: 0000000000080000 RSI: ffffffff815a5166 RDI: 0000000000000001
RBP: ffff888029ecac24 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000002
R13: 0000000000000000 R14: ffff888029ecac24 R15: 0000000000000001
FS:  00007fe44972e6c0(0000) GS:ffff88806a800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007febbbce66a8 CR3: 0000000030864000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __refcount_sub_and_test include/linux/refcount.h:275 [inline]
 __refcount_dec_and_test include/linux/refcount.h:307 [inline]
 refcount_dec_and_test include/linux/refcount.h:325 [inline]
 skb_unref include/linux/skbuff.h:1233 [inline]
 __sk_skb_reason_drop net/core/skbuff.c:1213 [inline]
 sk_skb_reason_drop+0x183/0x1a0 net/core/skbuff.c:1241
 kfree_skb_reason include/linux/skbuff.h:1263 [inline]
 kfree_skb include/linux/skbuff.h:1272 [inline]
 j1939_session_destroy+0x163/0x460 net/can/j1939/transport.c:282
 __j1939_session_release net/can/j1939/transport.c:294 [inline]
 kref_put include/linux/kref.h:65 [inline]
 j1939_session_put+0x64/0x90 net/can/j1939/transport.c:299
 j1939_sk_send_loop net/can/j1939/socket.c:1202 [inline]
 j1939_sk_sendmsg+0xf12/0x1370 net/can/j1939/socket.c:1277
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg net/socket.c:726 [inline]
 ____sys_sendmsg+0xaaf/0xc90 net/socket.c:2583
 ___sys_sendmsg+0x135/0x1e0 net/socket.c:2637
 __sys_sendmsg+0x16e/0x220 net/socket.c:2669
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe44897ff19
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:00007fe44972e058 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe448b46080 RCX: 00007fe44897ff19
RDX: 0000000004008000 RSI: 00000000200002c0 RDI: 000000000000000a
RBP: 00007fe4489f3986 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fe448b46080 R15: 00007fffd4135408
 </TASK>