------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 12348 at lib/refcount.c:28 refcount_warn_saturate+0x138/0x19c lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 12348 Comm: syz.0.3158 Not tainted 6.12.0-syzkaller-12113-gbcc8eda6d349 #0
Hardware name: linux,dummy-virt (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : refcount_warn_saturate+0x138/0x19c lib/refcount.c:28
lr : refcount_warn_saturate+0x138/0x19c lib/refcount.c:28
sp : ffff8000a07776e0
x29: ffff8000a07776e0 x28: ffff00001418f99c x27: 0000000000000002
x26: 1fffe0000320b300 x25: 1fffe0000320b318 x24: ffff0000190598c2
x23: ffff00001418f99c x22: 0000000000000000 x21: ffff800084ea1424
x20: ffff00001418f99c x19: 0000000000000003 x18: 00000000ee36cdfb
x17: 0000000000000000 x16: 0000000000000000 x15: 1fffe00001e5aca4
x14: 1ffff000110e62fd x13: ffff00000f2d6540 x12: ffff60000d3eb69b
x11: 1fffe0000d3eb69a x10: ffff60000d3eb69a x9 : dfff800000000000
x8 : ffff000069f5b4d3 x7 : 0000000000000001 x6 : ffff60000d3eb69a
x5 : ffff000069f5b4d0 x4 : 1fffe00001e5ab59 x3 : dfff800000000000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff00000f2d5ac0
Call trace:
 refcount_warn_saturate+0x138/0x19c lib/refcount.c:28 (P)
 refcount_warn_saturate+0x138/0x19c lib/refcount.c:28 (L)
 __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+0x154/0x174 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+0x104/0x36c 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+0x80/0xac net/can/j1939/transport.c:299
 j1939_sk_send_loop net/can/j1939/socket.c:1202 [inline]
 j1939_sk_sendmsg+0xaf4/0xf60 net/can/j1939/socket.c:1277
 sock_sendmsg_nosec net/socket.c:711 [inline]
 __sock_sendmsg+0xc8/0x168 net/socket.c:726
 ____sys_sendmsg+0x54c/0x6dc net/socket.c:2583
 ___sys_sendmsg+0x11c/0x19c net/socket.c:2637
 __sys_sendmsg+0x114/0x198 net/socket.c:2669
 __compat_sys_sendmsg net/compat.c:346 [inline]
 __do_compat_sys_sendmsg net/compat.c:353 [inline]
 __se_compat_sys_sendmsg net/compat.c:350 [inline]
 __arm64_compat_sys_sendmsg+0x74/0xa4 net/compat.c:350
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49
 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132
 do_el0_svc_compat+0x40/0x68 arch/arm64/kernel/syscall.c:157
 el0_svc_compat+0x4c/0x17c arch/arm64/kernel/entry-common.c:887
 el0t_32_sync_handler+0x98/0x13c arch/arm64/kernel/entry-common.c:897
 el0t_32_sync+0x19c/0x1a0 arch/arm64/kernel/entry.S:605
irq event stamp: 596
hardirqs last  enabled at (595): [<ffff80008032d374>] __up_console_sem+0x74/0x94 kernel/printk/printk.c:344
hardirqs last disabled at (596): [<ffff8000852ef3f8>] el1_dbg+0x24/0x9c arch/arm64/kernel/entry-common.c:488
softirqs last  enabled at (570): [<ffff8000801ae1d0>] softirq_handle_end kernel/softirq.c:400 [inline]
softirqs last  enabled at (570): [<ffff8000801ae1d0>] handle_softirqs+0x88c/0xdb4 kernel/softirq.c:582
softirqs last disabled at (533): [<ffff800080010758>] __do_softirq+0x14/0x20 kernel/softirq.c:588
---[ end trace 0000000000000000 ]---