------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 12354 at lib/refcount.c:28 refcount_warn_saturate+0x138/0x19c lib/refcount.c:28
Modules linked in:
CPU: 0 UID: 0 PID: 12354 Comm: syz.1.3082 Not tainted 6.12.0-rc1-syzkaller-00125-g0c559323bbaa #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 : ffff8000a13976c0
x29: ffff8000a13976c0 x28: ffff0000125edadc x27: 0000000000000002
x26: 1fffe00002e42080 x25: 1fffe00002e42098 x24: ffff0000172104c2
x23: ffff0000125edadc x22: 0000000000000000 x21: ffff800084d6a4d4
x20: ffff0000125edadc x19: 0000000000000003 x18: 000000008b1a7cdb
x17: 0000000000000000 x16: 0000000000000000 x15: ffff000016124680
x14: 1fffe00002c248cf x13: 1fffe00002c248d9 x12: ffff60000d3f2a93
x11: 1fffe0000d3f2a92 x10: ffff60000d3f2a92 x9 : dfff800000000000
x8 : ffff000069f95493 x7 : 0000000000000001 x6 : ffff60000d3f2a92
x5 : ffff000069f95490 x4 : 1fffe00002c24781 x3 : dfff800000000000
x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000016123c00
Call trace:
 refcount_warn_saturate+0x138/0x19c lib/refcount.c:28
 __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:1232 [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:1262 [inline]
 kfree_skb include/linux/skbuff.h:1271 [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:729 [inline]
 __sock_sendmsg+0xc8/0x168 net/socket.c:744
 ____sys_sendmsg+0x54c/0x6dc net/socket.c:2602
 ___sys_sendmsg+0x11c/0x19c net/socket.c:2656
 __sys_sendmsg+0xe0/0x174 net/socket.c:2685
 __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:852
 el0t_32_sync_handler+0x98/0x13c arch/arm64/kernel/entry-common.c:862
 el0t_32_sync+0x194/0x198 arch/arm64/kernel/entry.S:603
irq event stamp: 572
hardirqs last  enabled at (571): [<ffff800080319adc>] __up_console_sem+0x74/0x94 kernel/printk/printk.c:344
hardirqs last disabled at (572): [<ffff8000851a4a50>] el1_dbg+0x24/0x9c arch/arm64/kernel/entry-common.c:470
softirqs last  enabled at (546): [<ffff80008019e314>] softirq_handle_end kernel/softirq.c:400 [inline]
softirqs last  enabled at (546): [<ffff80008019e314>] handle_softirqs+0x878/0xd40 kernel/softirq.c:582
softirqs last disabled at (499): [<ffff800080010758>] __do_softirq+0x14/0x20 kernel/softirq.c:588
---[ end trace 0000000000000000 ]---