------------[ cut here ]------------
WARNING: CPU: 0 PID: 4859 at lib/refcount.c:28 refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28
refcount_t: underflow; use-after-free.
Modules linked in:
Kernel panic - not syncing: kernel: panic_on_warn set ...
CPU: 0 UID: 0 PID: 4859 Comm: syz.1.189 Not tainted 6.11.0-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: frame pointer underflow
[<81966cb8>] (dump_backtrace) from [<81966db4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:826228c4 r5:00000000 r4:8200e404
[<81966d9c>] (show_stack) from [<81984a58>] (__dump_stack lib/dump_stack.c:93 [inline])
[<81966d9c>] (show_stack) from [<81984a58>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:119)
[<81984a04>] (dump_stack_lvl) from [<81984a98>] (dump_stack+0x18/0x1c lib/dump_stack.c:128)
 r5:00000000 r4:8286ed18
[<81984a80>] (dump_stack) from [<8196785c>] (panic+0x120/0x368 kernel/panic.c:354)
[<8196773c>] (panic) from [<802421d4>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<8196773c>] (panic) from [<802421d4>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:81ff6c38 r0:81ffea04
 r7:8081a110
[<80242160>] (check_panic_on_warn) from [<80242328>] (__warn+0x7c/0x180 kernel/panic.c:741)
[<802422ac>] (__warn) from [<80242614>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:774)
 r8:00000009 r7:8205cdc4 r6:df801c94 r5:84f05400 r4:00000000
[<80242430>] (warn_slowpath_fmt) from [<8081a110>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:20000013 r9:851cdd5c r8:84464f00 r7:00000000 r6:817f7394 r5:00000002
 r4:84464f00
[<80819fd4>] (refcount_warn_saturate) from [<8146782c>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<80819fd4>] (refcount_warn_saturate) from [<8146782c>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<80819fd4>] (refcount_warn_saturate) from [<8146782c>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<80819fd4>] (refcount_warn_saturate) from [<8146782c>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<80819fd4>] (refcount_warn_saturate) from [<8146782c>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<80819fd4>] (refcount_warn_saturate) from [<8146782c>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<81467654>] (sk_skb_reason_drop) from [<817f7394>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<81467654>] (sk_skb_reason_drop) from [<817f7394>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<81467654>] (sk_skb_reason_drop) from [<817f7394>] (j1939_session_skb_drop_old net/can/j1939/transport.c:347 [inline])
[<81467654>] (sk_skb_reason_drop) from [<817f7394>] (j1939_xtp_rx_cts_one net/can/j1939/transport.c:1445 [inline])
[<81467654>] (sk_skb_reason_drop) from [<817f7394>] (j1939_xtp_rx_cts+0x220/0x3d0 net/can/j1939/transport.c:1484)
 r9:851cdd5c r8:84464f00 r7:8535c498 r6:00000df2 r5:851cdd00 r4:851cdd14
[<817f7174>] (j1939_xtp_rx_cts) from [<817f8308>] (j1939_tp_cmd_recv net/can/j1939/transport.c:2089 [inline])
[<817f7174>] (j1939_xtp_rx_cts) from [<817f8308>] (j1939_tp_recv+0x3f4/0x530 net/can/j1939/transport.c:2161)
 r10:dddd0ec8 r9:00000040 r8:8535c490 r7:835a9000 r6:835a9008 r5:835a9000
 r4:85682000
[<817f7f14>] (j1939_tp_recv) from [<817f1da0>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108)
 r7:835a9000 r6:835a9008 r5:835a9810 r4:85682000
[<817f1bbc>] (j1939_can_recv) from [<817e7b6c>] (deliver net/can/af_can.c:572 [inline])
[<817f1bbc>] (j1939_can_recv) from [<817e7b6c>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606)
 r9:00000040 r8:847106a0 r7:98c80000 r6:85682240 r5:00000001 r4:8510c6c0
[<817e7ad0>] (can_rcv_filter) from [<817e8510>] (can_receive+0xb4/0xf0 net/can/af_can.c:663)
 r9:00000040 r8:00000000 r7:84710000 r6:842eb6c0 r5:84c68000 r4:85682240
[<817e845c>] (can_receive) from [<817e85d0>] (can_rcv+0x84/0xac net/can/af_can.c:687)
 r9:00000040 r8:00000002 r7:00000000 r6:00000000 r5:817e854c r4:85682240
[<817e854c>] (can_rcv) from [<814886a4>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5662)
 r5:817e854c r4:84710000
[<81488648>] (__netif_receive_skb_one_core) from [<81488710>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5775)
 r5:dddd0fb0 r4:85682240
[<814886f8>] (__netif_receive_skb) from [<81488a00>] (process_backlog+0x88/0x15c net/core/dev.c:6107)
 r5:dddd0fb0 r4:85682240
[<81488978>] (process_backlog) from [<81489904>] (__napi_poll+0x34/0x240 net/core/dev.c:6771)
 r10:dddd0ec0 r9:dddd1100 r8:df801ed0 r7:df801ecb r6:00000040 r5:dddd0fb0
 r4:00000001
[<814898d0>] (__napi_poll) from [<8148a13c>] (napi_poll net/core/dev.c:6840 [inline])
[<814898d0>] (__napi_poll) from [<8148a13c>] (net_rx_action+0x338/0x420 net/core/dev.c:6962)
 r9:dddd1100 r8:df801ed0 r7:0000012c r6:ffffe7ac r5:dddd0fb0 r4:00000000
[<81489e04>] (net_rx_action) from [<8024b5d8>] (handle_softirqs+0x15c/0x468 kernel/softirq.c:554)
 r10:00000008 r9:84f05400 r8:00000101 r7:00400040 r6:00000003 r5:00000004
 r4:8260408c
[<8024b47c>] (handle_softirqs) from [<802012d0>] (__do_softirq+0x14/0x18 kernel/softirq.c:588)
 r10:00000126 r9:84f05400 r8:00000002 r7:84cfd660 r6:852f7880 r5:00000001
 r4:60000013
[<802012bc>] (__do_softirq) from [<80208800>] (____do_softirq+0x10/0x14 arch/arm/kernel/irq.c:77)
[<802087f0>] (____do_softirq) from [<81936768>] (call_with_stack+0x1c/0x20 arch/arm/lib/call_with_stack.S:40)
[<8193674c>] (call_with_stack) from [<8020883c>] (do_softirq_own_stack+0x38/0x3c arch/arm/kernel/irq.c:82)
[<80208804>] (do_softirq_own_stack) from [<8024baf0>] (do_softirq kernel/softirq.c:455 [inline])
[<80208804>] (do_softirq_own_stack) from [<8024baf0>] (do_softirq+0x5c/0x64 kernel/softirq.c:442)
[<8024ba94>] (do_softirq) from [<8024bbc4>] (__local_bh_enable_ip+0xcc/0xd0 kernel/softirq.c:382)
 r5:00000001 r4:84f05400
[<8024baf8>] (__local_bh_enable_ip) from [<81991a78>] (__raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline])
[<8024baf8>] (__local_bh_enable_ip) from [<81991a78>] (_raw_spin_unlock_bh+0x34/0x38 kernel/locking/spinlock.c:210)
 r5:84cfd4ec r4:84cfd400
[<81991a44>] (_raw_spin_unlock_bh) from [<8145a574>] (spin_unlock_bh include/linux/spinlock.h:396 [inline])
[<81991a44>] (_raw_spin_unlock_bh) from [<8145a574>] (lock_sock_nested+0x38/0x48 net/core/sock.c:3618)
[<8145a53c>] (lock_sock_nested) from [<817f2df8>] (lock_sock include/net/sock.h:1609 [inline])
[<8145a53c>] (lock_sock_nested) from [<817f2df8>] (j1939_sk_setsockopt+0xdc/0x2d8 net/can/j1939/socket.c:717)
 r5:00000002 r4:84cfd400
[<817f2d20>] (j1939_sk_setsockopt) from [<8145195c>] (do_sock_setsockopt+0xb0/0x17c net/socket.c:2330)
 r8:8020029c r7:00000000 r6:84856280 r5:00000000 r4:817f2d1c
[<814518ac>] (do_sock_setsockopt) from [<81454ef0>] (__sys_setsockopt net/socket.c:2353 [inline])
[<814518ac>] (do_sock_setsockopt) from [<81454ef0>] (__do_sys_setsockopt net/socket.c:2362 [inline])
[<814518ac>] (do_sock_setsockopt) from [<81454ef0>] (sys_setsockopt+0x78/0xbc net/socket.c:2359)
 r6:84856280 r5:00000001 r4:0000006b
[<81454e78>] (sys_setsockopt) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67)
Exception stack(0xdfe41fa8 to 0xdfe41ff0)
1fa0:                   00000040 00000000 00000004 0000006b 00000001 20000700
1fc0: 00000040 00000000 002862f8 00000126 00000000 00006364 003d0f00 76be60bc
1fe0: 76be5ec0 76be5eb0 000189d0 00132da0
 r7:00000126 r6:002862f8 r5:00000000 r4:00000040
Rebooting in 86400 seconds..