------------[ cut here ]------------
WARNING: CPU: 1 PID: 5154 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: 1 UID: 0 PID: 5154 Comm: syz.0.225 Not tainted 6.11.0-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: frame pointer underflow
[<81983358>] (dump_backtrace) from [<81983454>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:826228c4 r5:00000000 r4:820355f0
[<8198343c>] (show_stack) from [<819a13b8>] (__dump_stack lib/dump_stack.c:93 [inline])
[<8198343c>] (show_stack) from [<819a13b8>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:119)
[<819a1364>] (dump_stack_lvl) from [<819a13f8>] (dump_stack+0x18/0x1c lib/dump_stack.c:128)
 r5:00000000 r4:8286ed18
[<819a13e0>] (dump_stack) from [<81983efc>] (panic+0x120/0x370 kernel/panic.c:354)
[<81983ddc>] (panic) from [<802421cc>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<81983ddc>] (panic) from [<802421cc>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:8201dda8 r0:82025b74
 r7:80832e10
[<80242158>] (check_panic_on_warn) from [<8024232c>] (__warn+0x80/0x188 kernel/panic.c:748)
[<802422ac>] (__warn) from [<8024261c>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:783)
 r8:00000009 r7:820840e0 r6:df805c94 r5:85340000 r4:00000000
[<80242438>] (warn_slowpath_fmt) from [<80832e10>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:20000013 r9:84e8865c r8:85192c00 r7:00000000 r6:81813a2c r5:00000002
 r4:85192c00
[<80832cd4>] (refcount_warn_saturate) from [<81483ec4>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<81483ec4>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<81483ec4>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<81483ec4>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<81483ec4>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<80832cd4>] (refcount_warn_saturate) from [<81483ec4>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<81483cec>] (sk_skb_reason_drop) from [<81813a2c>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<81483cec>] (sk_skb_reason_drop) from [<81813a2c>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<81483cec>] (sk_skb_reason_drop) from [<81813a2c>] (j1939_session_skb_drop_old net/can/j1939/transport.c:347 [inline])
[<81483cec>] (sk_skb_reason_drop) from [<81813a2c>] (j1939_xtp_rx_cts_one net/can/j1939/transport.c:1445 [inline])
[<81483cec>] (sk_skb_reason_drop) from [<81813a2c>] (j1939_xtp_rx_cts+0x220/0x3d0 net/can/j1939/transport.c:1484)
 r9:84e8865c r8:85192c00 r7:83fbe6d8 r6:00000df2 r5:84e88600 r4:84e88614
[<8181380c>] (j1939_xtp_rx_cts) from [<818149a0>] (j1939_tp_cmd_recv net/can/j1939/transport.c:2089 [inline])
[<8181380c>] (j1939_xtp_rx_cts) from [<818149a0>] (j1939_tp_recv+0x3f4/0x530 net/can/j1939/transport.c:2161)
 r10:ddde4ec8 r9:00000040 r8:83fbe6d0 r7:8462c000 r6:8462c008 r5:8462c000
 r4:85190000
[<818145ac>] (j1939_tp_recv) from [<8180e438>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108)
 r7:8462c000 r6:8462c008 r5:8462c810 r4:85190000
[<8180e254>] (j1939_can_recv) from [<81804204>] (deliver net/can/af_can.c:572 [inline])
[<8180e254>] (j1939_can_recv) from [<81804204>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606)
 r9:00000040 r8:85328680 r7:98c80000 r6:85190f00 r5:00000001 r4:8477a360
[<81804168>] (can_rcv_filter) from [<81804ba8>] (can_receive+0xb4/0xf0 net/can/af_can.c:663)
 r9:00000040 r8:00000000 r7:85328000 r6:850924c0 r5:84108d00 r4:85190f00
[<81804af4>] (can_receive) from [<81804c68>] (can_rcv+0x84/0xac net/can/af_can.c:687)
 r9:00000040 r8:00000001 r7:00000000 r6:00000000 r5:81804be4 r4:85190f00
[<81804be4>] (can_rcv) from [<814a4d3c>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5662)
 r5:81804be4 r4:85328000
[<814a4ce0>] (__netif_receive_skb_one_core) from [<814a4da8>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5775)
 r5:ddde4fb0 r4:85190f00
[<814a4d90>] (__netif_receive_skb) from [<814a5098>] (process_backlog+0x88/0x15c net/core/dev.c:6107)
 r5:ddde4fb0 r4:85190f00
[<814a5010>] (process_backlog) from [<814a5f9c>] (__napi_poll+0x34/0x240 net/core/dev.c:6771)
 r10:ddde4ec0 r9:ddde5100 r8:df805ed0 r7:df805ecb r6:00000040 r5:ddde4fb0
 r4:00000001
[<814a5f68>] (__napi_poll) from [<814a67d4>] (napi_poll net/core/dev.c:6840 [inline])
[<814a5f68>] (__napi_poll) from [<814a67d4>] (net_rx_action+0x338/0x420 net/core/dev.c:6962)
 r9:ddde5100 r8:df805ed0 r7:0000012c r6:ffffe22c r5:ddde4fb0 r4:00000000
[<814a649c>] (net_rx_action) from [<8024b5e0>] (handle_softirqs+0x158/0x464 kernel/softirq.c:554)
 r10:00000008 r9:85340000 r8:00000101 r7:00400040 r6:00000003 r5:00000004
 r4:8260408c
[<8024b488>] (handle_softirqs) from [<802012d0>] (__do_softirq+0x14/0x18 kernel/softirq.c:588)
 r10:003d0f00 r9:853400e0 r8:8286e084 r7:85340000 r6:ecac8b10 r5:00000001
 r4:60000013
[<802012bc>] (__do_softirq) from [<80208800>] (____do_softirq+0x10/0x14 arch/arm/kernel/irq.c:77)
[<802087f0>] (____do_softirq) from [<81952e00>] (call_with_stack+0x1c/0x20 arch/arm/lib/call_with_stack.S:40)
[<81952de4>] (call_with_stack) from [<8020883c>] (do_softirq_own_stack+0x38/0x3c arch/arm/kernel/irq.c:82)
[<80208804>] (do_softirq_own_stack) from [<8024baf8>] (do_softirq kernel/softirq.c:455 [inline])
[<80208804>] (do_softirq_own_stack) from [<8024baf8>] (do_softirq+0x5c/0x64 kernel/softirq.c:442)
[<8024ba9c>] (do_softirq) from [<8024bbcc>] (__local_bh_enable_ip+0xcc/0xd0 kernel/softirq.c:382)
 r5:00000001 r4:85340000
[<8024bb00>] (__local_bh_enable_ip) from [<80202d6c>] (local_bh_enable include/linux/bottom_half.h:33 [inline])
[<8024bb00>] (__local_bh_enable_ip) from [<80202d6c>] (vfp_support_entry+0xac/0x2a0 arch/arm/vfp/vfpmodule.c:775)
 r5:40000000 r4:dfa81fb0
[<80202cc0>] (vfp_support_entry) from [<8020c930>] (call_undef_hook arch/arm/kernel/traps.c:449 [inline])
[<80202cc0>] (vfp_support_entry) from [<8020c930>] (do_undefinstr+0xe4/0x1e0 arch/arm/kernel/traps.c:488)
 r9:00006364 r8:80202cc0 r7:ecac8b10 r6:0014d300 r5:dfa81fb0 r4:8261c9c4
[<8020c84c>] (do_undefinstr) from [<80200fe4>] (__und_usr+0x84/0xa0 arch/arm/kernel/entry-armv.S:470)
Exception stack(0xdfa81fb0 to 0xdfa81ff8)
1fa0:                                     76bc2b10 00000000 0fffb0d6 00db9828
1fc0: 00000000 00286380 00188a5c 00188a64 00000000 00006364 003d0f00 76bc20bc
1fe0: 76bc2b38 76bc1ee8 0001c9b4 0014d300 20000010 ffffffff
 r9:00006364 r8:824ae044 r7:85340000 r6:ffffffff r5:20000010 r4:0014d304
Rebooting in 86400 seconds..