------------[ cut here ]------------
WARNING: CPU: 1 PID: 5935 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: 5935 Comm: syz.0.352 Not tainted 6.11.0-syzkaller #0
Hardware name: ARM-Versatile Express
Call trace: frame pointer underflow
[<81985d00>] (dump_backtrace) from [<81985dfc>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257)
 r7:00000000 r6:826228c4 r5:00000000 r4:82035a40
[<81985de4>] (show_stack) from [<819a40dc>] (__dump_stack lib/dump_stack.c:93 [inline])
[<81985de4>] (show_stack) from [<819a40dc>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:119)
[<819a4088>] (dump_stack_lvl) from [<819a411c>] (dump_stack+0x18/0x1c lib/dump_stack.c:128)
 r5:00000000 r4:8286dd18
[<819a4104>] (dump_stack) from [<81986928>] (panic+0x120/0x370 kernel/panic.c:354)
[<81986808>] (panic) from [<802421dc>] (check_panic_on_warn kernel/panic.c:243 [inline])
[<81986808>] (panic) from [<802421dc>] (get_taint+0x0/0x1c kernel/panic.c:238)
 r3:8260c5c4 r2:00000001 r1:8201e0e4 r0:82025eb0
 r7:80834680
[<80242168>] (check_panic_on_warn) from [<8024233c>] (__warn+0x80/0x188 kernel/panic.c:748)
[<802422bc>] (__warn) from [<8024262c>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:783)
 r8:00000009 r7:82084afc r6:df805c94 r5:85399800 r4:00000000
[<80242448>] (warn_slowpath_fmt) from [<80834680>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28)
 r10:20000013 r9:8530e85c r8:83db4600 r7:00000000 r6:81816254 r5:00000002
 r4:83db4600
[<80834544>] (refcount_warn_saturate) from [<81486590>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline])
[<80834544>] (refcount_warn_saturate) from [<81486590>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline])
[<80834544>] (refcount_warn_saturate) from [<81486590>] (refcount_dec_and_test include/linux/refcount.h:325 [inline])
[<80834544>] (refcount_warn_saturate) from [<81486590>] (skb_unref include/linux/skbuff.h:1232 [inline])
[<80834544>] (refcount_warn_saturate) from [<81486590>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline])
[<80834544>] (refcount_warn_saturate) from [<81486590>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241)
[<814863b8>] (sk_skb_reason_drop) from [<81816254>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline])
[<814863b8>] (sk_skb_reason_drop) from [<81816254>] (kfree_skb include/linux/skbuff.h:1271 [inline])
[<814863b8>] (sk_skb_reason_drop) from [<81816254>] (j1939_session_skb_drop_old net/can/j1939/transport.c:347 [inline])
[<814863b8>] (sk_skb_reason_drop) from [<81816254>] (j1939_xtp_rx_cts_one net/can/j1939/transport.c:1445 [inline])
[<814863b8>] (sk_skb_reason_drop) from [<81816254>] (j1939_xtp_rx_cts+0x220/0x3d0 net/can/j1939/transport.c:1484)
 r9:8530e85c r8:83db4600 r7:858fe918 r6:00000df2 r5:8530e800 r4:8530e814
[<81816034>] (j1939_xtp_rx_cts) from [<818171c8>] (j1939_tp_cmd_recv net/can/j1939/transport.c:2089 [inline])
[<81816034>] (j1939_xtp_rx_cts) from [<818171c8>] (j1939_tp_recv+0x3f4/0x530 net/can/j1939/transport.c:2161)
 r10:ddde5048 r9:00000040 r8:858fe910 r7:85723000 r6:85723008 r5:85723000
 r4:84c5b900
[<81816dd4>] (j1939_tp_recv) from [<81810c60>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108)
 r7:85723000 r6:85723008 r5:85723810 r4:84c5b900
[<81810a7c>] (j1939_can_recv) from [<81806a2c>] (deliver net/can/af_can.c:572 [inline])
[<81810a7c>] (j1939_can_recv) from [<81806a2c>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606)
 r9:00000040 r8:84e3c6a0 r7:98c80000 r6:84c5bb40 r5:00000001 r4:83fae330
[<81806990>] (can_rcv_filter) from [<818073d0>] (can_receive+0xb4/0xf0 net/can/af_can.c:663)
 r9:00000040 r8:00000000 r7:84e3c000 r6:84621540 r5:845e8000 r4:84c5bb40
[<8180731c>] (can_receive) from [<81807490>] (can_rcv+0x84/0xac net/can/af_can.c:687)
 r9:00000040 r8:00000002 r7:00000000 r6:00000000 r5:8180740c r4:84c5bb40
[<8180740c>] (can_rcv) from [<814a7408>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5662)
 r5:8180740c r4:84e3c000
[<814a73ac>] (__netif_receive_skb_one_core) from [<814a7474>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5775)
 r5:ddde5130 r4:84c5bb40
[<814a745c>] (__netif_receive_skb) from [<814a7764>] (process_backlog+0x88/0x15c net/core/dev.c:6107)
 r5:ddde5130 r4:84c5bb40
[<814a76dc>] (process_backlog) from [<814a8668>] (__napi_poll+0x34/0x240 net/core/dev.c:6771)
 r10:ddde5040 r9:ddde5280 r8:df805ed0 r7:df805ecb r6:00000040 r5:ddde5130
 r4:00000001
[<814a8634>] (__napi_poll) from [<814a8ea0>] (napi_poll net/core/dev.c:6840 [inline])
[<814a8634>] (__napi_poll) from [<814a8ea0>] (net_rx_action+0x338/0x420 net/core/dev.c:6962)
 r9:ddde5280 r8:df805ed0 r7:0000012c r6:00003b50 r5:ddde5130 r4:00000000
[<814a8b68>] (net_rx_action) from [<8024b604>] (handle_softirqs+0x158/0x464 kernel/softirq.c:554)
 r10:00000008 r9:85399800 r8:00000101 r7:00400040 r6:00000003 r5:00000004
 r4:8260408c
[<8024b4ac>] (handle_softirqs) from [<802012d0>] (__do_softirq+0x14/0x18 kernel/softirq.c:588)
 r10:003d0f00 r9:853998e0 r8:8286d084 r7:85399800 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 [<819556f4>] (call_with_stack+0x1c/0x20 arch/arm/lib/call_with_stack.S:40)
[<819556d8>] (call_with_stack) from [<8020883c>] (do_softirq_own_stack+0x38/0x3c arch/arm/kernel/irq.c:82)
[<80208804>] (do_softirq_own_stack) from [<8024bb1c>] (do_softirq kernel/softirq.c:455 [inline])
[<80208804>] (do_softirq_own_stack) from [<8024bb1c>] (do_softirq+0x5c/0x64 kernel/softirq.c:442)
[<8024bac0>] (do_softirq) from [<8024bbf0>] (__local_bh_enable_ip+0xcc/0xd0 kernel/softirq.c:382)
 r5:00000001 r4:85399800
[<8024bb24>] (__local_bh_enable_ip) from [<80202d6c>] (local_bh_enable include/linux/bottom_half.h:33 [inline])
[<8024bb24>] (__local_bh_enable_ip) from [<80202d6c>] (vfp_support_entry+0xac/0x2a0 arch/arm/vfp/vfpmodule.c:775)
 r5:40000000 r4:dfb69fb0
[<80202cc0>] (vfp_support_entry) from [<8020c938>] (call_undef_hook arch/arm/kernel/traps.c:449 [inline])
[<80202cc0>] (vfp_support_entry) from [<8020c938>] (do_undefinstr+0xe4/0x1e0 arch/arm/kernel/traps.c:488)
 r9:00006364 r8:80202cc0 r7:ecac8b10 r6:0014d310 r5:dfb69fb0 r4:8261c9c4
[<8020c854>] (do_undefinstr) from [<80200fe4>] (__und_usr+0x84/0xa0 arch/arm/kernel/entry-armv.S:470)
Exception stack(0xdfb69fb0 to 0xdfb69ff8)
9fa0:                                     76ba2b10 00000000 0fffb0d6 00db9828
9fc0: 00000000 002862f0 00188a6c 00188a74 00000000 00006364 003d0f00 76ba20bc
9fe0: 76ba2b38 76ba1ee8 0001c9cc 0014d310 20000010 ffffffff
 r9:00006364 r8:824b0044 r7:85399800 r6:ffffffff r5:20000010 r4:0014d314
Rebooting in 86400 seconds..