vcan0: j1939_tp_rxtimer: 0x845d4700: rx timeout, send abort vcan0: j1939_xtp_rx_abort_one: 0x845d4700: 0x40000: (3) A timeout occurred and this is the connection abort to close the session. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 15 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: 15 Comm: ksoftirqd/0 Not tainted 6.12.0-rc7-syzkaller #0 Hardware name: ARM-Versatile Express Call trace: [<8199d498>] (dump_backtrace) from [<8199d594>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257) r7:00000000 r6:82622f44 r5:00000000 r4:8203de58 [<8199d57c>] (show_stack) from [<819bba28>] (__dump_stack lib/dump_stack.c:94 [inline]) [<8199d57c>] (show_stack) from [<819bba28>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120) [<819bb9d4>] (dump_stack_lvl) from [<819bba68>] (dump_stack+0x18/0x1c lib/dump_stack.c:129) r5:00000000 r4:82870d18 [<819bba50>] (dump_stack) from [<8199e0c0>] (panic+0x120/0x374 kernel/panic.c:354) [<8199dfa0>] (panic) from [<80242118>] (check_panic_on_warn kernel/panic.c:243 [inline]) [<8199dfa0>] (panic) from [<80242118>] (get_taint+0x0/0x1c kernel/panic.c:238) r3:8260c5c4 r2:00000001 r1:8202622c r0:8202dc94 r7:80840e78 [<802420a4>] (check_panic_on_warn) from [<8024227c>] (__warn+0x80/0x188 kernel/panic.c:748) [<802421fc>] (__warn) from [<8024256c>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:783) r8:00000009 r7:8208c680 r6:df855bd4 r5:82e3b000 r4:00000000 [<80242388>] (warn_slowpath_fmt) from [<80840e78>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28) r10:dddd10c8 r9:00000003 r8:00000001 r7:00000000 r6:8182aad4 r5:00000002 r4:8534a900 [<80840d3c>] (refcount_warn_saturate) from [<8149c5b0>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline]) [<80840d3c>] (refcount_warn_saturate) from [<8149c5b0>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline]) [<80840d3c>] (refcount_warn_saturate) from [<8149c5b0>] (refcount_dec_and_test include/linux/refcount.h:325 [inline]) [<80840d3c>] (refcount_warn_saturate) from [<8149c5b0>] (skb_unref include/linux/skbuff.h:1232 [inline]) [<80840d3c>] (refcount_warn_saturate) from [<8149c5b0>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline]) [<80840d3c>] (refcount_warn_saturate) from [<8149c5b0>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241) [<8149c3d8>] (sk_skb_reason_drop) from [<8182aad4>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline]) [<8149c3d8>] (sk_skb_reason_drop) from [<8182aad4>] (kfree_skb include/linux/skbuff.h:1271 [inline]) [<8149c3d8>] (sk_skb_reason_drop) from [<8182aad4>] (j1939_session_destroy+0x78/0x200 net/can/j1939/transport.c:282) r9:00000003 r8:00000001 r7:8521181c r6:845d4750 r5:845d4700 r4:8534a900 [<8182aa5c>] (j1939_session_destroy) from [<8182b2c0>] (__j1939_session_release net/can/j1939/transport.c:294 [inline]) [<8182aa5c>] (j1939_session_destroy) from [<8182b2c0>] (kref_put include/linux/kref.h:65 [inline]) [<8182aa5c>] (j1939_session_destroy) from [<8182b2c0>] (j1939_session_put net/can/j1939/transport.c:299 [inline]) [<8182aa5c>] (j1939_session_destroy) from [<8182b2c0>] (j1939_xtp_rx_abort_one+0xbc/0x2a4 net/can/j1939/transport.c:1354) r6:85211000 r5:845d4700 r4:8534a840 [<8182b204>] (j1939_xtp_rx_abort_one) from [<8182e078>] (j1939_xtp_rx_abort net/can/j1939/transport.c:1362 [inline]) [<8182b204>] (j1939_xtp_rx_abort_one) from [<8182e078>] (j1939_tp_cmd_recv net/can/j1939/transport.c:2128 [inline]) [<8182b204>] (j1939_xtp_rx_abort_one) from [<8182e078>] (j1939_tp_recv+0x4c4/0x530 net/can/j1939/transport.c:2161) r9:00000040 r8:84978b50 r7:85211000 r6:85211008 r5:85211000 r4:8534a840 [<8182dbb4>] (j1939_tp_recv) from [<81827a40>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108) r7:85211000 r6:85211008 r5:85211810 r4:8534a840 [<8182785c>] (j1939_can_recv) from [<8181d810>] (deliver net/can/af_can.c:572 [inline]) [<8182785c>] (j1939_can_recv) from [<8181d810>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:606) r9:00000040 r8:850b4680 r7:98ecfd00 r6:8534ab40 r5:00000001 r4:84992390 [<8181d774>] (can_rcv_filter) from [<8181e1b4>] (can_receive+0xb4/0xf0 net/can/af_can.c:663) r9:00000040 r8:00000000 r7:850b4000 r6:84677500 r5:84544100 r4:8534ab40 [<8181e100>] (can_receive) from [<8181e274>] (can_rcv+0x84/0xac net/can/af_can.c:687) r9:00000040 r8:00000001 r7:00000000 r6:00000000 r5:8181e1f0 r4:8534ab40 [<8181e1f0>] (can_rcv) from [<814bd524>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5670) r5:8181e1f0 r4:850b4000 [<814bd4c8>] (__netif_receive_skb_one_core) from [<814bd590>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5783) r5:dddd11b0 r4:8534ab40 [<814bd578>] (__netif_receive_skb) from [<814bd898>] (process_backlog+0xa0/0x17c net/core/dev.c:6115) r5:dddd11b0 r4:8534ab40 [<814bd7f8>] (process_backlog) from [<814be7a4>] (__napi_poll+0x34/0x240 net/core/dev.c:6779) r10:dddd10c0 r9:dddd1300 r8:df855e38 r7:df855e33 r6:00000040 r5:dddd11b0 r4:00000001 [<814be770>] (__napi_poll) from [<814bf018>] (napi_poll net/core/dev.c:6848 [inline]) [<814be770>] (__napi_poll) from [<814bf018>] (net_rx_action+0x358/0x440 net/core/dev.c:6970) r9:dddd1300 r8:df855e38 r7:0000012c r6:0001e320 r5:dddd11b0 r4:00000000 [<814becc0>] (net_rx_action) from [<8024b55c>] (handle_softirqs+0x158/0x464 kernel/softirq.c:554) r10:00000008 r9:82e3b000 r8:00000100 r7:04208040 r6:00000003 r5:00000004 r4:8260408c [<8024b404>] (handle_softirqs) from [<8024b8ac>] (run_ksoftirqd kernel/softirq.c:927 [inline]) [<8024b404>] (handle_softirqs) from [<8024b8ac>] (run_ksoftirqd+0x44/0x4c kernel/softirq.c:919) r10:00000000 r9:00000002 r8:82624734 r7:00000001 r6:82e3b000 r5:82cb7100 r4:00000000 [<8024b868>] (run_ksoftirqd) from [<80275158>] (smpboot_thread_fn+0x16c/0x284 kernel/smpboot.c:164) [<80274fec>] (smpboot_thread_fn) from [<8026fd40>] (kthread+0x104/0x134 kernel/kthread.c:389) r10:00000000 r9:df819de8 r8:82cb7240 r7:82cb7100 r6:80274fec r5:82e3b000 r4:82cb7140 r3:00000000 [<8026fc3c>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137) Exception stack(0xdf855fb0 to 0xdf855ff8) 5fa0: 00000000 00000000 00000000 00000000 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:8026fc3c r4:82cb7140 Rebooting in 86400 seconds..