------------[ 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-syzkaller #0 Hardware name: ARM-Versatile Express Call trace: [<819b7fb8>] (dump_backtrace) from [<819b80b4>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257) r7:00000000 r6:82623304 r5:00000000 r4:820413b8 [<819b809c>] (show_stack) from [<819d60dc>] (__dump_stack lib/dump_stack.c:94 [inline]) [<819b809c>] (show_stack) from [<819d60dc>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120) [<819d6088>] (dump_stack_lvl) from [<819d611c>] (dump_stack+0x18/0x1c lib/dump_stack.c:129) r5:00000000 r4:82874d18 [<819d6104>] (dump_stack) from [<819b8be0>] (panic+0x120/0x374 kernel/panic.c:354) [<819b8ac0>] (panic) from [<802426d0>] (check_panic_on_warn kernel/panic.c:243 [inline]) [<819b8ac0>] (panic) from [<802426d0>] (get_taint+0x0/0x1c kernel/panic.c:238) r3:8260c604 r2:00000001 r1:82029878 r0:82031344 r7:8084bbd8 [<8024265c>] (check_panic_on_warn) from [<80242834>] (__warn+0x80/0x188 kernel/panic.c:748) [<802427b4>] (__warn) from [<80242b24>] (warn_slowpath_fmt+0x1e8/0x1f4 kernel/panic.c:783) r8:00000009 r7:8209017c r6:df855bdc r5:82e3b000 r4:00000000 [<80242940>] (warn_slowpath_fmt) from [<8084bbd8>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28) r10:dddd0e88 r9:00000040 r8:8469b8d0 r7:00000000 r6:81841f64 r5:00000002 r4:85212f00 [<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline]) [<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline]) [<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (refcount_dec_and_test include/linux/refcount.h:325 [inline]) [<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (skb_unref include/linux/skbuff.h:1233 [inline]) [<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline]) [<8084ba9c>] (refcount_warn_saturate) from [<814aa974>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241) [<814aa79c>] (sk_skb_reason_drop) from [<81841f64>] (kfree_skb_reason include/linux/skbuff.h:1263 [inline]) [<814aa79c>] (sk_skb_reason_drop) from [<81841f64>] (kfree_skb include/linux/skbuff.h:1272 [inline]) [<814aa79c>] (sk_skb_reason_drop) from [<81841f64>] (j1939_session_destroy+0x78/0x200 net/can/j1939/transport.c:282) r9:00000040 r8:8469b8d0 r7:859c981c r6:847dd550 r5:847dd500 r4:85212f00 [<81841eec>] (j1939_session_destroy) from [<818430c4>] (__j1939_session_release net/can/j1939/transport.c:294 [inline]) [<81841eec>] (j1939_session_destroy) from [<818430c4>] (kref_put include/linux/kref.h:65 [inline]) [<81841eec>] (j1939_session_destroy) from [<818430c4>] (j1939_session_put net/can/j1939/transport.c:299 [inline]) [<81841eec>] (j1939_session_destroy) from [<818430c4>] (j1939_xtp_rx_eoma+0x120/0x234 net/can/j1939/transport.c:1411) r6:852123c0 r5:847dd500 r4:847dd514 [<81842fa4>] (j1939_xtp_rx_eoma) from [<818454ec>] (j1939_tp_cmd_recv net/can/j1939/transport.c:2113 [inline]) [<81842fa4>] (j1939_xtp_rx_eoma) from [<818454ec>] (j1939_tp_recv+0x4a8/0x530 net/can/j1939/transport.c:2161) r7:859c9000 r6:859c9008 r5:859c9000 r4:852123c0 [<81845044>] (j1939_tp_recv) from [<8183eed0>] (j1939_can_recv+0x1e4/0x2dc net/can/j1939/main.c:108) r7:859c9000 r6:859c9008 r5:859c9810 r4:852123c0 [<8183ecec>] (j1939_can_recv) from [<81834b94>] (deliver net/can/af_can.c:573 [inline]) [<8183ecec>] (j1939_can_recv) from [<81834b94>] (can_rcv_filter+0x9c/0x218 net/can/af_can.c:607) r9:00000040 r8:84b686c0 r7:98ec0000 r6:85212c00 r5:00000001 r4:8474b360 [<81834af8>] (can_rcv_filter) from [<81835610>] (can_receive+0xb4/0xf0 net/can/af_can.c:664) r9:00000040 r8:00000000 r7:84b68000 r6:8498ca80 r5:848e8000 r4:85212c00 [<8183555c>] (can_receive) from [<818356d0>] (can_rcv+0x84/0xac net/can/af_can.c:688) r9:00000040 r8:00000001 r7:00000000 r6:00000000 r5:8183564c r4:85212c00 [<8183564c>] (can_rcv) from [<814cc17c>] (__netif_receive_skb_one_core+0x5c/0x80 net/core/dev.c:5672) r5:8183564c r4:84b68000 [<814cc120>] (__netif_receive_skb_one_core) from [<814cc1e8>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:5785) r5:dddd0f70 r4:85212c00 [<814cc1d0>] (__netif_receive_skb) from [<814cc4f0>] (process_backlog+0xa0/0x17c net/core/dev.c:6117) r5:dddd0f70 r4:85212c00 [<814cc450>] (process_backlog) from [<814cd3f0>] (__napi_poll+0x34/0x240 net/core/dev.c:6877) r10:dddd0e80 r9:dddd10c0 r8:df855e38 r7:df855e33 r6:00000040 r5:dddd0f70 r4:00000001 [<814cd3bc>] (__napi_poll) from [<814cdc64>] (napi_poll net/core/dev.c:6946 [inline]) [<814cd3bc>] (__napi_poll) from [<814cdc64>] (net_rx_action+0x358/0x440 net/core/dev.c:7068) r9:dddd10c0 r8:df855e38 r7:0000012c r6:00003276 r5:dddd0f70 r4:00000000 [<814cd90c>] (net_rx_action) from [<8024ba68>] (handle_softirqs+0x158/0x464 kernel/softirq.c:554) r10:00000008 r9:82e3b000 r8:00000100 r7:04208040 r6:00000003 r5:00000004 r4:8260408c [<8024b910>] (handle_softirqs) from [<8024bdb8>] (run_ksoftirqd kernel/softirq.c:943 [inline]) [<8024b910>] (handle_softirqs) from [<8024bdb8>] (run_ksoftirqd+0x44/0x4c kernel/softirq.c:935) r10:00000000 r9:00000002 r8:82624b08 r7:00000001 r6:82e3b000 r5:82cb7140 r4:00000000 [<8024bd74>] (run_ksoftirqd) from [<80275edc>] (smpboot_thread_fn+0x16c/0x284 kernel/smpboot.c:164) [<80275d70>] (smpboot_thread_fn) from [<80270ae0>] (kthread+0x104/0x134 kernel/kthread.c:389) r10:00000000 r9:df819de8 r8:82cb7280 r7:82cb7140 r6:80275d70 r5:82e3b000 r4:82cb7180 r3:00000000 [<802709dc>] (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 r5:802709dc r4:82cb7180 Rebooting in 86400 seconds..