------------[ cut here ]------------ WARNING: CPU: 0 PID: 10047 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: 10047 Comm: syz.1.1403 Not tainted 6.12.0-rc7-syzkaller #0 Hardware name: ARM-Versatile Express Call trace: [<8199ca58>] (dump_backtrace) from [<8199cb54>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257) r7:00000000 r6:82622f44 r5:00000000 r4:8203dc0c [<8199cb3c>] (show_stack) from [<819bafe8>] (__dump_stack lib/dump_stack.c:94 [inline]) [<8199cb3c>] (show_stack) from [<819bafe8>] (dump_stack_lvl+0x54/0x7c lib/dump_stack.c:120) [<819baf94>] (dump_stack_lvl) from [<819bb028>] (dump_stack+0x18/0x1c lib/dump_stack.c:129) r5:00000000 r4:82870d18 [<819bb010>] (dump_stack) from [<8199d680>] (panic+0x120/0x374 kernel/panic.c:354) [<8199d560>] (panic) from [<80242118>] (check_panic_on_warn kernel/panic.c:243 [inline]) [<8199d560>] (panic) from [<80242118>] (get_taint+0x0/0x1c kernel/panic.c:238) r3:8260c5c4 r2:00000001 r1:82025fe0 r0:8202da48 r7:808408b8 [<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 r7:8208c41c r6:dfa81d6c r5:84909800 r4:00000000 [<80242388>] (warn_slowpath_fmt) from [<808408b8>] (refcount_warn_saturate+0x13c/0x174 lib/refcount.c:28) r10:000001b4 r9:846c8280 r8:0000006c r7:00000000 r6:8182a12c r5:00000002 r4:8af8ed80 [<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (__refcount_sub_and_test include/linux/refcount.h:275 [inline]) [<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (__refcount_dec_and_test include/linux/refcount.h:307 [inline]) [<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (refcount_dec_and_test include/linux/refcount.h:325 [inline]) [<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (skb_unref include/linux/skbuff.h:1232 [inline]) [<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (__sk_skb_reason_drop net/core/skbuff.c:1213 [inline]) [<8084077c>] (refcount_warn_saturate) from [<8149bbe8>] (sk_skb_reason_drop+0x1d8/0x248 net/core/skbuff.c:1241) [<8149ba10>] (sk_skb_reason_drop) from [<8182a12c>] (kfree_skb_reason include/linux/skbuff.h:1262 [inline]) [<8149ba10>] (sk_skb_reason_drop) from [<8182a12c>] (kfree_skb include/linux/skbuff.h:1271 [inline]) [<8149ba10>] (sk_skb_reason_drop) from [<8182a12c>] (j1939_session_destroy+0x78/0x200 net/can/j1939/transport.c:282) r9:846c8280 r8:0000006c r7:846c8284 r6:8507b750 r5:8507b700 r4:8af8ed80 [<8182a0b4>] (j1939_session_destroy) from [<8182b448>] (__j1939_session_release net/can/j1939/transport.c:294 [inline]) [<8182a0b4>] (j1939_session_destroy) from [<8182b448>] (kref_put include/linux/kref.h:65 [inline]) [<8182a0b4>] (j1939_session_destroy) from [<8182b448>] (j1939_session_put+0x54/0x58 net/can/j1939/transport.c:299) r6:846c8278 r5:846c8278 r4:846c8278 [<8182b3f4>] (j1939_session_put) from [<81828508>] (j1939_sk_queue_drop_all+0x7c/0xc4 net/can/j1939/socket.c:144) [<8182848c>] (j1939_sk_queue_drop_all) from [<81828748>] (j1939_sk_release+0x1f8/0x200 net/can/j1939/socket.c:642) r9:84909800 r8:82e9d310 r7:846c8274 r6:83cdd000 r5:833cdb80 r4:846c8000 [<81828550>] (j1939_sk_release) from [<81485214>] (__sock_release+0x44/0xbc net/socket.c:658) r8:82e9d310 r7:00000000 r6:81c7e894 r5:833cdc80 r4:833cdb80 [<814851d0>] (__sock_release) from [<814852a4>] (sock_close+0x18/0x20 net/socket.c:1426) r7:833cdc00 r6:84c417f8 r5:082e0003 r4:84632000 [<8148528c>] (sock_close) from [<80518d8c>] (__fput+0xdc/0x2e4 fs/file_table.c:431) [<80518cb0>] (__fput) from [<8051901c>] (____fput+0x14/0x18 fs/file_table.c:459) r9:84909800 r8:82871694 r7:84909800 r6:8490a084 r5:8490a054 r4:846325a8 [<80519008>] (____fput) from [<8026c67c>] (task_work_run+0x90/0xb8 kernel/task_work.c:239) [<8026c5ec>] (task_work_run) from [<8020bde0>] (resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]) [<8026c5ec>] (task_work_run) from [<8020bde0>] (do_work_pending+0x448/0x4f8 arch/arm/kernel/signal.c:631) r9:84909800 r8:8020029c r7:000001b4 r6:8020029c r5:dfa81fb0 r4:84909800 [<8020b998>] (do_work_pending) from [<80200088>] (slow_work_pending+0xc/0x24) Exception stack(0xdfa81fb0 to 0xdfa81ff8) 1fa0: 00000000 ffffffff 00000000 00000000 1fc0: 00000000 00000000 002862f0 000001b4 00000000 00006364 003d0f00 76b250bc 1fe0: 76b24ec0 76b24eb0 00018b10 00133470 60000010 00000004 r10:000001b4 r9:84909800 r8:8020029c r7:000001b4 r6:002862f0 r5:00000000 r4:00000000 Rebooting in 86400 seconds..