------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 8448 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 8448 Comm: kworker/u4:6 Not tainted 5.9.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: qrtr_ns_handler qrtr_ns_worker Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 panic+0x347/0x7c0 kernel/panic.c:231 __warn.cold+0x20/0x46 kernel/panic.c:600 report_bug+0x1bd/0x210 lib/bug.c:198 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536 RIP: 0010:refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25 Code: 07 31 ff 89 de e8 77 d3 d8 fd 84 db 0f 85 36 ff ff ff e8 2a d7 d8 fd 48 c7 c7 00 dc 93 88 c6 05 76 0d 12 07 01 e8 19 d8 a9 fd <0f> 0b e9 17 ff ff ff e8 0b d7 d8 fd 0f b6 1d 5b 0d 12 07 31 ff 89 RSP: 0018:ffffc900166779d8 EFLAGS: 00010086 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888058a2a0c0 RSI: ffffffff815db9a7 RDI: fffff52002ccef2d RBP: 0000000000000002 R08: 0000000000000001 R09: ffff8880ae720f8b R10: 0000000000000000 R11: 0000000034343854 R12: ffff8880a9229640 R13: ffff8880a0ff8400 R14: ffff888050167bb0 R15: ffff888050167bb4 refcount_add include/linux/refcount.h:204 [inline] refcount_inc include/linux/refcount.h:241 [inline] kref_get include/linux/kref.h:45 [inline] qrtr_node_acquire net/qrtr/qrtr.c:196 [inline] qrtr_node_lookup net/qrtr/qrtr.c:388 [inline] qrtr_send_resume_tx net/qrtr/qrtr.c:980 [inline] qrtr_recvmsg+0x845/0x970 net/qrtr/qrtr.c:1043 sock_recvmsg_nosec net/socket.c:885 [inline] sock_recvmsg net/socket.c:903 [inline] sock_recvmsg net/socket.c:899 [inline] kernel_recvmsg+0x110/0x160 net/socket.c:928 qrtr_ns_worker+0x15a/0x14fc net/qrtr/ns.c:624 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Shutting down cpus with NMI Kernel Offset: disabled Rebooting in 86400 seconds..