------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 0 PID: 472 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25 Modules linked in: CPU: 0 PID: 472 Comm: kworker/u4:6 Not tainted 5.11.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: qrtr_ns_handler qrtr_ns_worker RIP: 0010:refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25 Code: 09 31 ff 89 de e8 c7 65 b3 fd 84 db 0f 85 36 ff ff ff e8 3a 5f b3 fd 48 c7 c7 c0 9e 9e 89 c6 05 fd fc cf 09 01 e8 91 56 fa 04 <0f> 0b e9 17 ff ff ff e8 1b 5f b3 fd 0f b6 1d e2 fc cf 09 31 ff 89 RSP: 0018:ffffc9000285f9f8 EFLAGS: 00010086 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff8880131bd340 RSI: ffffffff815b73e5 RDI: fffff5200050bf31 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815b05be R11: 0000000000000000 R12: ffff888140c98000 R13: ffff88802881bc00 R14: ffff8880152ac2b0 R15: ffff8880152ac2b4 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd658411000 CR3: 0000000027d45000 CR4: 0000000000350ef0 Call Trace: __refcount_add include/linux/refcount.h:199 [inline] __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] kref_get include/linux/kref.h:45 [inline] qrtr_node_acquire net/qrtr/qrtr.c:201 [inline] qrtr_node_lookup net/qrtr/qrtr.c:394 [inline] qrtr_send_resume_tx net/qrtr/qrtr.c:1004 [inline] qrtr_recvmsg+0x84a/0x980 net/qrtr/qrtr.c:1067 sock_recvmsg_nosec net/socket.c:886 [inline] sock_recvmsg net/socket.c:904 [inline] sock_recvmsg net/socket.c:900 [inline] kernel_recvmsg+0x110/0x160 net/socket.c:929 qrtr_ns_worker+0x15a/0x1710 net/qrtr/ns.c:684 process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421 kthread+0x3b1/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296