------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 53 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25 Modules linked in: CPU: 1 PID: 53 Comm: kworker/u4:2 Tainted: G W 5.13.0-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: 0a 31 ff 89 de e8 17 63 a2 fd 84 db 0f 85 36 ff ff ff e8 ca 5c a2 fd 48 c7 c7 a0 2e e3 89 c6 05 a2 b6 03 0a 01 e8 44 74 0c 05 <0f> 0b e9 17 ff ff ff e8 ab 5c a2 fd 0f b6 1d 87 b6 03 0a 31 ff 89 RSP: 0018:ffffc90000f3fa00 EFLAGS: 00010082 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888015dcd4c0 RSI: ffffffff815d7275 RDI: fffff520001e7f32 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815d10de R11: 0000000000000000 R12: ffff888143988000 R13: ffff8880188c9400 R14: ffff888030886030 R15: ffff888030886034 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004e4da0 CR3: 0000000027472000 CR4: 00000000001506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 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:202 [inline] qrtr_node_lookup net/qrtr/qrtr.c:398 [inline] qrtr_send_resume_tx net/qrtr/qrtr.c:995 [inline] qrtr_recvmsg+0x85a/0x990 net/qrtr/qrtr.c:1063 sock_recvmsg_nosec net/socket.c:936 [inline] sock_recvmsg net/socket.c:954 [inline] sock_recvmsg net/socket.c:950 [inline] kernel_recvmsg+0x110/0x160 net/socket.c:979 qrtr_ns_worker+0x15a/0x1710 net/qrtr/ns.c:684 process_one_work+0x98d/0x1630 kernel/workqueue.c:2276 worker_thread+0x658/0x11f0 kernel/workqueue.c:2422 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295