------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 202 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 lib/refcount.c:25 Modules linked in: CPU: 1 PID: 202 Comm: kworker/u4:4 Not tainted 5.12.0-rc2-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 37 d1 b0 fd 84 db 0f 85 36 ff ff ff e8 7a ca b0 fd 48 c7 c7 a0 0b bf 89 c6 05 68 33 ee 09 01 e8 db d2 fc 04 <0f> 0b e9 17 ff ff ff e8 5b ca b0 fd 0f b6 1d 4d 33 ee 09 31 ff 89 RSP: 0018:ffffc9000134f9f8 EFLAGS: 00010086 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888011d30000 RSI: ffffffff815c0eb5 RDI: fffff52000269f31 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815b9c4e R11: 0000000000000000 R12: ffff888140d08000 R13: ffff88801d0d5800 R14: ffff88802b00ddf0 R15: ffff88802b00ddf4 FS: 0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000522330 CR3: 0000000016dde000 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: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:888 [inline] sock_recvmsg net/socket.c:906 [inline] sock_recvmsg net/socket.c:902 [inline] kernel_recvmsg+0x110/0x160 net/socket.c:931 qrtr_ns_worker+0x15a/0x1710 net/qrtr/ns.c:684 process_one_work+0x98d/0x1600 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:294