On Fri, May 18, 2018 at 1:50 PM, Ying Xue <ying....@windriver.com> wrote: > As variable s of struct tipc_subscr type is not initialized > in tipc_conn_rcv_from_sock() before it is used in tipc_conn_rcv_sub(), > KMSAN reported the following uninit-value type complaint: > > ================================================================== > BUG: KMSAN: uninit-value in tipc_conn_rcv_sub+0x184/0x950 > net/tipc/topsrv.c:373 > CPU: 0 PID: 66 Comm: kworker/u4:4 Not tainted 4.17.0-rc3+ #88 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Workqueue: tipc_rcv tipc_conn_recv_work > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x185/0x1d0 lib/dump_stack.c:113 > kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 > __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683 > tipc_conn_rcv_sub+0x184/0x950 net/tipc/topsrv.c:373 > tipc_conn_rcv_from_sock net/tipc/topsrv.c:409 [inline] > tipc_conn_recv_work+0x3cd/0x560 net/tipc/topsrv.c:424 > process_one_work+0x12c6/0x1f60 kernel/workqueue.c:2145 > worker_thread+0x113c/0x24f0 kernel/workqueue.c:2279 > kthread+0x539/0x720 kernel/kthread.c:239 > ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:412 > > Local variable description: ----s.i@tipc_conn_recv_work > Variable was created at: > tipc_conn_recv_work+0x65/0x560 net/tipc/topsrv.c:419 > process_one_work+0x12c6/0x1f60 kernel/workqueue.c:2145 > ================================================================== > Kernel panic - not syncing: panic_on_warn set ... > > CPU: 0 PID: 66 Comm: kworker/u4:4 Tainted: G B 4.17.0-rc3+ > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Workqueue: tipc_rcv tipc_conn_recv_work > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x185/0x1d0 lib/dump_stack.c:113 > panic+0x39d/0x940 kernel/panic.c:184 > kmsan_report+0x238/0x240 mm/kmsan/kmsan.c:1083 > __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683 > tipc_conn_rcv_sub+0x184/0x950 net/tipc/topsrv.c:373 > tipc_conn_rcv_from_sock net/tipc/topsrv.c:409 [inline] > tipc_conn_recv_work+0x3cd/0x560 net/tipc/topsrv.c:424 > process_one_work+0x12c6/0x1f60 kernel/workqueue.c:2145 > worker_thread+0x113c/0x24f0 kernel/workqueue.c:2279 > kthread+0x539/0x720 kernel/kthread.c:239 > ret_from_fork+0x35/0x40 arch/x86/entry/entry_64.S:412 > Dumping ftrace buffer: > (ftrace buffer empty) > Kernel Offset: disabled > Rebooting in 86400 seconds.. > > Reported-by: syzbot+8951a3065ee7fd6d6...@syzkaller.appspotmail.com > Signed-off-by: Ying Xue <ying....@windriver.com> > --- > net/tipc/topsrv.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/net/tipc/topsrv.c b/net/tipc/topsrv.c > index c8e34ef..fe47a62 100644 > --- a/net/tipc/topsrv.c > +++ b/net/tipc/topsrv.c > @@ -397,6 +397,7 @@ static int tipc_conn_rcv_from_sock(struct tipc_conn *con) > struct kvec iov; > int ret; > > + memset(&s, 0, sizeof(s)); > iov.iov_base = &s; > iov.iov_len = sizeof(s); > msg.msg_name = NULL;
Isn't the kernel bug here that sock_recvmsg does a short read? It seems that sock_recvmsg should initialize all of s.
