I am unable to activate hotspot in my tumbleweed os. I tried it by using NetworkManager and pc freezes when I connect the network .

I guess you'd better ask on a networkmanager forum, but depending on the deepness of the freeze (kernel? can you still switch VTs with Ctrl+Alt+F[1,9]?) this might be a problem with the kernel module for the wifi chip.

No nothing works for almost 3 - 4 minutes and system reboots

Sounds largely like a problem with the WiFi kernel module. I'd google in that direction (check lspci for the type)

localhost:/home/prafuldev # lspci
00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1 (rev c4)
00:1c.1 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 2 (rev c4)
00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation 7 Series Chipset Family LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation 7 Series/C210 Series Chipset Family SMBus Controller (rev 04)
01:00.0 Ethernet controller: Qualcomm Atheros AR8162 Fast Ethernet (rev 10)
02:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8723AE PCIe Wireless Network Adapter

That chip: RTL8723AE
Google yourself, seems like heck of a troublemaker