Re: [Crash-utility] Why module's global symbol cannot be displayed in crash? [ARM]

Mika, On Fri, Mar 22, 2013 at 9:03 PM, Mika Westerberg <mika.westerberg(a)iki.fi&gt; wrote: > On Thu, Mar 21, 2013 at 03:02:54PM -0400, Dave Anderson wrote: >> If for some reason you can't get them, I can make them available to you. >> And Lei Wen can also give you a sample dumpfile from his environment. > > Got them from Luc. > >> > Are you able to access module symbols on ARM dump (the one that Luc provided)? >> > Or is it failing completely? >> >> I *think* so... >> >> This module text disassembly looks right: >> >> crash> dis usbnet_suspend >> 0xbf000ae8 <usbnet_suspend>: push {r3, r4, r5, lr} >> 0xbf000aec <usbnet_suspend+4>: add r0, r0, #32 >> 0xbf000af0 <usbnet_suspend+8>: mov r5, r1 >> 0xbf000af4 <usbnet_suspend+12>: bl 0xc01b8264 <dev_get_drvdata> >> 0xbf000af8 <usbnet_suspend+16>: ldrb r3, [r0, #36] ; 0x24 >> 0xbf000afc <usbnet_suspend+20>: mov r4, r0 >> 0xbf000b00 <usbnet_suspend+24>: add r2, r3, #1 >> 0xbf000b04 <usbnet_suspend+28>: cmp r3, #0 >> 0xbf000b08 <usbnet_suspend+32>: strb r2, [r0, #36] ; 0x24 >> 0xbf000b0c <usbnet_suspend+36>: bne 0xbf000bdc <usbnet_suspend+244> >> 0xbf000b10 <usbnet_suspend+40>: mrs r3, CPSR >> 0xbf000b14 <usbnet_suspend+44>: orr r3, r3, #128 ; 0x80 >> 0xbf000b18 <usbnet_suspend+48>: msr CPSR_c, r3 >> 0xbf000b1c <usbnet_suspend+52>: mov r0, #1 >> 0xbf000b20 <usbnet_suspend+56>: bl 0xc0015f40 <add_preempt_count> >> 0xbf000b24 <usbnet_suspend+60>: ldr r3, [r4, #200] ; 0xc8 >> 0xbf000b28 <usbnet_suspend+64>: cmp r3, #0 >> 0xbf000b2c <usbnet_suspend+68>: beq 0xbf000b70 <usbnet_suspend+136> >> 0xbf000b30 <usbnet_suspend+72>: tst r5, #1024 ; 0x400 >> 0xbf000b34 <usbnet_suspend+76>: beq 0xbf000b70 <usbnet_suspend+136> >> 0xbf000b38 <usbnet_suspend+80>: mrs r3, CPSR >> ... >> >> This (r) data looks OK: >> >> crash> p smsc95xx_netdev_ops >> smsc95xx_netdev_ops = $8 = { >> ndo_init = 0, >> ndo_uninit = 0, >> ndo_open = 0xbf000514 <usbnet_open>, >> ndo_stop = 0xbf000bec <usbnet_stop>, >> ndo_start_xmit = 0xbf001a60 <usbnet_start_xmit>, >> ndo_select_queue = 0, >> ndo_change_rx_flags = 0, >> ndo_set_rx_mode = 0, >> ndo_set_multicast_list = 0xbf008abc <smsc95xx_set_multicast>, >> ndo_set_mac_address = 0xc025d854 <eth_mac_addr>, >> ndo_validate_addr = 0xc025d6f8 <eth_validate_addr>, >> ndo_do_ioctl = 0xbf00926c <smsc95xx_ioctl>, >> ndo_set_config = 0, >> ndo_change_mtu = 0xbf000de0 <usbnet_change_mtu>, >> ndo_neigh_setup = 0, >> ndo_tx_timeout = 0xbf000d4c <usbnet_tx_timeout>, >> ndo_get_stats64 = 0, >> ndo_get_stats = 0, >> ndo_vlan_rx_add_vid = 0, >> ndo_vlan_rx_kill_vid = 0, >> ndo_set_vf_mac = 0, >> ndo_set_vf_vlan = 0, >> ndo_set_vf_tx_rate = 0, >> ndo_get_vf_config = 0, >> ndo_set_vf_port = 0, >> ndo_get_vf_port = 0, >> ndo_setup_tc = 0, >> ndo_add_slave = 0, >> ndo_del_slave = 0, >> ndo_fix_features = 0, >> crash> > > I'm able to see the same. > > Setting suitable debug level reveals: > > bf00f040 (bf00f000): scsi_wait_scan syms: 0 gplsyms: 0 ksyms: 1 > bf00a1f8 (bf008000): smsc95xx syms: 0 gplsyms: 0 ksyms: 60 > bf002a40 (bf000000): usbnet syms: 0 gplsyms: 24 ksyms: 65 > > The ksyms comes from KALLSYMS and by default it only includes text and > inittext symbols. This explains why Lei is not able to see data etc. symbols > when he runs 'sym -m <module>'. Yep, that is my case. For data symbol would only be included in core section if CONFIG_KALLSYMS_ALL option is defined, so crash fail to extract the data symbol since it fail to see the data section is included in the dump image. But what I am confused is that since mod -S would reload all module image, which already include all symbols. So why we should confine us to only extract those symbol in the core section defined by the dump image?

I mean even with CONFIG_KALLSYMS be defined, I think it maybe doable to extract all data symbol. What are your guys' opinion here? :)