April 2012 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

Req help - Panic in VFS mount(Cramfs)
by KARTHIK SEKURU April 4, 2012

April 4, 2012

Hi, I'm doing kernel porting to arm926 based FPGA board, with very minimal setup. Only UART and timer devices are available as part of FPGA. Board details – Using ARM926e-js processor with 128MB SDRAM., Clock-33Mhz SDRAM Size = 128M CONFIG_PAGE_OFFSET = 0xc0000000 CONFIG_PHYS_OFFSET= 0x80000000 Loading the cramfs at 0x82000000 Start address for kernel is 0x80008000 Commandline(atags address) is 0x80000100 Kernel Lowmem = 32M HighMEM is not configured. Vmalloc_start = 0xC40000000 VMALLOC_END = Vmalloc_start + 64M = 0xC8000000 After mounting the CRAMFS filesystem, we are expecting a login prompt. But we are getting kernel panic message as shown below. Please help me in fix the issue. Kindly let me know if further information is needed. *Console message:* VFS: Mounted root (cramfs filesystem) readonly on device 1:0. Freeing init memory: 76K Error -3 while decompressing! c018b094(3087)->c016f000(4096) Error -5 while decompressing! c018bca3(3740)->c0170000(4096) Error -5 while decompressing! c018cb3f(3116)->c0171000(4096) Error -5 while decompressing! c018e76b(5370)->c0172000(4096) Error -3 while decompressing! c018b094(3087)->c016f000(4096) Failed to execute /linuxrc. Attempting defaults... Error -3 while decompressing! c018e8d8(3946)->c0173000(4096) Error -5 while decompressing! c018f842(4930)->c0174000(4096) Error -5 while decompressing! c0190b84(4854)->c0175000(4096) Error -3 while decompressing! c018e8d8(3946)->c0173000(4096) Error -3 while decompressing! c018b094(3087)->c016f000(4096) *Panic meaasge:* Kernel panic - not syncing: No init found. Try passing init= option to kernel. See Linux Documentation/init.txt for guidance. Backtrace: [<c000c378>] (dump_backtrace+0x0/0x10c) from [<c000c49c>] (dump_stack+0x18/0x1c) r6:c001afb4 r5:c0183760 r4:c0183780 r3:60000013 [<c000c484>] (dump_stack+0x0/0x1c) from [<c00179d4>] (panic+0x64/0x1b0) [<c0017970>] (panic+0x0/0x1b0) from [<c0008804>] (init_post+0xb0/0xd4) r3:c3824000 r2:c383a100 r1:c0204740 r0:c014595c r7:00000013 [<c0008754>] (init_post+0x0/0xd4) from [<c0163918>] (kernel_init+0xfc/0x12c) [<c016381c>] (kernel_init+0x0/0x12c) from [<c001afb4>] (do_exit+0x0/0x694) Karthik.

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modprobe succeeding despite mismatch on PCI-ID
by Jim Cromie April 4, 2012

April 4, 2012

hi all, I have a card which modprobes, despite a PCI-ID mismatch (though its a near match) root@voyage:~# lsmod | grep mwl8k mwl8k 30986 0 mac80211 261375 2 mwl8k,rtl8180 root@voyage:~# lsmod | grep mwl8k mwl8k 30986 0 mac80211 261375 2 mwl8k,rtl8180 cfg80211 123158 3 mwl8k,rtl8180,mac80211 root@voyage:~# modinfo mwl8k filename: /lib/modules/3.3.0-next-20120328-ske+/kernel/drivers/net/wireless/mwl8k.ko license: GPL author: Lennert Buytenhek <buytenh(a)marvell.com> version: 0.13 description: Marvell TOPDOG(R) 802.11 Wireless Network Driver ... firmware: mwl8k/helper_8363.fw srcversion: 7DE0D6B47B634A3BAF6D101 alias: pci:v000011ABd00002A43sv*sd*bc*sc*i* alias: pci:v000011ABd00002A40sv*sd*bc*sc*i* alias: pci:v000011ABd00002A30sv*sd*bc*sc*i* alias: pci:v000011ABd00002A2Bsv*sd*bc*sc*i* alias: pci:v000011ABd00002A24sv*sd*bc*sc*i* alias: pci:v000011ABd00002A0Csv*sd*bc*sc*i* alias: pci:v000011ABd00002A0Asv*sd*bc*sc*i* that last alias is the closest to the cards ID, but this isnt horseshoes. Or is it ? root@voyage:~# lspci -vvnnk -s 00:e 00:0e.0 Ethernet controller [0200]: Marvell Technology Group Ltd. 88W8361 [TopDog] 802.11n Wireless [11ab:2a02] (rev 03) Subsystem: Marvell Technology Group Ltd. 88W8361 [TopDog] 802.11n Wireless [11ab:2a02] Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx- Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 63, Cache Line Size: 32 bytes Interrupt: pin A routed to IRQ 5 Region 0: Memory at a0010000 (32-bit, non-prefetchable) [size=64K] Region 1: Memory at a0020000 (32-bit, non-prefetchable) [size=64K] Capabilities: [40] Power Management version 2 Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-) Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- I note that the -k option doesnt show a kernel driver bound to it, unlike others: 00:13.0 USB Controller [0c03]: Compaq Computer Corporation ZFMicro Chipset USB [0e11:a0f8] (rev 08) Kernel driver in use: ohci_hcd Kernel modules: ohci-hcd Given the pci-id mismatch shouldnt this just fail to modprobe ? is it a bug ? if not, why not - what reasons could justify a zombie (useless, taking up space) module ? the relevant code is: (I see nothing surprising) static DEFINE_PCI_DEVICE_TABLE(mwl8k_pci_id_table) = { { PCI_VDEVICE(MARVELL, 0x2a0a), .driver_data = MWL8363, }, { PCI_VDEVICE(MARVELL, 0x2a0c), .driver_data = MWL8363, }, { PCI_VDEVICE(MARVELL, 0x2a24), .driver_data = MWL8363, }, { PCI_VDEVICE(MARVELL, 0x2a2b), .driver_data = MWL8687, }, { PCI_VDEVICE(MARVELL, 0x2a30), .driver_data = MWL8687, }, { PCI_VDEVICE(MARVELL, 0x2a40), .driver_data = MWL8366, }, { PCI_VDEVICE(MARVELL, 0x2a43), .driver_data = MWL8366, }, { }, }; MODULE_DEVICE_TABLE(pci, mwl8k_pci_id_table); ... static struct pci_driver mwl8k_driver = { .name = MWL8K_NAME, .id_table = mwl8k_pci_id_table, .probe = mwl8k_probe, .remove = __devexit_p(mwl8k_remove), .shutdown = __devexit_p(mwl8k_shutdown), }; static int __init mwl8k_init(void) { return pci_register_driver(&mwl8k_driver); } Given that the "impossible" is happening, I guess Id blame mwl8k_probe, but doesnt/shouldnt pci_register_driver insist that the .id_table has a match ?? thanks Jim

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PER-CPU data
by Rajasekhar Pulluru April 4, 2012

April 4, 2012

Hi, I would like to know how per-cpu data are stored internally? And how are they protected from other cores? Thanks & Regards, Rajasekhar

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Re: How to debug a kernel thread?
by Mulyadi Santosa April 3, 2012

April 3, 2012

Hi :) On Tue, Apr 3, 2012 at 17:37, Parmenides <mobile.parmenides(a)gmail.com> wrote: > source tree. I compiled the kernel with kgdb and run it in qemu with > virtual serial port: > > qemu -kernel bzImage -initrd image.cpio.gz -append > "kgdboc=ttyS0,115200 kgdbwait" -serial tcp::1234,server > > In another console, the gdb was given command: > > (gdb) target remote local:1234 > (gdb) continue > > Then I pressed Ctrl+C to suspend the target, but got no reply. The gdb > got stuck and lost control to the target. As such, there is no IIRC, years ago I did the same thing like yours, using kgdb and qemu. What I forgot is how I hook into the remote kgdb stub. Here's my suggestion: try other option outside tcp, perhaps UNIX socket...or anything that's supported by gdb. And see if it makes any difference. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com

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i_block field
by Ganesh Patil April 2, 2012

April 2, 2012

Hello, I have printed the i_blocks[EXT4_N_BLOCKS] filed from ext4_inode structure. of my file (a.txt); code: ret= ext4_get_inode_loc(d_inode1, &iloc); e4_inode= ext4_raw_inode(&iloc); for(i=0;i<5;i++) { printk(KERN_INFO "%d",e4_inode->i_block[i]); } I got the following result.: 127754 4 0 0 1 8705 what is the 127754 (Address of extent or data block)? what is 8705 &1 ? -- Regards, Ganesh Patil.

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Unable to locate package kernel-headers-XXX
by Sraddha April 2, 2012

April 2, 2012

I have faced this problem before. I want to compile a Device driver module , simple thing as hello world for my kernel. I want to use the headers instead of downloading t entire source. I do this sudo apt-get install kernel-headers-$(uname -r) Reading package lists... Done Building dependency tree Reading state information... Done E: Unable to locate package kernel-headers-2.6.38-13-generic E: Couldn't find any package by regex 'kernel-headers-2.6.38-13-generic' How in the world shall I ever get these headers. Regards Sraddha

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Re: What is use of apply_alternative function from alternative.c
by Pritam Bankar April 2, 2012

April 2, 2012

Thanks Andrew , Jim On Tue, Mar 20, 2012 at 8:40 PM, Andrew Case <atcuno(a)gmail.com> wrote: > The feature is called SMP alternatives. See if this articles helps > you: http://lwn.net/Articles/164121/ > > On Tue, Mar 20, 2012 at 8:54 AM, Pritam Bankar > <pritambankar1988(a)gmail.com> wrote: > > Hi, > > Cal anyone help me in understanding alternative.c file from Linux source > > code. > > I want to learn function apply_alternative. AFAIK this code applies > better > > replacement to instruction set used by processor. > > But I am not sure what exactly it is doing ? > > > > -- > > > > Pritam Bankar > > > > _______________________________________________ > > Kernelnewbies mailing list > > Kernelnewbies(a)kernelnewbies.org > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > > > -- Pritam Bankar

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