April 2011 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

Device Driver Help
by Naveen Kumar April 12, 2011

April 12, 2011

Hi, I am very new to device driver area and has some basic knowledge of char and block device driver and linux kernel. I am little bit aware of some of subsystem of kernel but I am not able to co-relate which device driver file is pure software driver and more or less part of kernel subsystem to achieve hardware abstraction and which driver files deals with real hardware. It would be great help if someone can provide some real example with some open hardware datasheet, some basic code snippet will help me a lot. Thanks, A Kernel Newbie

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BSP device driver customization
by Naveen Kumar April 11, 2011

April 11, 2011

Hi, I am new to BSP and HAL development. I have a IP which is using BSP released by some of leading ARM Soc maker. The IP is designed by our company where my job is to customize the device driver for my IP to achieve performance. Can anyone please suggest me a starting point to find the bug specific to my board(Hardware) and fix them. Thanks, Naveen

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order of call to built-in modules
by David Shwatrz April 11, 2011

April 11, 2011

HI, The macros module_init() and module_exit() are used both in case a source is built-in (the code is called from the init stage) or as a kernel module (implementing a init_module symbol). In case 2 of /built-in/ modules I am wondering if it is possible to know by advance the order used to call the various module_init() entry points. Is it possible to fix this order? rgs, DS

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Kernel newbie mailing list subscription
by Naveen Kumar April 11, 2011

April 11, 2011

please confirm my subscription. Thanks, Naveen

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inode query
by mohit verma April 8, 2011

April 8, 2011

hi list, how can a utility like **find** command can map an inode number to a filename? i mean if we pass **find -inum inode_number / ** , it will show us the files associated with that "inode_number". What is the underlying mechanism used in all this ? I have peeped into the findutils code but it seems horrible to figure it out from that code .:) thanks in advance. -- ........................ *MOHIT VERMA*

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Mentoring for GSoC
by Greg Freemyer April 7, 2011

April 7, 2011

All, I've seen a couple posts here from students looking for GSoC mentors. >From the flip side, I just had someone ask me if they could be a GSoC mentor via kernelnewbies. (I'm a proposed mentor via opensuse. Still looking for a student/proposal.) Does anyone know the details of the GSoC / kernelnewbies mentoring setup? Can someone just request to be a mentor via google-melange and say they are associated with kernel.org, and then say in the comments that they are part of kernelnewbies? ie. This org is so unstructured, I'm not sure how that would work. Thanks Greg

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Interpreting call trace
by Daniel Baluta April 7, 2011

April 7, 2011

Hello, I have the following stack trace: [3992.172/0] BUG: soft lockup - CPU#0 stuck for 61s! [events/0:39] [ 3992.215/0] Pid: 39, comm: events/0 Tainted: P W 2.6.32 #1 X8DTT-H [ 3992.222/0] RIP: 0010:[<ffffffff8115f989>] [<ffffffff8115f989>] __write_lock_failed+0x9/0x20 [ 3992.231/0] RSP: 0018:ffff880028203908 EFLAGS: 00000287 [ 3992.236/0] RAX: ffff88063ce0bfd8 RBX: ffff880028203920 RCX: ffffffff814e1b00 [ 3992.243/0] RDX: ffff8800282144e0 RSI: ffff880028203abc RDI: ffffffff814e1b04 [ 3992.250/0] RBP: ffffffff8100c6f3 R08: 0000000000000004 R09: ffff880028203ab0 [ 3992.257/0] R10: ffff88061851fa08 R11: 0000000000000000 R12: ffff880028203880 [ 3992.264/0] R13: ffff88060404f800 R14: ffffffff814e1b04 R15: ffffffff8101fd88 [ 3992.272/0] FS: 0000000000000000(0000) GS:ffff880028200000(0000) knlGS:0000000000000000 [ 3992.280/0] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b [ 3992.286/0] CR2: 00007f9cc9fb9000 CR3: 0000000001001000 CR4: 00000000000006f0 [ 3992.293/0] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 3992.300/0] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 3992.307/0] Call Trace: [ 3992.309/0] <IRQ> [<ffffffff81374e12>] ? _write_lock_bh+0x22/0x30 [ 3992.316/0] [<ffffffff81297751>] ? neigh_create+0x2f1/0x6b0 [ 3992.321/0] [<ffffffff81374f00>] ? _read_unlock_bh+0x10/0x20 [ 3992.327/0] [<ffffffff81296401>] ? neigh_lookup+0xd1/0xf0 [ 3992.333/0] [<ffffffff81297b96>] ? neigh_event_ns+0x86/0xc0 [ 3992.338/0] [<ffffffff812f2cdb>] ? arp_process+0x9fb/0xbf0 [ 3992.344/0] [<ffffffff812f2ffc>] ? arp_rcv+0x11c/0x130 How could one interpret this? For example having: [ 3992.316/0] [<ffffffff81297751>] ? neigh_create+0x2f1/0x6b0 [ 3992.321/0] [<ffffffff81374f00>] ? _read_unlock_bh+0x10/0x20 means that _read_unlock_bh has been called & finished ? Or it has been interrupted by next function in trace (neigh_create). Any other info about interpreting call traces are welcomed. thanks, Daniel.

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Interested in Working on Linux kernel projects in TCP/IP stack
by murugan k April 7, 2011

April 7, 2011

Hi, I am Murugan. I am interested in working on projects involving TCP/IP stack of linux kernel. I have basic knowledge of Netfilters in linux.If there are any such projects kindly let me know. Thanks, Murugan -- * * *** * * * * * *** * * * * *

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Linux MMC framework
by Hanumant Singh April 7, 2011

April 7, 2011

HI I am looking for some documentation on the Linux mmc framework. I didnot find anything in the Documentation folder. Is there some book/link that I can refer to? Thanks Hanumant

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why only C?
by mohit verma April 6, 2011

April 6, 2011

Hi list, I have a very basic question. As far as i can decipher , we impose Object oriented paradigm in kernel space using C : like using gates to allow only one way entry and binding functions to structures in a OOP fashion and trying to make them private to that structure only , encapsulation of one struct into another structure (and lots of features ) and itself lots of kernel subsystem supports like driver interface and blah blah behaving like **objects** ....... why dont we use some fully OOPs supportive language like JAVA or partial supportive language like C++ to construct Linux Kernel???? I don't think that performance is the main reason behind all this . Is it?? Thanks a lot in advance. -- ........................ *MOHIT VERMA*

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