January 2011 - kernelnewbies@kernelnewbies.org

can't git the source code of nfs from linux-nfs
by kapenware Jan. 5, 2011

Jan. 5, 2011

hi, Everyone, I'm trying to get nfs's source code from bhalevy's Git repository. After a while of struggle, it give me this: git clone git://git.linux-nfs.org/projects/bhalevy/linux-pnfs.git Initialized empty Git repository in /home/kos/kernel/pnfs/linux-pnfs/.git/ git.linux-nfs.org[0: 173.201.45.137]: errno=Connection timed out fatal: unable to connect a socket (Connection timed out) Could anybody tell me what‘s wrong with this? And how can I get the source back? Lots of thanks.

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Re: fixed memory bytes
by John Mahoney Jan. 4, 2011

Jan. 4, 2011

Please reply all..I added back list. On Tue, Jan 4, 2011 at 1:58 PM, mohit verma <mohit89mlnc(a)gmail.com> wrote: > thnx john,......... > but i know that this indicates to compiler to align the structure to its > nearest boundries. is that so? I am not sure of your definition of boundary, but I would say it does the opposite. It tells the compiler not to align the struct to boundaries. -- John

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ASLR implementation
by Zubin Mithra Jan. 4, 2011

Jan. 4, 2011

Hi, I recently read about the Linux kernel implementing ASLR to prevent buffer overflow attacks. I would like to have a look at how this is implemented by reading the kernel source code. Could someone offer a few pointers on where to start looking?(It would make my work slightly easier.) Thanks, zm

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slab usage in linux
by Sowmya Sridharan Jan. 4, 2011

Jan. 4, 2011

Hi List, I have a few queries regarding slab memory and it's usage. I have seen slab cache increase by even 1GB, over two to three days on a stable system.(The system was sending and receiving bulk amounts of packets). When is slab usually freed? Also when I analyzed /proc/slabinfo, I was able to see that the number of active slab objects were increasing mostly for task_struct, dentry_cache and proc_inode_caches. When are these caches allotted objects, in general? Can anyone please explain the behavior related to slab allocation; or point to any reference material? Thanks, Sowmya. =====-----=====-----===== Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you

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sharing link about contribution to open source projects
by Anuz Pratap Singh Tomar Jan. 4, 2011

Jan. 4, 2011

Hi all, I came across this interesting blog by Miguel de Icaza(Gnome author): http://tirania.org/blog/archive/2010/Dec-31.html This is about how to and how not to contribute to open source project. This list is breeding ground for future kernel hackers, so I hope this article would be useful. Regards Anuz

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functions about dump backtrace function names in mips arch
by loody Jan. 4, 2011

Jan. 4, 2011

Dear all: If i remember correctly, when kernel panic there is a function I can use to dump all the names of backtrace functions. I have searched arch/mips/traps.c, but I only can see the dump functions of cpu registers, If my assumption is true, would anyone tell me what the name is or what Doc I can looking for? appreciate your help, miloody

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help : Not able to clone from the git.kernel.org, git-remote goes to infinite loop on poll and select
by Ashok Babu Jan. 4, 2011

Jan. 4, 2011

Admin Functions - Edit<http://support.github.com/discussions/repos/5208-not-able-to-close-from-the…> - Remove<http://support.github.com/discussions/repos/5208-not-able-to-close-from-the…> Hi All, I am sorry, If this question is not relevant here. If not please suggest me from where I can get help : I am trying to clone from the repository " http://www.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2....<http://www.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6.git> " After entering the command : git clone http://www.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2....<http://www.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6.git> The terminal hungs for more than an hour. After which I checked the disk size in the newly created folder : linux-omap-2.6$ du -hs . 424M . So I assumed atleast it did not hung and has downloaded 424M. ( Why there is no progress shown during downloading ?) -----> Atleast for a rookie like me, I would be happy if there is progress shown ? But later on I left it for one more hour, and the size still remained 424MB. Then I took strace of the "git-remote" process and observed that It goes into infinite loop in the "poll and select API's" select(0, [], [], [], {0, 50000}) = 0 (Timeout) poll([{fd=10, events=POLLIN|POLLPRI|POLLRDNORM|POLLRDBAND}], 1, 0) = 0 (Timeout) clock_gettime(CLOCK_MONOTONIC, {40319, 761125790}) = 0 clock_gettime(CLOCK_MONOTONIC, {40319, 761735093}) = 0 poll([{fd=11, events=POLLIN|POLLPRI|POLLRDNORM|POLLRDBAND}], 1, 0) = 0 (Timeout) clock_gettime(CLOCK_MONOTONIC, {40319, 762851171}) = 0 clock_gettime(CLOCK_MONOTONIC, {40319, 763482264}) = 0 clock_gettime(CLOCK_MONOTONIC, {40319, 764073129}) = 0 select(0, [], [], [], {0, 50000}) = 0 (Timeout) poll([{fd=10, events=POLLIN|POLLPRI|POLLRDNORM|POLLRDBAND}], 1, 0) = 0 (Timeout) clock_gettime(CLOCK_MONOTONIC, {40319, 815722241}) = 0 clock_gettime(CLOCK_MONOTONIC, {40319, 817421640}) = 0 poll([{fd=11, events=POLLIN|POLLPRI|POLLRDNORM|POLLRDBAND}], 1, 0) = 0 (Timeout) clock_gettime(CLOCK_MONOTONIC, {40319, 818608398}) = 0 clock_gettime(CLOCK_MONOTONIC, {40319, 819189485}) = 0 clock_gettime(CLOCK_MONOTONIC, {40319, 819829798}) = 0 ---> Is this a BUG ? ( FYI, I am behind a proxy server)

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Verifying module
by Mag Gam Jan. 4, 2011

Jan. 4, 2011

We are planning to deploy a system for a client. I was told that leaving unnecessary modules (ie. jfs, usb, etc...) will not cause latencies in the kernel however the client is very sensitive. They care about latencies in microseconds and I was wondering if leaving unnecessary modules loaded would cause it and how can I measure the kernel latency (with lmbench if possible) w/o necessary modules. TIA

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FPGA registers userspace interface?
by Kfir Lavi Jan. 3, 2011

Jan. 3, 2011

Hi, I have a FPGA that is constantly changing (its on development phase). I want to let userspace app to update those registers, but don't want to create an API yet. What is the best way to open a range of registers to userspace, so no driver update is required? Thanks, Kfir

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small ata driver enhancement project for someone
by Greg Freemyer Jan. 3, 2011

Jan. 3, 2011

All, I don't think the kernel is yet tracking SSD vs Rotational. It would be a nice patch if someone would do that. I don't maintain the subsystem, but I assume it would be accepted if well done. You could model your patch by looking at how the drive topology patches were done. Effectively this patch would do the same thing. (Petersen wrote those, so I think these are them: http://markmail.org/message/azj3z4tofrknnbbe) My thoughts: ===> How to tell For SATA: Per T13/1699-D Revision 4a (from May 2007) word 217 of the identify block should be populated with a "1" to identify non-rotating media. http://www.t13.org/Documents/UploadedDocuments/docs2007/D1699r4a-ATA8-ACS.p… IIRC: The identify block is read during drive query time, so you should not have to actually generate any i/o. Just patch the portion of the kernel working with the identify block. ie. See the topology patch. For SCSI - no idea, but I'd be surprised if they did not already have a scsi flag for it. The topology patch also handled SCSI, so it's just a matter of finding the scsi field to use. ===> Quirks Lots of manufacturers don't follow the specs on something like this, so a quirks functionality is typically how the ATA driver handles it. ie. If you find a SSD that is not setting the flag, then setup a quirk to override the flag. The quirk table should be based on make & model at a minimum, and maybe firmware. You should be able to find existing quirk logic, so don't invent your own. SCSI seems to be followed much more accurately, so you may not need a quirks functionality for it. ===> userspace API Seems like there should be a "/sys/block/sda/*" file that allows userspace to interrogate. The topology patches added a few of these, so one more would be good. If you can generate the same data for scsi, maybe just create /sys/block/sda/rotation_speed and have it just reflect exactly word 217 of the identify block. Greg

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