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

failed to do make menuconfig
by Prashant Shah July 26, 2011

July 26, 2011

Hi, In the latest staging tree I cant do "make menuconfig" or even "make config" prashant@mint11 ~/linux-2.6 $ make menuconfig HOSTCC scripts/kconfig/mconf.o HOSTCC scripts/kconfig/zconf.tab.o In file included from scripts/kconfig/zconf.tab.c:90:0: scripts/kconfig/lkc.h:27:22: fatal error: lkc_defs.h: No such file or directory compilation terminated. make[1]: *** [scripts/kconfig/zconf.tab.o] Error 1 make: *** [menuconfig] Error 2 Even against the latest linux 3.0.0 tree I get this HOSTCC scripts/kconfig/zconf.tab.o In file included from scripts/kconfig/zconf.tab.c:90:0: scripts/kconfig/lkc.h:27:22: fatal error: lkc_defs.h: No such file or directory compilation terminated. make[1]: *** [scripts/kconfig/zconf.tab.o] Error 1 make: *** [menuconfig] Error 2 I am using latest version of Mint Linux

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Interesting case while taking Ramdump of Linux kernel based device
by sandeep kumar July 26, 2011

July 26, 2011

Hi all, In Android target mobiles there is a facility called "Ramdump", where the entire Ram image is copied to a file as the kernel goes to panic. Ramdump is implemented like this 1) As the panic() function is called target will be reset. 2) Bootloader boots up in specific mode, where it enables the USB driver in uploading mode. 3) Through USB entire RAM content is copied to a file in the host computer. 4) This file is parsed through different tools and we can get the logs info wat exactly happened just before kernel panic happend. Now here is the interesting part, While the mobile's RAM image is being uploaded to host computer, our bootloader is still running in the mobile's RAM. How can it copy its own running region. This triggered me the following questions, 1) When bootloader runs, will it run in a specific reserved region of RAM or it takes entire RAM? 2) When it hands over the control to kernel, will it relinquish the entire RAM or certain part of RAM is reserved for it? 3) Does kernel use the entire RAM while running? 4) When the kernel is running, is ther any chance that, control again be taken back to bootloader?(coz i saw in bootloader code kernel is being called, after that code also some code is there,some printks and error handling stuff) Pls help me out here.. -- With regards, Sandeep Kumar Anantapalli,

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no files can be opened in a C program
by Venkateswarlu P July 26, 2011

July 26, 2011

What is the Max no of files that can be opened simultaneously within a Single C program. i want this information for kenel compilation

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Query regarding kernel memory
by Vaibhav Jain July 26, 2011

July 26, 2011

Hi, I read a few articles on linux virtual memory management such as this one : http://lwn.net/Articles/75174/ which say that earlier linux kernel could only use memory slightly below 1 GB. They have given the reason for it but I am unable to understand.They further describe the use of High memory and low memory. Could anybody please explain the reason for kernel not being able to use the 1 GB completely? Also please provide references for high memory and low memory. Thanks Vaibhav Jain

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T.XYZ symbols
by Andreas Platschek July 25, 2011

July 25, 2011

Hi! I got a bunch of Call-Traces like this: 8312.002483] Call Trace: [ 8312.002502] [<c101eaff>] __might_sleep+0xd7/0xde [ 8312.002517] [<c1053478>] T.396+0x17/0x21 [ 8312.002531] [<c129edf3>] rt_spin_lock+0xb/0x28 [ 8312.002578] [<f966cf92>] b43_interrupt_handler+0x1a/0x34 [b43] [ 8312.002594] [<c106df92>] handle_irq_event_percpu+0x82/0x1bd [ 8312.002609] [<c106e0f9>] handle_irq_event+0x2c/0x43 <snip> and was wondering about the second symbol T.396. greping over the kernel tree only finds it in binaries and the System.map. I have been searching around without a real plan. any hints on that? thx! andi

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Re: Need help: How to set .RECIPEPREFIX variable to whitespaces
by amit mehta July 25, 2011

July 25, 2011

Asked 'Make' gurus today about this and here's what Paul D. Smith confirmed: "RECIPEPREFIX must be set to exactly one unique character. There's no way to set it to be "four spaces". Also note that this feature is only available in the latest version of GNU make and many systems do not include that version yet, so if you use this feature your makefiles will not be portable to older systems (you might not care about that). " - Amit On Mon, Jul 18, 2011 at 10:40 AM, amit mehta <gmate.amit(a)gmail.com> wrote: > Thank you. With your work around I do not need to edit my vimrc file > everytime i need to write a Makefile. > > -Amit > > On Wed, Jul 13, 2011 at 8:03 PM, DG <dangets(a)gmail.com> wrote: >> On Wed, Jul 13, 2011 at 1:52 AM, amit mehta <gmate.amit(a)gmail.com> wrote: >>> Hi, >>> >>> How to set .RECIPEPREFIX variable to whitespace(say 4 whitespces) , so that >>> make uses this particular set of characters to identify the recipe for >>> a particular target. >>> In my $HOME/.vimrc file, for code indentation purpose, I've put the >>> following entries >>> to replace tabs with 4 whitespaces: >>> >>> <<<snip from my $HOME/.vimrc file>>> >>> "replace tabs with spaces >>> set expandtab >>> set shiftwidth=4 >>> set tabstop=4 >>> <<<snip from my $HOME/.vimrc file>>> >>> >>> >>> but the above will cause problem in case you write your own makefile >>> for a kernel module, >>> because now the tab stroke will be replaced by 4 whitespaces which >>> 'make' will not understand. >>> Quoting from 'make' manual, >>> "Please note: you need to put a tab character at the beginning of >>> every recipe line!" >>> >>> Seems .RECIPEPREFIX will come for resuce, but as of now I don't know >>> how to use it >>> to fix my problem. >>> >>> Regards, >>> Amit >>> >>> -- >>> Life is elsewhere. Cross Frontiers. Fly away. >>> >>> - Salman Rushdie >>> >>> _______________________________________________ >>> Kernelnewbies mailing list >>> Kernelnewbies(a)kernelnewbies.org >>> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >>> >> >> I have my vimrc file setup to use different tabs/spacing depending on >> the filetype. 8-width tab in C, 4-space indent in Python, etc... >> >> Here's a snippet from my vimrc: >> >> "-------- C ------------------------- >> function! LANG_C() >> setlocal noexpandtab >> setlocal shiftwidth=8 >> setlocal tabstop=8 >> setlocal softtabstop=8 >> setlocal formatoptions=tcroq >> endfunction >> autocmd FileType c call LANG_C() >> >> "------- Python ---------------- >> function! LANG_PYTHON() >> setlocal shiftwidth=4 >> setlocal tabstop=4 >> setlocal softtabstop=4 >> setlocal expandtab >> "--- python indent keywords -------- >> setlocal cinwords=if,elif,else,for,while,try,except,finally,def,class,with >> endfunction >> autocmd FileType python call LANG_PYTHON() >> >> "------- Makefile -------------- >> function! LANG_MAKEFILE() >> setlocal noexpandtab " makefiles only work with tab-indents >> setlocal shiftwidth=8 >> setlocal tabstop=8 >> setlocal softtabstop=8 >> endfunction >> autocmd FileType make call LANG_MAKEFILE() >> >> >> There may be other/better ways to do this, but it works well for me. >> > > > > -- > Life is elsewhere. Cross Frontiers. Fly away. > > - Salman Rushdie > -- Life is elsewhere. Cross Frontiers. Fly away. - Salman Rushdie

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problem with queue numbers between bridge, bonding and lo devices
by jiangtao.jit July 25, 2011

July 25, 2011

Hi, all recently, i read some of the Kernel codes and i noticed that a bridge and lo device have only one queue when allocated but a bonding device can have multi queues they are all virtual devices why they can have diffrent queue numbers it confused me a lot i would really appreciate if someone could give me some guidelines thanks very much 2011-07-16 jiangtao.jit

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setitimer shows different between amd64 and ia32
by Adam Lee July 25, 2011

July 25, 2011

Hi, all I'm working on a test which invoking setitimer(), and it hang in ia32 and ppc, but passed in amd64, could you guys give some help? 1, I know the 'value.it_interval.tv_usec' is too short, but why amd64 passed? 2, If I switch clock source from "tsc" to "hpet" on ia32, it passed. 3, I compiled it in ia32 and run it with ia32-libs in amd64, it passed. Here is the source: #include <sys/time.h> #include <signal.h> #include <unistd.h> #include <stdio.h> #include <time.h> #include <errno.h> #define LOOP_LIMIT 1E2 volatile int sigcount = 0; void catcher(int sig) { struct itimerval value; int which = ITIMER_REAL; sigcount++; if (sigcount > 1) { getitimer(which, &value); value.it_value.tv_sec = 0; value.it_value.tv_usec = 0; /*setitimer( which, &value, NULL ); */ } } int main(int argc, char *argv[]) { int result = 0; struct itimerval value, ovalue, pvalue; int which = ITIMER_REAL; struct sigaction sact; volatile double count; time_t t; sigemptyset(&sact.sa_mask); sact.sa_flags = 0; sact.sa_handler = catcher; sigaction(SIGALRM, &sact, NULL); getitimer(which, &pvalue); /*Set a real time interval timer to repeat */ value.it_interval.tv_sec = 0; value.it_interval.tv_usec = 1; value.it_value.tv_sec = 0; value.it_value.tv_usec = 5; result = setitimer(which, &value, &ovalue); /*The interval timer value returned by setitimer() should be */ /*identical to the timer value returned by getitimer() */ if (ovalue.it_interval.tv_sec != pvalue.it_interval.tv_sec || ovalue.it_interval.tv_usec != pvalue.it_interval.tv_usec || ovalue.it_value.tv_sec != pvalue.it_value.tv_sec || ovalue.it_value.tv_usec != pvalue.it_value.tv_usec) { printf("Real time interval timer mismatch, test Failed\n"); result = -1; } time(&t); printf("Before loop, time is %s", ctime(&t)); for (count = 0; ((count < LOOP_LIMIT)); count++) ; time(&t); printf("After loop, time is %s\n", ctime(&t)); if (sigcount == 0) printf("The signal catcher never gained control\n"); else printf("The signal catcher gained control\n"); printf("The value of count is %.0f\n", count); return (result); } -- Regards, Adam Lee -------------------------------------------------- E-mail: adam8157(a)gmail.com Website: http://www.adam8157.info --------------------------------------------------

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regarding do_IRQ()
by santhosh kumars July 25, 2011

July 25, 2011

Hi I am reading robertlove implementing interrupt handlers. When interrupt comes, the processor immediately stops what it is doing, disables the interrupt system (I am assuming disables all local interrupts of that processor)and jumps to the initial entry point where it calls do_IRQ(). do_IRQ() acknowledges the receipt of the interrupt and disables the interrupt delivery on the line. Here is my question like ,If do_IRQ() disables the interrupt delivery on the line(I am assuming it disables the interrupt delivery to all other processors on that line),then what about the other devices which are sharing same interrupt line and trying to send interrupts to processors. thanks, santhu.

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"echo c > /proc/sysrq-trigger" is hung in fedora14 guest os.
by Sudhakar Jha July 24, 2011

July 24, 2011

Hi, I am running Fedora14 in "Virtualbox 4.0.8". The host OS is Windows-XP. I configured kdump, kexec & crash as per instruction in Fedora-14-Deployment_Guide. The system gets hung and crash file is not generated after running the command "echo c > /proc/sysrq-trigger". ------------------------------------------------------ $ uname -a Linux fc14 2.6.35.6-45.fc14.i686 #1 SMP Mon Oct 18 23:56:17 UTC 2010 i686 i686 i386 $ service kdump status Kdump is operational $ su -c 'echo 1 > /proc/sys/kernel/sysrq' Password: $ su -c 'echo c > /proc/sysrq-trigger' Password: ------------------------------------------------------ Regards, Sudhakar.

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