RE: How to set up a debugging environment.
>2010/3/8 Mulyadi Santosa : >> Hi... >sorry for interrupting your conversation :) Start a new thread then >I recently try to use kgdb to debug kernel. >my questions are: >1. there are 2 uart under my plarform, I intent to let one for console >one for kgdb. >how coudl I tell kernel which one is for console and which one is for kgdb? Give it as kernel parameters... http://www.linuxquestions.org/questions/programming-9/kgdb-module-debugging-question-657611/ >2. do I need to compile my kernel with any additionally CFLAG ? >appreciate your help, >miloody This Email may contain confidential or privileged information for the intended recipient (s) If you are not the intended recipient, please do not use or disseminate the information, notify the sender and delete it from your system. __ -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
Re: How to set up a debugging environment.
hi: 2010/3/8 Mulyadi Santosa : > Hi... > > You forgot to Cc: to the mailing listplease keep kernelnewbies intact... > > On Mon, Mar 8, 2010 at 2:43 PM, become who you are born to be > Chaitannya mahatme wrote: >> Hi , >> >> Actually after a few hours of trying I figured out this, but got this error >> message "During startup program terminated with signal SIGKILL." > > When did you see such message? During system boot inside Qemu? > >> Can some please explain me what has to be done. >> Also 1 more thing, I have heard that kgdb has been a part of mainline >> kernel. If so how to validate that? > > Simply check your kernel config. You should see something like below > if your kernel has kgdb: > $ grep -i kgdb /usr/src/kernels/linux-2.6.32/.config > CONFIG_HAVE_ARCH_KGDB=y > # CONFIG_KGDB is not set > sorry for interrupting your conversation :) I recently try to use kgdb to debug kernel. my questions are: 1. there are 2 uart under my plarform, I intent to let one for console one for kgdb. how coudl I tell kernel which one is for console and which one is for kgdb? 2. do I need to compile my kernel with any additionally CFLAG ? appreciate your help, miloody -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
SD Driver : FAT: FAT read failed (blocknr 8) in sd card error while removing sd card during writing
I have sd card on board ... During recording/writing SD card, remove SD card ... then i am getting endless error in dmesg as below : end_request: I/O error, dev mmcblk0, sector 24 FAT: FAT read failed (blocknr 8) mmcblk0: error -110 sending status comand<3>mmcblk0: error -110 sending read/write command, response 0x0, card status 0x0 Block mmc_blk_issue_rq function call 346 end_request: I/O error, dev mmcblk0, sector 4 FAT: FAT read failed (blocknr 4) MMC: killing requests for dead queue end_request: I/O error, dev mmcblk0, sector 8 FAT: FAT read failed (blocknr 8) FAT: FAT read failed (blocknr 4) FAT: FAT read failed (blocknr 8) FAT: FAT read failed (blocknr 4) FAT: FAT read failed (blocknr 8) FAT: FAT read failed (blocknr 4) FAT: FAT read failed (blocknr 8) How to stop this message ... what is ideal situation when we remove card while writing .. can u help me what to do ? where is the problem here? sd host controler driver problem or block driver problem or file system problem Note: I have formatted sd card with FAT32 file system . With EXT3 File system : Remove SD card while writing/recording we got error messages like below. but this is not endless. After some time it stops. === end_request: I/O error, dev mmcblk0, sector 156536 mmcblk0: error -110 sending status comand<3>mmcblk0: error -110 sending read/write command, response 0x0, card status 0x0 mmcblk0: error -110 requesting status end_request: I/O error, dev mmcblk0, sector 4736 Aborting journal on device mmcblk0p1. ext3_abort called. EXT3-fs error (device mmcblk0p1): ext3_journal_start_sb: Detected aborted journal Remounting filesystem read-only end_request: I/O error, dev mmcblk0, sector 4448 journal commit I/O error ===
Re: using gdb to debug a 64-bit kernel
On Thu, Jul 8, 2010 at 02:13, Robert P. J. Day wrote: > in fact, that's exactly the right value based on this snippet from > init/main.c: > > unsigned long loops_per_jiffy = (1<<12); > > which is, of course, 4096. Thanks for sharingso it's fixed in 64 bit environment...I assumen it's x64...not IA 64. So pls CMIIW about my assumption > > but i still don't know why i can't print the changing value of > jiffies if i clear the cache with: > > (gdb) core-file /proc/kcore But, is it changing if you quit gdb and run it again? Just a stupid confirmation.. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
Re: using gdb to debug a 64-bit kernel
ok, part of the mystery is solved and i'm just being an idiot: On Wed, 7 Jul 2010, Robert P. J. Day wrote: > and this is also weird: > > (gdb) p loops_per_jiffy > $16 = 4096 > > huh? that value is way too low for this system. on my old 32-bit > system, that value would be around 2 million or so. in fact, that's exactly the right value based on this snippet from init/main.c: unsigned long loops_per_jiffy = (1<<12); which is, of course, 4096. but i still don't know why i can't print the changing value of jiffies if i clear the cache with: (gdb) core-file /proc/kcore rday -- Robert P. J. Day Waterloo, Ontario, CANADA Top-notch, inexpensive online Linux/OSS/kernel courses http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
Re: using gdb to debug a 64-bit kernel
On Thu, 8 Jul 2010, Mulyadi Santosa wrote: > On Thu, Jul 8, 2010 at 01:19, Robert P. J. Day wrote: > > > however, since this *is* a 64-bit system, i apparently have no such > > symbol, i would just use: > > > > (gdb) p __jiffies > > $12 = 4294937296 > > (gdb) p __jiffies > > $13 = 4294937296 > > (gdb) p __jiffies > > $14 = 4294937296 > > two things I would check first: > - is the vmlinux file really the kernel uncompressed image of current > running kernel? i'm pretty sure that's true -- "uname -r" tells me: "2.6.35-rc4-rday", while when i start gdb, i get: ... Core was generated by `BOOT_IMAGE=/vmlinuz-2.6.35-rc4-rday i don't know how much more confident i can be that vmlinux matches the running kernel -- that's the only vmlinux file on the system. > - is your gdb capable to interpret 64 bit data and "report" it in 32 > bit realm? i'm not even sure what you're asking -- i simply installed gdb on this 64-bit version of ubuntu, what else do i need to worry about? and remember, i did say that this was the first time i've tried this on a 64-bit system so it may well be that there's something really obvious i don't know. rday -- Robert P. J. Day Waterloo, Ontario, CANADA Top-notch, inexpensive online Linux/OSS/kernel courses http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
Re: using gdb to debug a 64-bit kernel
On Thu, Jul 8, 2010 at 01:19, Robert P. J. Day wrote: > however, since this *is* a 64-bit system, i apparently have no such > symbol, i would just use: > > (gdb) p __jiffies > $12 = 4294937296 > (gdb) p __jiffies > $13 = 4294937296 > (gdb) p __jiffies > $14 = 4294937296 two things I would check first: - is the vmlinux file really the kernel uncompressed image of current running kernel? - is your gdb capable to interpret 64 bit data and "report" it in 32 bit realm? CMIIW people -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
using gdb to debug a 64-bit kernel
currently, i'm working on a short writeup showing how to use gdb to debug a running kernel and, when i first wrote this a while back, it was for a 32-bit system and things worked just fine. in short, i fired up gdb using the standard kernel-oriented invocation with: $ sudo gdb /tmp/vmlinux /proc/kcore where i copied the vmlinux file for the running kernel into /tmp to save keystrokes. and that's the standard way to use gdb to debug the kernel, but here's where it starts to get weird. on a 32-bit system, if i wanted to print the current value of jiffies, i used: (gdb) p jiffies_64 however, since this *is* a 64-bit system, i apparently have no such symbol, i would just use: (gdb) p __jiffies $12 = 4294937296 (gdb) p __jiffies $13 = 4294937296 (gdb) p __jiffies $14 = 4294937296 ... and as kernel-oriented gdb users know, you'll keep getting the same answer over and over until you flush the gdb cache and reread /proc/kcore: (gdb) core-file /proc/kcore but even after i do that, i'll get the same value. why? is there some really fundamental difference between debugging a 32-bit vs 64-bit kernel? and this is also weird: (gdb) p loops_per_jiffy $16 = 4096 huh? that value is way too low for this system. on my old 32-bit system, that value would be around 2 million or so. none of this makes sense. am i missing something fundamental? this is the first time i've tried this on a 64-bit system. rday -- Robert P. J. Day Waterloo, Ontario, CANADA Top-notch, inexpensive online Linux/OSS/kernel courses http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
Re: multiple alternate superblocks
On 7/7/10, Onkar Mahajan wrote: > Is it possible to supply multiple alternate superblocks > while doing a mount in Linux ? Why would you want to do that ? What is the expected behavior in such cases ? > > -Regards, > Onkar > > -- > > > Your work is going to fill a large part of your > life, and the only way to be truly satisfied is > to do what you believe is great work. And the > only way to do great work is to love what > you do. If you haven’t found it yet, keep > looking, and don’t settle. As with all matters > of the heart, you’ll know when you find it. >- Steve Jobs > > -- Thanks - Manish == [$\*.^ -- I miss being one of them == -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
SATA driver implementation
Hi, I am writing SATA driver for on chip SATA controller, here i have few questions: 1. AFAIK, SATA device falls under PCI class device in kernel, so its make use of some of the PCI API utilities to read the PCI header ( where one can get the information about the SATA controller base address ). But in kernel code, one of the driver ( /driver/ata/sata_fsl.c ) i have not seen any PCI API's used in the driver code but other drivers are extensively (driver/ata/sata*) using the PCI API's to get the controller information. Why is it so? 2. Can anybody give me the call flow how the user-space request reaches the actual SATA driver?. l am looking for a rough sequence call flow from system call ( read/write ) to the actual drivers API's getting called. Also can anyone point me to some good resource links on SATA & its example drivers. Thanks for your help!!! -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
Re: multiple alternate superblocks
On Wed, Jul 7, 2010 at 08:19, Onkar Mahajan wrote: > Is it possible to supply multiple alternate superblocks > while doing a mount in Linux ? I think your question might be interpreted vary between person to person. Do you mean, Linux kernel will use information according to multilple copy of superblock of a filesystem? If that's what you mean, IMO it's not...at least that's what I know. Even during fsck, you need to determine which superblock is the valid one that will be used as the base information. PS: Can't agree more with your quote...Steve Jobs is always one of my idol... -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecar...@nl.linux.org Please read the FAQ at http://kernelnewbies.org/FAQ
