Re: Linux SMP Test Cases
Hi Adam... On Tue, Apr 27, 2010 at 12:52, Adam Jiang jiang.a...@gmail.com wrote: This article is informative. Is there a way to watch how the scheduler do its job visibly? For example, could I know the specific IRQ is handled by which cpu? This is purely my idea. I think you can do it by periodically checking the output of /proc/interrupts. For example: watch -d 'cat /proc/interrupts | grep timer' Then see in which CPU the number grows bigger. There, we can conclude that for recent time interval, certain IRQ is handled by certain CPU. -- 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
Not able to boot Linux-2.6.33.2
Hello everyone, I wanted to upgrade form Linux-2.6.15-52-386 kernel to vanila Linux-2.6.33.2 kernel from kernel.org. I compiled and installed kernel with defualt configurion (except for disabling booting from NFS) Steps for compiling kernel: $make menuconfig --- to disable booting form NFS $make $make modules $make modules_install $make install $cd /boot/ $mkinitramfs -o initrd.img-2.6.33.2 2.6.33.2 Following is a list of messages that I get when I try boot with new kernel: modeprobe: FATAL: Could not load /lib/modules/2.6.33.2/modules.dep: No such file or directory. WARNING: Couldn't open directory /lib/modules/2.6.33.2: No such file or directory FATAL: Could not open /lib/modules/2.6.33.2/modules.dep.temp for writing: No such file or directory. ALERT!: /dev/hda1 does not exists. Dropping to a Shell! I'm trying all this on sun virtual box. My Linux-2.6.15-52-386 still works well. Following are grub entries: title Ubuntu, kernel 2.6.33.2 root (hd0, 0) kernel/boot/vmlinuz-2.6.33.2 root=/dev/hda1 ro quiet splash initrd /boot/initrd.img-2.6.33.2 savedefault boot Please help! -- Best Regards, Mukesh
Re: Not able to boot Linux-2.6.33.2
On Tue, 2010-04-27 at 13:06 +0530, Mukesh Yadav wrote: Hello everyone, I wanted to upgrade form Linux-2.6.15-52-386 kernel to vanila Linux-2.6.33.2 kernel from kernel.org. I compiled and installed kernel with defualt configurion (except for disabling booting from NFS) Following is a list of messages that I get when I try boot with new kernel: modeprobe: FATAL: Could not load /lib/modules/2.6.33.2/modules.dep: No such file or directory. Following are grub entries: title Ubuntu, kernel 2.6.33.2 root (hd0, 0) kernel/boot/vmlinuz-2.6.33.2 root=/dev/hda1 ro quiet splash initrd /boot/initrd.img-2.6.33.2 savedefault boot Have you tried this? root=/dev/sda1 In modern linux versions, the ata and scsi code has been merged, so all disks are now /dev/sd..., regardless of their actual physical interface. It looks like your kernel is booting, and the initrd is working fine, but is then unable to mount the correct root fs... Regards, Simon -- 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: Not able to boot Linux-2.6.33.2
More suggestions please. -- Regards Mukesh On Tue, Apr 27, 2010 at 3:26 PM, Mukesh Yadav mukesh...@gmail.com wrote: On Tue, Apr 27, 2010 at 3:04 PM, Anuz Pratap Singh Tomar chambilketha...@gmail.com wrote: On Tue, Apr 27, 2010 at 1:06 PM, Mukesh Yadav mukesh...@gmail.comwrote: Hello everyone, I wanted to upgrade form Linux-2.6.15-52-386 kernel to vanila Linux-2.6.33.2 kernel from kernel.org. I compiled and installed kernel with defualt configurion (except for disabling booting from NFS) Steps for compiling kernel: $make menuconfig --- to disable booting form NFS $make $make modules $make modules_install $make install $cd /boot/ $mkinitramfs -o initrd.img-2.6.33.2 2.6.33.2 Following is a list of messages that I get when I try boot with new kernel: modeprobe: FATAL: Could not load /lib/modules/2.6.33.2/modules.dep: No such file or directory. WARNING: Couldn't open directory /lib/modules/2.6.33.2: No such file or directory FATAL: Could not open /lib/modules/2.6.33.2/modules.dep.temp for writing: No such file or directory. ALERT!: /dev/hda1 does not exists. Dropping to a Shell! not sure, but seems like u need to fix the partition info /dev/hda1 may not be your root. If this is case then same partition should not work as root for Linux-2.6.15.-52-386. Isn't it. I'm trying all this on sun virtual box. My Linux-2.6.15-52-386 still works well. Following are grub entries: title Ubuntu, kernel 2.6.33.2 root (hd0, 0) kernel/boot/vmlinuz-2.6.33.2 root=/dev/hda1 ro quiet splash initrd /boot/initrd.img-2.6.33.2 savedefault boot Please help! -- Best Regards, Mukesh -- People ask the question... what's a RocknRolla? And I tell 'em - it's not about drums, drugs, and hospital drips, oh no. There's more there than that, my friend. We all like a bit of the good life - some the money, some the drugs, other the sex game, the glamour, or the fame. But a RocknRolla, oh, he's different. Why? Because a real RocknRolla wants the fucking lot.
Re: Not able to boot Linux-2.6.33.2
On Tue, Apr 27, 2010 at 4:19 PM, Mukesh Yadav mukesh...@gmail.com wrote: More suggestions please. Please post your /etc/fstab output please post your fdisk -l output As someone pointed out: scsi and ata are merged in recent kernels between .15 and .33: there are so many changes, its unlikely u can run it from older distros. Secondly, u can boot .15 with hda1 but newer kernels require sdXn Now they use UUID for recognizing partition, though not sure, if kernel forces such requirements. if you look at it: its not able to find /lib/modules/2.6.33.2/modules.dep,http://2.6.33.2/modules.dep Which is probably because its not able to mount /root -- Regards Mukesh On Tue, Apr 27, 2010 at 3:26 PM, Mukesh Yadav mukesh...@gmail.com wrote: On Tue, Apr 27, 2010 at 3:04 PM, Anuz Pratap Singh Tomar chambilketha...@gmail.com wrote: On Tue, Apr 27, 2010 at 1:06 PM, Mukesh Yadav mukesh...@gmail.comwrote: Hello everyone, I wanted to upgrade form Linux-2.6.15-52-386 kernel to vanila Linux-2.6.33.2 kernel from kernel.org. I compiled and installed kernel with defualt configurion (except for disabling booting from NFS) Steps for compiling kernel: $make menuconfig --- to disable booting form NFS $make $make modules $make modules_install $make install $cd /boot/ $mkinitramfs -o initrd.img-2.6.33.2 2.6.33.2 Following is a list of messages that I get when I try boot with new kernel: modeprobe: FATAL: Could not load /lib/modules/2.6.33.2/modules.dep: No such file or directory. WARNING: Couldn't open directory /lib/modules/2.6.33.2: No such file or directory FATAL: Could not open /lib/modules/2.6.33.2/modules.dep.temp for writing: No such file or directory. ALERT!: /dev/hda1 does not exists. Dropping to a Shell! not sure, but seems like u need to fix the partition info /dev/hda1 may not be your root. If this is case then same partition should not work as root for Linux-2.6.15.-52-386. Isn't it. I'm trying all this on sun virtual box. My Linux-2.6.15-52-386 still works well. Following are grub entries: title Ubuntu, kernel 2.6.33.2 root (hd0, 0) kernel/boot/vmlinuz-2.6.33.2 root=/dev/hda1 ro quiet splash initrd /boot/initrd.img-2.6.33.2 savedefault boot Please help! -- Best Regards, Mukesh -- People ask the question... what's a RocknRolla? And I tell 'em - it's not about drums, drugs, and hospital drips, oh no. There's more there than that, my friend. We all like a bit of the good life - some the money, some the drugs, other the sex game, the glamour, or the fame. But a RocknRolla, oh, he's different. Why? Because a real RocknRolla wants the fucking lot. -- People ask the question... what's a RocknRolla? And I tell 'em - it's not about drums, drugs, and hospital drips, oh no. There's more there than that, my friend. We all like a bit of the good life - some the money, some the drugs, other the sex game, the glamour, or the fame. But a RocknRolla, oh, he's different. Why? Because a real RocknRolla wants the fucking lot.
Re: Not able to boot Linux-2.6.33.2
On 27 April 2010 12:20, Anuz Pratap Singh Tomar chambilketha...@gmail.com wrote: Secondly, u can boot .15 with hda1 but newer kernels require sdXn if you look at it: its not able to find /lib/modules/2.6.33.2/modules.dep, Which is probably because its not able to mount /root I was under the impression that the kernel will give you a fatal message about not being able to find the root filesystem in that case. -Srdjan -- 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: Not able to boot Linux-2.6.33.2
On Tue, Apr 27, 2010 at 5:02 PM, Srdjan Todorovic todorovi...@googlemail.com wrote: On 27 April 2010 12:20, Anuz Pratap Singh Tomar chambilketha...@gmail.com wrote: Secondly, u can boot .15 with hda1 but newer kernels require sdXn if you look at it: its not able to find /lib/modules/ 2.6.33.2/modules.dep, Which is probably because its not able to mount /root I was under the impression that the kernel will give you a fatal message about not being able to find the root filesystem in that case. Not sure, why is this happening. For fedora, it says system going to sleep, which is strange. There are similar questions in ubuntu community googling ALERT! /dev/sda1 does not exist. Dropping to a shell will show the result.
Dynamic Kernel Module Section Addresses
Hi, i am trying to debug kernel modules on 2.6.32 with vmware workstation. For that, i need to add symbols to gdb using add-symbol-file by giving the various section addresses of the kernel module ( .text, .data, .bss etc ). I find these addresses by inserting the module looking into /sys/module/module-name/sections finally i rmmod the module. But the problem is, i add these module section addresses to gdb and attach gdb to the vmware instance now load the module again(this time, to debug), the section addresses of the module change. So i can't set any breakpoints. So, the question is - 1) Is there any way to tell the kernel not to load these module sections at different addresses every time the module is inserted removed . That is, can we have the module loaded at exactly the same address everytime? 2) Is there any way to overcome this problem so that i can debug the module using vmware even though the module is loaded at different addresses? Thanks. Regards, Venkatram Tummala
Re: Dynamic Kernel Module Section Addresses
Hi Venkatram... On Wed, Apr 28, 2010 at 05:34, Venkatram Tummala venkatram...@gmail.com wrote: 1) Is there any way to tell the kernel not to load these module sections at different addresses every time the module is inserted removed . That is, can we have the module loaded at exactly the same address everytime? None that I know. AFAIK the only way is to recheck the /sys entry and reinsert the symbol file (your kernel module file, which has been compiled with -g before) to proper position 2) Is there any way to overcome this problem so that i can debug the module using vmware even though the module is loaded at different addresses? AFAIK, again none that I know. -- 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: Dynamic Kernel Module Section Addresses
On Tue, Apr 27, 2010 at 5:04 PM, Mulyadi Santosa mulyadi.sant...@gmail.comwrote: Hi Venkatram... On Wed, Apr 28, 2010 at 05:34, Venkatram Tummala venkatram...@gmail.com wrote: 1) Is there any way to tell the kernel not to load these module sections at different addresses every time the module is inserted removed . That is, can we have the module loaded at exactly the same address everytime? None that I know. AFAIK the only way is to recheck the /sys entry and reinsert the symbol file (your kernel module file, which has been compiled with -g before) to proper position With this approach, i can set breakpoints in every function except for the function that initializes the module because i have to insert the module to get the kernel module section addresses from /sys as a result of which, the initializition routine finishes executing which means i can not set any breakpoints in the module initialize function. This is not a problem for the the module exit function or any other function though. There should be a way to tell the kernel that Look, I dont care where you put the segments of this module but put them at the same place everytime i re-insert the module again (atleast until the next reboot). Conceptually, this should not be hard to implement (if its not there already) because it is the same kernel the same unchanged KO module that i am asking it to insert. 2) Is there any way to overcome this problem so that i can debug the module using vmware even though the module is loaded at different addresses? AFAIK, again none that I know. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
Re: how to call system call from kernelspace
On Tue, Apr 27, 2010 at 7:55 AM, rahul patil rahul.deshmukhpa...@gmail.comwrote: Though it is bad idea to call a system call from kernel space is it possible any how to call a system call from kernel space? Generally a better idea to user kernel interfaces directly instead of sys calls. Further most sys call functions are not exported so you can't call them from your kernel module. You'll have to EXPORT_SYMBOL them and recompile your kernel which is kind of ugly. -Joel
Re: how to call system call from kernelspace
On Wed, Apr 28, 2010 at 8:09 AM, Joel Fernandes agnel.j...@gmail.comwrote: On Tue, Apr 27, 2010 at 7:55 AM, rahul patil rahul.deshmukhpa...@gmail.com wrote: Though it is bad idea to call a system call from kernel space is it possible any how to call a system call from kernel space? Generally a better idea to user kernel interfaces directly instead of sys calls. Further most sys call functions are not exported so you can't call them from your kernel module. You'll have to EXPORT_SYMBOL them and recompile your kernel which is kind of ugly. If you can tell us which syscalls you'd like to make, maybe we can suggest some alternatives -Joel
Re: how to call system call from kernelspace
i want to call open,write system calls from kernel space.
what i want to do actually is to wrap up open system call.I have done wrap
up part of open system call using jprobes.
Now i want to write name of file being opened in another file say
/home/rahul/log and code for it will be written in wrap-up part
since the wrap-up part of open system call also runs in kernel space i want
to open and write file /home/rahul/log from kernel
space.
so the code in my wrap up routine in jprobe module will look like.
long my_sys_open(char*name,int flag,int mode)
{
int fd;
fs = get_fs(); /* save previous value */
set_fs (get_ds()); /* use kernel limit */
fd=sys_open(/home/rahul/log,O_CREAT,O_RDRW);
set_fs(fs);
fs = get_fs(); /* save previous value */
set_fs (get_ds()); /* use kernel limit */
fwrite(fd,name,strlen(name));
set_fs(fs);
jprobe_return();
return 0;
}
I will take care that recursion will not happen since i am calling sys_open
from wrapper of sys_open
On Wed, Apr 28, 2010 at 8:10 AM, Joel Fernandes agnel.j...@gmail.comwrote:
On Wed, Apr 28, 2010 at 8:09 AM, Joel Fernandes agnel.j...@gmail.comwrote:
On Tue, Apr 27, 2010 at 7:55 AM, rahul patil
rahul.deshmukhpa...@gmail.com wrote:
Though it is bad idea to call a system call from kernel space
is it possible any how to call a system call from kernel space?
Generally a better idea to user kernel interfaces directly instead of sys
calls. Further most sys call functions are not exported so you can't call
them from your kernel module. You'll have to EXPORT_SYMBOL them and
recompile your kernel which is kind of ugly.
If you can tell us which syscalls you'd like to make, maybe we can suggest
some alternatives
-Joel
--
Regards,
Rahul Patil
Re: Dynamic Kernel Module Section Addresses
On Wed, Apr 28, 2010 at 6:38 AM, Venkatram Tummala venkatram...@gmail.com wrote: On Tue, Apr 27, 2010 at 5:04 PM, Mulyadi Santosa mulyadi.sant...@gmail.com wrote: Hi Venkatram... On Wed, Apr 28, 2010 at 05:34, Venkatram Tummala venkatram...@gmail.com wrote: 1) Is there any way to tell the kernel not to load these module sections at different addresses every time the module is inserted removed . That is, can we have the module loaded at exactly the same address everytime? None that I know. AFAIK the only way is to recheck the /sys entry and reinsert the symbol file (your kernel module file, which has been compiled with -g before) to proper position With this approach, i can set breakpoints in every function except for the function that initializes the module because i have to insert the module to get the kernel module section addresses from /sys as a result of which, the initializition routine finishes executing which means i can not set any breakpoints in the module initialize function. This is not a problem for the the module exit function or any other function though. There should be a way to tell the kernel that Look, I dont care where you put the segments of this module but put them at the same place everytime i re-insert the module again (atleast until the next reboot). Conceptually, this should not be hard to implement (if its not there already) because it is the same kernel the same unchanged KO module that i am asking it to insert. 2) Is there any way to overcome this problem so that i can debug the module using vmware even though the module is loaded at different addresses? Probably i didn't understand the question. Can't you find it by looking at p modules from gdb ? Thanks - Manish AFAIK, again none that I know. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- 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
Re: how to call system call from kernelspace
On Wed, Apr 28, 2010 at 8:35 AM, rahul patil rahul.deshmukhpa...@gmail.com
wrote:
i want to call open,write system calls from kernel space.
[oops, didn't hit reply-to-all at first, sorry rahul!]
Not sure about open, but for read/write system calls, provided you already
have file opened and have the file descriptor, the following code snippets
should work:
For reads:
struct file *file = fget(fd)
if (file) {
loff_t pos = file_pos_read(file);
ret = vfs_read(file, buf, count, pos);
file_pos_write(file, pos);
fput(file);
}
For writes:
struct file *file = fget(fd)
if (file) {
loff_t pos = file_pos_read(file);
ret = vfs_write(file, buf, count, pos);
file_pos_write(file, pos);
fput(file);
}
No magic there, this is essentially the same code that gets executed when
you make read/write system calls defined in fs/read_write.c except that you
don't have to export sys_read and sys_write
Its a better idea to call file-f_op-read and file-f_op-write directly
instead of vfs_write in the above code, skips a lot of checks and stuff. See
how loop driver does this in drivers/block/loop.c in function
__do_lo_send_write.
You could even call write_begin and write_end directly if your backs fs
supports address space ops. Again good examples in loop driver.
HTH,
-Joel
question about get_user
Hi, all,
I have a problem with get_user() macro. What I did is as follows:
I run the following program
int main()
{
int a = 20;
printf(address of a: %p, a);
sleep(200);
return 0;
}
When the program runs, it outputs the address of a, say, 0xbff91914.
Then I pass this address to a module running in Kernel Mode that
retrieves the contents at this address (at the time when I did this, I
also made sure the process didn't terminate, because I put it to sleep
for 200 seconds... ):
The address is firstly sent as a string, and I cast them into pointer type.
int * ptr = (int*)simple_strtol(buffer, NULL,16);
printk(address: %p,ptr); // I use this line to make sure the cast is
correct. When running, it does output bff91914
int val = 0;
int res;
res= get_user(val, (int*) ptr);
However, res is always not 0, meaning that get_user returns error. I
am wondering what is the problem
Thank you!!
--
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