Tracing memory address access in kernel
Hello,
I am facing issue of memory corruption where only one field of
allocated structure is getting corrupted. I have bio structure and one
of the page in bio vector is getting set to NULL.
crash> struct bio_vec 0x88009dc5eb00
struct bio_vec {
bv_page = 0xea000a434b80,
bv_len = 4096,
bv_offset = 0
}
crash> struct bio_vec 0x88009dc5eb10
struct bio_vec {
bv_page = 0x0,
bv_len = 4096,
bv_offset = 0
}
crash> struct bio_vec 0x88009dc5eb20
struct bio_vec {
bv_page = 0xea000a467500,
bv_len = 4096,
bv_offset = 0
}
I have allocated contagious memory for bio vectors. As you can see in
second bio vector bv_page is getting set to NULL. This address is
valid till the time I do some operations in my module. After some
operations bv_page is getting set to NULL. Other fields are having
valid data.
Is there any debugging technique / tool available which will track
access to specific memory access? I would like to dump stack every
time bv_page is accessed or modified
Thanks and regards,
Pritam Bankar
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System call service routine and interrupt context
Hi, My question is, do all the code of interrupt handler in system call gets executed in interrupt context? System calls generate software interrupts. So when I do open() syscall it we call do_sys_open() handler which will eventually call file system specific open function call. Will all this happen in interrupt context until I get open file descriptor in user land? If not when does context change? Thanks and regards, Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: user space vs kernel space address space
Thanks Miles, I was in assumption that every physical HAS to be mapped in some kernel virtual address. I have come across one more doubt please see my comments inline. On Sun, Dec 29, 2013 at 7:04 PM, Miles MH Chen orca.c...@gmail.comwrote: Hi Pritam, 1) Yes, all 512RAM will be direct mapped to kernel address space IF the kernel have a 896MB direct mapping area. Actually you can change the range of kernel direct mapping by the vmalloc=size in boot command line. In 32-bit and 3:1 split configuration, kernel direct mapping area + vmalloc area is roughly 1G. 2) User space and kernel space can have different virtual addresses mapping to the same physical frame at the same time. How above scenario of user space and kernel space having mapping to the same physical frame is handled. This would be like sharing kernel data with user which is not allowed. 3) Direct mapped or fixed map or permanent map are describing kernel VIRTUAL address space, you can see the virtual memory layout by 'dmesg'. When user space needs memory, the kernel allocates a free memory frame, and remaps the frame to user space. The frame does not have to have a valid kernel virtual address. But all physical memory/frames are eventually controlled by kernel , then how can there ever exist a frame which doesn't have mapping with kernel or kernel virtual address ? Regards, MH On Sun, Dec 29, 2013 at 5:42 PM, Pritam Bankar pritambankar1...@gmail.com wrote: Lets consider 32 bit Linux system with 512 physical RAM. Suppose I have standard 3:1 address space split. Now what I understand is (In general) 1. In the fourth gigabyte I have kernel space 2. Out of 1GB for kernel address space only 896MB is used as direct mapping and other 128 MB is used for Noncontiguous Memory Area Management, Fixed Mapping and Permanent Mapping. PCMIIW Following are my doubts : 1. Since my system has only 512MB RAM, will there be only direct mappings since 896 is enough to hold 512 RAM? 2. When user space program do malloc, we get some virtual address from userspace region (from first 3GB) of process. So will it be like, when I access some memory from that region, there is some physical frame associated with it AND same physical frame will also be mapped in kernel space ? So what I want to know, for every physical frame is there a mapping in userspace as well as kernel space ? (given that some address in user space of process map to same physical frame) 3. If we consider example of Linux system with 4GB, now if I do malloc from user space from which memory region kernel will give memory ? Direct mapped region or fixed map or permanent map ? Thanks and regards, Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies Thanks and regards, Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: user space vs kernel space address space
Miles thanks a lot for response but I still have some doubts please see my comments inline. On Sun, Dec 29, 2013 at 7:04 PM, Miles MH Chen orca.c...@gmail.com wrote: Hi Pritam, 1) Yes, all 512RAM will be direct mapped to kernel address space IF the kernel have a 896MB direct mapping area. Actually you can change the range of kernel direct mapping by the vmalloc=size in boot command line. In 32-bit and 3:1 split configuration, kernel direct mapping area + vmalloc area is roughly 1G. 2) User space and kernel space can have different virtual addresses mapping to the same physical frame at the same time. 3) Direct mapped or fixed map or permanent map are describing kernel VIRTUAL address space, you can see the virtual memory layout by 'dmesg'. When user space needs memory, the kernel allocates a free memory frame, and remaps the frame to user space. The frame does not have to have a valid kernel virtual address. But all physical memory/frames are eventually controlled by kernel , then how can there ever exist a frame which doesn't have mapping with kernel or kernel virtual address ? Regards, MH On Sun, Dec 29, 2013 at 5:42 PM, Pritam Bankar pritambankar1...@gmail.com wrote: Lets consider 32 bit Linux system with 512 physical RAM. Suppose I have standard 3:1 address space split. Now what I understand is (In general) 1. In the fourth gigabyte I have kernel space 2. Out of 1GB for kernel address space only 896MB is used as direct mapping and other 128 MB is used for Noncontiguous Memory Area Management, Fixed Mapping and Permanent Mapping. PCMIIW Following are my doubts : 1. Since my system has only 512MB RAM, will there be only direct mappings since 896 is enough to hold 512 RAM? 2. When user space program do malloc, we get some virtual address from userspace region (from first 3GB) of process. So will it be like, when I access some memory from that region, there is some physical frame associated with it AND same physical frame will also be mapped in kernel space ? So what I want to know, for every physical frame is there a mapping in userspace as well as kernel space ? (given that some address in user space of process map to same physical frame) 3. If we consider example of Linux system with 4GB, now if I do malloc from user space from which memory region kernel will give memory ? Direct mapped region or fixed map or permanent map ? Thanks and regards, Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies Thanks and regards, Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
user space vs kernel space address space
Lets consider 32 bit Linux system with 512 physical RAM. Suppose I have standard 3:1 address space split. Now what I understand is (In general) 1. In the fourth gigabyte I have kernel space 2. Out of 1GB for kernel address space only 896MB is used as direct mapping and other 128 MB is used for Noncontiguous Memory Area Management, Fixed Mapping and Permanent Mapping. PCMIIW Following are my doubts : 1. Since my system has only 512MB RAM, will there be only direct mappings since 896 is enough to hold 512 RAM? 2. When user space program do malloc, we get some virtual address from userspace region (from first 3GB) of process. So will it be like, when I access some memory from that region, there is some physical frame associated with it AND same physical frame will also be mapped in kernel space ? So what I want to know, for every physical frame is there a mapping in userspace as well as kernel space ? (given that some address in user space of process map to same physical frame) 3. If we consider example of Linux system with 4GB, now if I do malloc from user space from which memory region kernel will give memory ? Direct mapped region or fixed map or permanent map ? Thanks and regards, Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Query regarding physically discontiguous memory
On Wed, Dec 25, 2013 at 9:07 PM, valdis.kletni...@vt.edu wrote: On Wed, 25 Dec 2013 14:45:01 +0530, Pritam Bankar said: This is what I don't understand what does it mean by containing large holes? physical discontiguous memory? Is it like when I put 2 RAM chips in a system then memory for them will be discontiguous? Per my understanding RAM memory will ALWAYS be contiguous whether its 512 MB or 4 GB. Your understanding is wrong. That may be true on most x86-based desktops and laptops and the like, but it's often very wrong on other architectures. In fact, given that the x86 architecture is just one of like 27 archs that Linux supports, it's a good bet that there's more archs that *don't* enforce contiguous memory than do. Counting through the defconfigs to get a number is left as an exercise for the student. :) A common case for embedded systems is 256M of RAM at address 0, and 256M of RAM at address 0x8000 (or whatever the halfway mark for the architecture is). NUMA boxes are sometimes each node's RAM is at node number*4G or similar, which means lots of holes if each node is partly populated with only 2G. Thanks a lot Saptarshi and Valdis. Your comments cleared my doubt but while doing some more analysis I have come with following points. Following is a output of /proc/iomem on my system * [pritam@linux-box-1 ~]$ cat /proc/iomem -0009fbff : *System RAM* - : Crash kernel 0009fc00-0009 : reserved 000a-000b : Video RAM area 000c-000c7fff : Video ROM 000c8000-000c97ff : Adapter ROM 000c9800-000cafff : Adapter ROM 000f-000f : System ROM 0010-3ffe : *System RAM* 0040-005fed40 : Kernel code 005fed41-006d292f : Kernel data 3fff-3fffefff : ACPI Tables 3000-3fff : ACPI Non-volatile Storage fc90-fc9f : PCI Bus #01 fc9b-fc9b : :01:05.1 fc9b-fc9b : tg3 fc9e-fc9e : :01:05.0 fc9e-fc9e : tg3 fca0-feaf : PCI Bus #03 fd00-fdff : :03:04.0 feac-fead : :03:04.0 feafd000-feafdfff : :03:00.1 feafd000-feafdfff : ohci_hcd feafe000-feafefff : :03:00.0 feafe000-feafefff : ohci_hcd feaff000-feaf : :03:04.0 febfe000-febfefff : :00:0a.1 febff000-febf : :00:0b.1 ff50-ff5f : PCI Bus #01 ff78- : reserved ** PCMIIW, 1. From above output it is clear that System RAM is discontinuous. I calculated addresses in both sections assigned to System RAM (highlighted in above output) and they are of 1024 MB which is exactly my systems physical RAM is. 2. But for other IO devices lets say Video RAM, area is 000a-000b Now who has assigned these addresses? Do they remain same forever ? How kernel comes to know that there is no RAM at 000a-000b but its Video RAM? Thanks, Pritam ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Query regarding physically discontiguous memory
Hi, I just started reading Memory Managment chapter from book Professional Linux Kernel Architecture. At very start of chapter I came across terms FLATMEM, DISCONTIGMEM and SPARSEMEM. Out of these DISCONTIGMEM and SPARSEMEM are available to NUMA systens only. Book also says UMA systems can also choose DISCONTIGMEM option if there address space contains large holes. Some googling says DISCONTIGMEM is prefered when we have physical discontiguous memory. This is what I don't understand what does it mean by containing large holes? physical discontiguous memory? Is it like when I put 2 RAM chips in a system then memory for them will be discontiguous? Would /proc/iomem give me details I wanted? Per my understanding RAM memory will ALWAYS be contiguous whether its 512 MB or 4 GB. Please give me graceful example of discontiguous physical memory That will really help me out. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Fedora kernel rpmbuild query
Hi Shraddha, Please find my comments below, On Wed, Dec 26, 2012 at 1:35 PM, Shraddha Kamat sh200...@gmail.com wrote: Hi List, I do the following on Fedora kernel src rpm : (1) rpm -ivh kernel-xxx.rpm (2) Go to ~/rpmbuild/SPECS dir (2) rpmbuild -bp kernel.specs --nodeps then in the ~/rpmbuild/BUILD/ dir I get kernel-xxx dir where in there are two source dir - (1) linux-xxx A (2) vanilla-xxx B Why are these two dir created - How do I use the configuration file /boot/config-xxx to build vmlinuz and initrd image ? Directory B is vanilla kernel source which is standard kernel source. This is a same source which is available on kernel.org Directory A is actually for source which has been modified by user. In this case it will have patches from FEDORA above standard kernel from kernel.org. To build vmlinuz and initrd image copy /boot/config-xxx to Directory A (linux-xxx) and run sudo make oldconfig then follow normal compilation steps Which dir A or B sould I use for building ? You should be using directory A -- Shraddha ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies Thanks, Pritam ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
What is modpost ?
Hi guys, I want to confirm my understanding regarding modpost and Module.Symvers files. From my understanding a. modpost is used to add versioning information to module. b. modpost is also used to create mod.c and Module.Symvers files per module c. then we compile all *.mod.c files and link it to .ko Is my understanding correct ? For what else purpose modpost is useful ? What is specific data in mod.c file ? Thanks, Pritam ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Fwd: Memory split in 64-bit environment
Thanks Dmitry and Adam. Great explanation...! On Fri, Nov 2, 2012 at 9:20 PM, Dmitry Filippov filippov...@gmail.com wrote: Every user process in the system has its own virtual address range that extends from 0 to TASK_SIZE. The area above (from TASK_SIZE to 2^32 or 2^64 ) is reserved exclusively for the kernel — and may not be accessed by user processes. TASK_SIZE is an architecture-specific constant that divides the address space in a given ratio — in IA-32 systems, for instance, the address space is divided at 3 GiB so that the virtual address space for each process is 3 GiB; 1 GiB is available to the kernel because the total size of the virtual address space is 4 GiB. Although actual figures differ according to architecture, the general concepts do not. This division does not depend on how much RAM is available. As a result of address space virtualization, each user process thinks it has 3 GiB of memory. The userspaces of the individual system processes are totally separate from each other. The kernel space at the top end of the virtual address space is always the same, regardless of the process currently executing. Notice that the picture can be more complicated on 64-bit machines because these tend to use less than 64 bits to actually manage their huge principal virtual address space. Instead of 64 bits, they employ a smaller number, for instance, 42 or 47 bits. Because of this, the effectively addressable portion of the address space is smaller than the principal size. However, it is still larger than the amount of RAM that will ever be present in the machine, and is therefore completely sufficient. As an advantage, the CPU can save some effort because less bits are required to manage the effective address space than are required to address the complete virtual address space. The virtual address space will contain holes that are not addressable in principle in such cases. hopes this gives high level overview thanks, Dmitry 2012/11/2 Adam Lee adam8...@gmail.com: On Fri, Nov 02, 2012 at 07:40:11PM +0530, Pritam Bankar wrote: On Fri, Nov 2, 2012 at 4:26 PM, Mulyadi Santosa mulyadi.sant...@gmail.com wrote: Hi :) On Fri, Nov 2, 2012 at 5:46 PM, Pritam Bankar pritambankar1...@gmail.com wrote: But I have some questions, 1. How is memory split up on 64-bit architecture in this URL: http://unix.stackexchange.com/questions/32244/user-kernel-split-in-64bit-linux it says user space get 128 TiB...the rest you can read there :) 2. Can we override this 3:1 split ? sure just change PAGE_OFFSET if I remember correctly...however, the effects might be harmful, for example for certain virtualization since they assume certain address for memory allocation 3. If yes, who can do that user or kernel? kernel..for sure.. Thanks Mulyadi. I gone through link but there is no explanation. What can be the logic behind kernel space of only 512 MB for 64-bit machines. We have 1GB kernel space in 32-bit architecture so 64-bit should ideally have much more than that. 1, that 512MB is kernel text mapping(kernel image), not kernel space. 2, kernel space under x86_64 is 128TB _now_, same as user space. 3, _now_, the split is 1:1, because address space is large enough. 4, change PAGE_OFFSET is not enough, _now_, under x86_64, PAGE_OFFSET is 0x8800, the beginning of direct mapping of all phys memory, but the beginning of kernel space is 0x8000, there is a guard hole between them. Please check https://en.wikipedia.org/wiki/X86-64, and the reasons I underline _now_ are kernel's current design and https://en.wikipedia.org/wiki/X86-64#Canonical_form_addresses PS, if you can read Chinese(hopeless), check my blog: http://adam8157.info/blog/2012/07/linux-x86-64-vm/ -- Regards, Adam Lee http://adam8157.info ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Missing __versions section on .ko
Hi Ramesh thanks for great pdf. From whatever I understood after reading I fired command modinfo on my module and it gave output , vermagic: 3.2.0-23-generic-pae SMP mod_unload modversions 686 greping out vermagic. So I believe vermagic is behaving correctly. What is 686 in output ? Any other reason for missing __versions section ? On Wed, Sep 19, 2012 at 6:24 AM, Ramesh.P rames...@gmail.com wrote: Hi, 'Invalid module' is typically thrown when you don't compile your module against the kernel you are linking into. I think __versions section is added by vermagic.o as part of build process. Please refer http://lwn.net/images/pdf/LDD3/ch02.pdf, Version dependency section for more details. Thanks, Ramesh On Tue, Sep 18, 2012 at 7:10 AM, Pritam Bankar pritambankar1...@gmail.com wrote: On Tue, Sep 18, 2012 at 7:27 PM, Pritam Bankar pritambankar1...@gmail.com wrote: Any idea what causes __versions section to get added in *.ko module. A simple hello.ko on ubuntu 12.04 i386 machine gets loaded successfully. Other module just doesn't get loaded giving error Invalid module . When I compared both modules with objdump -h I found __versions section was missing from second module and that can be the reason its not getting loaded. How can I add this section to other .ko ? What causes __versions to get added in ko ? I have compiled both modules with modpost and Module.symvers. Thanks, Pritam Bankar -- Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Missing __versions section on .ko
Any idea what causes __versions section to get added in *.ko module. A simple hello.ko on ubuntu 12.04 i386 machine gets loaded successfully. Other module just doesn't get loaded giving error Invalid module . When I compared both modules with objdump -h I found __versions section was missing from second module and that can be the reason its not getting loaded. How can I add this section to other .ko ? What causes __versions to get added in ko ? Thanks, Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Missing __versions section on .ko
On Tue, Sep 18, 2012 at 7:27 PM, Pritam Bankar pritambankar1...@gmail.com wrote: Any idea what causes __versions section to get added in *.ko module. A simple hello.ko on ubuntu 12.04 i386 machine gets loaded successfully. Other module just doesn't get loaded giving error Invalid module . When I compared both modules with objdump -h I found __versions section was missing from second module and that can be the reason its not getting loaded. How can I add this section to other .ko ? What causes __versions to get added in ko ? I have compiled both modules with modpost and Module.symvers. Thanks, Pritam Bankar -- Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
How to know default gcc flags ?
How to know default flags used in specific gcc version ? I am looking for difference between 3.4.3 and 4.1.1 These two have some difference regarding -nosse option but how can I find this ? -- Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
How to know which programming model is used on may Linux machine
Hi, AFAIK there are three programming model that can be chosen on 64 bit environment. These models are LP64, ILP64, LLP64 Question 1) But how can I know which model is used on my system ? Question 2) Does long long data type is limited for LLP64 type model ? (My system is redhat 6.2 64bit) Thanks Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
What is difference between declaring long and long int
Hi, long long x; long long int y; Anybody please tell me, is there any difference between declaring variable with long long and long long int ? Does both declaration mean same thing ? Thanks, Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
no-op error in dmesg
Hi, I have one structure called foo. Address of object of foo(say objfoo) is passed to ioctl call status = ioctl(fd, arg, objfoo); But during manipulation I am not getting ioctl error 5 (input/output error). I am more confused about error in dmesg which is *foo: no-op * What does no-op indicate? If it is no-operation, how can we relate this to foo structure? Thanks, Pritam ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Re: Problem with OOM killer killing process even when there is plenty of RAM.
Hi, use of get_zeroed_page(unsigned int flags); or get_free_page(unsigned int flags); might help you. Thanks, Pritam On Thu, Dec 8, 2011 at 9:47 PM, Mulyadi Santosa mulyadi.sant...@gmail.comwrote: Hi... On Thu, Dec 8, 2011 at 02:06, mindentropy mindentr...@gmail.com wrote: mind to tell us, how do you allocate memory? kmalloc? Via kmalloc. As Greg said, you probably better use vmalloc for such allocation. Vmalloc can deal with non contigous physical pages... furthermore, could you kindly paste the content of /proc/meminfo right before OOM kicks in? Its kind of tough to do it as it happens so fast. I will try to write a script which polls. Alright, I just thought it will be better if we understand the overall virtual memory situation better. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Pritam Bankar ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
RE: What is RTNL lock?
Hi,
http://lists.openfabrics.org/pipermail/general/2008-July/052458.html
This might help you.
From: kernelnewbies-boun...@kernelnewbies.org
[mailto:kernelnewbies-boun...@kernelnewbies.org] On Behalf Of rohan puri
Sent: 28 November 2011 12:36
To: Vimal; kernelnewbies
Subject: Re: What is RTNL lock?
On Mon, Nov 28, 2011 at 12:19 PM, Vimal j.vi...@gmail.com wrote:
Hi Rohan
Yes, I understood this part, but I am wondering what is the purpose of
this lock. I am guessing it's to protect all network related
operations from critical events, for e.g.: protecting a packet
transmit during device removal, protecting routing table entry during
route lookup, etc., but I can't find its precise documentation
anywhere. Thanks,
On 27 November 2011 22:44, rohan puri rohan.pur...@gmail.com wrote:
On Sun, Nov 27, 2011 at 10:37 PM, Vimal j.vi...@gmail.com wrote:
Hi all,
In the Linux networking code, I see a lot of comments that say Must
be called with RTNL lock.
What is this lock? I tried searching for it but couldn't find any
explanation on what it is...
Thanks
--
Vimal
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Hello Vimal,
This is a mutex named rtnl_mutex. Refer file net/core/rtnetlink.c
static DEFINE_MUTEX(rtnl_mutex);
void rtnl_lock(void)
{
mutex_lock(rtnl_mutex);
}
EXPORT_SYMBOL(rtnl_lock);
Where ever you see those comments indicate that this mutex is to be held
before execution of that code path.
Regards,
Rohan
--
Vimal
This lock is used to serialize changes to net_device instances from runtime
events, conf changes
Refer book understanding Linux network internals for more details.
Regards,
Rohan Puri
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RE: a few questions regarding acpi and kernel configuration
Hi, To cut down drivers you should configure your .config file in your source. You will have to recompile kernel. For pata you have , CONFIG_PATA_AMD=y CONFIG_PATA_OLDPIIX=y CONFIG_PATA_SCH=y This can be set to n instead of y to remover support of pata. This can be done to other modules also. -Original Message- From: kernelnewbies-boun...@kernelnewbies.org [mailto:kernelnewbies-boun...@kernelnewbies.org] On Behalf Of Littlefield, Tyler Sent: 19 October 2011 03:43 To: kernelnewbies@kernelnewbies.org Subject: a few questions regarding acpi and kernel configuration Hello all: I have a few questions, I was hoping someone could help me out here. First, I'll start off by saying that my netbook is a sort of PDA for me. I just boot it up and when I'm taking care of stuff for work running around getting info and that, I can use it to grab the info. I use Linux for this, but my battery dies kind of quickly. I'm also looking to optomize performance as much as possible. So, I sat down and tried to optomize a kernel. Both to save space (since this is a smaller drive), and to make things a bit quicker, even by a little bit. I put the config here: http://tds-solutions.net/config.tar.bz2 First, I'm curious what else I can yank out of there to make everything smaller. I'd like to cut down on the drivers and all that, and just include the driver for my specific harddrive if that's possible, as well as the wireless card. Can I turn off scsi/pata/ata since I have a sata drive? Is there other stuff I missed that I could take out? Finally, my last two questions. 1) Is there a way to access acpi so I can put the computer into standby quickly? I'm not sure how to pull that off from the cli, but doing it with code would work. 2) Is there a way for me to detect when the lid of my laptop has been closed and put it into standby, and/or set an idle timer to put it into standby? If there are clients out there that can interface with acpi and help with this, awesome. If not, and I need to code something up, that works too. Finally, I'm trying to find a way, since I do not use it to turn off the display. Is this possible? -- Take care, Ty Web: http://tds-solutions.net The Aspen project: a light-weight barebones mud engine http://code.google.com/p/aspenmud Sent from my toaster. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
RE: building linux kernel 3.0.4
make defconfig takes default options present in config file at ( arch/x86/configs/) of particular architecture say x86_64_defconfig http://lxr.linux.no/linux+*/arch/x86/configs/x86_64_defconfig which is present in source code. Out of these modules you might not be needing all. So try using make oldconfig instead of make defconfig. From: Pritam Bankar [mailto:pritambankar1...@gmail.com] Sent: 08 November 2011 00:35 To: kernelnewbies@kernelnewbies.org Subject: Re: building linux kernel 3.0.4 On 07-11-2011 23:15, ashish anand wrote: Hi , I am using vmware on windows 7 and try to built kernel version 3.0.4 . I am following this procedure make defconfig make make modules make modules_install make install Every step succeds except make install Its throwing me following message sh /home/ashu/linux-3.0.4/linux-3.0.4/arch/x86/boot/install.sh 3.0.4 arch/x86/boot/bzImage \ System.map /boot ERROR: modinfo: could not find module fuse ERROR: modinfo: could not find module sunrpc ERROR: modinfo: could not find module ip6t_REJECT ERROR: modinfo: could not find module nf_conntrack_ipv6 ERROR: modinfo: could not find module ip6table_filter ERROR: modinfo: could not find module ip6_tables ERROR: modinfo: could not find module ipv6 ERROR: modinfo: could not find module uinput ERROR: modinfo: could not find module snd_ens1371 ERROR: modinfo: could not find module gameport ERROR: modinfo: could not find module snd_rawmidi ERROR: modinfo: could not find module snd_ac97_codec ERROR: modinfo: could not find module ac97_bus ERROR: modinfo: could not find module snd_seq ERROR: modinfo: could not find module snd_seq_device ERROR: modinfo: could not find module snd_pcm ERROR: modinfo: could not find module ppdev ERROR: modinfo: could not find module snd_timer ERROR: modinfo: could not find module parport_pc ERROR: modinfo: could not find module snd ERROR: modinfo: could not find module parport ERROR: modinfo: could not find module microcode ERROR: modinfo: could not find module soundcore ERROR: modinfo: could not find module vmware_balloon ERROR: modinfo: could not find module snd_page_alloc ERROR: modinfo: could not find module pcnet32 ERROR: modinfo: could not find module mii ERROR: modinfo: could not find module i2c_piix4 ERROR: modinfo: could not find module i2c_core ERROR: modinfo: could not find module mptspi ERROR: modinfo: could not find module mptscsih ERROR: modinfo: could not find module mptbase ERROR: modinfo: could not find module scsi_transport_spi I wonder if my Vmware workstation is creating a problem? Or If I am using make defconfig why are these modules not bulit. Please help I am stuck. Thanks and Regards Ashish Anand Growth Should Not Kill Innovation ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies make defconfig takes default options present in config file of particular architecture say x86_64 which is present in source code. Out of these modules you might not be needing all. So try using make oldconfig. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: building linux kernel 3.0.4
On 07-11-2011 23:15, ashish anand wrote: Hi , I am using vmware on windows 7 and try to built kernel version 3.0.4 . I am following this procedure make defconfig make make modules make modules_install make install Every step succeds except make install Its throwing me following message *sh /home/ashu/linux-3.0.4/linux-3.0.4/arch/x86/boot/install.sh 3.0.4 arch/x86/boot/bzImage \ System.map /boot ERROR: modinfo: could not find module fuse ERROR: modinfo: could not find module sunrpc ERROR: modinfo: could not find module ip6t_REJECT ERROR: modinfo: could not find module nf_conntrack_ipv6 ERROR: modinfo: could not find module ip6table_filter ERROR: modinfo: could not find module ip6_tables ERROR: modinfo: could not find module ipv6 ERROR: modinfo: could not find module uinput ERROR: modinfo: could not find module snd_ens1371 ERROR: modinfo: could not find module gameport ERROR: modinfo: could not find module snd_rawmidi ERROR: modinfo: could not find module snd_ac97_codec ERROR: modinfo: could not find module ac97_bus ERROR: modinfo: could not find module snd_seq ERROR: modinfo: could not find module snd_seq_device ERROR: modinfo: could not find module snd_pcm ERROR: modinfo: could not find module ppdev ERROR: modinfo: could not find module snd_timer ERROR: modinfo: could not find module parport_pc ERROR: modinfo: could not find module snd ERROR: modinfo: could not find module parport ERROR: modinfo: could not find module microcode ERROR: modinfo: could not find module soundcore ERROR: modinfo: could not find module vmware_balloon ERROR: modinfo: could not find module snd_page_alloc ERROR: modinfo: could not find module pcnet32 ERROR: modinfo: could not find module mii ERROR: modinfo: could not find module i2c_piix4 ERROR: modinfo: could not find module i2c_core ERROR: modinfo: could not find module mptspi ERROR: modinfo: could not find module mptscsih ERROR: modinfo: could not find module mptbase ERROR: modinfo: could not find module scsi_transport_spi *I wonder if my Vmware workstation is creating a problem? Or If I am using make defconfig why are these modules not bulit. Please help I am stuck. Thanks and Regards Ashish Anand Growth Should Not Kill Innovation ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies make defconfig takes default options present in config file of particular architecture say x86_64 which is present in source code. Out of these modules you might not be needing all. So try using make oldconfig. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: looking for 3.0 source
I think if have git installed then LXR might do it for you. On Wed, Sep 21, 2011 at 7:38 AM, Jacky Lam lamshu...@gmail.com wrote: Thanks Mirco. But how about if I want to download 3.0.4 source? Jacky On 9/15/2011 6:08 AM, Mirco Tischler wrote: 2011/9/14 Littlefield, Tylerty...@tysdomain.com: Hello: and I'm unsure of where to get what I want. I found the 2.6 branch on github, but I'm looking for kernel 3.0's source, not 3.4 or whatever we're on now. Is there somewhere I can get it? https://github.com/torvalds/linux is a clone of the main git repo on kernel.org. It contains all versions since 2.6.11, including 3.0 and the most recent 3.1-rc6. You can even download the tarballs there. Mirco ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies -- Pritam Bankar With the recent attacks on kernel.org, it's down ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
