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[Eudyptula Challenge] Not receiving tasks.
by Lucas Tanure May 5, 2014

May 5, 2014

Hi, I sent my task two over two days ago and didn't receive the task 03. I already sent 6 times the task 02 answer, but I got nothing instead. I used mutt, and a python script. The first time that I sent was two days ago. Has Eudyptula Challenge died ? Is down for a few days ? Thanks a Lot. -- Lucas Tanure The Python script tanure@archNote email $ cat sender.py #!/usr/bin/python3 from smtplib import SMTP from itertools import chain from errno import ECONNREFUSED from mimetypes import guess_type from subprocess import Popen, PIPE from email.mime.base import MIMEBase from email.mime.text import MIMEText from socket import error as SocketError from email.mime.multipart import MIMEMultipart from os.path import abspath, basename, expanduser import getpass # Define ID id_eudyptula = '[404ba4c8fd16]' # Define email addresses to use addr_to = 'little(a)eudyptula-challenge.org' addr_from = 'tanure(a)linux.com' # Define SMTP email server details smtp_server = SMTP("smtp.gmail.com",587) smtp_user = 'ltanure(a)gmail.com' smtp_pass = getpass.getpass() def get_mimetype(filename): content_type, encoding = guess_type(filename) if content_type is None or encoding is not None: content_type = "application/octet-stream" return content_type.split("/", 1) def mimify_file(filename): filename = abspath(expanduser(filename)) basefilename = basename(filename) msg = MIMEBase(*get_mimetype(filename)) msg.set_payload(open(filename, "r").read()) msg.add_header("Content-Disposition", "attachment", filename=basefilename) #encode_base64(msg) return msg def send_email(subject, text, files): # Prepare Message msg = MIMEMultipart() msg.preamble = subject msg.add_header("From", addr_from) msg.add_header("Subject", id_eudyptula + ' ' + subject) msg.add_header("To",addr_to) # Attach the main text msg.attach(MIMEText(text)) # Attach any files [msg.attach(mimify_file(filename)) for filename in files] # Contact local SMTP server and send Message try: smtp_server.ehlo() smtp_server.starttls() smtp_server.ehlo() smtp_server.login(smtp_user, smtp_pass) smtp_server.sendmail(addr_from, addr_to, msg.as_string()) smtp_server.quit() except SocketError as e: print(e) if __name__ == "__main__": text = open('text','r').read() send_email("Task 02 of the Eudyptula Challenge",text,['.config','dmesg'])

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Eudyptula Challenge
by Narendra Joshi May 5, 2014

May 5, 2014

Will the Eudyptula Challenge be always around? I want to do the challenge problems but I am busy these days. So I want to start doing them some time later. Will I be able to? -- narendra

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RE: Identifying neighbors within the LAN
by Hettiarachchige Hasitha Shan May 5, 2014

May 5, 2014

Dear Sir, > Step 1: When making security decisions, you probably don't need a list > of *all* neighbors - you only need an answer to "is *this* neighbor known or > not". And that would be a different API. If I am to get the information of known neighbors, which API should use in my kernel module. I searched this on Google for hours and that did not do any good. I am a novice at this, a reference/ example would be really great to point me in the right direction. Thank you very much sir, Best Regards, H. Hasitha Shan P.S. Thank you Mr. Valdis for pointing me that I should always reply beck to the kernennewbies mailing list. > To: hh_shan(a)live.com > CC: kernelnewbies(a)kernelnewbies.org > Subject: Re: Identifying neighbors within the LAN > From: Valdis.Kletnieks(a)vt.edu > Date: Sat, 3 May 2014 19:10:18 -0400 > > On Sat, 03 May 2014 11:01:19 -0700, Hettiarachchige Hasitha Shan said: > > > In the concept, it is required to obtain the list of neighbors within the > > LAN. I did some research online and I found out that I can obtain IPv4/ IPv6 > > neighbors by typing > > in "ip -4 neigh show" or "ip -6 neigh show" in the terminal where this > > feature is implemented by the module neighbour. > > > > My query is , If I am to obtain these information programatically through > > my kernel module, which methods should I call. > > Step 0: Figure out why a packet security module even *cares* what neighbors > are known. Why do you care if a neighbor is known or not? First, figure out > under what conditions a neighbor becomes known. What security decisions are you > planning to make based on "IPv4 address is in ARP table"? Whether an address > is in the ARP table is orthogonal to whether you should trust the host or not. > A trusted host can fail to be in the neighbor table simply because the ARP > entry has aged out. Or an untrusted host can be *in* your ARP table....) > > Step 1: When making security decisions, you probably don't need a list > of *all* neighbors - you only need an answer to "is *this* neighbor known or > not". And that would be a different API. > > (For bonus points, consider the case of a trusted host that has a longer > ARP table timeout than yours - then you can receive a packet from the host > without them ARP'ing for you first, but you still don't have a ARP entry > for them.

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confuse about generic_file_read_iter
by Jimmy Li May 5, 2014

May 5, 2014

Hello everyone, I'm trying to figure out how asyncchronous I/O implemented, but I'm confusing about the generic_file_read_iter in mm/filemap.c. major file systems use this function as read_iter for it's file_operations structure(eg, ext3). And it's called by syscall io_submit(fs/aio.c:1359): sys_io_submit -> do_io_submit -> io_submit_one -> aio_run_iocb The point I'm confusing is generic_file_read_iter seems do noting about asyncchronous I/O at all, as I see what generic_file_read_iter does: if opened with O_DIRECT flush pages; call direct_IO; else call do_generic_file_read(); Actually, I think it's syncchronous. It's that means file systems using generic_file_read_iter does not support aio(such as ext3)? I also tried `git log fs/aio.c`. I found retry-based AIO is removed at commit 41003a7bcfed1255032e1e7c7b487e505b22e298(Tue May 7 16:18:25 2013) Could anyone tell me how does linux AIO implement now? I'm working on linux-next(20140502) thanks.

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about the paing mode
by RS May 5, 2014

May 5, 2014

Hello I build my kernel with "CONFIG_HIGHMEM4G=y" option to disable the PAE, choose the 32-bit paging mode. In the runtime, the CR4 value is 0x0000 06D0, (bit 5 is 0, PAE=0, disabled). When I execute the code below: void *ret = kmalloc(sizeof(something), GFP_KERNEL); pte_t *pte = lookup_address(ret, &level); // int level the level value is 2(PG_LEVEL_2M), not the 1(PG_LEVEL_4K). So I think the kernel has used 2 kinds of pages, 4MB size page and 4KB size page. Is that right ? Thanks, HeChuan

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LKM related API documentation
by Abhijeet Kasurde May 4, 2014

May 4, 2014

Hi All, Can anyone point me to any location of documentation related to Linux Kernel Module APIs ? I am specifically looking for following APIs - 1. find_symbol 2. request_module 3. find_module etc. Thanks in advance.

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Regarding skb and net_device.
by Pranay Srivastava May 4, 2014

May 4, 2014

Hi, This is probably a stupid question, but i'm not able to find the answer. How does the networking subsystem decides which device to use for sending the skb. Can some one please guide me to the particular code. I seem to get lost in there :( -- ---P.K.S

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Question Regarding vm_area_struct
by Pranay Srivastava May 3, 2014

May 3, 2014

Hi, I'm trying to mmap a device's memory (not real device) and share it across processes. So far what I've understood is that, 1. I create a vm_operations_struct->fault and vm_operations_struct->page_mkwrite 2. The first time a fault occurs my fault handler would allocate a page and install it in the vm_fault structure. The corresponding vm_area_struct i'll mark as VM_SHARED|VM_READ. Should VM_SHARED be really set here? I'm sharing the page not the vm_area_struct. 3. On a fault I can just assign the same page and in page_mkwrite i can check if there's someone already writing to the page and tell other process that it has to wait or throw error that page can't be made writeable as of now. 4. vm_operations_struct->close, to have a put_page call. Question 1 Let's just say if each vma had to be allocated a page individually, that page would have been allocated using GFP_HIGHUSER|GFP_USER. In that case would the module needed to have kept track of the pages or when the process exits the page structure would be in same state as the last call to put_page? Question 2 If a process unmaps or just exits the unmap_vmas would be called which would call unmap_single_vmas. Now I haven't digged too much within that but it plays around with pte of the page but doesn't alter page_count or anything. So would that affect the other process's vmas which are sharing this page? I'm referring to zap_pte_range, but it seems to flush tlbs and not remove the pte actually[Correct?]. Since the same code would be used for page cache pages and their pte won't be removed in case they are low-mem pages. So if let's say somebody tries to access that particular address it'll not fault although the process owning it has exited? -- ---P.K.S

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MPC8640D Linux booting Process
by curieux.khetan＠gmail.com May 3, 2014

May 3, 2014

Hi, I have MPC8640D based custom designed board and ported Linux 3.14 successfully. Now I have enabled core1 and facing some issues. when I run smp Linux on it, its booting fine but whenever I am trying to use Ethernet on tsec2, tsec3, or tsec4 its getting panic. Any suggestion/pointer how to get more details why its panic? because while only running core0 all Ethernet ports are working fine. And how to run ASMP Linux on this board from u-boot? Thanks & Regards @$hi$h

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RE: MPC8641 based custom board Kernel stuck at 1000Mhz core clock
by curieux.khetan＠gmail.com May 3, 2014

May 3, 2014

hi thanks for your reply. the problem is still there. At 800MHZ core its working fine but for 1Ghz its still happening. Any suggestion or check point I can monitor. From: sanjeev sharma Sent: ‎02‎ ‎May‎ ‎2014 ‎09‎:‎22 To: Ashish CC: Valdis Kletnieks; scottwood(a)freescale.com; linuxppc-dev(a)lists.ozlabs.org; kernelnewbies Subject: Re: MPC8641 based custom board Kernel stuck at 1000Mhz core clock Hello Ashish, is this issue resolved and is this always happening when you are changing core to 1Ghz because i am confused here with sometime Keyword. Regards Sanjeev Sharma On Fri, Apr 4, 2014 at 1:12 PM, Ashish <curieux.khetan(a)gmail.com> wrote: On Thursday 03 April 2014 08:55 AM, sanjeev sharma wrote: Are you able to capture kernel logs ? Regards Sanjeev Sharma On Thu, Mar 27, 2014 at 10:01 PM, <Valdis.Kletnieks(a)vt.edu> wrote: On Thu, 27 Mar 2014 16:04:37 +0530, Ashish said: > Hi, > > I am using MPC8641-HPCN based custom board and able to boot linux at > MPX clock 400Mhz and core clock 800mhz. When I am increasing core > frequency ie MPX clock at 400Mhz and core at 1Ghz, kernel stuck. Step 0: Prove to us that your core actually runs reliable and stably at 1Ghz. Step 1: Figure out *where* it gets stuck. If you have earlyprintk working on your board, adding 'initcall_debug ignore_loglevel' to the kernel cmdline often helps track down where a kernel hangs during boot. _______________________________________________ Kernelnewbies mailing list Kernelnewbies(a)kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies Hi, Does kernel logs means debugging information that kernel prints while booting using printk or it is something else? Here is kernel boot logs that kernel printed while booting... U-Boot 2013.04 (Jan 27 2014 - 11:21:21) Unicore software on multiprocessor system!! To enable mutlticore build define CONFIG_MP CPU: 8641, Version: 2.1, (0x80900021) Core: E600 Core 0, Version: 2.2, (0x80040202) Clock Configuration: CPU:1000 MHz, MPX:400 MHz DDR:200 MHz (400 MT/s data rate), LBC:25 MHz L1: D-cache 32 KB enabled I-cache 32 KB enabled L2: 512 KB enabled Board: MPC8641-HPCN I2C: ready DRAM: 512 MiB SDRAM test phase 1: SDRAM test phase 2: SDRAM test passed. Flash: 16 MiB EEPROM: NXID v1 In: serial Out: serial Err: serial Net: eTSEC1, eTSEC2, eTSEC3, eTSEC4 [PRIME] Hit any key to stop autoboot: Speed: 1000, full duplex Using eTSEC4 device TFTP from server 192.168.10.1; our IP address is 192.168.10.2 Filename 'uRamdisk'. Load address: 0x600000 Loading: * ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################################# ################################################## 13.1 MiB/s done Bytes transferred = 22680188 (15a127c hex) Speed: 1000, full duplex Using eTSEC4 device TFTP from server 192.168.10.1; our IP address is 192.168.10.2 Filename 'uImage'. Load address: 0x16000000 Loading: * ################################################################# ################################################################# ####################################### 14 MiB/s done Bytes transferred = 2476304 (25c910 hex) Speed: 1000, full duplex Using eTSEC4 device TFTP from server 192.168.10.1; our IP address is 192.168.10.2 Filename 'mpc8641_hpcn.dtb'. Load address: 0x14000000 Loading: * # 2.6 MiB/s done Bytes transferred = 5540 (15a4 hex) ## Booting kernel from Legacy Image at 16000000 ... Image Name: Linux-3.13.6 Image Type: PowerPC Linux Kernel Image (gzip compressed) Data Size: 2476240 Bytes = 2.4 MiB Load Address: 00000000 Entry Point: 00000000 Verifying Checksum ... OK ## Loading init Ramdisk from Legacy Image at 00600000 ... Image Name: rootfs Image Type: PowerPC Linux RAMDisk Image (gzip compressed) Data Size: 22680124 Bytes = 21.6 MiB Load Address: 00000000 Entry Point: 00000000 Verifying Checksum ... OK ## Flattened Device Tree blob at 14000000 Booting using the fdt blob at 0x14000000 Uncompressing Kernel Image ... OK Loading Ramdisk to 1e923000, end 1fec423c ... OK Loading Device Tree to 007fb000, end 007ff5a3 ... OK (some times it stucking here) Using MPC86xx HPCN machine description Total memory = 512MB; using 1024kB for hash table (at cff00000) Linux version 3.13.6 (ashish@ashish-VirtualBox) (gcc version 4.7.2 (GCC) ) #8 Sat Mar 29 10:31:58 IST 2014 Found initrd at 0xde923000:0xdfec423c bootconsole [udbg0] enabled setup_arch: bootmem mpc86xx_hpcn_setup_arch() MPC86xx HPCN board from Freescale Semiconductor arch: exit Zone ranges: DMA [mem 0x00000000-0x1fffffff] Normal empty HighMem empty Movable zone start for each node Early memory node ranges node 0: [mem 0x00000000-0x1fffffff] (some times here)

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