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

Re: academia contribution to the kernel
by bodhimonk＠gmail.com May 31, 2011

May 31, 2011

Hi! Thanks for the speedy reply. My problem is that I can't read and copy the files within the said filesystem. I searched the net and the forums but there seem no final guide or resolution to it. Is there? If so, pls. advice. In my office I use Debian 6 for both server and workstation. Thanks again. Sincerely, Brian. ------Original Message------ From: Greg KH To: Brian Augustus Pepino Cc: kernelnewbies-bounces(a)kernelnewbies.org Cc: Javier Martinez Canillas Cc: kernelnewbies Subject: Re: academia contribution to the kernel Sent: May 31, 2011 15:46 On Tue, May 31, 2011 at 06:43:34AM +0000, bodhimonk(a)gmail.com wrote: > On that note, my question is will Linux Kernel 3.0 finally solve the > issues with Macintosh's HPS+ filesystem and finally support it or at > least have a full integration between the two OS? What is wrong with Linux's current implementation of HPS+ that causes you problems? Have you notified the Linux kernel developers of this? thanks, greg k-h "Sent via BlackBerry"

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academia contribution to the kernel
by Javier Martinez Canillas May 31, 2011

May 31, 2011

Hello, A few days ago Greg k-h posted in his blog asking to send questions that he could make in his interview with Linus at LinuxCon Japan. Sadly his keynote is tomorrow so I'm a bit late to send him a question I would like to ask Linus, key kernel developers and companies sponsoring Linux development. Instead I will make the question in this list to know what you people think about. My question is: why academia contribution to the Linux kernel is negligible? In the last linux foundation report about who is sponsoring the Linux kernel development, academia contribution was less than 1.5%. Being involved in the academia as a PhD student I have my own conclusions that are very similar to the ones exposed by Thomas Gleixner in his lwn.net article "academia v. reality" (http://lwn.net/Articles/397422/) How can the Linux foundation and companies behind Linux improve this? Academia has too much resources (both human and financial) that can be used to improve Linux. LTTng and Linux Checkpoint/Restart (linux-cr) are two examples that academia can produce features to enhance the kernel. Best regards, -- Javier Martínez Canillas (+34) 682 39 81 69 PhD Student in High Performance Computing Computer Architecture and Operating System Department (CAOS) Universitat Autònoma de Barcelona Barcelona, Spain

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Re: academia contribution to the kernel
by bodhimonk＠gmail.com May 31, 2011

May 31, 2011

Thanks, Greg! I will do it. Thanks again! :) ------Original Message------ From: Greg KH To: Brian Augustus Pepino Cc: Javier Martinez Canillas Cc: kernelnewbies-bounces(a)kernelnewbies.org Cc: kernelnewbies Subject: Re: academia contribution to the kernel Sent: May 31, 2011 20:58 On Tue, May 31, 2011 at 08:09:31AM +0000, bodhimonk(a)gmail.com wrote: > Hi! > > Thanks for the speedy reply. > > My problem is that I can't read and copy the files within the said > filesystem. I searched the net and the forums but there seem no final > guide or resolution to it. Is there? If so, pls. advice. > > In my office I use Debian 6 for both server and workstation. Then please file a bug with Debian for this issue and they will be glad to work with you to resolve it. Hope this helps, greg k-h "Sent via BlackBerry"

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Re: [Kgdb-bugreport] KGDB problem at first breakpoint
by Prabhu nath May 31, 2011

May 31, 2011

No luck. Atleast, I am interested to know, if it is working for anyone or there is a bug in kgdb implementation in the kernel. If so, I can cool off for some more days until it gets rectified. Thanks, Prabhu On Fri, May 27, 2011 at 10:06 PM, Dongdong Deng <libfetion(a)gmail.com> wrote: > On Fri, May 20, 2011 at 12:23 PM, Prabhu nath <gprabhunath(a)gmail.com> > wrote: > > Enabling CONFIG_DEBUG_RODATA also didn't work. > > > I am sorry, the CONFIG_DEBUG_RODATA should be disabled... > > > Could you try to pass full parameters to kgdboc module? > "kgdboc=ttyS0,115200 kgdbwait" > > > Dongdong > > > > > > > -Prabhu > > > > > > On Thu, May 19, 2011 at 6:45 AM, Dongdong Deng <libfetion(a)gmail.com> > wrote: > >> > >> On Wed, May 18, 2011 at 7:23 PM, Prabhu nath <gprabhunath(a)gmail.com> > >> wrote: > >> > Dear All, > >> > > >> > There is a problem with the KGDB at the very first break point > >> > after > >> > executing the gdb command "target remote /dev/ttyS0" from the host. > >> > I have verbatim, followed the KGDB document > >> > http://kernel.org/pub/linux/kernel/people/jwessel/kdb/ > >> > > >> > Problem Logs: > >> > --------------------- > >> > > >> > Details of my hardware and system software: > >> > ------------------------------------------------------------------- > >> > > >> > *Host (Development machine): * > >> > Intel Pentium IV Machine with Fedora Core 12 > >> > Linux Version : 2.6.31.5-127.fc12.i686.PAE > >> > gdb version : GNU gdb (GDB) Fedora (7.0-3.fc12) > >> > > >> > *Target:* > >> > Intel Pentium IV Machine with Fedora Core 12 > >> > Customized Linux Version : 2.6.38 > >> > > >> > Host is connected to Target via a null modem cable > >> > > >> > *Snapshot of .config of linux version 2.6.38 on the target * > >> > * > >> > * > >> > # CONFIG_DEBUG_RODATA is not set > >> > >> > >> Hi Prabhu, > >> > >> The CONFIG_DEBUG_RODATA was suggested to set at KGDB, > >> Could you enable it? > >> > >> CONFIG_DEBUG_RODATA = y > >> > >> Dongdong > >> > > > >> > >> > > >> > CONFIG_HAVE_ARCH_KGDB=y > >> > CONFIG_FRAME_POINTER=y > >> > CONFIG_DEBUG_INFO=y > >> > CONFIG_KGDB=y > >> > CONFIG_KGDB_SERIAL_CONSOLE=y > >> > CONFIG_KGDB_LOW_LEVEL_TRAP=y > >> > > >> > *Grub config on the target machine* > >> > * > >> > * > >> > title Fedora (2.6.38) > >> > root (hd0,0) > >> > kernel /boot/vmlinuz-2.6.38 ro > >> > root=UUID=fb7800fb-cfe7-438d-bc7f-c153ba4353d1 LANG=en_US.UTF-8 > >> > SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc > >> > KEYTABLE=us*console=ttyS0,115200n8 > >> > kgdboc=ttyS0 kgdbwai*t > >> > initrd /boot/initrd-2.6.38.img > >> > > >> > > >> > On power on of the target, linux kernel boots and the logs are seen on > >> > the > >> > minicom console of the host and it will wait for the gdb on the host > to > >> > connect. Here is the last 4 lines of the logs seen on the minicom > >> > > >> > Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled > >> > serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A > >> > 00:06: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A > >> > kgdb: Registered I/O driver kgdboc. > >> > kgdb: Waiting for connection from remote gdb.. > >> > > >> > *--- Now I close the minicom console (Ctrl-A X) and start the gdb on > the > >> > host. Here is the steps I follow. * > >> > * > >> > * > >> > *On the host machine:* > >> > * > >> > * > >> > > >> > [root@localhost kgdb]# gdb vmlinux > >> > > >> > GNU gdb (GDB) Fedora (7.0-3.fc12) > >> > Copyright (C) 2009 Free Software Foundation, Inc. > >> > License GPLv3+: GNU GPL version 3 or later > >> > <http://gnu.org/licenses/gpl.html > >> >> > >> > This is free software: you are free to change and redistribute it. > >> > There is NO WARRANTY, to the extent permitted by law. Type "show > >> > copying" > >> > and "show warranty" for details. > >> > This GDB was configured as "i686-redhat-linux-gnu". > >> > For bug reporting instructions, please see: > >> > <http://www.gnu.org/software/gdb/bugs/>... > >> > Reading symbols from /root/kgdb/vmlinux...done. > >> > > >> > (gdb) set remotebaud 115200 > >> > (gdb) set debug remote 1 > >> > (gdb) target remote /dev/ttyS0 > >> > Remote debugging using /dev/ttyS0 > >> > Sending packet: $qSupported#37...Ack > >> > Packet received: > >> > Packet qSupported (supported-packets) is NOT supported > >> > Sending packet: $Hg0#df...Ack > >> > Packet received: OK > >> > Sending packet: $?#3f...Ack > >> > Packet received: S05 > >> > Sending packet: $Hc-1#09...Ack > >> > Packet received: OK > >> > Sending packet: $qC#b4...Ack > >> > Packet received: QC01 > >> > Sending packet: $qAttached#8f...Ack > >> > Packet received: > >> > Packet qAttached (query-attached) is NOT supported > >> > Sending packet: $qOffsets#4b...Ack > >> > Packet received: > >> > Sending packet: $g#67...Ack > >> > Packet received: > >> > > >> > > 36000000ffffffff0abaffff20d98bc06c3f86de783f86de803ac8dd803f86de885747c00202000060000000680000007b00c8dd7b0086deffff0000ffff0000 > >> > Sending packet: $mc0475788,1#a4...Ack > >> > Packet received: 0f > >> > Sending packet: $mc0475788,8#ab...Ack > >> > Packet received: 0faef889f6ff0d08 > >> > Sending packet: $mc0475788,7#aa...Ack > >> > Packet received: 0faef889f6ff0d > >> > 0xc0475788 in ?? () > >> > Sending packet: $qSymbol::#5b...Ack > >> > Packet received: > >> > Packet qSymbol (symbol-lookup) is NOT supported > >> > (gdb) s > >> > Cannot find bounds of current function > >> > (gdb) > >> > > >> > > >> > *Observation:* > >> > *1.* Ideally the kernel being debugged should > break > >> > at > >> > legitimate address and the corresponding line number should > >> > be displayed instead of " 0xc0475788 in ?? > ()". > >> > > >> > 2. On inspecting section header in vmlinux > >> > executable, > >> > I found the .text section address range is from > >> > 0xC1000000 to 0xC1326e58 and no section's > >> > contents > >> > associate with the address 0xC0475788. > >> > > >> > *3.* Hence on single stepping, gdb logs the error > >> > as* "Cannot > >> > find bounds of current function"* > >> > * > >> > * > >> > Humbly request you to help me in addressing this issue. > >> > > >> > Thanks and Regards, > >> > Prabhu > >> > > >> > > ------------------------------------------------------------------------------ > >> > What Every C/C++ and Fortran developer Should Know! > >> > Read this article and learn how Intel has extended the reach of its > >> > next-generation tools to help Windows* and Linux* C/C++ and Fortran > >> > developers boost performance applications - including clusters. > >> > http://p.sf.net/sfu/intel-dev2devmay > >> > _______________________________________________ > >> > Kgdb-bugreport mailing list > >> > Kgdb-bugreport(a)lists.sourceforge.net > >> > https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport > >> > > > > > >

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executable ELF is rm-ed from disk, but still running RAM..
by Mulyadi Santosa May 31, 2011

May 31, 2011

Hi all.. As the subject says, I was thinking about that issue. I know that rm-ing a file doesn't delete the data block from the backing device, thus the executable could still survive and running. But logically, we usually expect that once a file is rm-ed, it should also "stop", right? What does POSIX say about this case anyway? Anyone could kindly give his/her opinion? -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com

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Re: academia contribution to the kernel
by bodhimonk＠gmail.com May 31, 2011

May 31, 2011

I mean precious time. Sorry for the typo. Thanks. "Sent via BlackBerry" -----Original Message----- From: bodhimonk(a)gmail.com Date: Tue, 31 May 2011 06:43:34 To: Greg KH<greg(a)kroah.com>; <kernelnewbies-bounces(a)kernelnewbies.org>; Javier Martinez Canillas<martinez.javier(a)gmail.com> Reply-To: bodhimonk(a)gmail.com Cc: kernelnewbies<kernelnewbies(a)kernelnewbies.org> Subject: Re: academia contribution to the kernel Hello! My question is very noobish and I hope Linus would not laugh at this but I am now near my wits end on this issue especially that our creative team keeps on using a Mac computer and would not migrate to gimp in order to make my life easier. On that note, my question is will Linux Kernel 3.0 finally solve the issues with Macintosh's HPS+ filesystem and finally support it or at least have a full integration between the two OS? Thank you and I am sorry if I took your precious for such a noob question. Sincerely, Brian. "Sent via BlackBerry" -----Original Message----- From: Greg KH <greg(a)kroah.com> Sender: kernelnewbies-bounces(a)kernelnewbies.org Date: Tue, 31 May 2011 12:49:01 To: Javier Martinez Canillas<martinez.javier(a)gmail.com> Cc: kernelnewbies<kernelnewbies(a)kernelnewbies.org> Subject: Re: academia contribution to the kernel On Tue, May 31, 2011 at 01:05:28AM +0200, Javier Martinez Canillas wrote: > Hello, > > A few days ago Greg k-h posted in his blog asking to send questions > that he could make in his interview with Linus at LinuxCon Japan. > Sadly his keynote is tomorrow so I'm a bit late to send him a question It's not too late, I'm still here, and we have many hours until the presentation (i.e about 14). > I would like to ask Linus, key kernel developers and companies > sponsoring Linux development. Instead I will make the question in this > list to know what you people think about. > > My question is: why academia contribution to the Linux kernel is negligible? <snip> I think you already answered your own question, and there's not much we can do about this other than the efforts that Thomas is working on right now. Any other suggestions of how the community could help academia out would of course be appreciated. Any other question that anyone would like me to ask Linus tomorrow? Technical is always better, at least for the both of us. thanks, greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies(a)kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

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question about nic driver implementation(about TCP checksum offload )
by Gang Lei (雷刚) May 31, 2011

May 31, 2011

Hi All: I want to build TOE(tcp checksum offload engine) in our hardware to improve the overall performance of NIC, however, i met a problem as follow: AS you know, the TCP checksum protect the TCP pseudo header+TCP header+Data, if TCP packet is fragmented into many fragments, the hardware will have not enough information to generate tcp checksum for the whole TCP PDU, how to overcome this problem? I searched in NIC driver source code of different vendor, found that TOE is generally used, I wonder whether the kernel will calculate the TCP checksum even we set features of this device as NETIF_F_IP_CSUM when fragmentation happens. Can anyone throw some lights on this problem? Thanks a lot. Rick.

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Question regarding purging of specific dcache entries
by João Eduardo Luís May 30, 2011

May 30, 2011

Hi, I've been developing in the kernel's FS subsystem for quite a while now, and though I've been able to accomplish everything I've set myself up to, it seems I can't figure out how to do a little something. Currently, I need to guarantee that, at a specific moment in time, all entries in the dcache associated with a directory and its children are purged from the cache, forcing a new file system lookup for each and every single one of them. Although I've looked up in dcache.c for a suitable method, I believe d_genocide() may not do the trick, and d_invalidate() won't invalidate a dentry if other dentries can be reached through it. And I have no idea how to walk the dcache, trying to find the required entries in order to invalidate them one by one up to the topmost entry. Any help would sure be appreciated. Cheers. Joao --- João Eduardo Luís gpg key: 477C26E5 from pool.keyserver.eu

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Compiling linux kernel for beagle board
by Abbas Raza May 30, 2011

May 30, 2011

Hi, I am new to kernel and want to learn it alot :) I just got my beagle board and want to compile linux kernel for it. I downloaded the latest kernel source from kernel.org. Cross compiled it for ARM beagle board and it got working on my board. During investigation on kernel sources i found that git repo at "git:// git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6.git" contains support for beagle board too. I am confused that what is the difference between both the kernels i.e latest base kernel and OMAP3 linux kernel? why all the documents on internet ask to get kernel from above link (linux kernel for OMAP3 family of processors) for beagle board and not the base kernel simply from kernel.org? Also i have seen a linux recipe for beagle board in openembedded . It fetches OMAP3 kernel and applies lots of patches on it as give below ######################################## SRC_URI = "git:// git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6.git;protocol=… file://defconfig" SRC_URI_append = " \ file://no-empty-flash-warnings.patch \ file://no-cortex-deadlock.patch \ file://read_die_ids.patch \ file://fix-install.patch \ file://dss2/0001-Revert-gro-Fix-legacy-path-napi_complete-crash.patch \ file://dss2/0002-OMAPFB-move-omapfb.h-to-include-linux.patch \ ----- ------- ###################################### So now i see 3 different linux kernel sources... base kernel, OMAP3 kernel, OMAP3 patched kernel made by openembedded. Which one should be used? Is not base kernel enough for beagle board? Please help and guide i am very much confused .. thanks -- Abbas Raza

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Secondary ip address nonfunctional in 2.6.14
by Harshada Senad May 30, 2011

May 30, 2011

Hi, I am facing issue with secondary ip addresses in 2.6.14 kernel after setting the proc entry ?promote_secondaries? to 1. Code to set proc entry ?promote_secondaries. net.ipv4.conf.default.promote_secondaries = 1 cat /proc/sys/net/ipv4/conf/bond1/promote_secondaries 1 Problem statement:- Secondary ip addresses become non functional after deleting the primary ip address. Even self ping to secondary ip address does not work. I can not see this issue with secondary ip address in 2.6.27 kernel. Query: - It is a known issue in 2.6.14 kernel? Is there any configuration options that needs to be set for secondary ip addresses to be functional in 2.6.14? Add IP address on bond1 interface:- ip add add 10.1.2.3/24 dev bond1 ip add add 10.1.2.4/24 dev bond1 ip add add 10.1.2.5/24 dev bond1 ip add add 10.1.2.6/24 dev bond1 ip add add 10.1.2.7/24 dev bond1 ip add show bond1 12: bond1: <BROADCAST,MULTICAST,MASTER,UP> mtu 1500 qdisc noqueue link/ether 00:80:f9:8b:b6:f8 brd ff:ff:ff:ff:ff:ff inet 172.25.0.3/16 brd 172.25.255.255 scope global bond1 inet 10.1.2.3/24 scope global bond1 inet 10.1.2.4/24 scope global secondary bond1 inet 10.1.2.5/24 scope global secondary bond1 inet 10.1.2.6/24 scope global secondary bond1 inet 10.1.2.7/24 scope global secondary bond1 inet6 fe80::200:ff:fe00:0/64 scope link valid_lft forever preferred_lft forever Delete the primary IP address: ip add delete 10.1.2.3/24 dev bond1 ip add show bond1 12: bond1: <BROADCAST,MULTICAST,MASTER,UP> mtu 1500 qdisc noqueue link/ether 00:80:f9:8b:b6:f8 brd ff:ff:ff:ff:ff:ff inet 172.25.0.3/16 brd 172.25.255.255 scope global bond1 inet 10.1.2.4/24 scope global bond1 inet 10.1.2.5/24 scope global secondary bond1 inet 10.1.2.6/24 scope global secondary bond1 inet 10.1.2.7/24 scope global secondary bond1 inet6 fe80::200:ff:fe00:0/64 scope link valid_lft forever preferred_lft forever Ping output: ping 10.1.2.4 PING 10.1.2.4 (10.1.2.4) 56(84) bytes of data. 64 bytes from 10.1.2.4: icmp_seq=1 ttl=64 time=0.033 ms 64 bytes from 10.1.2.4: icmp_seq=2 ttl=64 time=0.026 ms --- 10.1.2.4 ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1000ms rtt min/avg/max/mdev = 0.026/0.029/0.033/0.006 ms Rest of the secondary ip addresses are not pingable. ping 10.1.2.5 PING 10.1.2.5 (10.1.2.5) 56(84) bytes of data. >From 10.1.2.4 icmp_seq=1 Destination Host Unreachable >From 10.1.2.4 icmp_seq=2 Destination Host Unreachable --- 10.1.2.5 ping statistics --- 4 packets transmitted, 0 received, +2 errors, 100% packet loss, time 3000ms , pipe 2 ping 10.1.2.6 PING 10.1.2.6 (10.1.2.6) 56(84) bytes of data. >From 10.1.2.4 icmp_seq=1 Destination Host Unreachable >From 10.1.2.4 icmp_seq=2 Destination Host Unreachable >From 10.1.2.4 icmp_seq=3 Destination Host Unreachable --- 10.1.2.6 ping statistics --- 4 packets transmitted, 0 received, +3 errors, 100% packet loss, time 3002ms , pipe 3 ping 10.1.2.7 PING 10.1.2.7 (10.1.2.7) 56(84) bytes of data. >From 10.1.2.4 icmp_seq=1 Destination Host Unreachable >From 10.1.2.4 icmp_seq=2 Destination Host Unreachable >From 10.1.2.4 icmp_seq=3 Destination Host Unreachable >From 10.1.2.4 icmp_seq=4 Destination Host Unreachable --- 10.1.2.7 ping statistics --- 5 packets transmitted, 0 received, +4 errors, 100% packet loss, time 3999ms , pipe 4 Thanks and Regards, Harshada Senad =====-----=====-----===== Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you

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