April 2012 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

Migrating from SA_INTERRUPT to IRQF_DISABLED...
by Praveen kumar April 11, 2012

April 11, 2012

Hi, There is an old bug come up while migrating from 2.6.18 to 2.6.33....The interrupts were generating correctly in 2.6.18 where the interrupt was registered using SA_INTERRUPT then while migrating to 2.6.33 this has been changed to IRQF_DISABLED this is the only change in migration... after doing this interrupt comes only once .Interrupts does not behave how they were used to in 2.6.18. Are any additional changes needs to be done here??? ...to get things working here... what could be the problem here....I dont have the option of moving to latest kernel... Praveen R

1 0

Re: ubuntu 11.10, systemtap and building my own kernel
by Robert P. J. Day April 10, 2012

April 10, 2012

On Tue, 10 Apr 2012, Frank Ch. Eigler wrote: > > rpjday wrote: > > > [...] > > $ stap -e 'probe kernel.function("sys_open") {log("hello world") exit()}' > > and got: > > ===== start ===== > > [...] > > cc1: all warnings being treated as errors > > make[1]: *** [/tmp/stapadEYdA/stap_59bddd394f89d5f186da7e250db36434_876.o] Error 1 > > make: *** [_module_/tmp/stapadEYdA] Error 2 > > Pass 4: compilation failed. Try again with another '--vp 0001' option. > > Please try systemtap 1.7, or build one out of > <git://sourceware.org/git/systemtap.git>. Newer kernels sometimes > break systemtap assumptions; these are fixed pretty quickly in the > source tree, and get rolled into later releases. > > Please report any further problems at <systemtap(a)sourceware.org>, > including /usr/bin/stap-report output, if able. just FYI, this is the current problem: ===== begin ===== $ git show 615399c84d1b8d8d8752629e5e5ab4e5044d6918 commit 615399c84d1b8d8d8752629e5e5ab4e5044d6918 Author: Rusty Russell <rusty(a)rustcorp.com.au> Date: Thu Mar 29 15:38:31 2012 +1030 cpumask: remove old cpu_*_map. These are obsolete: cpu_*_mask provides (const) pointers. Signed-off-by: Rusty Russell <rusty(a)rustcorp.com.au> diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 1ffdb98..a2c819d 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -764,12 +764,6 @@ static inline const struct cpumask *get_cpu_mask(unsigned int cpu) * */ #ifndef CONFIG_DISABLE_OBSOLETE_CPUMASK_FUNCTIONS -/* These strip const, as traditionally they weren't const. */ -#define cpu_possible_map (*(cpumask_t *)cpu_possible_mask) -#define cpu_online_map (*(cpumask_t *)cpu_online_mask) -#define cpu_present_map (*(cpumask_t *)cpu_present_mask) -#define cpu_active_map (*(cpumask_t *)cpu_active_mask) - #define cpumask_of_cpu(cpu) (*get_cpu_mask(cpu)) #define CPU_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(NR_CPUS) ===== end ===== in current systemtap, runtime.h: #define stp_for_each_cpu(cpu) for_each_cpu_mask((cpu), cpu_possible_map) so that's definitely going to fail. rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================

2 3

Re: ubuntu 11.10, systemtap and building my own kernel
by Robert P. J. Day April 10, 2012

April 10, 2012

On Tue, 10 Apr 2012, Frank Ch. Eigler wrote: > > rpjday wrote: > > > [...] > > $ stap -e 'probe kernel.function("sys_open") {log("hello world") exit()}' > > and got: > > ===== start ===== > > [...] > > cc1: all warnings being treated as errors > > make[1]: *** [/tmp/stapadEYdA/stap_59bddd394f89d5f186da7e250db36434_876.o] Error 1 > > make: *** [_module_/tmp/stapadEYdA] Error 2 > > Pass 4: compilation failed. Try again with another '--vp 0001' option. > > Please try systemtap 1.7, or build one out of > <git://sourceware.org/git/systemtap.git>. Newer kernels sometimes > break systemtap assumptions; these are fixed pretty quickly in the > source tree, and get rolled into later releases. > > Please report any further problems at <systemtap(a)sourceware.org>, > including /usr/bin/stap-report output, if able. ok, that solved that problem, but i'm still getting: /home/rpjday/systemtap/share/systemtap/runtime/stat.c:214:2: error: ‘cpu_possible_map’ undeclared (first use in this function) if this is a simple fix, could you enlighten me? or if it isn't, i can move this to the systemtap mailing list. rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================

1 0

Re: ubuntu 11.10, systemtap and building my own kernel
by Robert P. J. Day April 10, 2012

April 10, 2012

On Tue, 10 Apr 2012, Frank Ch. Eigler wrote: > > rpjday wrote: > > > [...] > > $ stap -e 'probe kernel.function("sys_open") {log("hello world") exit()}' > > and got: > > ===== start ===== > > [...] > > cc1: all warnings being treated as errors > > make[1]: *** [/tmp/stapadEYdA/stap_59bddd394f89d5f186da7e250db36434_876.o] Error 1 > > make: *** [_module_/tmp/stapadEYdA] Error 2 > > Pass 4: compilation failed. Try again with another '--vp 0001' option. > > Please try systemtap 1.7, or build one out of > <git://sourceware.org/git/systemtap.git>. Newer kernels sometimes > break systemtap assumptions; these are fixed pretty quickly in the > source tree, and get rolled into later releases. > > Please report any further problems at <systemtap(a)sourceware.org>, > including /usr/bin/stap-report output, if able. ok, but i'm curious ... i took a quick look at earlier kernels and i don't see where "struct hlist_head" *ever* had a "next" member field that is required by this version of systemtap (1.4). can you clarify which kernel version(s) would have worked with this version of systemtap? thanks. rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================

2 1

No subject
by Martynov Semen April 10, 2012

April 10, 2012

Good afternoon, I would like to understand, why I can't make the built-in object, when my code is in a folder /samples... I have my module-code and if I put it in a folder /samples, I can receive only loadable module (.ko) but if I want to receive the built-in object - it turns out nothing (.о-file is created, but my code doesn't get in a kernel). When I allocate my module-code in any other folder (for example, /drivers) it works normally - I can receive .ko and I can make the built-in object. Question - why I can't receive the built-in object when my code is in the folder /samples? What instruction in a make-file restricts it, and how? P.S.: Sorry for my english. -- Best regards, Semen A Martynov. Saint Petersburg, Russia. https://www.facebook.com/semen.martynov

3 5

[Q] TinyLinux project status (resend)
by Ezequiel García April 10, 2012

April 10, 2012

Hello, I would like to know what is the current status of the tiny linux project? (The current goals, status and activeness). I've found this: http://elinux.org/Linux_Tiny but it seems a bit outdated. I'm adding Thomas to CC, cause he maintains (or used to according to elinux) a list of relevant patches. What's the status of this? Also, I would like to know what's the smallest kernel (static and dynamic memory footprint) that can be achieved right now (without losing signicant funcionality). Is it possible to run linux a 1 MB SRAM board (no DRAM) ? (I am thinking at a ARM7 LPC2294 header board). I now this might sound crazy, but perhaps with In-Place stuff and some hacks it could be possible. I've seen tests with 2 MB but not with 1 MB. Also, I've seen presentations by Matt Mackall [1] and Thomas Petazzoni [2]. but they're a few years old (ages in kernel time, right? :) Also, wich is the relevant mailing list? Not sure. Thanks a lot, Ezequiel. [1] http://ols.fedoraproject.org/OLS/Reprints-2004/Reprint-Mackall-OLS2004.pdf [2] http://www.celinux.org/elc08_presentations/linux-tiny.pdf

1 0

ubuntu 11.10, systemtap and building my own kernel
by Robert P. J. Day April 10, 2012

April 10, 2012

(sort of a combo of ubuntu, systemtap and kernel question, hoping it's not too far off-topic.) for the purpose of an upcoming tutorial, i decided to install systemtap on my fully-updated 64-bit ubuntu 11.10 laptop, then build a new kernel and show how simple it is to use systemtap. it didn't turn out well. since i would be using a self-built kernel, i started here: http://sourceware.org/systemtap/wiki/SystemTapWithSelfBuiltKernel but i'm not convinced that page is entirely correct. while i made sure all of the listed kernel options were selected, my first concern is that i'm not sure why i should have to do "make headers_install". all that does is populate the in-tree usr/include/ directory with the exported header files. i'm not sure why that's necessary. is it really required? does systemtap actually go looking there for header files? also, the rest of that page seems to explain how to make sure systemtap can find your kernel build tree. but if you build and install, then /lib/modules/<release>/build is a symlink to the build tree, so i'm not sure anything else has to be done. the rest of that page also seems unnecessary. thoughts? in any event, i configured, built and installed my new kernel (based on latest "git pull" from development kernel source), and rebooted to get: $ uname -r 3.4.0-rc2+ $ which is correct so, theoretically, i should be read to try a simple systemtap example. reading here: http://www.domaigne.com/blog/random/running-systemtap-on-ubuntu/ i tried: $ stap -e 'probe kernel.function("sys_open") {log("hello world") exit()}' and got: ===== start ===== In file included from /usr/share/systemtap/runtime/transport/transport.c:53:0, from /usr/share/systemtap/runtime/print.c:18, from /usr/share/systemtap/runtime/runtime.h:128, from /tmp/stapadEYdA/stap_59bddd394f89d5f186da7e250db36434_876.c:55: /usr/share/systemtap/runtime/transport/relay_v2.c:242:2: error: initialization from incompatible pointer type [-Werror] /usr/share/systemtap/runtime/transport/relay_v2.c:242:2: error: (near initialization for ‘__stp_relay_callbacks.create_buf_file’) [-Werror] In file included from /usr/share/systemtap/runtime/print.c:18:0, from /usr/share/systemtap/runtime/runtime.h:128, from /tmp/stapadEYdA/stap_59bddd394f89d5f186da7e250db36434_876.c:55: /usr/share/systemtap/runtime/transport/transport.c: In function ‘_stp_get_root_dir’: /usr/share/systemtap/runtime/transport/transport.c:380:8: error: ‘struct hlist_head’ has no member named ‘next’ In file included from /tmp/stapadEYdA/stap_59bddd394f89d5f186da7e250db36434_876.c:57:0: /usr/share/systemtap/runtime/stat.c: In function ‘_stp_stat_get’: /usr/share/systemtap/runtime/stat.c:213:2: error: ‘cpu_possible_map’ undeclared (first use in this function) /usr/share/systemtap/runtime/stat.c:213:2: note: each undeclared identifier is reported only once for each function it appears in /usr/share/systemtap/runtime/stat.c: In function ‘_stp_stat_clear’: /usr/share/systemtap/runtime/stat.c:248:2: error: ‘cpu_possible_map’ undeclared (first use in this function) cc1: all warnings being treated as errors make[1]: *** [/tmp/stapadEYdA/stap_59bddd394f89d5f186da7e250db36434_876.o] Error 1 make: *** [_module_/tmp/stapadEYdA] Error 2 Pass 4: compilation failed. Try again with another '--vp 0001' option. ===== end ===== that doesn't look good. in particular, this error just looks strange: /usr/share/systemtap/runtime/transport/transport.c:380:8: error: ‘struct hlist_head’ has no member named ‘next’ to make a long story short, that diagnostic is entirely correct -- "struct hlist_head" as it's defined in <types.h> is: struct hlist_head { struct hlist_node *first; }; but that systemtap source file is trying to refer to a member called "next", which clearly does not exist. am i doing something silly? can someone else with an ubuntu system try this and let me know what happens? thanks. rday -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ========================================================================

1 0

Re: wrapfs sources
by V.Ravikumar April 10, 2012

April 10, 2012

Hi, I ported latest wrapfs code compile against 2.6.18 kernel. Now I'm able to build module ,but there my be bugs. insmod of the file system module that was built was successful. But when I do a mount (mount -t wrapfs /home/abc/lower /mnt/wrapfs) I'm getting unknown symbol file system wrapfs error. Here is file_system_type structure definition. static struct file_system_type wrapfs_fs_type = { .owner = THIS_MODULE, .name = "wrapfs", .get_sb = wrapfs_get_sb, .kill_sb = generic_shutdown_super, }; Also attached complete ported wrapfs sources which are compatible with 2.6.18 kernel. I'm immature in kernel development so I'm requesting to help in resolving unknown file system error. Thanks, Ravi. On Wed, Apr 4, 2012 at 8:35 PM, Erez Zadok <ezk(a)cs.stonybrook.edu> wrote: > Sorry, I don't have wrapfs sources going so far as 2.6.18. I don't have > enough manpower to support all the kernels people want, so I maintain only > the last few stable kernels. If someone were to backport wrapfs to an > older kernel, I'll be happy to test and maintain it going forward. > > Cheers, > Erez. > > On Apr 4, 2012, at 12:28 AM, V.Ravikumar wrote: > > > Hi ezk, > > > > I'm going through wrapfs documentation and feel that stackable file > system concept is the best suit for my need.(File/directory change > notification along with UID who modified it). > > > > I got sources but those are not in congruent to linux 2.6.18 sources. > > > > I sources that I got are compatible with latest kernel sources. > > > > So I'm requesting you to let me know compatible sources for Linux 2.6.18 > kernel > > > > Thanks & Regards, > > Ravi > >

2 1

__initdata access at runtime
by Jim Cromie April 10, 2012

April 10, 2012

hi folks, Ive written a pair of patches which have an issue with __initdata [PATCH 1/3] bug.h: add BUILD_BUG_DECL, usable at file scope [PATCH 2/3] bug.h: add test/demo module 1st one declares a BUILD_BUG_DECL(name, condition) which breaks compile if the condition is true, much like the other *BUG* macros. Its usable at file scope, which lets it verify that 2 arrays are the same size: int arr1[] = {1,2,3}; int arr2[] = {1,2,4}; BUILD_BUG_DECL(arr1_VS_arr2, ARRAY_SIZE(arr1) != ARRAY_SIZE( arr2)); heres the macro: +#define BUILD_BUG_DECL(name, cond) \ + static __initdata struct { \ + int BUILD_BUG_DECL_ ## name[1 - 2*!!(cond)]; \ + } BUILD_BUG_DECL_ ##name[0] __attribute__((unused)) + which expands the above like: static __attribute__ ((__section__(".init.data"))) struct { int BUILD_BUG_DECL_arr1_VS_arr1[1 - 2*!!(sizeof(arr1) != sizeof(arr2))]; } BUILD_BUG_DECL_arr1_VS_arr1[0] __attribute__((unused)); It works as pretty much as intended, but there are a few wrinkes, as exposed by the run-time part of the test module (patch 2). The macro attempts to create no storage (by sizing the array as [0]), and put it into the .init.data section of the object code. The test module does 3 things: 1 - proves the macro works. Remove the // on commented BUILD_BUG_DECL statements to try for yourself. 2 - references the variable defined by the macro, during module_init. Printing that value works, its always 0, why ? I thought that the __attribute__((unused)) would have prevented or warned about this access. I also tried __attribute__((nodref, unused)), but compiler warned about it, so I pulled that out. 3 - references the variable defined by the macro, during runtime. ie: $> cat /sys/module/build-asserts/cbint That gets a paging error. This makes sense, as the .init.data has been freed after module_init is done. Why doesnt the compiler warn or error about referencing an __initdata var from a non-__init function ?

1 2

SRIOV memory allocation
by J.Hwan Kim April 9, 2012

April 9, 2012

Hi, everyone I'd like to know what routine of the PCIe allocates SR-IOV BAR memory. When I put into the network card supporting SR-IOV in my system, it returns error indicating "MMIO resource" is insufficient when sriov is enabled. The routine is in iov.c for (i = 0; i < PCI_SRIOV_NUM_BARS/*6*/; i++) { res = dev->resource + PCI_IOV_RESOURCES + i; if (res->parent) nres++; } if (nres != iov->nres) { dev_err(&dev->dev, "not enough MMIO resources for SR-IOV\n"); return -ENOMEM; } So, I hope to know where the resources of IOV is assigned the parent pointer. Thanks in advance. Best Regards, J.Hwan Kim

2 2