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2008-07-24mm: add a basic debugging framework for memory initialisationMel Gorman
Boot initialisation is very complex, with significant numbers of architecture-specific routines, hooks and code ordering. While significant amounts of the initialisation is architecture-independent, it trusts the data received from the architecture layer. This is a mistake, and has resulted in a number of difficult-to-diagnose bugs. This patchset adds some validation and tracing to memory initialisation. It also introduces a few basic defensive measures. The validation code can be explicitly disabled for embedded systems. This patch: Add additional debugging and verification code for memory initialisation. Once enabled, the verification checks are always run and when required additional debugging information may be outputted via a mminit_loglevel= command-line parameter. The verification code is placed in a new file mm/mm_init.c. Ideally other mm initialisation code will be moved here over time. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-23Merge branch 'core/softlockup-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core/softlockup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: softlockup: fix invalid proc_handler for softlockup_panic softlockup: fix watchdog task wakeup frequency softlockup: fix watchdog task wakeup frequency softlockup: show irqtrace softlockup: print a module list on being stuck softlockup: fix NMI hangs due to lock race - 2.6.26-rc regression softlockup: fix false positives on nohz if CPU is 100% idle for more than 60 seconds softlockup: fix softlockup_thresh fix softlockup: fix softlockup_thresh unaligned access and disable detection at runtime softlockup: allow panic on lockup
2008-07-21debugfs: Add a reference to the debugfs API documentation.Robert P. J. Day
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Cc: Jesper Juhl <jesper.juhl@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-07-15Merge branch 'linus' into core/softlockupIngo Molnar
Conflicts: kernel/softlockup.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-15Merge branch 'core/rcu' into core/rcu-for-linusIngo Molnar
2008-07-15Merge branch 'core/stacktrace' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core/stacktrace' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: generic-ipi: powerpc/generic-ipi tree build failure stacktrace: fix build failure on sparc64 stacktrace: export save_stack_trace[_tsk] stacktrace: fix modular build, export print_stack_trace and save_stack_trace backtrace: replace timer with tasklet + completions stacktrace: add saved stack traces to backtrace self-test stacktrace: print_stack_trace() cleanup debugging: make stacktrace independent from DEBUG_KERNEL stacktrace: don't crash on invalid stack trace structs
2008-06-27stacktrace: add saved stack traces to backtrace self-testVegard Nossum
This patch adds saved stack-traces to the backtrace suite of self-tests. Note that we don't depend on or unconditionally enable CONFIG_STACKTRACE because not all architectures may have it (and we still want to enable the other tests for those architectures). Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-19rcu: make rcutorture more vicious: reinstate boot-time testingPaul E. McKenney
This patch re-institutes the ability to build rcutorture directly into the Linux kernel. The reason that this capability was removed was that this could result in your kernel being pretty much useless, as rcutorture would be running starting from early boot. This problem has been avoided by (1) making rcutorture run only three seconds of every six by default, (2) adding a CONFIG_RCU_TORTURE_TEST_RUNNABLE that permits rcutorture to be quiesced at boot time, and (3) adding a sysctl in /proc named /proc/sys/kernel/rcutorture_runnable that permits rcutorture to be quiesced and unquiesced when built into the kernel. Please note that this /proc file is -not- available when rcutorture is built as a module. Please also note that to get the earlier take-no-prisoners behavior, you must use the boot command line to set rcutorture's "stutter" parameter to zero. The rcutorture quiescing mechanism is currently quite crude: loops in each rcutorture process that poll a global variable once per tick. Suggestions for improvement are welcome. The default action will be to reduce the polling rate to a few times per second. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Suggested-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-16Revert "prohibit rcutorture from being compiled into the kernel"Ingo Molnar
This reverts commit 9aaffc898ff4a3df18c5fc4b9e0fa47e779ad726. That commit was a very bad idea. RCU_TORTURE found many boot timing bugs and other sorts of bugs in the past, so excluding it from boot images is very silly. The option already depends on DEBUG_KERNEL and is disabled by default. Even when it runs, the test threads are reniced. If it annoys people we could add a runtime sysctl.
2008-05-25debugging: make stacktrace independent from DEBUG_KERNELIngo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-25softlockup: allow panic on lockupIngo Molnar
allow users to configure the softlockup detector to generate a panic instead of a warning message. high-availability systems might opt for this strict method (combined with panic_timeout= boot option/sysctl), instead of generating softlockup warnings ad infinitum. also, automated tests work better if the system reboots reliably (into a safe kernel) in case of a lockup. The full spectrum of configurability is supported: boot option, sysctl option and Kconfig option. it's default-disabled. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-23ftrace: add basic support for gcc profiler instrumentationArnaldo Carvalho de Melo
If CONFIG_FTRACE is selected and /proc/sys/kernel/ftrace_enabled is set to a non-zero value the ftrace routine will be called everytime we enter a kernel function that is not marked with the "notrace" attribute. The ftrace routine will then call a registered function if a function happens to be registered. [ This code has been highly hacked by Steven Rostedt and Ingo Molnar, so don't blame Arnaldo for all of this ;-) ] Update: It is now possible to register more than one ftrace function. If only one ftrace function is registered, that will be the function that ftrace calls directly. If more than one function is registered, then ftrace will call a function that will loop through the functions to call. Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-30debugobjects: add timer specific object debugging codeThomas Gleixner
Add calls to the generic object debugging infrastructure and provide fixup functions which allow to keep the system alive when recoverable problems have been detected by the object debugging core code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Greg KH <greg@kroah.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30infrastructure to debug (dynamic) objectsThomas Gleixner
We can see an ever repeating problem pattern with objects of any kind in the kernel: 1) freeing of active objects 2) reinitialization of active objects Both problems can be hard to debug because the crash happens at a point where we have no chance to decode the root cause anymore. One problem spot are kernel timers, where the detection of the problem often happens in interrupt context and usually causes the machine to panic. While working on a timer related bug report I had to hack specialized code into the timer subsystem to get a reasonable hint for the root cause. This debug hack was fine for temporary use, but far from a mergeable solution due to the intrusiveness into the timer code. The code further lacked the ability to detect and report the root cause instantly and keep the system operational. Keeping the system operational is important to get hold of the debug information without special debugging aids like serial consoles and special knowledge of the bug reporter. The problems described above are not restricted to timers, but timers tend to expose it usually in a full system crash. Other objects are less explosive, but the symptoms caused by such mistakes can be even harder to debug. Instead of creating specialized debugging code for the timer subsystem a generic infrastructure is created which allows developers to verify their code and provides an easy to enable debug facility for users in case of trouble. The debugobjects core code keeps track of operations on static and dynamic objects by inserting them into a hashed list and sanity checking them on object operations and provides additional checks whenever kernel memory is freed. The tracked object operations are: - initializing an object - adding an object to a subsystem list - deleting an object from a subsystem list Each operation is sanity checked before the operation is executed and the subsystem specific code can provide a fixup function which allows to prevent the damage of the operation. When the sanity check triggers a warning message and a stack trace is printed. The list of operations can be extended if the need arises. For now it's limited to the requirements of the first user (timers). The core code enqueues the objects into hash buckets. The hash index is generated from the address of the object to simplify the lookup for the check on kfree/vfree. Each bucket has it's own spinlock to avoid contention on a global lock. The debug code can be compiled in without being active. The runtime overhead is minimal and could be optimized by asm alternatives. A kernel command line option enables the debugging code. Thanks to Ingo Molnar for review, suggestions and cleanup patches. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Greg KH <greg@kroah.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-25Add option to enable -Wframe-larger-than= on gcc 4.4Andi Kleen
Add option to enable -Wframe-larger-than= on gcc 4.4 gcc mainline (upcoming 4.4) added a new -Wframe-larger-than=... option to warn at build time about too large stack frames. Add a config option to enable this warning, since this very useful for the kernel. I choose (somewhat arbitarily) 2048 as default warning threshold for 64bit and 1024 as default for 32bit architectures. With some research and fixing all the code for smaller values these defaults should be probably lowered. With the default allyesconfigs have some new warnings, but I think that is all code that should be just fixed. At some point (when gcc 4.4 is released and widely used) this should obsolete make checkstack Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-04-19[PATCH] r/o bind mounts: debugging for missed callsDave Hansen
There have been a few oopses caused by 'struct file's with NULL f_vfsmnts. There was also a set of potentially missed mnt_want_write()s from dentry_open() calls. This patch provides a very simple debugging framework to catch these kinds of bugs. It will WARN_ON() them, but should stop us from having any oopses or mnt_writer count imbalances. I'm quite convinced that this is a good thing because it found bugs in the stuff I was working on as soon as I wrote it. [hch: made it conditional on a debug option. But it's still a little bit too ugly] [hch: merged forced remount r/o fix from Dave and akpm's fix for the fix] Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-04-18Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6: (43 commits) firewire: cleanups firewire: fix synchronization of gap counts firewire: wait until PHY configuration packet was transmitted (fix bus reset loop) firewire: remove unused struct member firewire: use bitwise and to get reg in handle_registers firewire: replace more hex values with defined csr constants firewire: reread config ROM when device reset the bus firewire: replace static ROM cache by allocated cache firewire: fw-ohci: work around generation bug in TI controllers (fix AV/C and more) firewire: fw-ohci: extend logging of bus generations and node ID firewire: fw-ohci: conditionally log busReset interrupts firewire: fw-ohci: don't append to AT context when it's not active firewire: fw-ohci: log regAccessFail events firewire: fw-ohci: make sure HCControl register LPS bit is set firewire: fw-ohci: missing PPC PMac feature calls in failure path firewire: fw-ohci: untangle a mixed unsigned/signed expression firewire: debug interrupt events firewire: fw-ohci: catch self_id_count == 0 firewire: fw-ohci: add self ID error check firewire: fw-ohci: refactor probe, remove, suspend, resume ...
2008-04-18firewire: fw-ohci: add option for remote debuggingStefan Richter
This way firewire-ohci can be used for remote debugging like ohci1394. Version with amendment from Fri, 11 Apr 2008 00:08:08 +0200. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Acked-by: Bernhard Kaindl <bk@suse.de>
2008-04-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdbLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-kgdb: kgdb: always use icache flush for sw breakpoints kgdb: fix SMP NMI kgdb_handle_exception exit race kgdb: documentation fixes kgdb: allow static kgdbts boot configuration kgdb: add documentation kgdb: Kconfig fix kgdb: add kgdb internal test suite kgdb: fix several kgdb regressions kgdb: kgdboc pl011 I/O module kgdb: fix optional arch functions and probe_kernel_* kgdb: add x86 HW breakpoints kgdb: print breakpoint removed on exception kgdb: clocksource watchdog kgdb: fix NMI hangs kgdb: fix kgdboc dynamic module configuration kgdb: document parameters x86: kgdb support consoles: polling support, kgdboc kgdb: core uaccess: add probe_kernel_write()
2008-04-18Merge branch 'semaphore' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc * 'semaphore' of git://git.kernel.org/pub/scm/linux/kernel/git/willy/misc: Remove DEBUG_SEMAPHORE from Kconfig Improve semaphore documentation Simplify semaphore implementation Add down_timeout and change ACPI to use it Introduce down_killable() Generic semaphore implementation Add semaphore.h to kernel_lock.c Fix quota.h includes
2008-04-17kgdb: coreJason Wessel
kgdb core code. Handles the protocol and the arch details. [ mingo@elte.hu: heavily modified, simplified and cleaned up. ] [ xemul@openvz.org: use find_task_by_pid_ns ] Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jan Kiszka <jan.kiszka@web.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-17Remove DEBUG_SEMAPHORE from KconfigMatthew Wilcox
Alpha and FRV mutexes had an option to print lots of debugging messages in their semaphore implementation. This feature has not been carried over to the generic semaphores, so remove the stale Kconfig option. Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
2008-04-14slub: Deal with config variable dependenciesChristoph Lameter
count_partial() is used by both slabinfo and the sysfs proc support. Move the function directly before the beginning of the sysfs code so that it can be easily found. Rework the preprocessor conditional to take into account that slub sysfs support depends on CONFIG_SYSFS *and* CONFIG_SLUB_DEBUG. Make CONFIG_SLUB_STATS depend on CONFIG_SLUB_DEBUG and CONFIG_SYSFS. There is no point of keeping statistics if no one can restrive them. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
2008-02-23make LKDTM depend on BLOCKChris Snook
Make LKDTM depend on BLOCK to prevent build failures with certain configs. Signed-off-by: Chris Snook <csnook@redhat.com> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-15kbuild: explain why DEBUG_SECTION_MISMATCH is UNDEFINEDSam Ravnborg
We started to see patches enabling this - so explain why it is disabled and the condition to enable it again. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-02-09x86, core: remove CONFIG_FORCED_INLININGHarvey Harrison
Other than the defconfigs, remove the entry in compiler-gcc4.h, Kconfig.debug and feature-removal-schedule.txt. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-08mn10300: add the MN10300/AM33 architecture to the kernelDavid Howells
Add architecture support for the MN10300/AM33 CPUs produced by MEI to the kernel. This patch also adds board support for the ASB2303 with the ASB2308 daughter board, and the ASB2305. The only processor supported is the MN103E010, which is an AM33v2 core plus on-chip devices. [akpm@linux-foundation.org: nuke cvs control strings] Signed-off-by: Masakazu Urade <urade.masakazu@jp.panasonic.com> Signed-off-by: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07SLUB: Support for performance statisticsChristoph Lameter
The statistics provided here allow the monitoring of allocator behavior but at the cost of some (minimal) loss of performance. Counters are placed in SLUB's per cpu data structure. The per cpu structure may be extended by the statistics to grow larger than one cacheline which will increase the cache footprint of SLUB. There is a compile option to enable/disable the inclusion of the runtime statistics and its off by default. The slabinfo tool is enhanced to support these statistics via two options: -D Switches the line of information displayed for a slab from size mode to activity mode. -A Sorts the slabs displayed by activity. This allows the display of the slabs most important to the performance of a certain load. -r Report option will report detailed statistics on Example (tbench load): slabinfo -AD ->Shows the most active slabs Name Objects Alloc Free %Fast skbuff_fclone_cache 33 111953835 111953835 99 99 :0000192 2666 5283688 5281047 99 99 :0001024 849 5247230 5246389 83 83 vm_area_struct 1349 119642 118355 91 22 :0004096 15 66753 66751 98 98 :0000064 2067 25297 23383 98 78 dentry 10259 28635 18464 91 45 :0000080 11004 18950 8089 98 98 :0000096 1703 12358 10784 99 98 :0000128 762 10582 9875 94 18 :0000512 184 9807 9647 95 81 :0002048 479 9669 9195 83 65 anon_vma 777 9461 9002 99 71 kmalloc-8 6492 9981 5624 99 97 :0000768 258 7174 6931 58 15 So the skbuff_fclone_cache is of highest importance for the tbench load. Pretty high load on the 192 sized slab. Look for the aliases slabinfo -a | grep 000192 :0000192 <- xfs_btree_cur filp kmalloc-192 uid_cache tw_sock_TCP request_sock_TCPv6 tw_sock_TCPv6 skbuff_head_cache xfs_ili Likely skbuff_head_cache. Looking into the statistics of the skbuff_fclone_cache is possible through slabinfo skbuff_fclone_cache ->-r option implied if cache name is mentioned .... Usual output ... Slab Perf Counter Alloc Free %Al %Fr -------------------------------------------------- Fastpath 111953360 111946981 99 99 Slowpath 1044 7423 0 0 Page Alloc 272 264 0 0 Add partial 25 325 0 0 Remove partial 86 264 0 0 RemoteObj/SlabFrozen 350 4832 0 0 Total 111954404 111954404 Flushes 49 Refill 0 Deactivate Full=325(92%) Empty=0(0%) ToHead=24(6%) ToTail=1(0%) Looks good because the fastpath is overwhelmingly taken. skbuff_head_cache: Slab Perf Counter Alloc Free %Al %Fr -------------------------------------------------- Fastpath 5297262 5259882 99 99 Slowpath 4477 39586 0 0 Page Alloc 937 824 0 0 Add partial 0 2515 0 0 Remove partial 1691 824 0 0 RemoteObj/SlabFrozen 2621 9684 0 0 Total 5301739 5299468 Deactivate Full=2620(100%) Empty=0(0%) ToHead=0(0%) ToTail=0(0%) Descriptions of the output: Total: The total number of allocation and frees that occurred for a slab Fastpath: The number of allocations/frees that used the fastpath. Slowpath: Other allocations Page Alloc: Number of calls to the page allocator as a result of slowpath processing Add Partial: Number of slabs added to the partial list through free or alloc (occurs during cpuslab flushes) Remove Partial: Number of slabs removed from the partial list as a result of allocations retrieving a partial slab or by a free freeing the last object of a slab. RemoteObj/Froz: How many times were remotely freed object encountered when a slab was about to be deactivated. Frozen: How many times was free able to skip list processing because the slab was in use as the cpuslab of another processor. Flushes: Number of times the cpuslab was flushed on request (kmem_cache_shrink, may result from races in __slab_alloc) Refill: Number of times we were able to refill the cpuslab from remotely freed objects for the same slab. Deactivate: Statistics how slabs were deactivated. Shows how they were put onto the partial list. In general fastpath is very good. Slowpath without partial list processing is also desirable. Any touching of partial list uses node specific locks which may potentially cause list lock contention. Signed-off-by: Christoph Lameter <clameter@sgi.com>
2008-02-03kbuild: Spelling/grammar fixes for config DEBUG_SECTION_MISMATCHGeert Uytterhoeven
Including additional fixes from Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-02-03kbuild: print only total number of section mismatces foundSam Ravnborg
We have too many section mismatches detected at the moment. So silence modpost and prevent the option from being set in a typical allyesconfig build. Tell the user how to see all the deteils in the summary message from modpost. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-02-01latencytop: Change Kconfig dependency.Heiko Carstens
Change latencytop Kconfig entry so it doesn't list the archictectures that support it. Instead introduce HAVE_LATENCY_SUPPORT which any architecture can set. Should reduce patch conflicts. Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Holger Wolf <wolf@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-30x86: early boot debugging via FireWire (ohci1394_dma=early)Bernhard Kaindl
This patch adds a new configuration option, which adds support for a new early_param which gets checked in arch/x86/kernel/setup_{32,64}.c:setup_arch() to decide wether OHCI-1394 FireWire controllers should be initialized and enabled for physical DMA access to allow remote debugging of early problems like issues ACPI or other subsystems which are executed very early. If the config option is not enabled, no code is changed, and if the boot paramenter is not given, no new code is executed, and independent of that, all new code is freed after boot, so the config option can be even enabled in standard, non-debug kernels. With specialized tools, it is then possible to get debugging information from machines which have no serial ports (notebooks) such as the printk buffer contents, or any data which can be referenced from global pointers, if it is stored below the 4GB limit and even memory dumps of of the physical RAM region below the 4GB limit can be taken without any cooperation from the CPU of the host, so the machine can be crashed early, it does not matter. In the extreme, even kernel debuggers can be accessed in this way. I wrote a small kgdb module and an accompanying gdb stub for FireWire which allows to gdb to talk to kgdb using remote remory reads and writes over FireWire. An version of the gdb stub fore FireWire is able to read all global data from a system which is running a a normal kernel without any kernel debugger, without any interruption or support of the system's CPU. That way, e.g. the task struct and so on can be read and even manipulated when the physical DMA access is granted. A HOWTO is included in this patch, in Documentation/debugging-via-ohci1394.txt and I've put a copy online at ftp://ftp.suse.de/private/bk/firewire/docs/debugging-via-ohci1394.txt It also has links to all the tools which are available to make use of it another copy of it is online at: ftp://ftp.suse.de/private/bk/firewire/kernel/ohci1394_dma_early-v2.diff Signed-Off-By: Bernhard Kaindl <bk@suse.de> Tested-By: Thomas Renninger <trenn@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: add a simple backtrace test moduleArjan van de Ven
During the work on the x86 32 and 64 bit backtrace code I found it useful to have a simple test module to test a process and irq context backtrace. Since the existing backtrace code was buggy, I figure it might be useful to have such a test module in the kernel so that maybe we can even detect such bugs earlier.. [ mingo@elte.hu: build fix ] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: kprobes: add kprobes smoke tests that run on bootAnanth N Mavinakayanahalli
Here is a quick and naive smoke test for kprobes. This is intended to just verify if some unrelated change broke the *probes subsystem. It is self contained, architecture agnostic and isn't of any great use by itself. This needs to be built in the kernel and runs a basic set of tests to verify if kprobes, jprobes and kretprobes run fine on the kernel. In case of an error, it'll print out a message with a "BUG" prefix. This is a start; we intend to add more tests to this bucket over time. Thanks to Jim Keniston and Masami Hiramatsu for comments and suggestions. Tested on x86 (32/64) and powerpc. Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-28kbuild: add verbose option to Section mismatch reporting in modpostSam Ravnborg
If the config option CONFIG_SECTION_MISMATCH is not set and we see a Section mismatch present the following to the user: modpost: Found 1 section mismatch(es). To see additional details select "Enable full Section mismatch analysis" in the Kernel Hacking menu (CONFIG_SECTION_MISMATCH). If the option CONFIG_SECTION_MISMATCH is selected then be verbose in the Section mismatch reporting from mdopost. Sample outputs: WARNING: o-x86_64/vmlinux.o(.text+0x7396): Section mismatch in reference from the function discover_ebda() to the variable .init.data:ebda_addr The function discover_ebda() references the variable __initdata ebda_addr. This is often because discover_ebda lacks a __initdata annotation or the annotation of ebda_addr is wrong. WARNING: o-x86_64/vmlinux.o(.data+0x74d58): Section mismatch in reference from the variable pci_serial_quirks to the function .devexit.text:pci_plx9050_exit() The variable pci_serial_quirks references the function __devexit pci_plx9050_exit() If the reference is valid then annotate the variable with __exit* (see linux/init.h) or name the variable: *driver, *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console, WARNING: o-x86_64/vmlinux.o(__ksymtab+0x630): Section mismatch in reference from the variable __ksymtab_arch_register_cpu to the function .cpuinit.text:arch_register_cpu() The symbol arch_register_cpu is exported and annotated __cpuinit Fix this by removing the __cpuinit annotation of arch_register_cpu or drop the export. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-01-28kbuild: introduce new option to enhance section mismatch analysisSam Ravnborg
Setting the option DEBUG_SECTION_MISMATCH will report additional section mismatch'es but this should in the end makes it possible to get rid of all of them. See help text in lib/Kconfig.debug for details. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2008-01-25sched: latencytop supportArjan van de Ven
LatencyTOP kernel infrastructure; it measures latencies in the scheduler and tracks it system wide and per process. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-11-23Blackfin arch: punt CONFIG_BFIN -- we already have CONFIG_BLACKFINMike Frysinger
Signed-off-by: Mike Frysinger <michael.frysinger@analog.com> Signed-off-by: Bryan Wu <bryan.wu@analog.com>
2007-10-25Permit silencing of __deprecated warnings.Jeff Garzik
The __deprecated marker is quite useful in highlighting the remnants of old APIs that want removing. However, it is quite normal for one or more years to pass, before the (usually ancient, bitrotten) code in question is either updated or deleted. Thus, like __must_check, add a Kconfig option that permits the silencing of this compiler warning. This change mimics the ifdef-ery and Kconfig defaults of MUST_CHECK as closely as possible. Signed-off-by: Jeff Garzik <jgarzik@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-22Add CONFIG_DEBUG_SG sg validationJens Axboe
Add a Kconfig entry which will toggle some sanity checks on the sg entry and tables. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2007-10-19markers: Add samples subdirMathieu Desnoyers
Begin infrastructure for kernel code samples in the samples/ directory. Add its Kconfig and Kbuild files. Source its Kconfig file in all arch/ Kconfigs. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16slow down printk during bootRandy Dunlap
Optionally add a boot delay after each kernel printk() call, crudely measured in milliseconds, with a maximum delay of 10 seconds per printk. Enable CONFIG_BOOT_PRINTK_DELAY=y and then add (e.g.): "lpj=loops_per_jiffy boot_delay=100" to the kernel command line. It has been useful in cases like "during boot, my machine just reboots or the screen goes black" by slowing down printk, (and adding initcall_debug), we can usually see the last thing that happened before the lights went out which is usually a valuable clue. [akpm@linux-foundation.org: not all architectures implement CONFIG_HZ] [akpm@linux-foundation.org: fix lots of stuff] [bunk@stusta.de: kernel/printk.c: make 2 variables static] [heiko.carstens@de.ibm.com: fix slow down printk on boot compile error] Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-11Merge branch 'master' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc * 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: (408 commits) [POWERPC] Add memchr() to the bootwrapper [POWERPC] Implement logging of unhandled signals [POWERPC] Add legacy serial support for OPB with flattened device tree [POWERPC] Use 1TB segments [POWERPC] XilinxFB: Allow fixed framebuffer base address [POWERPC] XilinxFB: Add support for custom screen resolution [POWERPC] XilinxFB: Use pdata to pass around framebuffer parameters [POWERPC] PCI: Add 64-bit physical address support to setup_indirect_pci [POWERPC] 4xx: Kilauea defconfig file [POWERPC] 4xx: Kilauea DTS [POWERPC] 4xx: Add AMCC Kilauea eval board support to platforms/40x [POWERPC] 4xx: Add AMCC 405EX support to cputable.c [POWERPC] Adjust TASK_SIZE on ppc32 systems to 3GB that are capable [POWERPC] Use PAGE_OFFSET to tell if an address is user/kernel in SW TLB handlers [POWERPC] 85xx: Enable FP emulation in MPC8560 ADS defconfig [POWERPC] 85xx: Killed <asm/mpc85xx.h> [POWERPC] 85xx: Add cpm nodes for 8541/8555 CDS [POWERPC] 85xx: Convert mpc8560ads to the new CPM binding. [POWERPC] mpc8272ads: Remove muram from the CPM reg property. [POWERPC] Make clockevents work on PPC601 processors ... Fixed up conflict in Documentation/powerpc/booting-without-of.txt manually.
2007-10-07lockstat: documentationPeter Zijlstra
Provide some documentation for CONFIG_LOCK_STAT. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Cc: Rob Landley <rob@landley.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-03Merge branch 'linux-2.6' into for-2.6.24Paul Mackerras
2007-10-03[POWERPC] ppc64: support CONFIG_DEBUG_PREEMPTHugh Dickins
Add CONFIG_DEBUG_PREEMPT support to ppc64: it was useful for testing get_paca() preemption. Cheat a little, just use debug_smp_processor_id() in the debug version of get_paca(): it contains all the right checks and reporting, though get_paca() doesn't really use smp_processor_id(). Use local_paca for what might have been called __raw_get_paca(). Silence harmless warnings from io.h and lparcfg.c with local_paca - it is okay for iseries_lparcfg_data to be referencing shared_proc with preemption enabled: all cpus should show the same value for shared_proc. Why do other architectures need TRACE_IRQFLAGS_SUPPORT for DEBUG_PREEMPT? I don't know, ppc64 appears to get along fine without it. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-09-25typo fix Kernel config optionDanny ter Haar
Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-31Remove the arm26 portAdrian Bunk
The arm26 port has been in a state where it was far from even compiling for quite some time. Ian Molton agreed with the removal. Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-19lockstat: core infrastructurePeter Zijlstra
Introduce the core lock statistics code. Lock statistics provides lock wait-time and hold-time (as well as the count of corresponding contention and acquisitions events). Also, the first few call-sites that encounter contention are tracked. Lock wait-time is the time spent waiting on the lock. This provides insight into the locking scheme, that is, a heavily contended lock is indicative of a too coarse locking scheme. Lock hold-time is the duration the lock was held, this provides a reference for the wait-time numbers, so they can be put into perspective. 1) lock 2) ... do stuff .. unlock 3) The time between 1 and 2 is the wait-time. The time between 2 and 3 is the hold-time. The lockdep held-lock tracking code is reused, because it already collects locks into meaningful groups (classes), and because it is an existing infrastructure for lock instrumentation. Currently lockdep tracks lock acquisition with two hooks: lock() lock_acquire() _lock() ... code protected by lock ... unlock() lock_release() _unlock() We need to extend this with two more hooks, in order to measure contention. lock_contended() - used to measure contention events lock_acquired() - completion of the contention These are then placed the following way: lock() lock_acquire() if (!_try_lock()) lock_contended() _lock() lock_acquired() ... do locked stuff ... unlock() lock_release() _unlock() (Note: the try_lock() 'trick' is used to avoid instrumenting all platform dependent lock primitive implementations.) It is also possible to toggle the two lockdep features at runtime using: /proc/sys/kernel/prove_locking /proc/sys/kernel/lock_stat (esp. turning off the O(n^2) prove_locking functionaliy can help) [akpm@linux-foundation.org: build fixes] [akpm@linux-foundation.org: nuke unneeded ifdefs] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16SLUB: support slub_debug on by defaultChristoph Lameter
Add a new configuration variable CONFIG_SLUB_DEBUG_ON If set then the kernel will be booted by default with slab debugging switched on. Similar to CONFIG_SLAB_DEBUG. By default slab debugging is available but must be enabled by specifying "slub_debug" as a kernel parameter. Also add support to switch off slab debugging for a kernel that was built with CONFIG_SLUB_DEBUG_ON. This works by specifying slub_debug=- as a kernel parameter. Dave Jones wanted this feature. http://marc.info/?l=linux-kernel&m=118072189913045&w=2 [akpm@linux-foundation.org: clean up switch statement] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>