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  1. Mar 24, 2009
    • Jason Baron's avatar
      dynamic debug: combine dprintk and dynamic printk · e9d376f0
      Jason Baron authored
      
      This patch combines Greg Bank's dprintk() work with the existing dynamic
      printk patchset, we are now calling it 'dynamic debug'.
      
      The new feature of this patchset is a richer /debugfs control file interface,
      (an example output from my system is at the bottom), which allows fined grained
      control over the the debug output. The output can be controlled by function,
      file, module, format string, and line number.
      
      for example, enabled all debug messages in module 'nf_conntrack':
      
      echo -n 'module nf_conntrack +p' > /mnt/debugfs/dynamic_debug/control
      
      to disable them:
      
      echo -n 'module nf_conntrack -p' > /mnt/debugfs/dynamic_debug/control
      
      A further explanation can be found in the documentation patch.
      
      Signed-off-by: default avatarGreg Banks <gnb@sgi.com>
      Signed-off-by: default avatarJason Baron <jbaron@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      e9d376f0
  2. Mar 05, 2009
  3. Mar 04, 2009
  4. Jan 16, 2009
    • Peter Zijlstra's avatar
      sched: make plist a library facility · ceacc2c1
      Peter Zijlstra authored
      
      Ingo Molnar wrote:
      
      > here's a new build failure with tip/sched/rt:
      >
      >   LD      .tmp_vmlinux1
      > kernel/built-in.o: In function `set_curr_task_rt':
      > sched.c:(.text+0x3675): undefined reference to `plist_del'
      > kernel/built-in.o: In function `pick_next_task_rt':
      > sched.c:(.text+0x37ce): undefined reference to `plist_del'
      > kernel/built-in.o: In function `enqueue_pushable_task':
      > sched.c:(.text+0x381c): undefined reference to `plist_del'
      
      Eliminate the plist library kconfig and make it available
      unconditionally.
      
      Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      ceacc2c1
  5. Jan 08, 2009
  6. Jan 05, 2009
  7. Jan 04, 2009
    • Alain Knaff's avatar
      bzip2/lzma: config and initramfs support for bzip2/lzma decompression · 30d65dbf
      Alain Knaff authored
      
      Impact: New code for initramfs decompression, new features
      
      This is the second part of the bzip2/lzma patch
      
      The bzip patch is based on an idea by Christian Ludwig, includes support for
      compressing the kernel with bzip2 or lzma rather than gzip. Both
      compressors give smaller sizes than gzip.  Lzma's decompresses faster
      than bzip2.
      
      It also supports ramdisks and initramfs' compressed using these two
      compressors.
      
      The functionality has been successfully used for a couple of years by
      the udpcast project
      
      This version applies to "tip" kernel 2.6.28
      
      This part contains:
      - support for new compressions (bzip2 and lzma) in initramfs and
      old-style ramdisk
      - config dialog for kernel compression (but new kernel compressions
      not yet supported)
      
      Signed-off-by: default avatarAlain Knaff <alain@knaff.lu>
      Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
      30d65dbf
  8. Dec 31, 2008
  9. Nov 13, 2008
    • David Howells's avatar
      CRED: Inaugurate COW credentials · d84f4f99
      David Howells authored
      Inaugurate copy-on-write credentials management.  This uses RCU to manage the
      credentials pointer in the task_struct with respect to accesses by other tasks.
      A process may only modify its own credentials, and so does not need locking to
      access or modify its own credentials.
      
      A mutex (cred_replace_mutex) is added to the task_struct to control the effect
      of PTRACE_ATTACHED on credential calculations, particularly with respect to
      execve().
      
      With this patch, the contents of an active credentials struct may not be
      changed directly; rather a new set of credentials must be prepared, modified
      and committed using something like the following sequence of events:
      
      	struct cred *new = prepare_creds();
      	int ret = blah(new);
      	if (ret < 0) {
      		abort_creds(new);
      		return ret;
      	}
      	return commit_creds(new);
      
      There are some exceptions to this rule: the keyrings pointed to by the active
      credentials may be instantiated - keyrings violate the COW rule as managing
      COW keyrings is tricky, given t...
      d84f4f99
  10. Oct 20, 2008
  11. Oct 16, 2008
    • Jason Baron's avatar
      driver core: basic infrastructure for per-module dynamic debug messages · 346e15be
      Jason Baron authored
      
      Base infrastructure to enable per-module debug messages.
      
      I've introduced CONFIG_DYNAMIC_PRINTK_DEBUG, which when enabled centralizes
      control of debugging statements on a per-module basis in one /proc file,
      currently, <debugfs>/dynamic_printk/modules. When, CONFIG_DYNAMIC_PRINTK_DEBUG,
      is not set, debugging statements can still be enabled as before, often by
      defining 'DEBUG' for the proper compilation unit. Thus, this patch set has no
      affect when CONFIG_DYNAMIC_PRINTK_DEBUG is not set.
      
      The infrastructure currently ties into all pr_debug() and dev_dbg() calls. That
      is, if CONFIG_DYNAMIC_PRINTK_DEBUG is set, all pr_debug() and dev_dbg() calls
      can be dynamically enabled/disabled on a per-module basis.
      
      Future plans include extending this functionality to subsystems, that define 
      their own debug levels and flags.
      
      Usage:
      
      Dynamic debugging is controlled by the debugfs file, 
      <debugfs>/dynamic_printk/modules. This file contains a list of the modules that
      can be enabled. The format of the file is as follows:
      
      	<module_name> <enabled=0/1>
      		.
      		.
      		.
      
      	<module_name> : Name of the module in which the debug call resides
      	<enabled=0/1> : whether the messages are enabled or not
      
      For example:
      
      	snd_hda_intel enabled=0
      	fixup enabled=1
      	driver enabled=0
      
      Enable a module:
      
      	$echo "set enabled=1 <module_name>" > dynamic_printk/modules
      
      Disable a module:
      
      	$echo "set enabled=0 <module_name>" > dynamic_printk/modules
      
      Enable all modules:
      
      	$echo "set enabled=1 all" > dynamic_printk/modules
      
      Disable all modules:
      
      	$echo "set enabled=0 all" > dynamic_printk/modules
      
      Finally, passing "dynamic_printk" at the command line enables
      debugging for all modules. This mode can be turned off via the above
      disable command.
      
      [gkh: minor cleanups and tweaks to make the build work quietly]
      
      Signed-off-by: default avatarJason Baron <jbaron@redhat.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
      
      346e15be
  12. Oct 03, 2008
  13. Jul 26, 2008
    • Johannes Weiner's avatar
      lib: generic show_mem() · 454c63b0
      Johannes Weiner authored
      
      This implements a platform-independent version of show_mem().
      
      Signed-off-by: default avatarJohannes Weiner <hannes@saeurebad.de>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
      Cc: Bryan Wu <cooloney@kernel.org>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Jeff Dike <jdike@addtoit.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Greg Ungerer <gerg@uclinux.org>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Roman Zippel <zippel@linux-m68k.org>
      Cc: Hirokazu Takata <takata@linux-m32r.org>
      Cc: Mikael Starvik <starvik@axis.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      454c63b0
    • Roland McGrath's avatar
      task_current_syscall · bbc69863
      Roland McGrath authored
      
      This adds the new function task_current_syscall() on machines where the
      asm/syscall.h interface is supported (CONFIG_HAVE_ARCH_TRACEHOOK).  It's
      exported for modules to use in the future.  This function safely samples
      the state of a blocked thread to collect what system call it is blocked
      in, and the six system call argument registers.
      
      Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
      Cc: Oleg Nesterov <oleg@tv-sign.ru>
      Reviewed-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bbc69863
  14. Jul 24, 2008
  15. Jul 17, 2008
    • Ingo Molnar's avatar
      ftrace: do not trace library functions · 2464a609
      Ingo Molnar authored
      
      make function tracing more robust: do not trace library functions.
      
      We've already got a sizable list of exceptions:
      
       ifdef CONFIG_FTRACE
       # Do not profile string.o, since it may be used in early boot or vdso
       CFLAGS_REMOVE_string.o = -pg
       # Also do not profile any debug utilities
       CFLAGS_REMOVE_spinlock_debug.o = -pg
       CFLAGS_REMOVE_list_debug.o = -pg
       CFLAGS_REMOVE_debugobjects.o = -pg
       CFLAGS_REMOVE_find_next_bit.o = -pg
       CFLAGS_REMOVE_cpumask.o = -pg
       CFLAGS_REMOVE_bitmap.o = -pg
       endif
      
      ... and the pattern has been that random library functionality showed
      up in ftrace's critical path (outside of its recursion check), causing
      hard to debug lockups.
      
      So be a bit defensive about it and exclude all lib/*.o functions by
      default. It's not that they are overly interesting for tracing purposes
      anyway. Specific ones can still be traced, in an opt-in manner.
      
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      2464a609
    • Ingo Molnar's avatar
      ftrace: fix lockup with MAXSMP · 9fa11137
      Ingo Molnar authored
      
      MAXSMP brings in lots of use of various bitops in smp_processor_id()
      and friends - causing ftrace to lock up during bootup:
      
        calling  anon_inode_init+0x0/0x130
        initcall anon_inode_init+0x0/0x130 returned 0 after 0 msecs
        calling  acpi_event_init+0x0/0x57
        [ hard hang ]
      
      So exclude the bitops facilities from tracing.
      
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      9fa11137
  16. Jul 12, 2008
  17. May 23, 2008
  18. Apr 30, 2008
    • Thomas Gleixner's avatar
      infrastructure to debug (dynamic) objects · 3ac7fe5a
      Thomas Gleixner authored
      
      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: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarIngo 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: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3ac7fe5a
  19. Apr 29, 2008
  20. Apr 26, 2008
    • Alexander van Heukelum's avatar
      x86: generic versions of find_first_(zero_)bit, convert i386 · 77b9bd9c
      Alexander van Heukelum authored
      
      Generic versions of __find_first_bit and __find_first_zero_bit
      are introduced as simplified versions of __find_next_bit and
      __find_next_zero_bit. Their compilation and use are guarded by
      a new config variable GENERIC_FIND_FIRST_BIT.
      
      The generic versions of find_first_bit and find_first_zero_bit
      are implemented in terms of the newly introduced __find_first_bit
      and __find_first_zero_bit.
      
      This patch does not remove the i386-specific implementation,
      but it does switch i386 to use the generic functions by setting
      GENERIC_FIND_FIRST_BIT=y for X86_32.
      
      Signed-off-by: default avatarAlexander van Heukelum <heukelum@fastmail.fm>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      77b9bd9c
  21. Apr 17, 2008
  22. Mar 28, 2008
  23. Feb 14, 2008
  24. Feb 08, 2008
  25. Feb 05, 2008
  26. Jan 28, 2008
  27. Nov 15, 2007
  28. Oct 19, 2007
    • Paul Menage's avatar
      Fix cpusets update_cpumask · 8707d8b8
      Paul Menage authored
      
      Cause writes to cpuset "cpus" file to update cpus_allowed for member tasks:
      
      - collect batches of tasks under tasklist_lock and then call
        set_cpus_allowed() on them outside the lock (since this can sleep).
      
      - add a simple generic priority heap type to allow efficient collection
        of batches of tasks to be processed without duplicating or missing any
        tasks in subsequent batches.
      
      - make "cpus" file update a no-op if the mask hasn't changed
      
      - fix race between update_cpumask() and sched_setaffinity() by making
        sched_setaffinity() post-check that it's not running on any cpus outside
        cpuset_cpus_allowed().
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: default avatarPaul Menage <menage@google.com>
      Cc: Paul Jackson <pj@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Balbir Singh <balbir@in.ibm.com>
      Cc: Cedric Le Goater <clg@fr.ibm.com>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Serge Hallyn <serue@us.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8707d8b8
  29. Oct 17, 2007
  30. Oct 12, 2007
  31. Oct 07, 2007
  32. Aug 23, 2007
  33. Jul 31, 2007
  34. Jul 18, 2007
    • Jeremy Fitzhardinge's avatar
      add argv_split() · d84d1cc7
      Jeremy Fitzhardinge authored
      
      argv_split() is a helper function which takes a string, splits it at
      whitespace, and returns a NULL-terminated argv vector.  This is
      deliberately simple - it does no quote processing of any kind.
      
      [ Seems to me that this is something which is already being done in
        the kernel, but I couldn't find any other implementations, either to
        steal or replace.  Keep an eye out. ]
      
      Signed-off-by: default avatarJeremy Fitzhardinge <jeremy@xensource.com>
      Signed-off-by: default avatarChris Wright <chrisw@sous-sol.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Randy Dunlap <randy.dunlap@oracle.com>
      d84d1cc7
  35. Jul 17, 2007
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