linux-toradex.git/kernel/kprobes.c, branch v2.6.22

Kprobes: The ON/OFF knob thru debugfs

2007-05-08T18:15:19+00:00

This patch provides a debugfs knob to turn kprobes on/off

o A new file /debug/kprobes/enabled indicates if kprobes is enabled or
  not (default enabled)
o Echoing 0 to this file will disarm all installed probes
o Any new probe registration when disabled will register the probe but
  not arm it. A message will be printed out in such a case.
o When a value 1 is echoed to the file, all probes (including ones
  registered in the intervening period) will be enabled
o Unregistration will happen irrespective of whether probes are globally
  enabled or not.
o Update Documentation/kprobes.txt to reflect these changes. While there
  also update the doc to make it current.

We are also looking at providing sysrq key support to tie to the disabling
feature provided by this patch.

[akpm@linux-foundation.org: Use bool like a bool!]
[akpm@linux-foundation.org: add printk facility levels]
[cornelia.huck@de.ibm.com: Add the missing arch_trampoline_kprobe() for s390]
Signed-off-by: Ananth N Mavinakayanahalli 
Signed-off-by: Srinivasa DS 
Signed-off-by: Cornelia Huck 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kprobes: kretprobes simplifications

2007-05-08T18:15:19+00:00

 - consolidate duplicate code in all arch_prepare_kretprobe instances
   into common code
 - replace various odd helpers that use hlist_for_each_entry to get
   the first elemenet of a list with either a hlist_for_each_entry_save
   or an opencoded access to the first element in the caller
 - inline add_rp_inst into it's only remaining caller
 - use kretprobe_inst_table_head instead of opencoding it

Signed-off-by: Christoph Hellwig 
Cc: Prasanna S Panchamukhi 
Acked-by: Ananth N Mavinakayanahalli 
Cc: Anil S Keshavamurthy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kprobes: codingstyle cleanups

2007-05-08T18:15:19+00:00

Remove superflous braces and fix indentation aswell as comments.

Signed-off-by: Christoph Hellwig 
Cc: Prasanna S Panchamukhi 
Cc: Ananth N Mavinakayanahalli 
Cc: Anil S Keshavamurthy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kprobes: use hlist_for_each_entry

2007-05-08T18:15:19+00:00

Signed-off-by: Christoph Hellwig 
Cc: Prasanna S Panchamukhi 
Cc: Ananth N Mavinakayanahalli 
Cc: Anil S Keshavamurthy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Simplify kallsyms_lookup()

2007-05-08T18:15:08+00:00

Several kallsyms_lookup() pass dummy arguments but only need, say, module's
name.  Make kallsyms_lookup() accept NULLs where possible.

Also, makes picture clearer about what interfaces are needed for all symbol
resolving business.

Signed-off-by: Alexey Dobriyan 
Cc: Rusty Russell 
Acked-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

move die notifier handling to common code

2007-05-08T18:15:04+00:00

This patch moves the die notifier handling to common code.  Previous
various architectures had exactly the same code for it.  Note that the new
code is compiled unconditionally, this should be understood as an appel to
the other architecture maintainer to implement support for it aswell (aka
sprinkling a notify_die or two in the proper place)

arm had a notifiy_die that did something totally different, I renamed it to
arm_notify_die as part of the patch and made it static to the file it's
declared and used at.  avr32 used to pass slightly less information through
this interface and I brought it into line with the other architectures.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix vmalloc_sync_all bustage]
[bryan.wu@analog.com: fix vmalloc_sync_all in nommu]
Signed-off-by: Christoph Hellwig 
Cc: 
Cc: Russell King 
Signed-off-by: Bryan Wu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kprobes: fix sparse NULL warning

2007-05-08T18:15:04+00:00

Fix sparse NULL warnings:
kernel/kprobes.c:915:49: warning: Using plain integer as NULL pointer

Signed-off-by: Randy Dunlap 
Acked-by: Ananth N Mavinakayanahalli 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] kprobes: list all active probes in the system

2007-02-21T01:10:14+00:00

This patch lists all active probes in the system by scanning through
kprobe_table[].  It takes care of aggregate handlers and prints the type of
the probe.  Letter "k" for kprobes, "j" for jprobes, "r" for kretprobes.
It also lists address of the instruction,its symbolic name(function name +
offset) and the module name.  One can access this file through
/sys/kernel/debug/kprobes/list.

Output looks like this
=====================
llm40:~/a # cat /sys/kernel/debug/kprobes/list
c0169ae3  r  sys_read+0x0
c0169ae3  k  sys_read+0x0
c01694c8  k  vfs_write+0x0
c0167d20  r  sys_open+0x0
f8e658a6  k  reiserfs_delete_inode+0x0  reiserfs
c0120f4a  k  do_fork+0x0
c0120f4a  j  do_fork+0x0
c0169b4a  r  sys_write+0x0
c0169b4a  k  sys_write+0x0
c0169622  r  vfs_read+0x0
=================================

[akpm@linux-foundation.org: cleanup]
[ananth@in.ibm.com: sparc build fix]
Signed-off-by: Srinivasa DS 
Cc: Prasanna S Panchamukhi 
Cc: Ananth N Mavinakayanahalli 
Cc: Anil S Keshavamurthy 
Signed-off-by: Ananth N Mavinakayanahalli 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] kprobes: replace magic numbers with enum

2007-01-31T00:01:35+00:00

Replace the magic numbers with an enum, and gets rid of a warning on the
specific architectures (ex.  powerpc) on which the compiler considers
'char' as 'unsigned char'.

Signed-off-by: Masami Hiramatsu 
Cc: Prasanna S Panchamukhi 
Cc: Ananth N Mavinakayanahalli 
Cc: Anil S Keshavamurthy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] kprobes: enable booster on the preemptible kernel

2006-12-07T16:39:38+00:00

When we are unregistering a kprobe-booster, we can't release its
instruction buffer immediately on the preemptive kernel, because some
processes might be preempted on the buffer.  The freeze_processes() and
thaw_processes() functions can clean most of processes up from the buffer.
There are still some non-frozen threads who have the PF_NOFREEZE flag.  If
those threads are sleeping (not preempted) at the known place outside the
buffer, we can ensure safety of freeing.

However, the processing of this check routine takes a long time.  So, this
patch introduces the garbage collection mechanism of insn_slot.  It also
introduces the "dirty" flag to free_insn_slot because of efficiency.

The "clean" instruction slots (dirty flag is cleared) are released
immediately.  But the "dirty" slots which are used by boosted kprobes, are
marked as garbages.  collect_garbage_slots() will be invoked to release
"dirty" slots if there are more than INSNS_PER_PAGE garbage slots or if
there are no unused slots.

Cc: "Keshavamurthy, Anil S" 
Cc: Ananth N Mavinakayanahalli 
Cc: "bibo,mao" 
Cc: Prasanna S Panchamukhi 
Cc: Yumiko Sugita 
Cc: Satoshi Oshima 
Cc: Hideo Aoki 
Signed-off-by: Masami Hiramatsu 
Acked-by: Ingo Molnar 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds