linux-stable.git/include/linux/kprobes.h, branch linux-2.6.24.y

kprobes: support kretprobe blacklist

2007-10-16T16:43:10+00:00

Introduce architecture dependent kretprobe blacklists to prohibit users
from inserting return probes on the function in which kprobes can be
inserted but kretprobes can not.

This patch also removes "__kprobes" mark from "__switch_to" on x86_64 and
registers "__switch_to" to the blacklist on x86-64, because that mark is to
prohibit user from inserting only kretprobe.

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

jprobes: make jprobes a little safer for users

2007-07-19T17:04:44+00:00

I realise jprobes are a razor-blades-included type of interface, but that
doesn't mean we can't try and make them safer to use.  This guy I know once
wrote code like this:

struct jprobe jp = { .kp.symbol_name = "foo", .entry = "jprobe_foo" };

And then his kernel exploded. Oops.

This patch adds an arch hook, arch_deref_entry_point() (I don't like it
either) which takes the void * in a struct jprobe, and gives back the text
address that it represents.

We can then use that in register_jprobe() to check that the entry point we're
passed is actually in the kernel text, rather than just some random value.

Signed-off-by: Michael Ellerman 
Cc: Prasanna S Panchamukhi 
Acked-by: Ananth N Mavinakayanahalli 
Cc: Anil S Keshavamurthy 
Cc: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

jprobes: remove JPROBE_ENTRY()

2007-07-19T17:04:44+00:00

AFAICT now that jprobe.entry is a void *, JPROBE_ENTRY doesn't do anything
useful - so remove it ..

I've left a do-nothing version so that out-of-tree jprobes code will still
compile without modifications.

Signed-off-by: Michael Ellerman 
Cc: Prasanna S Panchamukhi 
Acked-by: Ananth N Mavinakayanahalli 
Cc: Anil S Keshavamurthy 
Cc: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

jprobes: make struct jprobe.entry a void *

2007-07-19T17:04:44+00:00

Currently jprobe.entry is a kprobe_opcode_t *, but that's a lie.  On some
platforms it doesn't point to an opcode at all, it points to a function
descriptor.

It's really a pointer to something that the arch code can turn into a function
entry point.  And that's what actually happens, none of the generic code ever
looks at jprobe.entry, it's only ever dereferenced by arch code.

So just make it a void *.

Signed-off-by: Michael Ellerman 
Cc: Prasanna S Panchamukhi 
Acked-by: Ananth N Mavinakayanahalli 
Cc: Anil S Keshavamurthy 
Cc: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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: print details of kretprobe on assertion failure

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

In certain cases like when the real return address can't be found or when
the number of tracked calls to a kretprobed function is less than the
number of returns, we may not be able to find the correct return address
after processing a kretprobe.  Currently we just do a BUG_ON, but no
information is provided about the actual failing kretprobe.

Print out details of the kretprobe before calling BUG().

Signed-off-by: Ananth N Mavinakayanahalli 
Cc: Prasanna S Panchamukhi 
Cc: Jim Keniston 
Cc: Anil S Keshavamurthy 
Cc: Maneesh Soni 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Kprobes: Make kprobe.symbol_name const

2007-05-08T18:15:03+00:00

Kprobes doesn't scribble the kprobe.symbol_name field.  Its only set by the
module when registering the probe.  Modules that exercise good hygiene
using the "const" qualifier will see warnings...

	warning: assignment discards qualifiers from pointer target type

Make struct kprobe.symbol_name const char *

Signed-off-by: Ananth N Mavinakayanahalli 
Signed-off-by: Jim Keniston 
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

[PATCH] kretprobe spinlock deadlock patch

2006-10-02T14:57:16+00:00

kprobe_flush_task() possibly calls kfree function during holding
kretprobe_lock spinlock, if kfree function is probed by kretprobe that will
incur spinlock deadlock.  This patch moves kfree function out scope of
kretprobe_lock.

Signed-off-by: bibo, mao 
Signed-off-by: Ananth N Mavinakayanahalli 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds