Commit Graph

149 Commits

Author SHA1 Message Date
Joe Mario ab76786561 kprobes: use KSYM_NAME_LEN to size identifier buffers
Use KSYM_NAME_LEN to size identifier buffers, so that it can be easier
increased.

Signed-off-by: Joe Mario <jmario@redhat.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:26 +09:00
Heiko Carstens af96397de8 kprobes: allow to specify custom allocator for insn caches
The current two insn slot caches both use module_alloc/module_free to
allocate and free insn slot cache pages.

For s390 this is not sufficient since there is the need to allocate insn
slots that are either within the vmalloc module area or within dma memory.

Therefore add a mechanism which allows to specify an own allocator for an
own insn slot cache.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:58:52 -07:00
Heiko Carstens c802d64a35 kprobes: unify insn caches
The current kpropes insn caches allocate memory areas for insn slots
with module_alloc().  The assumption is that the kernel image and module
area are both within the same +/- 2GB memory area.

This however is not true for s390 where the kernel image resides within
the first 2GB (DMA memory area), but the module area is far away in the
vmalloc area, usually somewhere close below the 4TB area.

For new pc relative instructions s390 needs insn slots that are within
+/- 2GB of each area.  That way we can patch displacements of
pc-relative instructions within the insn slots just like x86 and
powerpc.

The module area works already with the normal insn slot allocator,
however there is currently no way to get insn slots that are within the
first 2GB on s390 (aka DMA area).

Therefore this patch set modifies the kprobes insn slot cache code in
order to allow to specify a custom allocator for the insn slot cache
pages.  In addition architecure can now have private insn slot caches
withhout the need to modify common code.

Patch 1 unifies and simplifies the current insn and optinsn caches
        implementation. This is a preparation which allows to add more
        insn caches in a simple way.

Patch 2 adds the possibility to specify a custom allocator.

Patch 3 makes s390 use the new insn slot mechanisms and adds support for
        pc-relative instructions with long displacements.

This patch (of 3):

The two insn caches (insn, and optinsn) each have an own mutex and
alloc/free functions (get_[opt]insn_slot() / free_[opt]insn_slot()).

Since there is the need for yet another insn cache which satifies dma
allocations on s390, unify and simplify the current implementation:

- Move the per insn cache mutex into struct kprobe_insn_cache.
- Move the alloc/free functions to kprobe.h so they are simply
  wrappers for the generic __get_insn_slot/__free_insn_slot functions.
  The implementation is done with a DEFINE_INSN_CACHE_OPS() macro
  which provides the alloc/free functions for each cache if needed.
- move the struct kprobe_insn_cache to kprobe.h which allows to generate
  architecture specific insn slot caches outside of the core kprobes
  code.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-09-11 15:58:52 -07:00
Mathias Krause 10fb46d5f7 kprobes: handle empty/invalid input to debugfs "enabled" file
When writing invalid input to 'debug/kprobes/enabled' it'll silently be
ignored.  Even worse, when writing an empty string to this file, the
outcome is purely random as the switch statement will make its decision
based on the value of an uninitialized stack variable.

Fix this by handling invalid/empty input as error returning -EINVAL.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03 16:07:46 -07:00
Masami Hiramatsu 7b959fc582 kprobes: Fix to free gone and unused optprobes
Fix to free gone and unused optprobes. This bug will
cause a kernel panic if the user reuses the killed and
unused probe.

Reported at:

  http://sourceware.org/ml/systemtap/2013-q2/msg00142.html

In the normal path, an optprobe on an init function is
unregistered when a module goes live.

unregister_kprobe(kp)
 -> __unregister_kprobe_top
   ->__disable_kprobe
     ->disarm_kprobe(ap == op)
       ->__disarm_kprobe
        ->unoptimize_kprobe : the op is queued
                              on unoptimizing_list
and do nothing in __unregister_kprobe_bottom

After a while (usually wait 5 jiffies), kprobe_optimizer
runs to unoptimize and free optprobe.

kprobe_optimizer
 ->do_unoptimize_kprobes
   ->arch_unoptimize_kprobes : moved to free_list
 ->do_free_cleaned_kprobes
   ->hlist_del: the op is removed
   ->free_aggr_kprobe
     ->arch_remove_optimized_kprobe
     ->arch_remove_kprobe
     ->kfree: the op is freed

Here, if kprobes_module_callback is called and the delayed
unoptimizing probe is picked BEFORE kprobe_optimizer runs,

kprobes_module_callback
 ->kill_kprobe
   ->kill_optimized_kprobe : dequeued from unoptimizing_list <=!!!
     ->arch_remove_optimized_kprobe
   ->arch_remove_kprobe
   (but op is not freed, and on the kprobe hash table)

This doesn't happen if the probe unregistration is done AFTER
kprobes_module_callback is called (because at that time the op
is gone), and kprobe-tracer does it.

To fix this bug, this patch changes kprobes_module_callback to
enqueue the op to freeing_list at kill_optimized_kprobe only
if the op is unused. The unused probes on freeing_list will
be freed in do_free_cleaned_kprobes.

Note that this calls arch_remove_*kprobe twice on the
same probe. Thus those functions have to check the double free.
Fortunately, most of arch codes already checked that except
for mips. This will be fixed in the next patch.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Timo Juhani Lindfors <timo.lindfors@iki.fi>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: systemtap@sourceware.org
Cc: yrl.pp-manager.tt@hitachi.com
Cc: David S. Miller <davem@davemloft.net>
Cc: "David S. Miller" <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20130522093409.9084.63554.stgit@mhiramat-M0-7522
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-05-28 10:37:59 +02:00
Masami Hiramatsu 5c51543b0a kprobes: Fix a double lock bug of kprobe_mutex
Fix a double locking bug caused when debug.kprobe-optimization=0.
While the proc_kprobes_optimization_handler locks kprobe_mutex,
wait_for_kprobe_optimizer locks it again and that causes a double lock.
To fix the bug, this introduces different mutex for protecting
sysctl parameter and locks it in proc_kprobes_optimization_handler.
Of course, since we need to lock kprobe_mutex when touching kprobes
resources, that is done in *optimize_all_kprobes().

This bug was introduced by commit ad72b3bea7 ("kprobes: fix
wait_for_kprobe_optimizer()")

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-18 08:58:38 -07:00
Sasha Levin b67bfe0d42 hlist: drop the node parameter from iterators
I'm not sure why, but the hlist for each entry iterators were conceived

        list_for_each_entry(pos, head, member)

The hlist ones were greedy and wanted an extra parameter:

        hlist_for_each_entry(tpos, pos, head, member)

Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.

Besides the semantic patch, there was some manual work required:

 - Fix up the actual hlist iterators in linux/list.h
 - Fix up the declaration of other iterators based on the hlist ones.
 - A very small amount of places were using the 'node' parameter, this
 was modified to use 'obj->member' instead.
 - Coccinelle didn't handle the hlist_for_each_entry_safe iterator
 properly, so those had to be fixed up manually.

The semantic patch which is mostly the work of Peter Senna Tschudin is here:

@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;

type T;
expression a,c,d,e;
identifier b;
statement S;
@@

-T b;
    <+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
    ...+>

[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:24 -08:00
Linus Torvalds 1eaec8212e Merge branch 'for-3.9-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue [delayed_]work_pending() cleanups from Tejun Heo:
 "This is part of on-going cleanups to remove / minimize usages of
  workqueue interfaces which are deprecated and/or misleading.

  This round drops a number of usages of [delayed_]work_pending(), which
  are dangerous as they lack any form of synchronization and thus often
  lead to buggy / unnecessary code.  There are a couple legitimate use
  cases in kernel.  Hopefully, they can be converted and
  [delayed_]work_pending() can be removed completely.  Even if not,
  removing most of misuses should make it more difficult to find
  examples of misuses and thus slow down growth of them.

  These changes are independent from other workqueue changes."

* 'for-3.9-cleanups' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  wimax/i2400m: fix i2400m->wake_tx_skb handling
  kprobes: fix wait_for_kprobe_optimizer()
  ipw2x00: simplify scan_event handling
  video/exynos: don't use [delayed_]work_pending()
  tty/max3100: don't use [delayed_]work_pending()
  x86/mce: don't use [delayed_]work_pending()
  rfkill: don't use [delayed_]work_pending()
  wl1251: don't use [delayed_]work_pending()
  thinkpad_acpi: don't use [delayed_]work_pending()
  mwifiex: don't use [delayed_]work_pending()
  sja1000: don't use [delayed_]work_pending()
2013-02-19 21:58:52 -08:00
Tejun Heo ad72b3bea7 kprobes: fix wait_for_kprobe_optimizer()
wait_for_kprobe_optimizer() seems largely broken.  It uses
optimizer_comp which is never re-initialized, so
wait_for_kprobe_optimizer() will never wait for anything once
kprobe_optimizer() finishes all pending jobs for the first time.

Also, aside from completion, delayed_work_pending() is %false once
kprobe_optimizer() starts execution and wait_for_kprobe_optimizer()
won't wait for it.

Reimplement it so that it flushes optimizing_work until
[un]optimizing_lists are empty.  Note that this also makes
optimizing_work execute immediately if someone's waiting for it, which
is the nicer behavior.

Only compile tested.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
2013-02-09 11:32:42 -08:00
Masami Hiramatsu e7dbfe349d kprobes/x86: Move ftrace-based kprobe code into kprobes-ftrace.c
Split ftrace-based kprobes code from kprobes, and introduce
CONFIG_(HAVE_)KPROBES_ON_FTRACE Kconfig flags.
For the cleanup reason, this also moves kprobe_ftrace check
into skip_singlestep.

Link: http://lkml.kernel.org/r/20120928081520.3560.25624.stgit@ltc138.sdl.hitachi.co.jp

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-01-21 13:22:36 -05:00
Masami Hiramatsu c6aaf4d0bb kprobes/x86: Fix to support jprobes on ftrace-based kprobe
Fix kprobes/x86 to support jprobes on ftrace-based kprobes.
Because of -mfentry support of ftrace, ftrace is now put
on the beginning of function where jprobes are put.

Originally ftrace-based kprobes doesn't support jprobe
because it will change regs->ip and ftrace doesn't support
changing IP and ftrace itself doesn't conflict jprobe.
However, ftrace -mfentry support moves mcount call on the
top of functions where jprobes are put. This means that
jprobe always conflicts with ftrace-based kprobe and fails.

This patch allows ftrace-based kprobes to support jprobes
by allowing to modify regs->ip and kprobes breakpoint
handler also allows to skip singlestepping because there
is a ftrace call (not an original instruction).

Link: http://lkml.kernel.org/r/20120905143125.10329.90836.stgit@localhost.localdomain

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-09-13 22:52:11 -04:00
Masami Hiramatsu e525389651 kprobes/x86: ftrace based optimization for x86
Add function tracer based kprobe optimization support
handlers on x86. This allows kprobes to use function
tracer for probing on mcount call.

Link: http://lkml.kernel.org/r/20120605102838.27845.26317.stgit@localhost.localdomain

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

[ Updated to new port of ftrace save regs functions ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-07-31 10:29:59 -04:00
Masami Hiramatsu ae6aa16fdc kprobes: introduce ftrace based optimization
Introduce function trace based kprobes optimization.

With using ftrace optimization, kprobes on the mcount calling
address, use ftrace's mcount call instead of breakpoint.
Furthermore, this optimization works with preemptive kernel
not like as current jump-based optimization. Of cource,
this feature works only if the probe is on mcount call.

Only if kprobe.break_handler is set, that probe is not
optimized with ftrace (nor put on ftrace). The reason why this
limitation comes is that this break_handler may be used only
from jprobes which changes ip address (for fetching the function
arguments), but function tracer ignores modified ip address.

Changes in v2:
 - Fix ftrace_ops registering right after setting its filter.
 - Unregister ftrace_ops if there is no kprobe using.
 - Remove notrace dependency from __kprobes macro.

Link: http://lkml.kernel.org/r/20120605102832.27845.63461.stgit@localhost.localdomain

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-07-31 10:29:58 -04:00
Masami Hiramatsu 25764288d8 kprobes: Move locks into appropriate functions
Break a big critical region into fine-grained pieces at
registering kprobe path. This helps us to solve circular
locking dependency when introducing ftrace-based kprobes.

Link: http://lkml.kernel.org/r/20120605102826.27845.81689.stgit@localhost.localdomain

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-07-31 10:29:57 -04:00
Masami Hiramatsu f7fa6ef0de kprobes: cleanup to separate probe-able check
Separate probe-able address checking code from
register_kprobe().

Link: http://lkml.kernel.org/r/20120605102820.27845.90133.stgit@localhost.localdomain

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-07-31 10:29:56 -04:00
Steven Rostedt 72ef3794c5 kprobes: Inverse taking of module_mutex with kprobe_mutex
Currently module_mutex is taken before kprobe_mutex, but this
can cause issues when we have kprobes register ftrace, as the ftrace
mutex is taken before enabling a tracepoint, which currently takes
the module mutex.

If module_mutex is taken before kprobe_mutex, then we can not
have kprobes use the ftrace infrastructure.

There seems to be no reason that the kprobe_mutex can't be taken
before the module_mutex. Running lockdep shows that it is safe
among the kernels I've run.

Link: http://lkml.kernel.org/r/20120605102814.27845.21047.stgit@localhost.localdomain

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-07-31 10:29:55 -04:00
Prashanth Nageshappa f986a499ef kprobes: return proper error code from register_kprobe()
register_kprobe() aborts if the address of the new request falls in a
prohibited area (such as ftrace pouch, __kprobes annotated functions,
non-kernel text addresses, jump label text).  We however don't return the
right error on this abort, resulting in a silent failure - incorrect
adding/reporting of kprobes ('perf probe do_fork+18' or 'perf probe
mcount' for instance).

In V2 we are incorporating Masami Hiramatsu's  feedback.

This patch fixes it by returning -EINVAL upon failure.

While we are here, rename the label used for exit to be more appropriate.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Prashanth K Nageshappa <prashanth@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05 15:49:42 -08:00
Jiang Liu 55ca6140e9 kprobes: fix a memory leak in function pre_handler_kretprobe()
In function pre_handler_kretprobe(), the allocated kretprobe_instance
object will get leaked if the entry_handler callback returns non-zero.
This may cause all the preallocated kretprobe_instance objects exhausted.

This issue can be reproduced by changing
samples/kprobes/kretprobe_example.c to probe "mutex_unlock".  And the fix
is straightforward: just put the allocated kretprobe_instance object back
onto the free_instances list.

[akpm@linux-foundation.org: use raw_spin_lock/unlock]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: Jim Keniston <jkenisto@us.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03 16:16:41 -08:00
Ananth N Mavinakayanahalli d496aab567 kprobes: initialize before using a hlist
Commit ef53d9c5e ("kprobes: improve kretprobe scalability with hashed
locking") introduced a bug where we can potentially leak
kretprobe_instances since we initialize a hlist head after having used
it.

Initialize the hlist head before using it.

Reported by: Jim Keniston <jkenisto@us.ibm.com>
Acked-by: Jim Keniston <jkenisto@us.ibm.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Srinivasa D S <srinivasa@in.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23 08:38:48 -08:00
Stephen Boyd efeb156e72 kprobes: silence DEBUG_STRICT_USER_COPY_CHECKS=y warning
Enabling DEBUG_STRICT_USER_COPY_CHECKS causes the following warning:

  In file included from arch/x86/include/asm/uaccess.h:573,
                   from kernel/kprobes.c:55:
  In function 'copy_from_user',
      inlined from 'write_enabled_file_bool' at
      kernel/kprobes.c:2191:
  arch/x86/include/asm/uaccess_64.h:65:
  warning: call to 'copy_from_user_overflow' declared with attribute warning: copy_from_user() buffer size is not provably correct

presumably due to buf_size being signed causing GCC to fail to see that
buf_size can't become negative.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12 20:13:02 -08:00
Paul Gortmaker 9984de1a5a kernel: Map most files to use export.h instead of module.h
The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else.  Revector them
onto the isolated export header for faster compile times.

Nothing to see here but a whole lot of instances of:

  -#include <linux/module.h>
  +#include <linux/export.h>

This commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-10-31 09:20:12 -04:00
Thomas Gleixner ec484608c5 locking, kprobes: Annotate the hash locks and kretprobe.lock as raw
The kprobe locks can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-09-13 11:11:45 +02:00
Masami Hiramatsu bc81d48d13 kprobes: Return -ENOENT if probe point doesn't exist
Return -ENOENT if probe point doesn't exist, but still returns
-EINVAL if both of kprobe->addr and kprobe->symbol_name are
specified or both are not specified.

Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20110627072650.6528.67329.stgit@fedora15
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-07-15 15:11:47 -04:00
Linus Torvalds 72eb6a7914 Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (30 commits)
  gameport: use this_cpu_read instead of lookup
  x86: udelay: Use this_cpu_read to avoid address calculation
  x86: Use this_cpu_inc_return for nmi counter
  x86: Replace uses of current_cpu_data with this_cpu ops
  x86: Use this_cpu_ops to optimize code
  vmstat: User per cpu atomics to avoid interrupt disable / enable
  irq_work: Use per cpu atomics instead of regular atomics
  cpuops: Use cmpxchg for xchg to avoid lock semantics
  x86: this_cpu_cmpxchg and this_cpu_xchg operations
  percpu: Generic this_cpu_cmpxchg() and this_cpu_xchg support
  percpu,x86: relocate this_cpu_add_return() and friends
  connector: Use this_cpu operations
  xen: Use this_cpu_inc_return
  taskstats: Use this_cpu_ops
  random: Use this_cpu_inc_return
  fs: Use this_cpu_inc_return in buffer.c
  highmem: Use this_cpu_xx_return() operations
  vmstat: Use this_cpu_inc_return for vm statistics
  x86: Support for this_cpu_add, sub, dec, inc_return
  percpu: Generic support for this_cpu_add, sub, dec, inc_return
  ...

Fixed up conflicts: in arch/x86/kernel/{apic/nmi.c, apic/x2apic_uv_x.c, process.c}
as per Tejun.
2011-01-07 17:02:58 -08:00
Christoph Lameter b76834bc1b kprobes: Use this_cpu_ops
Use this_cpu ops in various places to optimize per cpu data access.

Cc: Jason Baron <jbaron@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2010-12-17 15:07:19 +01:00
Masami Hiramatsu f984ba4eb5 kprobes: Use text_poke_smp_batch for unoptimizing
Use text_poke_smp_batch() on unoptimization path for reducing
the number of stop_machine() issues. If the number of
unoptimizing probes is more than MAX_OPTIMIZE_PROBES(=256),
kprobes unoptimizes first MAX_OPTIMIZE_PROBES probes and kicks
optimizer for remaining probes.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20101203095434.2961.22657.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-06 17:59:32 +01:00
Masami Hiramatsu cd7ebe2298 kprobes: Use text_poke_smp_batch for optimizing
Use text_poke_smp_batch() in optimization path for reducing
the number of stop_machine() issues. If the number of optimizing
probes is more than MAX_OPTIMIZE_PROBES(=256), kprobes optimizes
first MAX_OPTIMIZE_PROBES probes and kicks optimizer for
remaining probes.

Changes in v5:
- Use kick_kprobe_optimizer() instead of directly calling
  schedule_delayed_work().
- Rescheduling optimizer outside of kprobe mutex lock.

Changes in v2:
- Allocate code buffer and parameters in arch_init_kprobes()
  instead of using static arraies.
- Merge previous max optimization limit patch into this patch.
  So, this patch introduces upper limit of optimization at
  once.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20101203095428.2961.8994.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-06 17:59:31 +01:00
Masami Hiramatsu 0490cd1f9d kprobes: Reuse unused kprobe
Reuse unused (waiting for unoptimizing and no user handler)
kprobe on given address instead of returning -EBUSY for
registering a new kprobe.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20101203095416.2961.39080.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-06 17:59:31 +01:00
Masami Hiramatsu 6274de4984 kprobes: Support delayed unoptimizing
Unoptimization occurs when a probe is unregistered or disabled,
and is heavy because it recovers instructions by using
stop_machine(). This patch delays unoptimization operations and
unoptimize several probes at once by using
text_poke_smp_batch(). This can avoid unexpected system slowdown
coming from stop_machine().

Changes in v5:
- Split this patch into several cleanup patches and this patch.
- Fix some text_mutex lock miss.
- Use bool instead of int for behavior flags.
- Add additional comment for (un)optimizing path.

Changes in v2:
- Use dynamic allocated buffers and params.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20101203095409.2961.82733.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-06 17:59:30 +01:00
Masami Hiramatsu 61f4e13ffd kprobes: Separate kprobe optimizing code from optimizer
Separate kprobe optimizing code from optimizer, this
will make easy to introducing unoptimizing code in
optimizer.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20101203095403.2961.91201.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-06 17:59:30 +01:00
Masami Hiramatsu 6f0f1dd719 kprobes: Cleanup disabling and unregistering path
Merge disabling kprobe to unregistering kprobe function
and add comments for disabing/unregistring process.

Current unregistering code disables(disarms) kprobes after
checking target kprobe status. This patch changes it to
disabling kprobe first after that it changing the kprobe's
state. This allows to share probe disabling code between
disable_kprobe() and unregister_kprobe().

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20101203095356.2961.30152.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-06 17:59:29 +01:00
Masami Hiramatsu 6d8e40a85e kprobes: Rename old_p to more appropriate name
Rename irrelevant uses of "old_p" to more appropriate names.
Originally, "old_p" just meant "the old kprobe on given address"
but current code uses that name as "just another kprobe" or
something like that. This patch renames those pointer names
to more appropriate one for maintainability.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
LKML-Reference: <20101203095350.2961.48110.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-06 17:59:29 +01:00
Steven Rostedt de31c3ca81 jump label: Fix error with preempt disable holding mutex
Kprobes and jump label were having a race between mutexes that
was fixed by reordering the jump label. But this reordering
moved the jump label mutex into a preempt disable location.

This patch does a little fiddling to move the grabbing of
the jump label mutex from inside the preempt disable section
and still keep the order correct between the mutex and the
kprobes lock.

Reported-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jason Baron <jbaron@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-29 12:55:55 -04:00
Jason Baron 91bad2f8d3 jump label: Fix deadlock b/w jump_label_mutex vs. text_mutex
register_kprobe() downs the 'text_mutex' and then calls
jump_label_text_reserved(), which downs the 'jump_label_mutex'.
However, the jump label code takes those mutexes in the reverse
order.

Fix by requiring the caller of jump_label_text_reserved() to do
the jump label locking via the newly added: jump_label_lock(),
jump_label_unlock(). Currently, kprobes is the only user
of jump_label_text_reserved().

Reported-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
LKML-Reference: <759032c48d5e30c27f0bba003d09bffa8e9f28bb.1285965957.git.jbaron@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-10-28 09:17:40 -04:00
Linus Torvalds a042e26137 Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (50 commits)
  perf python scripting: Add futex-contention script
  perf python scripting: Fixup cut'n'paste error in sctop script
  perf scripting: Shut up 'perf record' final status
  perf record: Remove newline character from perror() argument
  perf python scripting: Support fedora 11 (audit 1.7.17)
  perf python scripting: Improve the syscalls-by-pid script
  perf python scripting: print the syscall name on sctop
  perf python scripting: Improve the syscalls-counts script
  perf python scripting: Improve the failed-syscalls-by-pid script
  kprobes: Remove redundant text_mutex lock in optimize
  x86/oprofile: Fix uninitialized variable use in debug printk
  tracing: Fix 'faild' -> 'failed' typo
  perf probe: Fix format specified for Dwarf_Off parameter
  perf trace: Fix detection of script extension
  perf trace: Use $PERF_EXEC_PATH in canned report scripts
  perf tools: Document event modifiers
  perf tools: Remove direct slang.h include
  perf_events: Fix for transaction recovery in group_sched_in()
  perf_events: Revert: Fix transaction recovery in group_sched_in()
  perf, x86: Use NUMA aware allocations for PEBS/BTS/DS allocations
  ...
2010-10-27 18:48:00 -07:00
Masami Hiramatsu 43948f5027 kprobes: Remove redundant text_mutex lock in optimize
Remove text_mutex locking in optimize_all_kprobes, because
this function doesn't modify text. It simply queues probes on
optimization list for kprobe_optimizer worker thread.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101025131801.19160.70939.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-25 15:51:55 +02:00
Linus Torvalds 092e0e7e52 Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
* 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
  vfs: make no_llseek the default
  vfs: don't use BKL in default_llseek
  llseek: automatically add .llseek fop
  libfs: use generic_file_llseek for simple_attr
  mac80211: disallow seeks in minstrel debug code
  lirc: make chardev nonseekable
  viotape: use noop_llseek
  raw: use explicit llseek file operations
  ibmasmfs: use generic_file_llseek
  spufs: use llseek in all file operations
  arm/omap: use generic_file_llseek in iommu_debug
  lkdtm: use generic_file_llseek in debugfs
  net/wireless: use generic_file_llseek in debugfs
  drm: use noop_llseek
2010-10-22 10:52:56 -07:00
Arnd Bergmann 6038f373a3 llseek: automatically add .llseek fop
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
2010-10-15 15:53:27 +02:00
Jason Baron 4c3ef6d793 jump label: Add jump_label_text_reserved() to reserve jump points
Add a jump_label_text_reserved(void *start, void *end), so that other
pieces of code that want to modify kernel text, can first verify that
jump label has not reserved the instruction.

Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
LKML-Reference: <06236663a3a7b1c1f13576bb9eccb6d9c17b7bfe.1284733808.git.jbaron@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-09-22 16:30:46 -04:00
Jason Baron bf5438fca2 jump label: Base patch for jump label
base patch to implement 'jump labeling'. Based on a new 'asm goto' inline
assembly gcc mechanism, we can now branch to labels from an 'asm goto'
statment. This allows us to create a 'no-op' fastpath, which can subsequently
be patched with a jump to the slowpath code. This is useful for code which
might be rarely used, but which we'd like to be able to call, if needed.
Tracepoints are the current usecase that these are being implemented for.

Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jason Baron <jbaron@redhat.com>
LKML-Reference: <ee8b3595967989fdaf84e698dc7447d315ce972a.1284733808.git.jbaron@redhat.com>

[ cleaned up some formating ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-09-22 16:29:41 -04:00
Namhyung Kim 635c17c2b2 kprobes: Add sparse context annotations
This removes following warnings when build with C=1

 warning: context imbalance in 'kretprobe_hash_lock' - wrong count at exit
 warning: context imbalance in 'kretprobe_table_lock' - wrong count at exit
 warning: context imbalance in 'kretprobe_hash_unlock' - unexpected unlock
 warning: context imbalance in 'kretprobe_table_unlock' - unexpected unlock

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
LKML-Reference: <1284512670-2369-6-git-send-email-namhyung@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-15 10:44:02 +02:00
Namhyung Kim 6376b22975 kprobes: Make functions static
Make following (internal) functions static to make sparse
happier :-)

 * get_optimized_kprobe: only called from static functions
 * kretprobe_table_unlock: _lock function is static
 * kprobes_optinsn_template_holder: never called but holding asm code

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
LKML-Reference: <1284512670-2369-4-git-send-email-namhyung@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-15 10:44:01 +02:00
Namhyung Kim 05662bdb64 kprobes: Verify jprobe entry point
Verify jprobe's entry point is a function entry point
using kallsyms' offset value.

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
LKML-Reference: <1284512670-2369-3-git-send-email-namhyung@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-15 10:44:01 +02:00
Namhyung Kim edbaadbe42 kprobes: Remove redundant address check
Remove call to kernel_text_address() in register_jprobes()
because it is called right after in register_kprobe().

Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
LKML-Reference: <1284512670-2369-2-git-send-email-namhyung@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-15 10:44:00 +02:00
Masami Hiramatsu c0614829c1 kprobes: Move enable/disable_kprobe() out from debugfs code
Move enable/disable_kprobe() API out from debugfs related code,
because these interfaces are not related to debugfs interface.

This fixes a compiler warning.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by:  Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20100427223312.2322.60512.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-08 18:08:30 +02:00
Masami Hiramatsu 83ff56f46a kprobes: Calculate the index correctly when freeing the out-of-line execution slot
From : Ananth N Mavinakayanahalli <ananth@in.ibm.com>

When freeing the instruction slot, the arithmetic to calculate
the index of the slot in the page needs to account for the total
size of the instruction on the various architectures.

Calculate the index correctly when freeing the out-of-line
execution slot.

Reported-by: Sachin Sant <sachinp@in.ibm.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <4B9667AB.9050507@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 14:06:16 +01:00
Masami Hiramatsu b2be84df99 kprobes: Jump optimization sysctl interface
Add /proc/sys/debug/kprobes-optimization sysctl which enables
and disables kprobes jump optimization on the fly for debugging.

Changes in v7:
 - Remove ctl_name = CTL_UNNUMBERED for upstream compatibility.

Changes in v6:
- Update comments and coding style.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133415.6725.8274.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 17:49:25 +01:00
Masami Hiramatsu afd66255b9 kprobes: Introduce kprobes jump optimization
Introduce kprobes jump optimization arch-independent parts.
Kprobes uses breakpoint instruction for interrupting execution
flow, on some architectures, it can be replaced by a jump
instruction and interruption emulation code. This gains kprobs'
performance drastically.

To enable this feature, set CONFIG_OPTPROBES=y (default y if the
arch supports OPTPROBE).

Changes in v9:
 - Fix a bug to optimize probe when enabling.
 - Check nearby probes can be optimize/unoptimize when disarming/arming
   kprobes, instead of registering/unregistering. This will help
   kprobe-tracer because most of probes on it are usually disabled.

Changes in v6:
 - Cleanup coding style for readability.
 - Add comments around get/put_online_cpus().

Changes in v5:
 - Use get_online_cpus()/put_online_cpus() for avoiding text_mutex
   deadlock.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133407.6725.81992.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25 17:49:24 +01:00
Masami Hiramatsu 4610ee1d36 kprobes: Introduce generic insn_slot framework
Make insn_slot framework support various size slots.
Current insn_slot just supports one-size instruction buffer
slot. However, kprobes jump optimization needs larger size
buffers.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133358.6725.82430.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
2010-02-25 17:49:24 +01:00
Masami Hiramatsu 5ecaafdbf4 kprobes: Add mcount to the kprobes blacklist
Since mcount function can be called from everywhere,
it should be blacklisted. Moreover, the "mcount" symbol
is a special symbol name. So, it is better to put it in
the generic blacklist.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100205062433.3745.36726.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-05 08:13:57 +01:00