* [patch 1/3] Kprobes - use a mutex to protect the instruction pages list.
2008-02-02 20:37 [patch 0/3] Kprobes mutex cleanup Mathieu Desnoyers
@ 2008-02-02 20:37 ` Mathieu Desnoyers
2008-02-02 20:37 ` [patch 2/3] Kprobes - do not use kprobes mutex in arch code Mathieu Desnoyers
2008-02-02 20:37 ` [patch 3/3] Kprobes - declare kprobe_mutex static Mathieu Desnoyers
2 siblings, 0 replies; 4+ messages in thread
From: Mathieu Desnoyers @ 2008-02-02 20:37 UTC (permalink / raw)
To: akpm, linux-kernel
Cc: Mathieu Desnoyers, Ananth N Mavinakayanahalli, hch,
anil.s.keshavamurthy, davem
[-- Attachment #1: kprobes-use-mutex-for-insn-pages.patch --]
[-- Type: text/plain, Size: 3601 bytes --]
Protect the instruction pages list by a specific insn pages mutex, called in
get_insn_slot() and free_insn_slot(). It makes sure that architectures that does
not need to call arch_remove_kprobe() does not take an unneeded kprobes mutex.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
CC: hch@infradead.org
CC: anil.s.keshavamurthy@intel.com
CC: davem@davemloft.net
---
kernel/kprobes.c | 27 +++++++++++++++++++++------
1 file changed, 21 insertions(+), 6 deletions(-)
Index: linux-2.6-lttng/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/kernel/kprobes.c 2007-08-27 11:48:56.000000000 -0400
+++ linux-2.6-lttng/kernel/kprobes.c 2007-08-27 11:48:58.000000000 -0400
@@ -95,6 +95,10 @@ enum kprobe_slot_state {
SLOT_USED = 2,
};
+/*
+ * Protects the kprobe_insn_pages list. Can nest into kprobe_mutex.
+ */
+static DEFINE_MUTEX(kprobe_insn_mutex);
static struct hlist_head kprobe_insn_pages;
static int kprobe_garbage_slots;
static int collect_garbage_slots(void);
@@ -131,7 +135,9 @@ kprobe_opcode_t __kprobes *get_insn_slot
{
struct kprobe_insn_page *kip;
struct hlist_node *pos;
+ kprobe_opcode_t *ret;
+ mutex_lock(&kprobe_insn_mutex);
retry:
hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
if (kip->nused < INSNS_PER_PAGE) {
@@ -140,7 +146,8 @@ kprobe_opcode_t __kprobes *get_insn_slot
if (kip->slot_used[i] == SLOT_CLEAN) {
kip->slot_used[i] = SLOT_USED;
kip->nused++;
- return kip->insns + (i * MAX_INSN_SIZE);
+ ret = kip->insns + (i * MAX_INSN_SIZE);
+ goto end;
}
}
/* Surprise! No unused slots. Fix kip->nused. */
@@ -154,8 +161,10 @@ kprobe_opcode_t __kprobes *get_insn_slot
}
/* All out of space. Need to allocate a new page. Use slot 0. */
kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL);
- if (!kip)
- return NULL;
+ if (!kip) {
+ ret = NULL;
+ goto end;
+ }
/*
* Use module_alloc so this page is within +/- 2GB of where the
@@ -165,7 +174,8 @@ kprobe_opcode_t __kprobes *get_insn_slot
kip->insns = module_alloc(PAGE_SIZE);
if (!kip->insns) {
kfree(kip);
- return NULL;
+ ret = NULL;
+ goto end;
}
INIT_HLIST_NODE(&kip->hlist);
hlist_add_head(&kip->hlist, &kprobe_insn_pages);
@@ -173,7 +183,10 @@ kprobe_opcode_t __kprobes *get_insn_slot
kip->slot_used[0] = SLOT_USED;
kip->nused = 1;
kip->ngarbage = 0;
- return kip->insns;
+ ret = kip->insns;
+end:
+ mutex_unlock(&kprobe_insn_mutex);
+ return ret;
}
/* Return 1 if all garbages are collected, otherwise 0. */
@@ -207,7 +220,7 @@ static int __kprobes collect_garbage_slo
struct kprobe_insn_page *kip;
struct hlist_node *pos, *next;
- /* Ensure no-one is preepmted on the garbages */
+ /* Ensure no-one is preempted on the garbages */
if (check_safety() != 0)
return -EAGAIN;
@@ -231,6 +244,7 @@ void __kprobes free_insn_slot(kprobe_opc
struct kprobe_insn_page *kip;
struct hlist_node *pos;
+ mutex_lock(&kprobe_insn_mutex);
hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
if (kip->insns <= slot &&
slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
@@ -247,6 +261,7 @@ void __kprobes free_insn_slot(kprobe_opc
if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
collect_garbage_slots();
+ mutex_unlock(&kprobe_insn_mutex);
}
#endif
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
^ permalink raw reply [flat|nested] 4+ messages in thread* [patch 2/3] Kprobes - do not use kprobes mutex in arch code
2008-02-02 20:37 [patch 0/3] Kprobes mutex cleanup Mathieu Desnoyers
2008-02-02 20:37 ` [patch 1/3] Kprobes - use a mutex to protect the instruction pages list Mathieu Desnoyers
@ 2008-02-02 20:37 ` Mathieu Desnoyers
2008-02-02 20:37 ` [patch 3/3] Kprobes - declare kprobe_mutex static Mathieu Desnoyers
2 siblings, 0 replies; 4+ messages in thread
From: Mathieu Desnoyers @ 2008-02-02 20:37 UTC (permalink / raw)
To: akpm, linux-kernel
Cc: Mathieu Desnoyers, Ananth N Mavinakayanahalli,
anil.s.keshavamurthy, davem
[-- Attachment #1: kprobes-dont-use-kprobes-mutex-in-arch-code.patch --]
[-- Type: text/plain, Size: 4520 bytes --]
Remove the kprobes mutex from kprobes.h, since it does not belong there. Also
remove all use of this mutex in the architecture specific code, replacing it by
a proper mutex lock/unlock in the architecture agnostic code.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
CC: anil.s.keshavamurthy@intel.com
CC: davem@davemloft.net
---
arch/ia64/kernel/kprobes.c | 2 --
arch/powerpc/kernel/kprobes.c | 2 --
arch/s390/kernel/kprobes.c | 2 --
arch/x86/kernel/kprobes.c | 2 --
include/linux/kprobes.h | 2 --
kernel/kprobes.c | 2 ++
6 files changed, 2 insertions(+), 10 deletions(-)
Index: linux-2.6-lttng/include/linux/kprobes.h
===================================================================
--- linux-2.6-lttng.orig/include/linux/kprobes.h 2008-01-30 09:06:02.000000000 -0500
+++ linux-2.6-lttng/include/linux/kprobes.h 2008-01-30 09:15:48.000000000 -0500
@@ -35,7 +35,6 @@
#include <linux/percpu.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
-#include <linux/mutex.h>
#ifdef CONFIG_KPROBES
#include <asm/kprobes.h>
@@ -192,7 +191,6 @@ static inline int init_test_probes(void)
#endif /* CONFIG_KPROBES_SANITY_TEST */
extern spinlock_t kretprobe_lock;
-extern struct mutex kprobe_mutex;
extern int arch_prepare_kprobe(struct kprobe *p);
extern void arch_arm_kprobe(struct kprobe *p);
extern void arch_disarm_kprobe(struct kprobe *p);
Index: linux-2.6-lttng/arch/x86/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/arch/x86/kernel/kprobes.c 2008-01-30 09:06:01.000000000 -0500
+++ linux-2.6-lttng/arch/x86/kernel/kprobes.c 2008-01-30 09:15:48.000000000 -0500
@@ -376,9 +376,7 @@ void __kprobes arch_disarm_kprobe(struct
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
- mutex_lock(&kprobe_mutex);
free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
- mutex_unlock(&kprobe_mutex);
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
Index: linux-2.6-lttng/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/kernel/kprobes.c 2008-01-30 09:14:29.000000000 -0500
+++ linux-2.6-lttng/kernel/kprobes.c 2008-01-30 09:15:48.000000000 -0500
@@ -644,7 +644,9 @@ valid_p:
list_del_rcu(&p->list);
kfree(old_p);
}
+ mutex_lock(&kprobe_mutex);
arch_remove_kprobe(p);
+ mutex_unlock(&kprobe_mutex);
} else {
mutex_lock(&kprobe_mutex);
if (p->break_handler)
Index: linux-2.6-lttng/arch/ia64/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/arch/ia64/kernel/kprobes.c 2008-01-30 09:04:21.000000000 -0500
+++ linux-2.6-lttng/arch/ia64/kernel/kprobes.c 2008-01-30 09:15:48.000000000 -0500
@@ -582,9 +582,7 @@ void __kprobes arch_disarm_kprobe(struct
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
- mutex_lock(&kprobe_mutex);
free_insn_slot(p->ainsn.insn, 0);
- mutex_unlock(&kprobe_mutex);
}
/*
* We are resuming execution after a single step fault, so the pt_regs
Index: linux-2.6-lttng/arch/powerpc/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/arch/powerpc/kernel/kprobes.c 2008-01-30 09:04:21.000000000 -0500
+++ linux-2.6-lttng/arch/powerpc/kernel/kprobes.c 2008-01-30 09:15:48.000000000 -0500
@@ -88,9 +88,7 @@ void __kprobes arch_disarm_kprobe(struct
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
- mutex_lock(&kprobe_mutex);
free_insn_slot(p->ainsn.insn, 0);
- mutex_unlock(&kprobe_mutex);
}
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
Index: linux-2.6-lttng/arch/s390/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/arch/s390/kernel/kprobes.c 2008-01-30 09:04:21.000000000 -0500
+++ linux-2.6-lttng/arch/s390/kernel/kprobes.c 2008-01-30 09:15:48.000000000 -0500
@@ -220,9 +220,7 @@ void __kprobes arch_disarm_kprobe(struct
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
- mutex_lock(&kprobe_mutex);
free_insn_slot(p->ainsn.insn, 0);
- mutex_unlock(&kprobe_mutex);
}
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
^ permalink raw reply [flat|nested] 4+ messages in thread* [patch 3/3] Kprobes - declare kprobe_mutex static
2008-02-02 20:37 [patch 0/3] Kprobes mutex cleanup Mathieu Desnoyers
2008-02-02 20:37 ` [patch 1/3] Kprobes - use a mutex to protect the instruction pages list Mathieu Desnoyers
2008-02-02 20:37 ` [patch 2/3] Kprobes - do not use kprobes mutex in arch code Mathieu Desnoyers
@ 2008-02-02 20:37 ` Mathieu Desnoyers
2 siblings, 0 replies; 4+ messages in thread
From: Mathieu Desnoyers @ 2008-02-02 20:37 UTC (permalink / raw)
To: akpm, linux-kernel
Cc: Mathieu Desnoyers, Ananth N Mavinakayanahalli, hch,
anil.s.keshavamurthy, davem
[-- Attachment #1: kprobes-declare-kprobes-mutex-static.patch --]
[-- Type: text/plain, Size: 1205 bytes --]
Since it will not be used by other kernel objects, it makes sense to declare it
static.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
CC: hch@infradead.org
CC: anil.s.keshavamurthy@intel.com
CC: davem@davemloft.net
---
kernel/kprobes.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6-lttng/kernel/kprobes.c
===================================================================
--- linux-2.6-lttng.orig/kernel/kprobes.c 2007-08-19 09:09:15.000000000 -0400
+++ linux-2.6-lttng/kernel/kprobes.c 2007-08-19 17:18:07.000000000 -0400
@@ -68,7 +68,7 @@ static struct hlist_head kretprobe_inst_
/* NOTE: change this value only with kprobe_mutex held */
static bool kprobe_enabled;
-DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
+static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */
static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
^ permalink raw reply [flat|nested] 4+ messages in thread