The patch titled
kprobes: add kprobe_insn_mutex and cleanup arch_remove_kprobe()
has been added to the -mm tree. Its filename is
kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe.patch
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------------------------------------------------------
Subject: kprobes: add kprobe_insn_mutex and cleanup arch_remove_kprobe()
From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Add kprobe_insn_mutex for protecting kprobe_insn_pages hlist, and remove
kprobe_mutex from architecture dependent code.
This allows us to call arch_remove_kprobe() (and free_insn_slot) while
holding kprobe_mutex.
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Acked-by: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@xxxxxxxxx>
Cc: Russell King <rmk@xxxxxxxxxxxxxxxx>
Cc: "Luck, Tony" <tony.luck@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm/kernel/kprobes.c | 2 --
arch/ia64/kernel/kprobes.c | 8 +++++---
arch/powerpc/kernel/kprobes.c | 7 ++++---
arch/s390/kernel/kprobes.c | 7 ++++---
arch/x86/kernel/kprobes.c | 7 ++++---
include/linux/kprobes.h | 1 -
kernel/kprobes.c | 25 +++++++++++++++++++++----
7 files changed, 38 insertions(+), 19 deletions(-)
diff -puN arch/arm/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe arch/arm/kernel/kprobes.c
--- a/arch/arm/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe
+++ a/arch/arm/kernel/kprobes.c
@@ -92,9 +92,7 @@ void __kprobes arch_disarm_kprobe(struct
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
if (p->ainsn.insn) {
- mutex_lock(&kprobe_mutex);
free_insn_slot(p->ainsn.insn, 0);
- mutex_unlock(&kprobe_mutex);
p->ainsn.insn = NULL;
}
}
diff -puN arch/ia64/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe arch/ia64/kernel/kprobes.c
--- a/arch/ia64/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe
+++ a/arch/ia64/kernel/kprobes.c
@@ -670,9 +670,11 @@ 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.inst_flag & INST_FLAG_BOOSTABLE);
- mutex_unlock(&kprobe_mutex);
+ if (p->ainsn.insn) {
+ free_insn_slot(p->ainsn.insn,
+ p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
+ p->ainsn.insn = NULL;
+ }
}
/*
* We are resuming execution after a single step fault, so the pt_regs
diff -puN arch/powerpc/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe arch/powerpc/kernel/kprobes.c
--- a/arch/powerpc/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe
+++ a/arch/powerpc/kernel/kprobes.c
@@ -96,9 +96,10 @@ 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);
+ if (p->ainsn.insn) {
+ free_insn_slot(p->ainsn.insn, 0);
+ p->ainsn.insn = NULL;
+ }
}
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
diff -puN arch/s390/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe arch/s390/kernel/kprobes.c
--- a/arch/s390/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe
+++ a/arch/s390/kernel/kprobes.c
@@ -218,9 +218,10 @@ 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);
+ if (p->ainsn.insn) {
+ free_insn_slot(p->ainsn.insn, 0);
+ p->ainsn.insn = NULL;
+ }
}
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
diff -puN arch/x86/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe arch/x86/kernel/kprobes.c
--- a/arch/x86/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe
+++ a/arch/x86/kernel/kprobes.c
@@ -376,9 +376,10 @@ 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);
+ if (p->ainsn.insn) {
+ free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
+ p->ainsn.insn = NULL;
+ }
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
diff -puN include/linux/kprobes.h~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe include/linux/kprobes.h
--- a/include/linux/kprobes.h~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe
+++ a/include/linux/kprobes.h
@@ -201,7 +201,6 @@ static inline int init_test_probes(void)
}
#endif /* CONFIG_KPROBES_SANITY_TEST */
-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);
diff -puN kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe kernel/kprobes.c
--- a/kernel/kprobes.c~kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe
+++ a/kernel/kprobes.c
@@ -69,7 +69,7 @@ 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 */
static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
static struct {
spinlock_t lock ____cacheline_aligned_in_smp;
@@ -115,6 +115,7 @@ enum kprobe_slot_state {
SLOT_USED = 2,
};
+static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */
static struct hlist_head kprobe_insn_pages;
static int kprobe_garbage_slots;
static int collect_garbage_slots(void);
@@ -144,10 +145,10 @@ loop_end:
}
/**
- * get_insn_slot() - Find a slot on an executable page for an instruction.
+ * __get_insn_slot() - Find a slot on an executable page for an instruction.
* We allocate an executable page if there's no room on existing ones.
*/
-kprobe_opcode_t __kprobes *get_insn_slot(void)
+static kprobe_opcode_t __kprobes *__get_insn_slot(void)
{
struct kprobe_insn_page *kip;
struct hlist_node *pos;
@@ -196,6 +197,15 @@ kprobe_opcode_t __kprobes *get_insn_slot
return kip->insns;
}
+kprobe_opcode_t __kprobes *get_insn_slot(void)
+{
+ kprobe_opcode_t *ret;
+ mutex_lock(&kprobe_insn_mutex);
+ ret = __get_insn_slot();
+ mutex_unlock(&kprobe_insn_mutex);
+ return ret;
+}
+
/* Return 1 if all garbages are collected, otherwise 0. */
static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
{
@@ -226,9 +236,13 @@ static int __kprobes collect_garbage_slo
{
struct kprobe_insn_page *kip;
struct hlist_node *pos, *next;
+ int safety;
/* Ensure no-one is preepmted on the garbages */
- if (check_safety() != 0)
+ mutex_unlock(&kprobe_insn_mutex);
+ safety = check_safety();
+ mutex_lock(&kprobe_insn_mutex);
+ if (safety != 0)
return -EAGAIN;
hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) {
@@ -251,6 +265,7 @@ 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)) {
@@ -267,6 +282,8 @@ void __kprobes free_insn_slot(kprobe_opc
if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
collect_garbage_slots();
+
+ mutex_unlock(&kprobe_insn_mutex);
}
#endif
_
Patches currently in -mm which might be from mhiramat@xxxxxxxxxx are
origin.patch
kprobes-bugfix-try_module_get-even-if-calling_mod-is-null.patch
kprobes-indirectly-call-kprobe_target.patch
kprobes-add-tests-for-register_kprobes.patch
module-add-within_module_core-and-within_module_init.patch
kprobes-add-kprobe_insn_mutex-and-cleanup-arch_remove_kprobe.patch
kprobes-add-__kprobes-to-kprobe-internal-functions.patch
kprobes-support-probing-module-__exit-function.patch
kprobes-support-probing-module-__exit-function-fix.patch
kprobes-remove-called_from-argument.patch
kprobes-remove-called_from-argument-fix.patch
module-add-module_state_live-notify.patch
kprobes-support-probing-module-__init-function.patch
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