Commit f709b122 authored by Keshavamurthy Anil S's avatar Keshavamurthy Anil S Committed by Linus Torvalds
Browse files

[PATCH] kprobes-changed-from-using-spinlock-to-mutex fix



Based on some feedback from Oleg Nesterov, I have made few changes to
previously posted patch.

Signed-off-by: default avatarAnil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 49a2a1b8
......@@ -35,7 +35,6 @@
#include <asm/kdebug.h>
#include <asm/sstep.h>
static DECLARE_MUTEX(kprobe_mutex);
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
......@@ -54,9 +53,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
/* insn must be on a special executable page on ppc64 */
if (!ret) {
down(&kprobe_mutex);
p->ainsn.insn = get_insn_slot();
up(&kprobe_mutex);
if (!p->ainsn.insn)
ret = -ENOMEM;
}
......
......@@ -43,7 +43,7 @@
#include <asm/kdebug.h>
void jprobe_return_end(void);
void __kprobes arch_copy_kprobe(struct kprobe *p);
static void __kprobes arch_copy_kprobe(struct kprobe *p);
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
......@@ -180,7 +180,7 @@ static inline s32 *is_riprel(u8 *insn)
return NULL;
}
void __kprobes arch_copy_kprobe(struct kprobe *p)
static void __kprobes arch_copy_kprobe(struct kprobe *p)
{
s32 *ripdisp;
memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE);
......
......@@ -431,7 +431,7 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p,
copy_kprobe(old_p, p);
ret = add_new_kprobe(old_p, p);
} else {
ap = kcalloc(1, sizeof(struct kprobe), GFP_ATOMIC);
ap = kcalloc(1, sizeof(struct kprobe), GFP_KERNEL);
if (!ap)
return -ENOMEM;
add_aggr_kprobe(ap, old_p);
......@@ -491,7 +491,8 @@ int __kprobes register_kprobe(struct kprobe *p)
void __kprobes unregister_kprobe(struct kprobe *p)
{
struct module *mod;
struct kprobe *old_p, *cleanup_p;
struct kprobe *old_p, *list_p;
int cleanup_p;
down(&kprobe_mutex);
old_p = get_kprobe(p->addr);
......@@ -499,22 +500,25 @@ void __kprobes unregister_kprobe(struct kprobe *p)
up(&kprobe_mutex);
return;
}
if ((old_p->pre_handler == aggr_pre_handler) &&
if (p != old_p) {
list_for_each_entry_rcu(list_p, &old_p->list, list)
if (list_p == p)
/* kprobe p is a valid probe */
goto valid_p;
up(&kprobe_mutex);
return;
}
valid_p:
if ((old_p == p) || ((old_p->pre_handler == aggr_pre_handler) &&
(p->list.next == &old_p->list) &&
(p->list.prev == &old_p->list)) {
/* Only one element in the aggregate list */
(p->list.prev == &old_p->list))) {
/* Only probe on the hash list */
arch_disarm_kprobe(p);
hlist_del_rcu(&old_p->hlist);
cleanup_p = old_p;
} else if (old_p == p) {
/* Only one kprobe element in the hash list */
arch_disarm_kprobe(p);
hlist_del_rcu(&p->hlist);
cleanup_p = p;
cleanup_p = 1;
} else {
list_del_rcu(&p->list);
cleanup_p = NULL;
cleanup_p = 0;
}
up(&kprobe_mutex);
......@@ -524,7 +528,7 @@ void __kprobes unregister_kprobe(struct kprobe *p)
module_put(mod);
if (cleanup_p) {
if (cleanup_p->pre_handler == aggr_pre_handler) {
if (p != old_p) {
list_del_rcu(&p->list);
kfree(old_p);
}
......
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