Commit 99219a3f authored by bibo,mao's avatar bibo,mao Committed by Linus Torvalds
Browse files

[PATCH] kretprobe spinlock deadlock patch



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: default avatarbibo, mao <bibo.mao@intel.com>
Signed-off-by: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent f2aa85a0
......@@ -396,11 +396,12 @@ no_kprobe:
fastcall void *__kprobes trampoline_handler(struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head;
struct hlist_head *head, empty_rp;
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
......@@ -429,7 +430,7 @@ fastcall void *__kprobes trampoline_handler(struct pt_regs *regs)
}
orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri);
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
/*
......@@ -444,6 +445,10 @@ fastcall void *__kprobes trampoline_handler(struct pt_regs *regs)
spin_unlock_irqrestore(&kretprobe_lock, flags);
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
return (void*)orig_ret_address;
}
......
......@@ -338,12 +338,13 @@ static void kretprobe_trampoline(void)
int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head;
struct hlist_head *head, empty_rp;
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address =
((struct fnptr *)kretprobe_trampoline)->ip;
INIT_HLIST_HEAD(&empty_rp);
spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
......@@ -369,7 +370,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
ri->rp->handler(ri, regs);
orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri);
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
/*
......@@ -387,6 +388,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
spin_unlock_irqrestore(&kretprobe_lock, flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler
......
......@@ -260,11 +260,12 @@ void kretprobe_trampoline_holder(void)
int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head;
struct hlist_head *head, empty_rp;
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
......@@ -290,7 +291,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
ri->rp->handler(ri, regs);
orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri);
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
/*
......@@ -308,6 +309,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
spin_unlock_irqrestore(&kretprobe_lock, flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler
......
......@@ -369,11 +369,12 @@ void __kprobes kretprobe_trampoline_holder(void)
int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head;
struct hlist_head *head, empty_rp;
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
......@@ -399,7 +400,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
ri->rp->handler(ri, regs);
orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri);
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address) {
/*
......@@ -417,6 +418,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
spin_unlock_irqrestore(&kretprobe_lock, flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler
......
......@@ -405,11 +405,12 @@ no_kprobe:
int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head;
struct hlist_head *head, empty_rp;
struct hlist_node *node, *tmp;
unsigned long flags, orig_ret_address = 0;
unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(current);
......@@ -435,7 +436,7 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
ri->rp->handler(ri, regs);
orig_ret_address = (unsigned long)ri->ret_addr;
recycle_rp_inst(ri);
recycle_rp_inst(ri, &empty_rp);
if (orig_ret_address != trampoline_address)
/*
......@@ -453,6 +454,10 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
spin_unlock_irqrestore(&kretprobe_lock, flags);
preempt_enable_no_resched();
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
/*
* By returning a non-zero value, we are telling
* kprobe_handler() that we don't want the post_handler
......
......@@ -202,7 +202,7 @@ void unregister_kretprobe(struct kretprobe *rp);
struct kretprobe_instance *get_free_rp_inst(struct kretprobe *rp);
void add_rp_inst(struct kretprobe_instance *ri);
void kprobe_flush_task(struct task_struct *tk);
void recycle_rp_inst(struct kretprobe_instance *ri);
void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head);
#else /* CONFIG_KPROBES */
#define __kprobes /**/
......
......@@ -319,7 +319,8 @@ void __kprobes add_rp_inst(struct kretprobe_instance *ri)
}
/* Called with kretprobe_lock held */
void __kprobes recycle_rp_inst(struct kretprobe_instance *ri)
void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
struct hlist_head *head)
{
/* remove rp inst off the rprobe_inst_table */
hlist_del(&ri->hlist);
......@@ -331,7 +332,7 @@ void __kprobes recycle_rp_inst(struct kretprobe_instance *ri)
hlist_add_head(&ri->uflist, &ri->rp->free_instances);
} else
/* Unregistering */
kfree(ri);
hlist_add_head(&ri->hlist, head);
}
struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
......@@ -348,17 +349,23 @@ struct hlist_head __kprobes *kretprobe_inst_table_head(struct task_struct *tsk)
void __kprobes kprobe_flush_task(struct task_struct *tk)
{
struct kretprobe_instance *ri;
struct hlist_head *head;
struct hlist_head *head, empty_rp;
struct hlist_node *node, *tmp;
unsigned long flags = 0;
INIT_HLIST_HEAD(&empty_rp);
spin_lock_irqsave(&kretprobe_lock, flags);
head = kretprobe_inst_table_head(tk);
hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
if (ri->task == tk)
recycle_rp_inst(ri);
recycle_rp_inst(ri, &empty_rp);
}
spin_unlock_irqrestore(&kretprobe_lock, flags);
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
kfree(ri);
}
}
static inline void free_rp_inst(struct kretprobe *rp)
......
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