Re: [PATCH 3/3] kretprobe spinlock deadlock patch

From: Jiri Slaby
Date: Tue Sep 26 2006 - 02:54:38 EST

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In reply to: bibo,mao: "[PATCH 3/3] kretprobe spinlock deadlock patch"
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bibo,mao wrote:

Hi,
Function 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: bibo, mao <bibo.mao@xxxxxxxxx>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
thanks
bibo,mao

arch/i386/kernel/kprobes.c | 9 +++++++--
arch/ia64/kernel/kprobes.c | 9 +++++++--
arch/powerpc/kernel/kprobes.c | 9 +++++++--
arch/s390/kernel/kprobes.c | 9 +++++++--
arch/x86_64/kernel/kprobes.c | 9 +++++++--
include/linux/kprobes.h | 2 +-
kernel/kprobes.c | 15 +++++++++++----
7 files changed, 47 insertions(+), 15 deletions(-)
diff -Nruap 2.6.18-mm1.org/arch/i386/kernel/kprobes.c 2.6.18-mm1/arch/i386/kernel/kprobes.c
--- 2.6.18-mm1.org/arch/i386/kernel/kprobes.c 2006-09-26 10:49:26.000000000 +0800
+++ 2.6.18-mm1/arch/i386/kernel/kprobes.c 2006-09-26 10:53:16.000000000 +0800
@@ -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_hand
}

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_hand

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;
}

diff -Nruap 2.6.18-mm1.org/arch/ia64/kernel/kprobes.c 2.6.18-mm1/arch/ia64/kernel/kprobes.c
--- 2.6.18-mm1.org/arch/ia64/kernel/kprobes.c 2006-09-26 10:49:26.000000000 +0800
+++ 2.6.18-mm1/arch/ia64/kernel/kprobes.c 2006-09-26 10:53:16.000000000 +0800
@@ -340,12 +340,13 @@ 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);

@@ -371,7 +372,7 @@ int __kprobes trampoline_probe_handler(s
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)
/*
@@ -389,6 +390,10 @@ int __kprobes trampoline_probe_handler(s
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
diff -Nruap 2.6.18-mm1.org/arch/powerpc/kernel/kprobes.c 2.6.18-mm1/arch/powerpc/kernel/kprobes.c
--- 2.6.18-mm1.org/arch/powerpc/kernel/kprobes.c 2006-09-26 10:49:26.000000000 +0800
+++ 2.6.18-mm1/arch/powerpc/kernel/kprobes.c 2006-09-26 10:53:16.000000000 +0800
@@ -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(s
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(s
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
diff -Nruap 2.6.18-mm1.org/arch/s390/kernel/kprobes.c 2.6.18-mm1/arch/s390/kernel/kprobes.c
--- 2.6.18-mm1.org/arch/s390/kernel/kprobes.c 2006-09-25 16:11:56.000000000 +0800
+++ 2.6.18-mm1/arch/s390/kernel/kprobes.c 2006-09-26 10:53:16.000000000 +0800
@@ -368,11 +368,12 @@ void __kprobes kretprobe_trampoline_hold
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);

@@ -398,7 +399,7 @@ int __kprobes trampoline_probe_handler(s
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) {
/*
@@ -416,6 +417,10 @@ int __kprobes trampoline_probe_handler(s
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
diff -Nruap 2.6.18-mm1.org/arch/x86_64/kernel/kprobes.c 2.6.18-mm1/arch/x86_64/kernel/kprobes.c
--- 2.6.18-mm1.org/arch/x86_64/kernel/kprobes.c 2006-09-26 10:49:26.000000000 +0800
+++ 2.6.18-mm1/arch/x86_64/kernel/kprobes.c 2006-09-26 10:53:16.000000000 +0800
@@ -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(s
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(s
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
diff -Nruap 2.6.18-mm1.org/include/linux/kprobes.h 2.6.18-mm1/include/linux/kprobes.h
--- 2.6.18-mm1.org/include/linux/kprobes.h 2006-09-25 16:12:04.000000000 +0800
+++ 2.6.18-mm1/include/linux/kprobes.h 2006-09-26 10:53:16.000000000 +0800
@@ -202,7 +202,7 @@ void unregister_kretprobe(struct kretpro
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 /**/
diff -Nruap 2.6.18-mm1.org/kernel/kprobes.c 2.6.18-mm1/kernel/kprobes.c
--- 2.6.18-mm1.org/kernel/kprobes.c 2006-09-26 10:49:26.000000000 +0800
+++ 2.6.18-mm1/kernel/kprobes.c 2006-09-26 10:53:16.000000000 +0800
@@ -319,7 +319,8 @@ void __kprobes add_rp_inst(struct kretpr
}

/* 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 kr
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_i
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);

HLIST_HEAD(empty_rp); instead of that 2 changes?

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)

regards,
--
http://www.fi.muni.cz/~xslaby/ Jiri Slaby
faculty of informatics, masaryk university, brno, cz
e-mail: jirislaby gmail com, gpg pubkey fingerprint:
B674 9967 0407 CE62 ACC8 22A0 32CC 55C3 39D4 7A7E
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Next message: Christian Kujau: "Re: 2.6.18-rc6-mm2: __fscache_register_netfs compile error"
Previous message: Jiri Slaby: "Re: [PATCH 1/3] kprobe whitespace cleanup"
In reply to: bibo,mao: "[PATCH 3/3] kretprobe spinlock deadlock patch"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]