* [PATCH] kprobe: fix a memory leak in function pre_handler_kretprobe()
@ 2012-01-06 16:49 Jiang Liu
2012-01-06 17:56 ` Jim Keniston
2012-01-09 5:18 ` Ananth N Mavinakayanahalli
0 siblings, 2 replies; 3+ messages in thread
From: Jiang Liu @ 2012-01-06 16:49 UTC (permalink / raw)
To: Hien Nguyen, Jim Keniston, Prasanna S Panchamukhi, linux-kernel
From: Jiang Liu<liuj97@gmail.com>
In function pre_handler_kretprobe(), the allocated kretprobe_instance object will
be leaked if the entry_handler callback returns non-zero. This may cause all the
preallocated kretprobe_instance objects exhausted. This issue could be reproduced
by changing samples/kprobes/kretprobe_example.c to probe "mutex_unlock". And the
fix is straight forward, just put the allocated kretprobe_instance object back
onto the free_instances list.
Signed-off-by: Jiang Liu<liuj97@gmail.com>
Cc: Hien Nguyen<hien@us.ibm.com>
Cc: Jim Keniston<jkenisto@us.ibm.com>
Cc: Prasanna S Panchamukhi<prasanna@in.ibm.com>
---
kprobes.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1660,8 +1660,12 @@
ri->rp = rp;
ri->task = current;
- if (rp->entry_handler&& rp->entry_handler(ri, regs))
+ if (rp->entry_handler&& rp->entry_handler(ri, regs)) {
+ spin_lock_irqsave(&rp->lock, flags);
+ hlist_add_head(&ri->hlist,&rp->free_instances);
+ spin_unlock_irqrestore(&rp->lock, flags);
return 0;
+ }
arch_prepare_kretprobe(ri, regs);
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] kprobe: fix a memory leak in function pre_handler_kretprobe()
2012-01-06 16:49 [PATCH] kprobe: fix a memory leak in function pre_handler_kretprobe() Jiang Liu
@ 2012-01-06 17:56 ` Jim Keniston
2012-01-09 5:18 ` Ananth N Mavinakayanahalli
1 sibling, 0 replies; 3+ messages in thread
From: Jim Keniston @ 2012-01-06 17:56 UTC (permalink / raw)
To: Jiang Liu; +Cc: linux-kernel, Ananth N Mavinakayanahalli
On Sat, 2012-01-07 at 00:49 +0800, Jiang Liu wrote:
> From: Jiang Liu<liuj97@gmail.com>
>
> In function pre_handler_kretprobe(), the allocated kretprobe_instance object will
> be leaked if the entry_handler callback returns non-zero. This may cause all the
> preallocated kretprobe_instance objects exhausted. This issue could be reproduced
> by changing samples/kprobes/kretprobe_example.c to probe "mutex_unlock". And the
> fix is straight forward, just put the allocated kretprobe_instance object back
> onto the free_instances list.
>
> Signed-off-by: Jiang Liu<liuj97@gmail.com>
> Cc: Hien Nguyen<hien@us.ibm.com>
> Cc: Jim Keniston<jkenisto@us.ibm.com>
> Cc: Prasanna S Panchamukhi<prasanna@in.ibm.com>
Acked-by: Jim Keniston <jkenisto@us.ibm.com>
BTW, Prasanna is no longer at IBM, and Hien's address is
hienqngu@us.ibm.com . Ananth (cc-ed) is probably IBM's best kprobes
reviewer.
> ---
> kprobes.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1660,8 +1660,12 @@
> ri->rp = rp;
> ri->task = current;
>
> - if (rp->entry_handler&& rp->entry_handler(ri, regs))
> + if (rp->entry_handler&& rp->entry_handler(ri, regs)) {
> + spin_lock_irqsave(&rp->lock, flags);
> + hlist_add_head(&ri->hlist,&rp->free_instances);
> + spin_unlock_irqrestore(&rp->lock, flags);
> return 0;
> + }
>
> arch_prepare_kretprobe(ri, regs);
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] kprobe: fix a memory leak in function pre_handler_kretprobe()
2012-01-06 16:49 [PATCH] kprobe: fix a memory leak in function pre_handler_kretprobe() Jiang Liu
2012-01-06 17:56 ` Jim Keniston
@ 2012-01-09 5:18 ` Ananth N Mavinakayanahalli
1 sibling, 0 replies; 3+ messages in thread
From: Ananth N Mavinakayanahalli @ 2012-01-09 5:18 UTC (permalink / raw)
To: Jiang Liu; +Cc: Jim Keniston, linux-kernel, Masami Hiramatsu
On Sat, Jan 07, 2012 at 12:49:30AM +0800, Jiang Liu wrote:
> From: Jiang Liu<liuj97@gmail.com>
>
> In function pre_handler_kretprobe(), the allocated kretprobe_instance object will
> be leaked if the entry_handler callback returns non-zero. This may cause all the
> preallocated kretprobe_instance objects exhausted. This issue could be reproduced
> by changing samples/kprobes/kretprobe_example.c to probe "mutex_unlock". And the
> fix is straight forward, just put the allocated kretprobe_instance object back
> onto the free_instances list.
>
> Signed-off-by: Jiang Liu<liuj97@gmail.com>
> Cc: Hien Nguyen<hien@us.ibm.com>
> Cc: Jim Keniston<jkenisto@us.ibm.com>
> Cc: Prasanna S Panchamukhi<prasanna@in.ibm.com>
Thanks for the patch.
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
> ---
> kprobes.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1660,8 +1660,12 @@
> ri->rp = rp;
> ri->task = current;
>
> - if (rp->entry_handler&& rp->entry_handler(ri, regs))
> + if (rp->entry_handler&& rp->entry_handler(ri, regs)) {
> + spin_lock_irqsave(&rp->lock, flags);
> + hlist_add_head(&ri->hlist,&rp->free_instances);
> + spin_unlock_irqrestore(&rp->lock, flags);
> return 0;
> + }
Please fix up coding style issues and resend with acks from Jim and me.
Please also cc stable@kernel.org so this gets included in the earlier
kernels too.
Ananth
^ permalink raw reply [flat|nested] 3+ messages in thread
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2012-01-06 17:56 ` Jim Keniston
2012-01-09 5:18 ` Ananth N Mavinakayanahalli
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