* [PATCH] uprobes: Fix utask->depth accounting in handle_trampoline()
@ 2013-09-11 15:54 Oleg Nesterov
2013-09-12 6:49 ` Srikar Dronamraju
2013-09-12 6:53 ` Anton Arapov
0 siblings, 2 replies; 3+ messages in thread
From: Oleg Nesterov @ 2013-09-11 15:54 UTC (permalink / raw)
To: Ingo Molnar
Cc: anton, Hemant Kumar Shaw, masami.hiramatsu.pt, Mikhail Kulemin,
srikar, systemtap, linux-kernel
Currently utask->depth is simply the number of allocated/pending
return_instance's in uprobe_task->return_instances list.
handle_trampoline() should decrement this counter every time we
handle/free an instance, but due to typo it does this only if
->chained == T. This means that in the likely case this counter
is never decremented and the probed task can't report more than
MAX_URETPROBE_DEPTH events.
Cc: stable@vger.kernel.org
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Mikhail Kulemin <Mikhail.Kulemin@ru.ibm.com>
Reported-by: Hemant Kumar Shaw <hkshaw@linux.vnet.ibm.com>
---
kernel/events/uprobes.c | 4 +---
1 files changed, 1 insertions(+), 3 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index f356974..ad8e1bd 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1682,12 +1682,10 @@ static bool handle_trampoline(struct pt_regs *regs)
tmp = ri;
ri = ri->next;
kfree(tmp);
+ utask->depth--;
if (!chained)
break;
-
- utask->depth--;
-
BUG_ON(!ri);
}
--
1.5.5.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] uprobes: Fix utask->depth accounting in handle_trampoline()
2013-09-11 15:54 [PATCH] uprobes: Fix utask->depth accounting in handle_trampoline() Oleg Nesterov
@ 2013-09-12 6:49 ` Srikar Dronamraju
2013-09-12 6:53 ` Anton Arapov
1 sibling, 0 replies; 3+ messages in thread
From: Srikar Dronamraju @ 2013-09-12 6:49 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Ingo Molnar, anton, Hemant Kumar Shaw, masami.hiramatsu.pt,
Mikhail Kulemin, systemtap, linux-kernel
* Oleg Nesterov <oleg@redhat.com> [2013-09-11 17:47:26]:
> Currently utask->depth is simply the number of allocated/pending
> return_instance's in uprobe_task->return_instances list.
>
> handle_trampoline() should decrement this counter every time we
> handle/free an instance, but due to typo it does this only if
> ->chained == T. This means that in the likely case this counter
> is never decremented and the probed task can't report more than
> MAX_URETPROBE_DEPTH events.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> Reported-by: Mikhail Kulemin <Mikhail.Kulemin@ru.ibm.com>
> Reported-by: Hemant Kumar Shaw <hkshaw@linux.vnet.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Mikhail Kulemin has verified that this fix works for him.
> ---
> kernel/events/uprobes.c | 4 +---
> 1 files changed, 1 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index f356974..ad8e1bd 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -1682,12 +1682,10 @@ static bool handle_trampoline(struct pt_regs *regs)
> tmp = ri;
> ri = ri->next;
> kfree(tmp);
> + utask->depth--;
>
> if (!chained)
> break;
> -
> - utask->depth--;
> -
> BUG_ON(!ri);
> }
>
> --
> 1.5.5.1
>
>
--
Thanks and Regards
Srikar Dronamraju
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] uprobes: Fix utask->depth accounting in handle_trampoline()
2013-09-11 15:54 [PATCH] uprobes: Fix utask->depth accounting in handle_trampoline() Oleg Nesterov
2013-09-12 6:49 ` Srikar Dronamraju
@ 2013-09-12 6:53 ` Anton Arapov
1 sibling, 0 replies; 3+ messages in thread
From: Anton Arapov @ 2013-09-12 6:53 UTC (permalink / raw)
To: Oleg Nesterov
Cc: Ingo Molnar, Hemant Kumar Shaw, masami.hiramatsu.pt,
Mikhail Kulemin, srikar, systemtap, linux-kernel
On Wed, Sep 11, 2013 at 05:47:26PM +0200, Oleg Nesterov wrote:
> Currently utask->depth is simply the number of allocated/pending
> return_instance's in uprobe_task->return_instances list.
>
> handle_trampoline() should decrement this counter every time we
> handle/free an instance, but due to typo it does this only if
> ->chained == T. This means that in the likely case this counter
> is never decremented and the probed task can't report more than
> MAX_URETPROBE_DEPTH events.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> Reported-by: Mikhail Kulemin <Mikhail.Kulemin@ru.ibm.com>
> Reported-by: Hemant Kumar Shaw <hkshaw@linux.vnet.ibm.com>
Acked-by: Anton Arapov <anton@redhat.com>
> ---
> kernel/events/uprobes.c | 4 +---
> 1 files changed, 1 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
> index f356974..ad8e1bd 100644
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -1682,12 +1682,10 @@ static bool handle_trampoline(struct pt_regs *regs)
> tmp = ri;
> ri = ri->next;
> kfree(tmp);
> + utask->depth--;
>
> if (!chained)
> break;
> -
> - utask->depth--;
> -
> BUG_ON(!ri);
> }
>
> --
> 1.5.5.1
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2013-09-11 15:54 [PATCH] uprobes: Fix utask->depth accounting in handle_trampoline() Oleg Nesterov
2013-09-12 6:49 ` Srikar Dronamraju
2013-09-12 6:53 ` Anton Arapov
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