From: Andrew Morton <akpm@linux-foundation.org>
To: ananth@in.ibm.com
Cc: lkml <linux-kernel@vger.kernel.org>,
Prasanna S Panchamukhi <prasanna@in.ibm.com>,
Jim Keniston <jkenisto@us.ibm.com>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
Maneesh Soni <maneesh@in.ibm.com>
Subject: Re: [PATCH] Kprobes: Print details of kretprobe on assertion failure
Date: Mon, 2 Apr 2007 14:17:32 -0700 [thread overview]
Message-ID: <20070402141732.166f50bd.akpm@linux-foundation.org> (raw)
In-Reply-To: <20070402092636.GA27905@in.ibm.com>
On Mon, 2 Apr 2007 14:56:36 +0530
Ananth N Mavinakayanahalli <ananth@in.ibm.com> wrote:
> From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
>
> In certain cases like when the real return address can't be found or
> when the number of tracked calls to a kretprobed function is less than
> the number of returns, we may not be able to find the correct return
> address after processing a kretprobe. Currently we just do a BUG_ON, but
> no information is provided about the actual failing kretprobe.
>
> Print out details of the kretprobe before calling BUG().
>
> Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
>
> ---
> arch/i386/kernel/kprobes.c | 6 +++++-
> arch/ia64/kernel/kprobes.c | 7 ++++++-
> arch/powerpc/kernel/kprobes.c | 7 ++++++-
> arch/x86_64/kernel/kprobes.c | 7 ++++++-
> 4 files changed, 23 insertions(+), 4 deletions(-)
>
> Index: linux-2.6.21-rc5/arch/i386/kernel/kprobes.c
> ===================================================================
> --- linux-2.6.21-rc5.orig/arch/i386/kernel/kprobes.c
> +++ linux-2.6.21-rc5/arch/i386/kernel/kprobes.c
> @@ -440,7 +440,11 @@ fastcall void *__kprobes trampoline_hand
> break;
> }
>
> - BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
> + if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
> + printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
> + ri->rp, ri->rp->kp.addr);
> + BUG();
> + }
>
> spin_unlock_irqrestore(&kretprobe_lock, flags);
>
> Index: linux-2.6.21-rc5/arch/ia64/kernel/kprobes.c
> ===================================================================
> --- linux-2.6.21-rc5.orig/arch/ia64/kernel/kprobes.c
> +++ linux-2.6.21-rc5/arch/ia64/kernel/kprobes.c
> @@ -444,7 +444,12 @@ int __kprobes trampoline_probe_handler(s
> break;
> }
>
> - BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
> + if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
> + printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
> + ri->rp, ri->rp->kp.addr);
> + BUG();
> + }
> +
> regs->cr_iip = orig_ret_address;
>
> reset_current_kprobe();
> Index: linux-2.6.21-rc5/arch/powerpc/kernel/kprobes.c
> ===================================================================
> --- linux-2.6.21-rc5.orig/arch/powerpc/kernel/kprobes.c
> +++ linux-2.6.21-rc5/arch/powerpc/kernel/kprobes.c
> @@ -293,7 +293,12 @@ int __kprobes trampoline_probe_handler(s
> break;
> }
>
> - BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
> + if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
> + printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
> + ri->rp, ri->rp->kp.addr);
> + BUG();
> + }
> +
> regs->nip = orig_ret_address;
>
> reset_current_kprobe();
> Index: linux-2.6.21-rc5/arch/x86_64/kernel/kprobes.c
> ===================================================================
> --- linux-2.6.21-rc5.orig/arch/x86_64/kernel/kprobes.c
> +++ linux-2.6.21-rc5/arch/x86_64/kernel/kprobes.c
> @@ -438,7 +438,12 @@ int __kprobes trampoline_probe_handler(s
> break;
> }
>
> - BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
> + if (!orig_ret_address || (orig_ret_address == trampoline_address)) {
> + printk("kretprobe BUG!: Processing kretprobe %p @ %p\n",
> + ri->rp, ri->rp->kp.addr);
> + BUG();
> + }
> +
> regs->rip = orig_ret_address;
>
A lot of copying-and-pasting there. Would it be better if this assertion
was performed in a library function in kernel/kprobes.c?
next prev parent reply other threads:[~2007-04-02 21:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-02 9:26 [PATCH] Kprobes: Print details of kretprobe on assertion failure Ananth N Mavinakayanahalli
2007-04-02 21:17 ` Andrew Morton [this message]
2007-04-03 5:49 ` Ananth N Mavinakayanahalli
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20070402141732.166f50bd.akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=ananth@in.ibm.com \
--cc=anil.s.keshavamurthy@intel.com \
--cc=jkenisto@us.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=maneesh@in.ibm.com \
--cc=prasanna@in.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox