On Mon, 2 Apr 2007 14:56:36 +0530
Ananth N Mavinakayanahalli <[EMAIL PROTECTED]> wrote:
> From: Ananth N Mavinakayanahalli <[EMAIL PROTECTED]>
>
> 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 <[EMAIL PROTECTED]>
>
> ---
> 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?
-
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