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Date: Tue, 26 Mar 2013 17:36:44 +0530
From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Subject: Re: [PATCH v2 3/4] uprobes/powerpc: teach uprobes to ignore gdb
 breakpoints
Message-ID: <20130326120644.GC20399@linux.vnet.ibm.com>
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 <20130322151838.GD20010@in.ibm.com>
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* Ananth N Mavinakayanahalli <ananth@in.ibm.com> [2013-03-22 20:48:38]:

> From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
> 
> Powerpc has many trap variants that could be used by entities like gdb.
> Currently, running gdb on a program being traced by uprobes causes an
> endless loop since uprobes doesn't understand that the trap was inserted
> by some other entity and a SIGTRAP needs to be delivered.
> 
> Teach uprobes to ignore breakpoints that do not belong to it.
> 
> Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>

Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

> ---
>  arch/powerpc/kernel/uprobes.c |   10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> Index: linux-3.9-rc3/arch/powerpc/kernel/uprobes.c
> ===================================================================
> --- linux-3.9-rc3.orig/arch/powerpc/kernel/uprobes.c
> +++ linux-3.9-rc3/arch/powerpc/kernel/uprobes.c
> @@ -31,6 +31,16 @@
>  #define UPROBE_TRAP_NR	UINT_MAX
> 
>  /**
> + * is_trap_insn - check if the instruction is a trap variant
> + * @insn: instruction to be checked.
> + * Returns true if @insn is a trap variant.
> + */
> +bool is_trap_insn(uprobe_opcode_t *insn)
> +{
> +	return (is_trap(*insn));
> +}
> +
> +/**
>   * arch_uprobe_analyze_insn
>   * @mm: the probed address space.
>   * @arch_uprobe: the probepoint information.

-- 
Thanks and Regards
Srikar Dronamraju