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From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Masami Hiramatsu <mhiramat@redhat.com>,
	Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
	David Miller <davem@davemloft.net>,
	hskinnemoen@atmel.com, schwidefsky@de.ibm.com,
	tony.luck@intel.com, Ingo Molnar <mingo@elte.hu>,
	Paul Mackerras <paulus@samba.org>,
	David Wilder <dwilder@us.ibm.com>,
	jkenisto@us.ibm.com
Subject: Re: [PATCHv4] kprobes: Introduce kprobe_handle_fault()
Date: Thu, 10 Jan 2008 00:16:21 +0100	[thread overview]
Message-ID: <20080109231620.GA9002@osiris.ibm.com> (raw)
In-Reply-To: <1199916062.6424.60.camel@brick>

>  arch/avr32/mm/fault.c   |   21 +--------------------
>  arch/ia64/mm/fault.c    |   24 +-----------------------
>  arch/powerpc/mm/fault.c |   25 +------------------------
>  arch/s390/mm/fault.c    |   25 +------------------------
>  arch/sparc64/mm/fault.c |   23 +----------------------
>  arch/x86/mm/fault_64.c  |   23 ++---------------------
>  include/linux/kprobes.h |   17 +++++++++++++++++
>  7 files changed, 24 insertions(+), 134 deletions(-)

Somehow I think you missed arch/x86/mm/fault_32.c :)

> This uncovered a possible bug in the s390 version as that purely
> copied the x86 version unconditionally passing 14 as the trapnr
> rather than the error_code parameter.

> diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
> index 2456b52..a9033cf 100644
> --- a/arch/s390/mm/fault.c
> +++ b/arch/s390/mm/fault.c
> @@ -51,29 +51,6 @@ extern int sysctl_userprocess_debug;
> 
>  extern void die(const char *,struct pt_regs *,long);
> 
> -#ifdef CONFIG_KPROBES
> -static inline int notify_page_fault(struct pt_regs *regs, long err)
> -{
> -	int ret = 0;
> -
> -	/* kprobe_running() needs smp_processor_id() */
> -	if (!user_mode(regs)) {
> -		preempt_disable();
> -		if (kprobe_running() && kprobe_fault_handler(regs, 14))
> -			ret = 1;
> -		preempt_enable();
> -	}
> -
> -	return ret;
> -}
> -#else
> -static inline int notify_page_fault(struct pt_regs *regs, long err)
> -{
> -	return 0;
> -}
> -#endif
> -
> -
>  /*
>   * Unlock any spinlocks which will prevent us from getting the
>   * message out.
> @@ -309,7 +286,7 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write)
>  	int si_code;
>  	int fault;
> 
> -	if (notify_page_fault(regs, error_code))
> +	if (kprobe_handle_fault(regs, 14))
>  		return;

Uhm.. yes. 14 is HFP-Significance exception. That doesn't make too much
sense. Passing error_code here would be the right thing to do.
Also I just checked with David Wilder: system tap itself doesn't have any
fault handlers. So it should be safe to change this.

  reply	other threads:[~2008-01-09 23:16 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-07 20:24 [PATCHv2] kprobes: Introduce is_kprobe_fault() Harvey Harrison
2008-01-08  5:37 ` Ananth N Mavinakayanahalli
2008-01-08 17:03 ` Masami Hiramatsu
2008-01-08 22:45 ` Paul Mackerras
2008-01-08 23:02   ` Harvey Harrison
2008-01-09  4:19     ` [PATCHv3] kprobes: Introduce kprobe_handle_fault() Harvey Harrison
2008-01-09  6:14       ` Heiko Carstens
2008-01-09  6:22         ` Harvey Harrison
2008-01-09 22:01           ` [PATCHv4] " Harvey Harrison
2008-01-09 23:16             ` Heiko Carstens [this message]
2008-01-10  0:25               ` Harvey Harrison
2008-01-10  0:44               ` [PATCH 1/2] " Harvey Harrison
2008-01-10  3:15                 ` Masami Hiramatsu
2008-01-10 12:50                 ` Ingo Molnar
2008-01-10  0:45               ` [PATCH 2/2] kprobe: remove preempt_enable/disable from kprobe_handle_fault() Harvey Harrison
2008-01-10  3:15                 ` Masami Hiramatsu
2008-01-09 23:31             ` [PATCHv4] kprobes: Introduce kprobe_handle_fault() Masami Hiramatsu
2008-01-09  7:58         ` [PATCHv3] " Christoph Hellwig
2008-01-09  7:57       ` Christoph Hellwig

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