Re: [PATCH]kprobe handler discard user space trap

[Prasanna S Panchamukhi <prasanna@in.ibm.com>]

On Tue, Feb 28, 2006 at 03:23:12PM +0800, bibo,mao wrote:
> Currently kprobe handler traps only happen in kernel space, so function
> kprobe_exceptions_notify should skip traps which happen in user space.
> This patch modifies this, and it is based on 2.6.16-rc4.

You need to remove the code which calculates the
user space address in kprobe_handler() and also you need 
to remove the code that checks for VM86 in i386, since
your patch check if user/vm86 at the top level.

Thanks
Prasanna

> 
> Signed-off-by: bibo mao <bibo.mao@intel.com>
> 
> diff -Nruap a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
> --- a/arch/i386/kernel/kprobes.c    2006-02-25 17:08:52.000000000 +0800
> +++ b/arch/i386/kernel/kprobes.c    2006-03-01 10:37:50.000000000 +0800
> @@ -463,6 +463,9 @@ int __kprobes kprobe_exceptions_notify(s
>      struct die_args *args = (struct die_args *)data;
>      int ret = NOTIFY_DONE;
> 
> +    if (user_mode(args->regs))
> +        return ret;
> +
>      switch (val) {
>      case DIE_INT3:
>          if (kprobe_handler(args->regs))
> diff -Nruap a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
> --- a/arch/ia64/kernel/kprobes.c    2006-02-25 17:08:53.000000000 +0800
> +++ b/arch/ia64/kernel/kprobes.c    2006-03-01 10:39:15.000000000 +0800
> @@ -740,6 +740,9 @@ int __kprobes kprobe_exceptions_notify(s
>      struct die_args *args = (struct die_args *)data;
>      int ret = NOTIFY_DONE;
> 
> +    if (user_mode(args->regs))
> +        return ret;
> +
>      switch(val) {
>      case DIE_BREAK:
>          /* err is break number from ia64_bad_break() */
> diff -Nruap a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
> --- a/arch/powerpc/kernel/kprobes.c    2006-02-25 17:08:52.000000000 +0800
> +++ b/arch/powerpc/kernel/kprobes.c    2006-03-01 10:39:53.000000000 +0800
> @@ -397,6 +397,9 @@ int __kprobes kprobe_exceptions_notify(s
>      struct die_args *args = (struct die_args *)data;
>      int ret = NOTIFY_DONE;
> 
> +    if (user_mode(args->regs))
> +        return ret;
> +
>      switch (val) {
>      case DIE_BPT:
>          if (kprobe_handler(args->regs))
> diff -Nruap a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c
> --- a/arch/sparc64/kernel/kprobes.c    2006-02-25 17:08:52.000000000 +0800
> +++ b/arch/sparc64/kernel/kprobes.c    2006-03-01 10:40:16.000000000 +0800
> @@ -324,6 +324,9 @@ int __kprobes kprobe_exceptions_notify(s
>      struct die_args *args = (struct die_args *)data;
>      int ret = NOTIFY_DONE;
> 
> +    if (user_mode(args->regs))
> +        return ret;
> +
>      switch (val) {
>      case DIE_DEBUG:
>          if (kprobe_handler(args->regs))
> diff -Nruap a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c
> --- a/arch/x86_64/kernel/kprobes.c    2006-02-25 17:08:52.000000000 +0800
> +++ b/arch/x86_64/kernel/kprobes.c    2006-03-01 10:38:48.000000000 +0800
> @@ -601,6 +601,9 @@ int __kprobes kprobe_exceptions_notify(s
>      struct die_args *args = (struct die_args *)data;
>      int ret = NOTIFY_DONE;
> 
> +    if (user_mode(args->regs))
> +        return ret;
> +
>      switch (val) {
>      case DIE_INT3:
>          if (kprobe_handler(args->regs))

-- 
Prasanna S Panchamukhi
Linux Technology Center
India Software Labs, IBM Bangalore
Email: prasanna@in.ibm.com
Ph: 91-80-51776329
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