Re: [PATH v4] itimers: Remove bogus NULL pointer check in sys_getitimer()

From: Chen Gang
Date: Thu Jul 04 2013 - 21:29:36 EST


Hello Maintainers:

Is this patch under the normal work flow (or I should need a little more
patience) ?

Thanks.

On 06/25/2013 09:16 AM, Chen Gang wrote:
> People might be tricked into assuming that the return value for a
> failed NULL pointer check should be -EINVAL instead of -EFAULT.
>
> Remove the misleading NULL pointer check to fix this nuisance.
>
> Aside of that this patch fixes the problem of NOMMU kernels, where
> a NULL pointer dereference is a valid operation. This allows to
> boot NOMMU kernels without working around the shortcomings of the
> getitimer() system call, which have been ignored since this NULL
> pointer check was introduced in Linux 0.96a.
>
> Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx>
> ---
> kernel/itimer.c | 13 ++++++-------
> 1 files changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/itimer.c b/kernel/itimer.c
> index 8d262b4..3b12271 100644
> --- a/kernel/itimer.c
> +++ b/kernel/itimer.c
> @@ -102,15 +102,14 @@ int do_getitimer(int which, struct itimerval *value)
>
> SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
> {
> - int error = -EFAULT;
> + int error;
> struct itimerval get_buffer;
>
> - if (value) {
> - error = do_getitimer(which, &get_buffer);
> - if (!error &&
> - copy_to_user(value, &get_buffer, sizeof(get_buffer)))
> - error = -EFAULT;
> - }
> + error = do_getitimer(which, &get_buffer);
> + if (!error &&
> + copy_to_user(value, &get_buffer, sizeof(get_buffer)))
> + error = -EFAULT;
> +
> return error;
> }
>
>


--
Chen Gang
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