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SubjectRe: [PATCH 1/1] tty: vt: Remove redundant null check before kfree.
On Wed, Nov 21, 2012 at 08:59:08PM +0530, Sachin Kamat wrote:
> On 21 November 2012 20:46, Greg KH <gregkh@linuxfoundation.org> wrote:
> > On Wed, Nov 21, 2012 at 08:21:40PM +0530, Sachin Kamat wrote:
> >> On 21 November 2012 20:16, Greg KH <gregkh@linuxfoundation.org> wrote:
> >> > On Wed, Nov 21, 2012 at 10:49:07AM +0530, Sachin Kamat wrote:
> >> >> kfree on a NULL pointer is a no-op.
> >> >>
> >> >> Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
> >> >> ---
> >> >> drivers/tty/vt/consolemap.c | 6 ++----
> >> >> 1 files changed, 2 insertions(+), 4 deletions(-)
> >> >>
> >> >> diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
> >> >> index 2aaa0c2..248381b 100644
> >> >> --- a/drivers/tty/vt/consolemap.c
> >> >> +++ b/drivers/tty/vt/consolemap.c
> >> >> @@ -410,10 +410,8 @@ static void con_release_unimap(struct uni_pagedir *p)
> >> >> kfree(p->inverse_translations[i]);
> >> >> p->inverse_translations[i] = NULL;
> >> >> }
> >> >> - if (p->inverse_trans_unicode) {
> >> >> - kfree(p->inverse_trans_unicode);
> >> >> - p->inverse_trans_unicode = NULL;
> >> >> - }
> >> >> + kfree(p->inverse_trans_unicode);
> >> >> + p->inverse_trans_unicode = NULL;
> >> >
> >> > kfree with NULL is a no-op, but the line after that just caused a kernel
> >> > crash if it was NULL, so I can't accept this type of thing.
> >> >
> >> > Please be more careful.
> >>
> >> My mistake. Apologies for the same.
> >>
> >> Do we need to assign the pointer to NULL after freeing?
> >
> > It depends if it is checked later on, is it?
>
> I will re-send this patch after deleting the assignment?

You tell me, please determine if it really is correct or not, before
sending a patch. You did test this, right?

greg k-h


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