From: Dan Carpenter <dan.carpenter@oracle.com>
To: Nigel Christian <nigel.l.christian@gmail.com>
Cc: kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] mm: hugetlb: checking for IS_ERR() instead of NULL
Date: Wed, 2 Jun 2021 17:47:52 +0300 [thread overview]
Message-ID: <20210602144752.GC10983@kadam> (raw)
In-Reply-To: <20210601205006.GA10983@kadam>
On Tue, Jun 01, 2021 at 11:50:06PM +0300, Dan Carpenter wrote:
> On Tue, Jun 01, 2021 at 10:51:23PM +0300, Dan Carpenter wrote:
> > The other thing which might be interesting is if you pass a NULL
> > to IS_ERR() and then dereference the NULL then print a warning about
> > that. This has a lot of overlaps with some of my existing checks, but
> > it's still a new idea so it belongs in a separate check. It's fine and
> > good even if one bug triggers a lot of different warnings. I'll write
> > that, hang on, brb.
>
> 100% untested. :) I'll test it tonight.
>
This test is decent, but I ended up making a few changes:
1) My devel version of Smatch had a new bug in it which caused some
false positives. Fixed now, hopefully.
2) The test:
if (get_state_expr(my_id, expr) != &null)
return;
check was not strict enough. I realized that I knew that from
square one but I was lazy. So now I have introduced a global helper
function and updated the code:
bool expr_has_possible_state(int owner, struct expression *expr, struct smatch_state *state)
{
struct sm_state *sm;
sm = get_sm_state_expr(owner, expr);
if (!sm)
return false;
return slist_has_state(sm->possible, state);
}
I replaced the test with:
if (!expr_has_possible_state(my_id, expr, &null))
3) The warning message was too vague and too similar to other warning
messages. It should be something unique to the test. It's now:
sm_error("potential NULL/IS_ERR bug '%s'", name);
I'll post the results tomorrow.
regards,
dan carpenter
next prev parent reply other threads:[~2021-06-02 14:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-01 9:25 [PATCH] mm: hugetlb: checking for IS_ERR() instead of NULL Dan Carpenter
2021-06-01 10:52 ` Mina Almasry
2021-06-01 17:54 ` Nigel Christian
2021-06-01 19:00 ` Dan Carpenter
2021-06-01 19:51 ` Dan Carpenter
2021-06-01 20:50 ` Dan Carpenter
2021-06-01 21:23 ` Nigel Christian
2021-06-02 6:11 ` Dan Carpenter
2021-06-02 14:47 ` Dan Carpenter [this message]
2021-06-02 16:01 ` Nigel Christian
2021-06-04 13:34 ` Dan Carpenter
2021-06-04 14:14 ` Nigel Christian
2021-06-04 14:21 ` Dan Carpenter
2021-06-02 14:22 ` Dan Carpenter
2021-06-02 15:57 ` Nigel Christian
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