From: Dan Carpenter <dan.carpenter@oracle.com>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Matthew Bobrowski <repnop@google.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [bug report] fanotify: fix copy_event_to_user() fid error clean up
Date: Thu, 22 Jul 2021 12:31:42 +0300 [thread overview]
Message-ID: <20210722093142.GU25548@kadam> (raw)
In-Reply-To: <CAOQ4uxgLZTTYV9h4SkCwYEm9D+Nd4VX5MbX8e-fUprsLOdPS2w@mail.gmail.com>
On Thu, Jul 22, 2021 at 12:01:41PM +0300, Amir Goldstein wrote:
> On Thu, Jul 22, 2021 at 1:39 AM Matthew Bobrowski <repnop@google.com> wrote:
> > To make things clearer, avoid any future confusion and possibly tripping
> > over such a bug, perhaps it'd be better to split up the fput(f) call into a
> > separate branch outside of the current conditional, simply i.e.
> >
> > ...
> >
> > if (f)
> > fput(f);
> >
> > ...
> >
> > Thoughts?
>
> smatch (apparently) does not know about the relation that f is non NULL
> if (fd == FAN_NOFD) it needs to study create_fd() for that.
>
> I suggest to move fd_install(fd, f); right after checking of return value
> from create_fd() and without the if (f) condition.
> That should make it clear for human and robots reading this function
> that the cleanup in out_close_fd label is correct.
Yeah. I got "f" and "fd" mixed up in my head when I was reviewing this
code. My bad.
Smatch is *supposed* to know about the relationship between those two.
The bug is actually that Smatch records in the database that create_fd()
always fails. It's a serious bug, and I'm trying to investigate what's
going on and I'm sure that I will fix this before the end of the week.
No need to change the code just to work around a static checker bug.
regards,
dan carpenter
next prev parent reply other threads:[~2021-07-22 9:32 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-21 12:54 [bug report] fanotify: fix copy_event_to_user() fid error clean up Dan Carpenter
2021-07-21 22:38 ` Matthew Bobrowski
2021-07-22 9:01 ` Amir Goldstein
2021-07-22 9:31 ` Dan Carpenter [this message]
2021-07-22 14:01 ` Dan Carpenter
2021-07-22 23:13 ` Matthew Bobrowski
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