From: Joel Fernandes <joel@joelfernandes.org>
To: Amol Grover <frextrite@gmail.com>
Cc: Paul Moore <paul@paul-moore.com>, Eric Paris <eparis@redhat.com>,
linux-kernel-mentees@lists.linuxfoundation.org,
Shuah Khan <skhan@linuxfoundation.org>,
linux-audit@redhat.com, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] kernel: audit.c: Add __rcu notation to RCU pointer
Date: Wed, 27 Nov 2019 10:25:57 -0500 [thread overview]
Message-ID: <CAEXW_YS=eDhmv+MaKLoRTCcPknscxqfHa2TyrjAEXpug1g67jw@mail.gmail.com> (raw)
In-Reply-To: <20191127052827.GA9782@workstation-portable>
On Wed, Nov 27, 2019 at 12:29 AM Amol Grover <frextrite@gmail.com> wrote:
>
> On Tue, Nov 26, 2019 at 09:29:25PM -0500, Joel Fernandes wrote:
> > On Tue, Nov 26, 2019 at 10:57:23PM +0530, Amol Grover wrote:
> > > add __rcu notation to RCU protected global pointer auditd_conn
> > >
> > > Fixes multiple instances of sparse error:
> > > error: incompatible types in comparison expression
> > > (different address spaces)
> > >
> > > Signed-off-by: Amol Grover <frextrite@gmail.com>
> > > ---
> > > kernel/audit.c | 6 ++++--
> > > 1 file changed, 4 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/kernel/audit.c b/kernel/audit.c
> > > index da8dc0db5bd3..30e7fc9b8da2 100644
> > > --- a/kernel/audit.c
> > > +++ b/kernel/audit.c
> > > @@ -102,12 +102,14 @@ struct audit_net {
> > > * This struct is RCU protected; you must either hold the RCU lock for reading
> > > * or the associated spinlock for writing.
> > > */
> > > -static struct auditd_connection {
> > > +struct auditd_connection {
> > > struct pid *pid;
> > > u32 portid;
> > > struct net *net;
> > > struct rcu_head rcu;
> > > -} *auditd_conn = NULL;
> > > +};
> > > +static struct auditd_connection __rcu *auditd_conn;
> > > +RCU_INIT_POINTER(auditd_conn);
> >
> > Looks like this causes a build error. Always please build test your patches
> > in the very least. And I also did not understand how RCU_INIT_POINTER can
> > even be used outside of a function. In C, executable code cannot be outside
> > functions.
> >
> > Is doing the following not sufficient to fix the sparse issue?
> >
> > thanks,
> >
> > - Joel
> >
> > ---8<-----------------------
> >
> > diff --git a/kernel/audit.c b/kernel/audit.c
> > index 49b6049b26ac..c5d4b5a2dea1 100644
> > --- a/kernel/audit.c
> > +++ b/kernel/audit.c
> > @@ -108,8 +108,8 @@ struct auditd_connection {
> > struct net *net;
> > struct rcu_head rcu;
> > };
> > -static struct auditd_connection __rcu *auditd_conn;
> > -RCU_INIT_POINTER(auditd_conn);
> > +static struct auditd_connection __rcu *auditd_conn = NULL;
>
> I ran a quick checkpatch and it gave me this error:
> ERROR: do not initialise statics to NULL
>
> So in order to fix it I decided to INIT the pointer (and failed)
Well, try to understand the checkpatch error then, and do the right thing :)
- Joel
next prev parent reply other threads:[~2019-11-27 15:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 17:27 [PATCH] kernel: audit.c: Add __rcu notation to RCU pointer Amol Grover
2019-11-27 2:29 ` Joel Fernandes
2019-11-27 5:28 ` Amol Grover
2019-11-27 15:25 ` Joel Fernandes [this message]
2019-11-28 15:09 ` Amol Grover
2019-11-29 20:08 ` Joel Fernandes
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAEXW_YS=eDhmv+MaKLoRTCcPknscxqfHa2TyrjAEXpug1g67jw@mail.gmail.com' \
--to=joel@joelfernandes.org \
--cc=eparis@redhat.com \
--cc=frextrite@gmail.com \
--cc=linux-audit@redhat.com \
--cc=linux-kernel-mentees@lists.linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=paul@paul-moore.com \
--cc=skhan@linuxfoundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).