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McKenney" To: Christian Brauner Message-ID: <20200126012354.GH2935@paulmck-ThinkPad-P72> References: <20200124045908.26389-1-madhuparnabhowmik10@gmail.com> <37A3FF92-0958-46DD-AFB1-CE72000B153F@ubuntu.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <37A3FF92-0958-46DD-AFB1-CE72000B153F@ubuntu.com> User-Agent: Mutt/1.9.4 (2018-02-28) Cc: juri.lelli@redhat.com, vincent.guittot@linaro.org, peterz@infradead.org, oleg@redhat.com, linux-kernel@vger.kernel.org, rcu@vger.kernel.org, madhuparnabhowmik10@gmail.com, mingo@redhat.com, ebiederm@xmission.com, joel@joelfernandes.org, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [Linux-kernel-mentees] [PATCH] sched.h: Annotate sighand_struct with __rcu X-BeenThere: linux-kernel-mentees@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: paulmck@kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-kernel-mentees-bounces@lists.linuxfoundation.org Sender: "Linux-kernel-mentees" On Sat, Jan 25, 2020 at 10:41:06PM +0100, Christian Brauner wrote: > On January 24, 2020 5:59:08 AM GMT+01:00, madhuparnabhowmik10@gmail.com wrote: > >From: Madhuparna Bhowmik > > > >This patch fixes the following sparse errors by annotating the > >sighand_struct with __rcu > > > >kernel/fork.c:1511:9: error: incompatible types in comparison > >expression > >kernel/exit.c:100:19: error: incompatible types in comparison > >expression > >kernel/signal.c:1370:27: error: incompatible types in comparison > >expression > > > >This fix introduces the following sparse error in signal.c due to > >checking the sighand pointer without rcu primitives: > > > >kernel/signal.c:1386:21: error: incompatible types in comparison > >expression > > > >This new sparse error is also fixed in this patch. > > > >Signed-off-by: Madhuparna Bhowmik Acked-by: Paul E. McKenney > >--- > > include/linux/sched.h | 2 +- > > kernel/signal.c | 2 +- > > 2 files changed, 2 insertions(+), 2 deletions(-) > > > >diff --git a/include/linux/sched.h b/include/linux/sched.h > >index b511e178a89f..7a351360ad54 100644 > >--- a/include/linux/sched.h > >+++ b/include/linux/sched.h > >@@ -918,7 +918,7 @@ struct task_struct { > > > > /* Signal handlers: */ > > struct signal_struct *signal; > >- struct sighand_struct *sighand; > >+ struct sighand_struct __rcu *sighand; > > sigset_t blocked; > > sigset_t real_blocked; > > /* Restored if set_restore_sigmask() was used: */ > >diff --git a/kernel/signal.c b/kernel/signal.c > >index bcd46f547db3..9ad8dea93dbb 100644 > >--- a/kernel/signal.c > >+++ b/kernel/signal.c > >@@ -1383,7 +1383,7 @@ struct sighand_struct *__lock_task_sighand(struct > >task_struct *tsk, > > * must see ->sighand == NULL. > > */ > > spin_lock_irqsave(&sighand->siglock, *flags); > >- if (likely(sighand == tsk->sighand)) > >+ if (likely(sighand == rcu_access_pointer(tsk->sighand))) > > break; > > spin_unlock_irqrestore(&sighand->siglock, *flags); > > } > > If Paul is happy with this and nobody wants to take it I'll pick this up. Works for me! Thanx, Paul _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees