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From: Jiri Pirko <jiri@resnulli.us>
To: madhuparnabhowmik10@gmail.com
Cc: paulmck@kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, jiri@mellanox.com,
	joel@joelfernandes.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	davem@davemloft.net
Subject: Re: [Linux-kernel-mentees] [PATCH] net: core: devlink.c: Use built-in RCU list checking
Date: Fri, 21 Feb 2020 18:20:08 +0100	[thread overview]
Message-ID: <20200221172008.GA2181@nanopsycho> (raw)
In-Reply-To: <20200221165141.24630-1-madhuparnabhowmik10@gmail.com>

Fri, Feb 21, 2020 at 05:51:41PM CET, madhuparnabhowmik10@gmail.com wrote:
>From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
>
>list_for_each_entry_rcu() has built-in RCU and lock checking.
>
>Pass cond argument to list_for_each_entry_rcu() to silence
>false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled
>by default.
>
>Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

Reviewed-by: Jiri Pirko <jiri@mellanox.com>

Thanks.

However, there is a callpath where not devlink lock neither rcu read is
taken:
devlink_dpipe_table_register()->devlink_dpipe_table_find()

I guess that was not the trace you were seeing, right?


>---
> net/core/devlink.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/net/core/devlink.c b/net/core/devlink.c
>index 4c63c9a4c09e..3e8c94155d93 100644
>--- a/net/core/devlink.c
>+++ b/net/core/devlink.c
>@@ -2107,7 +2107,8 @@ devlink_dpipe_table_find(struct list_head *dpipe_tables,
> {
> 	struct devlink_dpipe_table *table;
> 
>-	list_for_each_entry_rcu(table, dpipe_tables, list) {
>+	list_for_each_entry_rcu(table, dpipe_tables, list,
>+				lockdep_is_held(&devlink->lock)) {
> 		if (!strcmp(table->name, table_name))
> 			return table;
> 	}
>-- 
>2.17.1
>
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

WARNING: multiple messages have this Message-ID (diff)
From: Jiri Pirko <jiri@resnulli.us>
To: madhuparnabhowmik10@gmail.com
Cc: jiri@mellanox.com, davem@davemloft.net, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org, joel@joelfernandes.org,
	frextrite@gmail.com,
	linux-kernel-mentees@lists.linuxfoundation.org,
	paulmck@kernel.org
Subject: Re: [PATCH] net: core: devlink.c: Use built-in RCU list checking
Date: Fri, 21 Feb 2020 18:20:08 +0100	[thread overview]
Message-ID: <20200221172008.GA2181@nanopsycho> (raw)
In-Reply-To: <20200221165141.24630-1-madhuparnabhowmik10@gmail.com>

Fri, Feb 21, 2020 at 05:51:41PM CET, madhuparnabhowmik10@gmail.com wrote:
>From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
>
>list_for_each_entry_rcu() has built-in RCU and lock checking.
>
>Pass cond argument to list_for_each_entry_rcu() to silence
>false lockdep warning when CONFIG_PROVE_RCU_LIST is enabled
>by default.
>
>Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>

Reviewed-by: Jiri Pirko <jiri@mellanox.com>

Thanks.

However, there is a callpath where not devlink lock neither rcu read is
taken:
devlink_dpipe_table_register()->devlink_dpipe_table_find()

I guess that was not the trace you were seeing, right?


>---
> net/core/devlink.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/net/core/devlink.c b/net/core/devlink.c
>index 4c63c9a4c09e..3e8c94155d93 100644
>--- a/net/core/devlink.c
>+++ b/net/core/devlink.c
>@@ -2107,7 +2107,8 @@ devlink_dpipe_table_find(struct list_head *dpipe_tables,
> {
> 	struct devlink_dpipe_table *table;
> 
>-	list_for_each_entry_rcu(table, dpipe_tables, list) {
>+	list_for_each_entry_rcu(table, dpipe_tables, list,
>+				lockdep_is_held(&devlink->lock)) {
> 		if (!strcmp(table->name, table_name))
> 			return table;
> 	}
>-- 
>2.17.1
>

  reply	other threads:[~2020-02-21 17:20 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-21 16:51 [Linux-kernel-mentees] [PATCH] net: core: devlink.c: Use built-in RCU list checking madhuparnabhowmik10
2020-02-21 16:51 ` madhuparnabhowmik10
2020-02-21 17:20 ` Jiri Pirko [this message]
2020-02-21 17:20   ` Jiri Pirko
2020-02-21 17:35   ` [Linux-kernel-mentees] " Madhuparna Bhowmik
2020-02-21 17:35     ` Madhuparna Bhowmik
2020-02-21 17:54     ` [Linux-kernel-mentees] " Jiri Pirko
2020-02-21 17:54       ` Jiri Pirko
2020-02-21 18:00       ` [Linux-kernel-mentees] " Madhuparna Bhowmik
2020-02-21 18:00         ` Madhuparna Bhowmik
2020-02-23 11:03   ` [Linux-kernel-mentees] " Madhuparna Bhowmik
2020-02-23 11:03     ` Madhuparna Bhowmik
2020-02-23 18:19     ` [Linux-kernel-mentees] " Jiri Pirko
2020-02-23 18:19       ` Jiri Pirko
2020-02-24  0:28 ` [Linux-kernel-mentees] " kbuild test robot
2020-02-24  0:28   ` kbuild test robot
2020-02-24  0:28   ` kbuild test robot
  -- strict thread matches above, loose matches on Subject: below --
2020-02-24  9:30 [Linux-kernel-mentees] " madhuparnabhowmik10
2020-02-24 10:52 ` Jiri Pirko
2020-02-25 12:09   ` Madhuparna Bhowmik
2020-02-25 12:27 madhuparnabhowmik10
2020-02-25 13:06 ` Jiri Pirko
2020-02-27  0:59 ` David Miller

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