From: Amol Grover <frextrite@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: paulmck@kernel.org, yoshfuji@linux-ipv6.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
madhuparnabhowmik10@gmail.com, kuba@kernel.org,
joel@joelfernandes.org, kuznet@ms2.inr.ac.ru,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: Re: [Linux-kernel-mentees] [PATCH 2/2] ipmr: Add lockdep expression to ipmr_for_each_table macro
Date: Tue, 25 Feb 2020 18:40:41 +0530 [thread overview]
Message-ID: <20200225131041.GA8660@workstation-portable> (raw)
In-Reply-To: <20200224.131801.2179562246092982372.davem@davemloft.net>
On Mon, Feb 24, 2020 at 01:18:01PM -0800, David Miller wrote:
> From: Amol Grover <frextrite@gmail.com>
> Date: Sat, 22 Feb 2020 12:08:36 +0530
>
> > ipmr_for_each_table() uses list_for_each_entry_rcu() for
> > traversing outside of an RCU read-side critical section but
> > under the protection of pernet_ops_rwsem. Hence add the
> > corresponding lockdep expression to silence the following
> > false-positive warning at boot:
> >
> > [ 0.645292] =============================
> > [ 0.645294] WARNING: suspicious RCU usage
> > [ 0.645296] 5.5.4-stable #17 Not tainted
> > [ 0.645297] -----------------------------
> > [ 0.645299] net/ipv4/ipmr.c:136 RCU-list traversed in non-reader section!!
> >
> > Signed-off-by: Amol Grover <frextrite@gmail.com>
>
> This patch series causes build problems, please fix and resubmit the entire
> series:
>
> [davem@localhost net-next]$ make net/ipv4/ipmr.o
> CALL scripts/checksyscalls.sh
> CALL scripts/atomic/check-atomics.sh
> DESCEND objtool
> CC net/ipv4/ipmr.o
> In file included from ./include/linux/rculist.h:11,
> from ./include/linux/pid.h:5,
> from ./include/linux/sched.h:14,
> from ./include/linux/uaccess.h:5,
> from net/ipv4/ipmr.c:24:
> net/ipv4/ipmr.c: In function ‘ipmr_get_table’:
> ./include/linux/rculist.h:63:25: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
> RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(), \
> ./include/linux/rcupdate.h:263:52: note: in definition of macro ‘RCU_LOCKDEP_WARN’
> if (debug_lockdep_rcu_enabled() && !__warned && (c)) { \
> ^
> ./include/linux/rculist.h:381:7: note: in expansion of macro ‘__list_check_rcu’
> for (__list_check_rcu(dummy, ## cond, 0), \
> ^~~~~~~~~~~~~~~~
> net/ipv4/ipmr.c:113:2: note: in expansion of macro ‘list_for_each_entry_rcu’
> list_for_each_entry_rcu(mrt, &net->ipv4.mr_tables, list, \
> ^~~~~~~~~~~~~~~~~~~~~~~
> net/ipv4/ipmr.c:138:2: note: in expansion of macro ‘ipmr_for_each_table’
> ipmr_for_each_table(mrt, net) {
> ^~~~~~~~~~~~~~~~~~~
This is a build warning due to incorrect operator precedence in
__list_check_rcu macro. This has already been reported and the patch
submitted [1]. Infact the patch is currently queued for v5.7.
[1] https://lore.kernel.org/patchwork/patch/1181886/
Thanks
Amol
_______________________________________________
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: Amol Grover <frextrite@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org, kuba@kernel.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
joel@joelfernandes.org, madhuparnabhowmik10@gmail.com,
paulmck@kernel.org
Subject: Re: [PATCH 2/2] ipmr: Add lockdep expression to ipmr_for_each_table macro
Date: Tue, 25 Feb 2020 18:40:41 +0530 [thread overview]
Message-ID: <20200225131041.GA8660@workstation-portable> (raw)
In-Reply-To: <20200224.131801.2179562246092982372.davem@davemloft.net>
On Mon, Feb 24, 2020 at 01:18:01PM -0800, David Miller wrote:
> From: Amol Grover <frextrite@gmail.com>
> Date: Sat, 22 Feb 2020 12:08:36 +0530
>
> > ipmr_for_each_table() uses list_for_each_entry_rcu() for
> > traversing outside of an RCU read-side critical section but
> > under the protection of pernet_ops_rwsem. Hence add the
> > corresponding lockdep expression to silence the following
> > false-positive warning at boot:
> >
> > [ 0.645292] =============================
> > [ 0.645294] WARNING: suspicious RCU usage
> > [ 0.645296] 5.5.4-stable #17 Not tainted
> > [ 0.645297] -----------------------------
> > [ 0.645299] net/ipv4/ipmr.c:136 RCU-list traversed in non-reader section!!
> >
> > Signed-off-by: Amol Grover <frextrite@gmail.com>
>
> This patch series causes build problems, please fix and resubmit the entire
> series:
>
> [davem@localhost net-next]$ make net/ipv4/ipmr.o
> CALL scripts/checksyscalls.sh
> CALL scripts/atomic/check-atomics.sh
> DESCEND objtool
> CC net/ipv4/ipmr.o
> In file included from ./include/linux/rculist.h:11,
> from ./include/linux/pid.h:5,
> from ./include/linux/sched.h:14,
> from ./include/linux/uaccess.h:5,
> from net/ipv4/ipmr.c:24:
> net/ipv4/ipmr.c: In function ‘ipmr_get_table’:
> ./include/linux/rculist.h:63:25: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
> RCU_LOCKDEP_WARN(!cond && !rcu_read_lock_any_held(), \
> ./include/linux/rcupdate.h:263:52: note: in definition of macro ‘RCU_LOCKDEP_WARN’
> if (debug_lockdep_rcu_enabled() && !__warned && (c)) { \
> ^
> ./include/linux/rculist.h:381:7: note: in expansion of macro ‘__list_check_rcu’
> for (__list_check_rcu(dummy, ## cond, 0), \
> ^~~~~~~~~~~~~~~~
> net/ipv4/ipmr.c:113:2: note: in expansion of macro ‘list_for_each_entry_rcu’
> list_for_each_entry_rcu(mrt, &net->ipv4.mr_tables, list, \
> ^~~~~~~~~~~~~~~~~~~~~~~
> net/ipv4/ipmr.c:138:2: note: in expansion of macro ‘ipmr_for_each_table’
> ipmr_for_each_table(mrt, net) {
> ^~~~~~~~~~~~~~~~~~~
This is a build warning due to incorrect operator precedence in
__list_check_rcu macro. This has already been reported and the patch
submitted [1]. Infact the patch is currently queued for v5.7.
[1] https://lore.kernel.org/patchwork/patch/1181886/
Thanks
Amol
next prev parent reply other threads:[~2020-02-25 13:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-22 6:38 [Linux-kernel-mentees] [PATCH 1/2] ipmr: Fix RCU list debugging warning Amol Grover
2020-02-22 6:38 ` Amol Grover
2020-02-22 6:38 ` [Linux-kernel-mentees] [PATCH 2/2] ipmr: Add lockdep expression to ipmr_for_each_table macro Amol Grover
2020-02-22 6:38 ` Amol Grover
2020-02-24 21:18 ` [Linux-kernel-mentees] " David Miller
2020-02-24 21:18 ` David Miller
2020-02-25 13:10 ` Amol Grover [this message]
2020-02-25 13:10 ` Amol Grover
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=20200225131041.GA8660@workstation-portable \
--to=frextrite@gmail.com \
--cc=davem@davemloft.net \
--cc=joel@joelfernandes.org \
--cc=kuba@kernel.org \
--cc=kuznet@ms2.inr.ac.ru \
--cc=linux-kernel-mentees@lists.linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=madhuparnabhowmik10@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=paulmck@kernel.org \
--cc=yoshfuji@linux-ipv6.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.